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Sample records for juvenile blue crabs

  1. Diet selectivity of juvenile blue crabs (Callinectes sapidus) in Chesapeake Bay.

    Science.gov (United States)

    Seitz, Rochelle D; Knick, Kathleen E; Westphal, Miranda

    2011-10-01

    Shallow coves in Chesapeake Bay have abundant food and serve as nursery grounds for juvenile blue crabs. In this study, we examined the relationships between the diet of very small (4-40 mm CW) juvenile blue crabs and the benthic infauna in shallow, unvegetated nursery coves. We compared infauna in benthic samples with gut contents of juvenile blue crabs from six shallow coves in each of two sub-estuaries (Rappahannock and York Rivers) in Chesapeake Bay, Virginia, USA. Benthic communities differed depending on river and location, with abundant clams in upriver regions and abundant polychaetes in downriver regions. Juvenile crabs, like adults, appeared to be opportunistic feeders, with gut contents including clams, amphipods, polychaetes, small crustaceans, plant matter, and detritus. There was a positive relationship between polychaetes in the benthic samples and in crab guts, suggesting that juvenile crabs are opportunistic feeders on polychaetes in the benthos. Moreover, Ivlev's electivity index and foraging ratio showed that clams and polychaetes were selectively eaten at all locations. Alternatively, crabs selectively rejected amphipods. Crab densities corresponded positively with polychaete densities, which suggests that there may be bottom-up control of crab distributions and that food resources are important in nursery habitats.

  2. De novo assembly of a transcriptome from juvenile blue crabs (Callinectes sapidus) following exposure to surrogate Macondo crude oil.

    Science.gov (United States)

    Yednock, Bree K; Sullivan, Timothy J; Neigel, Joseph E

    2015-07-11

    The blue crab, Callinectes sapidus, is economically and ecologically important in western Atlantic and Gulf of Mexico coastal estuaries. In 2010 blue crabs in the northern Gulf of Mexico were exposed to crude oil and chemical dispersants from the Deepwater Horizon oil spill. To characterize the blue crab transcriptome and identify genes that could be regulated in response to oil exposure we sequenced transcriptomes from hepatopancreas and gill tissues of juvenile blue crabs after exposing them to a water-accommodated fraction of surrogate Macondo crude oil in the laboratory and compared them to transcriptomes from an unexposed control group. Illumina sequencing provided 42.5 million paired-end sequencing reads for the control group and 44.9 million paired-end reads for the treatment group. From these, 73,473 transcripts and 52,663 genes were assembled. Comparison of control and treatment transcriptomes revealed about 100 genes from each tissue type that were differentially expressed. However, a much larger number of transcripts, approximately 2000 from each tissue type, were differentially expressed. Several examples of alternatively spliced transcripts were verified by qPCR, some of which showed significantly different expression patterns. The combined transcriptome from all tissues and individuals was annotated to assign putative gene products to both major gene ontology categories as well as specific roles in responses to cold and heat, metabolism of xenobiotic compounds, defence, hypoxia, osmoregulation and ecdysis. Among the annotations for upregulated and alternatively-spliced genes were candidates for the metabolism of oil-derived compounds. Previously, few genomic resources were available for blue crabs or related brachyuran crabs. The transcriptome sequences reported here represent a major new resource for research on the biology of blue crabs. These sequences can be used for studies of differential gene expression or as a source of genetic markers. Genes

  3. AFSC/RACE/SAP/Long: Data from: Habitat, predation, growth, and coexistence: Could interactions between juvenile red and blue king crabs limit blue king crab productivity?

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is from a series of laboratory experiments examining the interactions between red and blue king crabs and habitat. We examined how density and predator...

  4. Toxicity of ozonated estuarine water to juvenile blue crabs (Callinectes sapidus) and Juvenile Atlantic menhaden (Brevoortia tyrannus)

    Energy Technology Data Exchange (ETDEWEB)

    Richardson, L.B.; Burton, D.T.

    1981-02-01

    Large quantitites of estuarine and marine water are treated with chlorine to prevent condenser system fouling at power plants. Chlorine and its residual by-products, however, are toxic to many forms of aquatic life. Ozone is one alternative oxidant which has proven to be an effective biocide and disinfectant in many fresh water applications. Ozonation of estuarine and marine waters, however, may produce residual compounds similar to those produced by chlorination. This study was initiated to provide baseline information on the toxicity of ozonated estuarine water to two representative estuarine species. The blue crab, Callinectes sapidus Rathbun, and the Atlantic menhaden, Brevoortia tyrannus Latrobe, were selected because of their wide distribution and commercial importance. The toxicity of ozone has been compared with chlorine toxicity data from the literature in an effort to examine possible similarities in toxicity.

  5. AFSC/RACE/SAP/Daly:Juvenile blue king crab cannibalism experiment conducted in the Kodiak Lab in 2014

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This dataset is part of a laboratory experiment, which evaluated how varying prey densities (year-0 blue king crabs) and habitat type (shell and sand) affect the...

  6. Effects of crude oil and oil/dispersant mixture on growth and expression of vitellogenin and heat shock protein 90 in blue crab, Callinectes sapidus, juveniles.

    Science.gov (United States)

    Chiasson, Susan C; Taylor, Caz M

    2017-06-30

    The 2010 Deepwater Horizon (DWH) oil spill in the northern Gulf of Mexico (NGOM) resulted in over 780million liters of crude oil spilling into Gulf waters. In an effort to disperse the oil, nearly 7.6million liters of dispersant was applied. Many commercially and recreationally important species reside in or near the area of the spill. The blue crab, Callinectes sapidus, is common in the NGOM and is both economically and ecologically important in this region. In this study, after exposing juvenile blue crabs to oil or a mixture of oil and dispersant we tested for relative expression of heat shock protein 90 (hsp90) and vitellogenin (vtg) by measuring their corresponding mRNA expression. We also monitored crabs over two molts to test for effects on growth. Expression of hsp90 was significantly downregulated, and we did not detect any effects of exposure to oil or oil/dispersant mixture on growth or vtg expression. Copyright © 2017 Elsevier Ltd. All rights reserved.

  7. AFSC/RACE/SAP/Daly: Juvenile red and blue king crab prey preference experiment conducted in the Kodiak Lab in 2014

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This dataset is part of a laboratory experiment, which evaluated how varying ratios of prey species (year-0 blue and red king crabs) and habitat type (shell and...

  8. Acute toxicity of sodium nitrate, potassium nitrate, and potassium chloride and their effects on the hemolymph composition and gill structure of early juvenile blue swimmer crabs(Portunus pelagicus Linnaeus, 1758) (Decapoda, Brachyura, Portunidae).

    Science.gov (United States)

    Romano, Nicholas; Zeng, Chaoshu

    2007-09-01

    Various nutrients, including K+ and NO3-, are increasingly being discharged into aquatic systems via anthropogenic sources, which may impact marine organisms. The present study was conducted on blue swimmer crab (Portunus pelagicus) early juveniles to determine the acute toxicity of NaNO3, KNO3, and KCl; if a toxicity interaction exists between K+ and NO3-; the hemolymph Na+, K+, and Ca2+ changes; and the gill histopathological alterations following exposure to elevated NaNO3, KNO3, and KCl levels. A total of 20 replicate crabs were exposed to each of the five NaNO3, KNO3, and KCl concentrations for 96 h. After 96 h, the surviving crabs were sampled for hemolymph Na+, K+, and Ca2+ levels and fixed for histological examination of the anterior gills. The 96-h median lethal concentration of NaNO3-N, KNO3-N, KNO3-K, and KCl-K was 3,452, 112, 312, and 356 mg/L, respectively, for early P. pelagicus juveniles. The toxicity of NaNO3-N was significantly less (p crabs had significantly higher (p crabs had significantly higher (p crabs appeared to be similar, including lamellae swelling, epithelial thickening, pillar cell disruption, necrosis, and distortion.

  9. Toxicity of the dispersant Corexit 9500 to early life stages of blue crab, Callinectes sapidus.

    Science.gov (United States)

    Anderson Lively, Julie A; McKenzie, Jon

    2014-12-01

    The Deepwater Horizon well released 4.4 million barrels of light crude oil offshore of Louisiana into one of the world's largest and most productive blue crab (Callinectes sapidus) fisheries. The objectives of this paper were to determine the toxicity of the dispersant Corexit(®) 9500A used in the 2010 oil spill on juvenile and larval blue crabs, and the long-term effects of sublethal acute exposure. Only the highest treatment levels of dispersant significantly increased mortality in larval and juvenile blue crabs (100 mg/L and 1,000 mg/L, respectively). This correlated to concentrations well above levels found in the Gulf of Mexico following the spill. Smaller and younger crabs showed higher mortality than older and larger crabs. This research indicates direct application of dispersants on crab larvae could cause acute mortality, but dilution through diffusion and natural weathering processes would minimize long-term effects.

  10. Sublethal Toxicity of Crude Oil Exposure in The Blue Crab, Callinectes sapidus, at Two Life History Stages.

    Science.gov (United States)

    Giltz, Sarah M; Taylor, Caz M

    2017-02-01

    The 2010 Deepwater Horizon oil spill occurred during peak spawning season for many Gulf of Mexico fish and invertebrates. Early life stages of important fishery species were at risk to encounter crude oil. In this study, we investigated the effect of crude oil exposure on two life stages of the blue crab (Callinectes sapidus). We tested the effects of oil exposure on the survival and growth of larval (pelagic) and juvenile (estuarine) blue crabs as well as the effects of oil on the molt frequency of juveniles. Larval crabs exposed to crude oil showed no discernable growth or mortality differences when compared to non-exposed controls. Juvenile crabs exposed to oil also showed no differences in size but exhibited increased intermolt duration (time between molts). Our study suggests that different life-stages may respond differently when exposed to crude oil and that oil exposure negatively affects growth rate of juvenile blue crabs.

  11. Chlorine, temperature, and exposure duration effects of power plant effluents on juvenile blue crabs Callinectes sapidus and grass shrimp Palaemonetes pugio

    Energy Technology Data Exchange (ETDEWEB)

    Hall, L.W. Jr.; Burton, D.T.; Margrey, S.L.

    1979-07-01

    The effects of interacting Cl, temperature, and exposure conditions similar to those found in power plant effluents were assessed for the blue crab Callinectes sapidus and the grass shrimp Palemonetes pugio. Test organisms were exposed to total residual Cl (TRC) concentrations of 0.00, 0.15, and 0.30 mg/l in combination with temperatures 2, 6, and 10/sup 0/C above ambient for 0.08, 2.0, and 4.0 h. The TRC concentrations were decayed over a 1 to 1.5-h period to < 0.01 mg/l. Temperatures were decayed over a 4-h period to 2/sup 0/C above ambient. These conditions were used to simulate Cl and temperature conditions encountered in power plant discharge canals and near-field receiving streams. Regression model techniques were used to establish the interaction of Cl, temperature excess (..delta..T), and exposure duration as factors that caused death up to 36 h after the exposure period. Mortality increased for grass shrimp as the Cl concentration, ..delta..T, and length of exposure increased. A percentage mortality model for grass shrimp shows that (1) the response to Cl concentration alone and ..delta..T alone is proportional to the square root of Cl concentration and ..delta..T, (2) the effect of duration of exposure is linear, and (3) no second-order interactions occurred among the variables tested. No significant mortality was found for blue crabs for any of the variables tested.

  12. Prevalence and distribution of three protozoan symbionts in blue crab (Callinectes sapidus) populations across Louisiana, USA.

    Science.gov (United States)

    Rogers, Holly A; Taylor, Sabrina S; Hawke, John P; Anderson Lively, Julie A

    2015-05-11

    Louisiana has one of the largest blue crab (Callinectes sapidus) fisheries in the USA, but little is known about blue crab diseases, parasites, and symbionts in this area. In 2013-2014, large juvenile and adult blue crabs were collected at 4 diverse sites to determine the prevalence of the protozoan symbionts associated with black gill disease (Lagenophrys callinectes), buckshot crabs (Urosporidium crescens), and bitter crab disease (Hematodinium perezi). A high aggregate prevalence of L. callinectes (93.2%) was identified across all seasons at all 4 collection sites regardless of salinity. A moderately low aggregate prevalence of U. crescens (22.4%) was identified across all seasons and sites. Prevalence of U. crescens depended on site salinity, with only 10% of infections detected at sites with callinectes and U. crescens are commensal parasites of blue crabs, infections can result in unmarketable and unappealing meat. In the Louisiana fishery, H. perezi has been blamed circumstantially for adult mortalities in the low salinity nearshore fishing grounds. Despite this, H. perezi was not detected in any of the large crabs sampled, even from the low salinity sites. The prevalence data reported here for these 3 protozoans are the first to include blue crabs sampled seasonally at multiple locations along the Louisiana coast over the period of a year.

  13. A low intensity sampling method for assessing blue crab abundance at Aransas National Wildlife Refuge and preliminary results on the relationship of blue crab abundance to whooping crane winter mortality

    Science.gov (United States)

    Pugesek, Bruce H.; Baldwin, Michael J.; Stehn, Thomas; Folk, Martin J.; Nesbitt, Stephen A.

    2008-01-01

    We sampled blue crabs (Callinectes sapidus) in marshes on the Aransas National Wildlife Refuge, Texas from 1997 to 2005 to determine whether whooping crane (Grus americana) mortality was related to the availability of this food source. For four years, 1997 - 2001, we sampled monthly from the fall through the spring. From these data, we developed a reduced sampling effort method that adequately characterized crab abundance and reduced the potential for disturbance to the cranes. Four additional years of data were collected with the reduced sampling effort methods. Yearly variation in crab numbers was high, ranging from a low of 0.1 crabs to a high of 3.4 crabs per 100-m transect section. Mortality among adult cranes was inversely related to crab abundance. We found no relationship between crab abundance and mortality among juvenile cranes, possibly as a result of a smaller population size of juveniles compared to adults.

  14. The effects of fipronil and the photodegradation product fipronil desulfinyl on growth and gene expression in juvenile blue crabs, Callinectes sapidus, at different salinities.

    Science.gov (United States)

    Goff, Andrew D; Saranjampour, Parichehr; Ryan, Lauren M; Hladik, Michelle L; Covi, Joseph A; Armbrust, Kevin L; Brander, Susanne M

    2017-05-01

    Endocrine disrupting compounds (EDCs) are now widely established to be present in the environment at concentrations capable of affecting wild organisms. Although many studies have been conducted in fish, less is known about effects in invertebrates such as decapod crustaceans. Decapods are exposed to low concentrations of EDCs that may cause infertility, decreased growth, and developmental abnormalities. The objective herein was to evaluate effects of fipronil and its photodegradation product fipronil desulfinyl. Fipronil desulfinyl was detected in the eggs of the decapod Callinectes sapidus sampled off the coast of South Carolina. As such, to examine specific effects on C. sapidus exposed in early life, we exposed laboratory-reared juveniles to fipronil and fipronil desulfinyl for 96h at three nominal concentrations (0.01, 0.1, 0.5μg/l) and two different salinities (10, 30ppt). The size of individual crabs (weight, carapace width) and the expression of several genes critical to growth and reproduction were evaluated. Exposure to fipronil and fipronil desulfinyl resulted in significant size increases in all treatments compared to controls. Levels of expression for vitellogenin (Vtg), an egg yolk precursor, and the ecdysone receptor (EcR), which binds to ecdysteroids that control molting, were inversely correlated with increasing fipronil and fipronil desulfinyl concentrations. Effects on overall growth and on the expression of EcR and Vtg differ depending on the exposure salinity. The solubility of fipronil is demonstrated to decrease considerably at higher salinities. This suggests that fipronil and its photodegradation products may be more bioavailable to benthic organisms as salinity increases, as more chemical would partition to tissues. Our findings suggest that endocrine disruption is occurring through alterations to gene expression in C. sapidus populations exposed to environmental levels of fipronil, and that effects may be dependent upon the salinity at

  15. The effects of fipronil and the photodegradation product fipronil desulfinyl on growth and gene expression in juvenile blue crabs, Callinectes sapidus, at different salinities

    Science.gov (United States)

    Goff, Andrew D.; Saranjampour, Parichehr; Ryan, Lauren M.; Hladik, Michelle; Covi, Joseph A.; Armbrust, Kevin L.; Brander, Susanne M.

    2017-01-01

    Endocrine disrupting compounds (EDCs) are now widely established to be present in the environment at concentrations capable of affecting wild organisms. Although many studies have been conducted in fish, less is known about effects in invertebrates such as decapod crustaceans. Decapods are exposed to low concentrations of EDCs that may cause infertility, decreased growth, and developmental abnormalities. The objective herein was to evaluate effects of fipronil and its photodegradation product fipronil desulfinyl. Fipronil desulfinyl was detected in the eggs of the decapod Callinectes sapidus sampled off the coast of South Carolina. As such, to examine specific effects on C. sapidus exposed in early life, we exposed laboratory-reared juveniles to fipronil and fipronil desulfinyl for 96 hours at three nominal concentrations (0.01, 0.1, 0.5 μg/L) and two different salinities (10, 30 ppt). The size of individual crabs (weight, carapace width) and the expression of several genes critical to growth and reproduction were evaluated. Exposure to fipronil and fipronil desulfinyl resulted in significant size increases in all treatments compared to controls. Levels of expression for vitellogenin (Vtg), an egg yolk precursor, and the ecdysone receptor (EcR), which binds to ecdysteroids that control molting, were inversely correlated with increasing fipronil and fipronil desulfinyl concentrations. Effects on overall growth and on the expression of EcR and Vtg differ depending on the exposure salinity. The solubility of fipronil is demonstrated to decrease considerably at higher salinities. This suggests that fipronil and its photodegradation products may be more bioavailable to benthic organisms as salinity increases, as more chemical would partition to tissues. Our findings suggest that endocrine disruption is occurring through alterations to gene expression in C. sapidus populations exposed to environmental levels of fipronil, and that effects may be dependent upon the

  16. Molecular detection of the parasitic dinoflagellate Hematodinium perezi from blue crabs Callinectes sapidus in Louisiana, USA.

    Science.gov (United States)

    Sullivan, Timothy J; Gelpi, Carey G; Neigel, Joseph E

    2016-06-15

    The dinoflagellate Hematodinium perezi is a prolific pathogen of the blue crab Callinectes sapidus along the Atlantic and Gulf of Mexico coasts of North America. High prevalence, sometimes approaching 100%, and outbreaks with high mortality are associated with higher salinities. H. perezi has not been reported previously in blue crabs from Louisiana, USA, where salinities in coastal habitats are generally below the parasite's favorable range. However, the possibility that H. perezi infects blue crabs in higher salinity habitats offshore has not been investigated. A PCR-based test for H. perezi was used to screen blue crabs collected from both high and low salinity areas. These included juvenile and adult crabs from inshore marshes where salinities are relatively low and from higher salinity offshore shoals that are spawning sites for females. H. perezi was detected in blue crabs from offshore shoals (prevalence=5.6%) but not in juvenile or adult crabs from inshore habitats. Megalopae (post-larvae) were also collected from inshore locations. Although megalopae settle inshore where salinities are relatively low, the megalopal stage is preceded by a planktonic phase in higher salinity offshore waters. We detected H. perezi in 11.2% of settling megalopae tested. Although the prevalence of H. perezi was relatively low within our samples, if spawning females and megalopae are especially vulnerable, the impact on the population could be compounded. This is the first report of H. perezi from blue crabs in Louisiana and demonstrates the importance of examining all life stages in determining the prevalence of a harmful parasite.

  17. AFSC/RACE/SAP/Long: Effects of ocean acidification on blue king crab

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This is data from a laboratory experiment in which blue king crab juveniles were held at three different pHs (ambient, pH 7.8, and pH 7.5) for a year. Growth,...

  18. Influence of salinity on toxicity of cadmium and chromium to the blue crab, Callinectes sapidus

    Energy Technology Data Exchange (ETDEWEB)

    Frank, P.M.; Robertson, P.B.

    1979-01-01

    This study reports the lethal concentrations of cadmium and chromium to juvenile blue crabs, Callinectes sapidus, in acute toxicity tests at three different salinities. This economically important crustacean ranges throughout estuaries from fresh water to marine salinities, and may be subject to heavy metal pollution in industrial areas.

  19. Effects of acidifying ocean conditions on growth and survival of two life stages of the blue crab, Callinectes sapidus.

    Science.gov (United States)

    Giltz, S.; Taylor, C.

    2016-02-01

    Blue crabs, Callinectes sapidus, begin their larval phase offshore and circulate for approximately 30 days before settling near shore. As crabs transition to the juvenile stage, they move into coastal or estuarine environments characterized by lower salinity. Presently the average pH of the ocean is 8.1, 30% down from the beginning of the industrial revolution and is forecasted to drop to 7.8 by 2100. Decreasing pH causes dissolution of calcium carbonate shells, but the overall effects on crustaceans, such as blue crabs, are unknown. This study investigated the effect of a lower pH environment on the growth, survival, carapace hardness and molt frequency of larval and juvenile blue crabs in the Northern Gulf of Mexico. Larval crabs showed delayed growth under low pH (7.8) conditions compared to crabs in a control (present day) pH (8.1) environment. Population crashes (complete mortality) were experienced in 55% of the low pH aquaria but not in any of the control aquaria, suggesting that acidification poses a mortality risk. Under low pH conditions the intermolt duration decreased in juveniles, but the body length and weight did not differ from crabs raised in the control pH. Larvae (in tanks that did not crash) and juveniles did not experience increased mortality from a lower pH, but there do appear to be sublethal effects on growth and molting that differ between life history stages.

  20. Orientation of larval and juvenile horseshoe crabs Limulus polyphemus to visual cues: Effects of chemical odors

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    Julie M. MEDINA, Richard A. TANKERSLEY

    2010-10-01

    Full Text Available Adult horseshoe crabs Limulus polyphemus have long served as models for the study of vision in marine arthropods. Yet, little is known about the ability of early life history stages to detect and respond to visual cues. We examined the visually directed movements of larvae and first stage juveniles to horizons containing dark visual targets of different sizes. The study tested the hypotheses that (1 larval and juvenile crabs can detect and respond to visual targets and (2 the direction of orientation varies with the presence of chemical cues associated with settlement habitats. Orientation of larval and juvenile crabs to rectangles subtending angles from 30-330o was tested in a circular arena containing water that either lacked estuarine chemical cues (offshore water or contained odors from aquatic vegetation or known predators. In the absence of chemical odors, larvae oriented toward and juveniles moved away from dark horizons subtending angles > 60°. When placed in water containing chemical odors from potential nursery habitats, including the seagrasses Halodule wrightii and Syringodium filiforme, crabs reversed their direction of orientation relative to their responses in offshore water. Odors from two known predators, the mummichug Fundulus grandis and blue crab Callinectes sapidus, had no affect on the orientation of larvae. Yet, juveniles responded to both odors by moving toward the visual target. Results support the hypothesis that the visual orientation of larval and juvenile horseshoe crabs changes upon exposure to habitat and predator cues and that the direction of the response undergoes an ontogenetic shift following metamorphosis [Current Zoology 56 (5: 618–633, 2010].

  1. A Lethal Virus of the Blue Crab Callinectes sapidus May Be Present Throughout its Trans-hemispheric Range

    Science.gov (United States)

    Schott, E. J.; Flowers, E. M.; Vinagre, A.; Brown, S.; Almeida, A.

    2016-02-01

    Blue crabs, Callinectes sapidus, are key epibenthic predators and support valuable fisheries throughout North and South America. On both continents, they are also used to produce soft shell crabs, a value added product. On the Atlantic coast of the USA, mortality of blue crabs in soft shell production is often 25% or greater. A majority of those crabs have been found to be infected with a reovirus lethal to blue crabs. The CsRV1 virus infects multiple ectodermal and mesodermal tissues and was first described as RLV (reo-like virus) in the late 1970s. However its potential for affecting large numbers of crabs was not fully recognized until 2010 when molecular methods were developed to study its prevalence in aquaculture and the wild. Using a sensitive Rt-qPCR assay for the virus, a multi-year survey of crabs from the mid-Atlantic USA coast and Chesapeake Bay revealed that approximately 20% of adult and juvenile crabs were positive for CsRV1 genomic RNA. If blue crabs in the wild die from CsRV1 infections as rapidly as captive infected crabs, it suggests that significant numbers of wild blue crabs die from CsRV1 infections. Crab fishery managers in the Chesapeake Bay recently recognized that there is a need to better understand the role of diseases in natural mortality. The CsRV1 virus is found in C. sapidus throughout the USA range, and has been discovered in diseased Brazilian C. sapidus from Rio Grande do Sul. Genetic analysis of the virus shows that strains of CsRV1 found in Brazil are distinct from the strains identified in the USA. This pan-hemispheric range suggests that the virus has long been a component of blue crab ecology. Much more study is needed to understand the history and impacts of CsRV1 throughout the USA, Brazil, and the vast coastline in between.

  2. The Feeding Ecology of the Blue Swimming Crab, Portunus pelagicus (Linnaeus, 1758), at Kung Krabaen Bay, Chanthaburi Province, Thailand

    OpenAIRE

    Kunsook, Chutapa; Gajaseni, Nantana; Paphavasit, Nittharatana

    2014-01-01

    The natural diet of blue swimming crabs, Portunus pelagicus, was investigated from October 2008 to October 2009 using hand sampling and a crab gill net. The results showed that the major prey items in the stomach contents of P. pelagicus were teleost fish (29.61%), organic matter (20.69%), crustaceans (18.3%) and shelled molluscs (11.46%). Significant differences were found in diet composition between juvenile and mature crabs, between crabs inside and outside the bay and among seasons. In co...

  3. Lack of transmission of Hematodinium sp. in the blue crab Callinectes sapidus through cannibalism.

    Science.gov (United States)

    Li, Caiwen; Wheeler, Kersten N; Shields, Jeffrey D

    2011-10-06

    Hematodinium spp. are parasitic dinoflagellates of marine crustaceans. Outbreaks of Hematodinium sp. have impacted commercial landings of the blue crab Callinectes sapidus in the coastal bays of Virginia and Maryland (USA), with seasonal peaks in prevalence reaching 85%. The life cycle and transmission routes of the parasite in blue crabs are poorly understood. Cannibalism and waterborne transmission may be routes of transmission, although little conclusive evidence has been reported for these modes. We examined cannibalism as a route by a series of experiments wherein we repeatedly fed adult and juvenile crabs the tissues of crabs infected with Hematodinium. In each experiment, feeding was done 3 times over the course of 1 wk. Only 2 of 120 crabs were infected within 7 to 9 d after feeding, and these 2 were likely infected prior to the experimental exposures. Crabs inoculated with hemolymph from infected donors served as positive controls. They developed infections over 11 to 21 d, indicating that the Hematodinium sp. used in the cannibalism trials was infectious at the time of inoculation. Because amphipods also harbor Hematodinium-like infections, we fed tissues of infected crabs to the estuarine amphipod Leptocheirus plumulosus. Hematodinium DNA was detected in amphipods shortly after feeding, but not in animals held for longer periods, nor was it observed in histological preparations. Amphipods did not obtain infections by scavenging infected crab tissues. Our results show that Hematodinium sp. is not effectively transmitted through ingestion of diseased tissues, indicating that cannibalism may not be a major route of transmission for Hematodinium sp. in blue crabs.

  4. Species profiles: Life histories and environmental requirements of coastal fishes and invertebrates (Mid-Atlantic): Blue crab

    Energy Technology Data Exchange (ETDEWEB)

    Hill, J.; Fowler, D.L.; Van Den Avyle, M.J.

    1989-03-01

    Species profiles are summaries of the literature on taxonomy, life history, and environmental requirements of coastal fishes and aquatic invertebrates. They are prepared to assist with impact assessment. The blue crab, Callinectes sapidus, occurs in lower reaches of freshwater rivers, estuaries, and coastal waters along the Atlantic seaboard and Gulf of Mexico, and the species supports the largest crab fishery in the United States. Chesapeake Bay provides the greatest production of blue crabs on the east coast. The blue crab's high abundance in estuaries, diverse feeding habits, and importance as prey for other marine animals indicate its important role in the structure and function of estuarine communities. Female blue crabs spawn in high-salinity lower estuaries of coastal areas; the resulting larvae are planktonic and develop into juveniles at 5 to 10 weeks of age. Juveniles gradually migrate into shallower, less-saline upper estuaries and rivers where they grow and mature at 1-2 yr of age. Mating occurs in the upper estuaries after which females migrate to areas having higher salinities. Growth and survival of blue crabs are strongly affected by water temperature and salinity, but tolerances vary with life stage. Larvae require temperatures of 20-30/degree/C and salinities of 10-30 ppt for proper development, but salinity and temperature tolerances are broad for advanced juveniles and adults. Blue crabs use nearly all areas within estuaries as nursery habitat, and crab populations are sensitive to changes in physical features of contamination of these areas. 94 refs., 4 figs., 2 tabs.

  5. Environmental Stress and Pathogen Dynamics in the Blue Crab Callinectes sapidus

    Science.gov (United States)

    Sullivan, T. J.; Neigel, J.; Gelpi, C. G.

    2016-02-01

    The blue crab Callinectes sapidus is an ecologically and economically valuable species along the Gulf of Mexico and Atlantic coasts of North America. Throughout its range, the blue crab encounters a diverse array of parasitic and pathogenic microorganisms that have episodic and occasionally severe impacts on population numbers and viability. This makes understanding factors that influence pathogen dynamics, such as host stress, an important priority. To explore the role of environmental stress on the susceptibility of blue crabs to pathogens we screened individuals collected during the summers of 2014 and 2015 for a number of infectious agents. We sampled three life stages (megalopae, juvenile, and adult) from multiple marsh and offshore locations in Louisiana. Duration of stressful environmental conditions at each location was quantified from hourly recordings provided by the Louisiana Coastwide Reference Monitoring System. Pathogenic microorganisms were detected in crabs from multiple locations and multiple years. Some of the variability in prevalence of infection can be explained by exposure to stressful extremes of temperature and salinity during summer months.

  6. Detection of naphthalene by the blue crab, Callinectes sapidus

    Energy Technology Data Exchange (ETDEWEB)

    Pearson, W.H.; Olla, B.L.

    1979-03-01

    Increases in the antennular flicking rate indicated that blue crabs, Callinectes sapidus, detected the petroleum hydrocarbon naphthalene. A low incidence of aggressive displays but no food searching or gathering followed naphthalene detection. The results suggest that the chemosensory abilities of decapod crustaceans cover a broader range of substances than previously supposed.

  7. Comparison of automated BAX polymerase chain reaction and standard culture methods for detection of Listeria monocyogenes in blue crab meat (Callinectus sapidus) and blue crab processing plants

    Science.gov (United States)

    This study compared the BAX Polymerase Chain Reaction method (BAX PCR) with the Standard Culture Method (SCM) for detection of L. monocytogenes in blue crab meat and crab processing plants. The aim of this study was to address this data gap. Raw crabs, finished products and environmental sponge samp...

  8. Three-Dimensional Concentration Measurements around Actively Tracking Blue Crabs

    Science.gov (United States)

    Dickman, B. D.; Jackson, J. L.; Weissburg, M. J.; Webster, D. R.

    2006-11-01

    Many aquatic arthropods locate food, suitable habitats, and mates solely through information extracted by chemical signals in their environment. Chemical plumes detected by larger animals are influenced by turbulence that creates an intermittent and unpredictable chemical stimulus environment. To link the stimulus pattern to behavior, we have developed a measurement system to quantify the instantaneous odor concentration surrounding a freely tracking blue crab through three-dimensional laser-induced fluorescence (3DLIF). A blue crab receives chemical stimulus at several locations, including the antennules near the mouth region and the distal tips of the legs and claws. Hence, three-dimensional measurements of the concentration field are required to link behavior to plume structure. During trials, crabs began their search 150 cm downstream of a source, and walking kinematics were recording simultaneously. The crabs were reversibly ``blindfolded'' during tracking to prevent aversive reactions to the intense laser light. Our experiments allow us to examine how hypothesized navigational cues, such as concentration bursts at the antennules and spatial asymmetry in concentration at the distributed chemosensory organs on the legs and claws, results in particular decisions during navigation.

  9. A new PCR-based method shows that blue crabs (Callinectes sapidus (Rathbun consume winter flounder (Pseudopleuronectes americanus (Walbaum.

    Directory of Open Access Journals (Sweden)

    Jackie L Collier

    Full Text Available Winter flounder (Pseudopleuronectes americanus once supported robust commercial and recreational fisheries in the New York (USA region, but since the 1990s populations have been in decline. Available data show that settlement of young-of-the-year winter flounder has not declined as sharply as adult abundance, suggesting that juveniles are experiencing higher mortality following settlement. The recent increase of blue crab (Callinectes sapidus abundance in the New York region raises the possibility that new sources of predation may be contributing to juvenile winter flounder mortality. To investigate this possibility we developed and validated a method to specifically detect winter flounder mitochondrial control region DNA sequences in the gut contents of blue crabs. A survey of 55 crabs collected from Shinnecock Bay (along the south shore of Long Island, New York in July, August, and September of 2011 showed that 12 of 42 blue crabs (28.6% from which PCR-amplifiable DNA was recovered had consumed winter flounder in the wild, empirically supporting the trophic link between these species that has been widely speculated to exist. This technique overcomes difficulties with visual identification of the often unrecognizable gut contents of decapod crustaceans, and modifications of this approach offer valuable tools to more broadly address their feeding habits on a wide variety of species.

  10. A new PCR-based method shows that blue crabs (Callinectes sapidus (Rathbun)) consume winter flounder (Pseudopleuronectes americanus (Walbaum)).

    Science.gov (United States)

    Collier, Jackie L; Fitzgerald, Sean P; Hice, Lyndie A; Frisk, Michael G; McElroy, Anne E

    2014-01-01

    Winter flounder (Pseudopleuronectes americanus) once supported robust commercial and recreational fisheries in the New York (USA) region, but since the 1990s populations have been in decline. Available data show that settlement of young-of-the-year winter flounder has not declined as sharply as adult abundance, suggesting that juveniles are experiencing higher mortality following settlement. The recent increase of blue crab (Callinectes sapidus) abundance in the New York region raises the possibility that new sources of predation may be contributing to juvenile winter flounder mortality. To investigate this possibility we developed and validated a method to specifically detect winter flounder mitochondrial control region DNA sequences in the gut contents of blue crabs. A survey of 55 crabs collected from Shinnecock Bay (along the south shore of Long Island, New York) in July, August, and September of 2011 showed that 12 of 42 blue crabs (28.6%) from which PCR-amplifiable DNA was recovered had consumed winter flounder in the wild, empirically supporting the trophic link between these species that has been widely speculated to exist. This technique overcomes difficulties with visual identification of the often unrecognizable gut contents of decapod crustaceans, and modifications of this approach offer valuable tools to more broadly address their feeding habits on a wide variety of species.

  11. Crab Hole Mosquito Blues—The Story

    Centers for Disease Control (CDC) Podcasts

    2011-05-12

    This podcast reports on a humorous song that takes a look at a very serious human and equine disease. Written and performed by the MARU Health Angels Band, Bill Dietz, director of the Division of Nutrition, Physical Activity and Obesity at CDC, talks about the song, "Crab Hole Mosquito Blues", and the history behind it.  Created: 5/12/2011 by National Center for Emerging Zoonotic and Infectious Diseases (NCEZID).   Date Released: 5/23/2011.

  12. AFSC/RACE/SAP/Long: Data from: Effects of Ocean Acidification on Juvenile Red King Crab (Paralithodes camtschaticus) and Tanner Crab (Chionoecetes bairdi) Growth, Condition, Calcification, and Survival

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set is the results of a laboratory experiment. Juvenile red king crab and Tanner crab were reared in individual containers for nearly 200 days in flowing...

  13. Predatory blue crabs induce stronger nonconsumptive effects in eastern oysters Crassostrea virginica than scavenging blue crabs

    Directory of Open Access Journals (Sweden)

    Avery E. Scherer

    2017-02-01

    Full Text Available By influencing critical prey traits such as foraging or habitat selection, predators can affect entire ecosystems, but the nature of cues that trigger prey reactions to predators are not well understood. Predators may scavenge to supplement their energetic needs and scavenging frequency may vary among individuals within a species due to preferences and prey availability. Yet prey reactions to consumers that are primarily scavengers versus those that are active foragers have not been investigated, even though variation in prey reactions to scavengers or predators might influence cascading nonconsumptive effects in food webs. Oysters Crassostrea virginica react to crab predators by growing stronger shells. We exposed oysters to exudates from crabs fed live oysters or fed aged oyster tissue to simulate scavenging, and to controls without crab cues. Oysters grew stronger shells when exposed to either crab exudate, but their shells were significantly stronger when crabs were fed live oysters. The stronger response to predators than scavengers could be due to inherent differences in diet cues representative of reduced risk in the presence of scavengers or to degradation of conspecific alarm cues in aged treatments, which may mask risk from potential predators subsisting by scavenging.

  14. Experimental infections of Orchitophrya stellarum (Scuticociliata) in American blue crabs (Callinectes sapidus) and fiddler crabs (Uca minax).

    Science.gov (United States)

    Miller, Terrence L; Small, Hamish J; Peemoeller, Bhae-Jin; Gibbs, David A; Shields, Jeffrey D

    2013-11-01

    Outbreaks of an unidentified ciliate have occurred on several occasions in blue crabs from Chesapeake Bay held during winter months in flow-through systems. The parasite was initially thought to be Mesanophrys chesapeakensis, but molecular analysis identified it as Orchitophyra stellarum, a facultative parasite of sea stars (Asteroidea). We investigated the host-parasite association of O. stellarum in the blue crab host. Crabs were inoculated with the ciliate, or they were held in bath exposures after experimentally induced autotomy of limbs in order to determine potential mechanisms for infection. Crabs inoculated with the ciliate, or exposed to it after experimental autotomy, rapidly developed fatal infections. Crabs that were not experimentally injured, but were exposed to the ciliate, rarely developed infections; thus, indicating that the parasite requires a wound or break in the cuticle as a portal of entry. For comparative purposes, fiddler crabs, Uca minax, were inoculated with the ciliate in a dose-titration experiment. Low doses of the ciliate (10 per crab) were sometimes able to establish infections, but high intensity infections developed quickly at doses over 500 ciliates per crab. Chemotaxis studies were initiated to determine if the ciliate preferentially selected blue crab serum (BCS) over other nutrient sources. Cultures grown on medium with BCS or fetal bovine serum showed some conditioning in their selection for different media, but the outcome in choice experiments indicated that the ciliate was attracted to BCS and not seawater. Our findings indicate that O. stellarum is a facultative parasite of blue crabs. It can cause infections in exposed crabs at 10-15°C, but it requires a portal of entry for successful host invasion, and it may find injured hosts using chemotaxis.

  15. Toxicity of oil and dispersed oil on juvenile mud crabs, Rhithropanopeus harrisii.

    Science.gov (United States)

    Anderson, Julie A; Kuhl, Adam J; Anderson, A Nikki

    2014-04-01

    In order to simulate an offshore oil spill event, we assessed the acute toxicity of the non-dispersed and the chemically dispersed water-accommodated fraction (WAF) of crude oil using Louisiana sweet crude and Corexit(®) 9500A with juvenile Harris mud crabs (Rhithropanopeus harrisii), an important Gulf of Mexico benthic crustacean. The chemical dispersion of crude oil significantly increased acute toxicity of the WAF in juvenile mud crabs compared to naturally dispersed oil. The majority of the mortality in the chemically dispersed treatments occurred within 24 h. While higher concentrations of chemically dispersed WAF had no survivors, at lower concentrations surviving juvenile crabs displayed no long-term effects. These results suggest that if the juvenile crabs survive initial exposure, acute exposure to dispersed or non-dispersed crude oil may not induce long-term effects.

  16. Species profiles: Life histories and environmental requirements of coastal fishes and invertebrates (Gulf of Mexico): Blue crab. [Callinectes sapidus

    Energy Technology Data Exchange (ETDEWEB)

    Perry, H.M.; McIlwain, T.D.

    1986-06-01

    The blue crab, Callinectes sapidus, is common in tidal marsh estuaries and coastal waters of the Gulf of Mexico, occupying a variety of habitats depending upon the physiological requirements of each particular stage in its life history. Spawning occurs from spring through fall in high salinity estuarine and/or coastal waters. Development through the 7 zoeal stages requires approximately 31 days and occurs offshore. The megalopal stage is usually completed within a week. Recruitment to the estuary occurs during the megalopal stage. Molt to the first crab takes place within the estuary. Juveniles exhibit wide seasonal and areal distribution. Growth is rapid and blue crabs in the Gulf of Mexico may reach maturity within a year. Factors affecting growth and survival include food availability, predation, substratum, available habitat, temperature, salinity and pollutants. Blue crabs do not conform to specific trophic levels and are characterized as opportunistic benthic omnivores. Their diverse feeding habits and their importance as prey species for a variety of organisms make them an integral part of coastal ecosystems.

  17. Use of blue crab (Callinectes sapidus) embryos for toxicity testing

    Energy Technology Data Exchange (ETDEWEB)

    Lee, R.; O`Malley, K. [Skidaway Inst. of Oceanography, Savannah, GA (United States)

    1995-12-31

    After fertilization, blue crab embryos develop in egg sacs attached to the female pleopods, often referred to as the sponge. Lipovitellin and lipid droplets in the egg sacs provide energy and nutrition for the developing embryos. Embryos were removed from the sponge and transferred to 24 well culture plates containing sea water with or without toxicants, Each well contained 10 embryos. After 7 to 10 days, embryos hatched to swimming zoea. The effects of toxicants at various concentrations on hatching were determined and the EC{sub 50} calculated. For example, the EC{sub 50} for tributyltin, fenvalerate and mercuric chloride were 50, 30 and 90 ng/liter, respectively. The hatching success of control embryos ranged from 95 to 98%. Formation of the heart, eyespot formation, appendage formation and utilization rate of lipovitellin were also effected by exposure to toxicants. At a low concentration of mercuric ion (30ng/liter) the heart formed, but there was no heart beat. Eyespot formation was abnormal in the presence of high concentrations of cadmium (2 {micro}g/liter) and zinc (5 {micro}g/liter), Crab embryos offer many advantages for toxicity testing of pure compounds or mixtures in water, including toxicity testing of sediment pore water. The crab embryos may also serve as models to understand the effect of specific toxicants on the heart and eye spots of crustaceans.

  18. Distribution of blue swimming crab (Portunus pelagicus Linnaeus, 1758 in Trang Province

    Directory of Open Access Journals (Sweden)

    Buncha Somboonsuke

    2010-07-01

    Full Text Available The fishery of the blue swimming crab (Portunus pelagicus Linnaeus, 1758 is very important to the economy of small-scale fishermen. Greater knowledge about its distribution could lead to more efficient management. This study was conducted in Trang Province from October 2006 to August 2007 using collapsible crab traps. To reveal the spatial distribution of the species, we analyzed the data using geostatistical methods. The standard interpolate procedure was applied to model the crab distribution. There were clear spatial distribution differences among the small crabs, large crabs and ovigerous females in study area. The mapping showed that small crabs (carapace width 10 cm were farther offshore. Ovigerous females peaked in abundance during 2 periods: March – April and August – September. This information can be used to support decision making concerning the designation of fishing zones and the optimization of the blue swimming crab fishery in the study area.

  19. The effect of salinity on experimental infections of a Hematodinium sp. in blue crabs, Callinectes sapidus.

    Science.gov (United States)

    Coffey, Anna H; Li, Caiwen; Shields, Jeffrey D

    2012-06-01

    The parasitic dinoflagellate Hematodinium sp. parasitizes blue crabs along the Atlantic seaboard of the United States. Infections in blue crabs have only been reported from waters where salinity is >11 practical salinity units (psu). Blue crabs maintain a hyperosmotic internal concentration at low salinities (0-5 psu), roughly comparable to 24 psu, and should be capable of maintaining an infection in low-salinity waters even if Hematodinium spp. cells are intolerant of low salinities. We tested this notion by observing the effect of low salinity on the progression of disease in crabs experimentally infected with the parasite. Blue crabs were acclimated to 5 psu or 30 psu salinity treatments. They were inoculated with Hematodinium sp. and necropsied 3, 7, 10, and 15 days post-inoculation. The low-salinity treatment did not have an effect on the proliferation of Hematodinium sp. infections in blue crabs; moreover, a greater proportion of infections in crabs in the low-salinity treatment developed dinospore stages than did those in the high-salinity treatment, indicating that salinity may affect the development of the parasite. However, dinospores from in vitro cultures rapidly became inactive when held in salinities crabs at low salinities, but that the parasite is incapable of transmission in this environment, which explains the lack of natural infections in crabs at low salinities.

  20. Comparative analysis of the proximate and elemental composition of the blue crab Callinectes sapidus, the warty crab Eriphia verrucosa, and the edible crab Cancer pagurus

    Directory of Open Access Journals (Sweden)

    Maurizio Zotti

    2016-02-01

    Full Text Available The proximate composition and element contents of claw muscle tissue of Atlantic blue crabs (Callinectes sapidus were compared with the native warty crab (Eriphia verrucosa and the commercially edible crab (Cancer pagurus. The scope of the analysis was to profile the chemical characteristics and nutritive value of the three crab species. Elemental fingerprints showed significant inter-specific differences, whereas non-significant variations in the moisture and ash contents were observed. In the blue crab, protein content was significantly lower than in the other two species, while its carbon content resulted lower than that characterizing only the warty crab. Among micro-elements, Ba, Cr, Cu, Li, Mn, Ni, and Pb showed extremely low concentrations and negligible among-species differences. Significant inter-specific differences were observed for Na, Sr, V, Ba, Cd and Zn; in particular, cadmium and zinc were characterized in the blue crab by concentrations significantly lower than in the other two species. The analysis of the available literature on the three species indicated a general lack of comparable information on their elemental composition. The need to implement extended elemental fingerprinting techniques for shellfish quality assessment is discussed, in view of other complementary profiling methods such as NMR-based metabolomics.

  1. Comparative analysis of the proximate and elemental composition of the blue crab Callinectes sapidus, the warty crab Eriphia verrucosa, and the edible crab Cancer pagurus.

    Science.gov (United States)

    Zotti, Maurizio; Coco, Laura Del; Pascali, Sandra Angelica De; Migoni, Danilo; Vizzini, Salvatrice; Mancinelli, Giorgio; Fanizzi, Francesco Paolo

    2016-02-01

    The proximate composition and element contents of claw muscle tissue of Atlantic blue crabs (Callinectes sapidus) were compared with the native warty crab (Eriphia verrucosa) and the commercially edible crab (Cancer pagurus). The scope of the analysis was to profile the chemical characteristics and nutritive value of the three crab species. Elemental fingerprints showed significant inter-specific differences, whereas non-significant variations in the moisture and ash contents were observed. In the blue crab, protein content was significantly lower than in the other two species, while its carbon content resulted lower than that characterizing only the warty crab. Among micro-elements, Ba, Cr, Cu, Li, Mn, Ni, and Pb showed extremely low concentrations and negligible among-species differences. Significant inter-specific differences were observed for Na, Sr, V, Ba, Cd and Zn; in particular, cadmium and zinc were characterized in the blue crab by concentrations significantly lower than in the other two species. The analysis of the available literature on the three species indicated a general lack of comparable information on their elemental composition. The need to implement extended elemental fingerprinting techniques for shellfish quality assessment is discussed, in view of other complementary profiling methods such as NMR-based metabolomics.

  2. Spontaneous alternation and locomotor activity in three species of marine crabs: green crab (Carcinus maenas), blue crab (Callinectes sapidus), and fiddler crab (Uca pugnax).

    Science.gov (United States)

    Balcı, Fuat; Ramey-Balcı, Patricia A; Ruamps, Perrine

    2014-02-01

    Spontaneous alternation refers to the tendency of organisms to explore places that they have least recently visited. Our previous work showed that alternation performance of Carcinus maenas (invasive European green crab) was significantly higher than Callinectes sapidus (native blue crab), and chance level performance (Ramey, P. A., Teichman, E., Oleksiak, J., & Balcı, F. [2009]. Spontaneous alternation in marine crabs: Invasive versus native species. Behavioural Processes, 82, 51-55.). In the current study, we first tested the robustness of these findings in the absence of visual cues, longer test durations, and wider maze dimensions. These manipulations enabled us to determine whether these two crab species relied on the visual cues provided during the spontaneous alternation task in our prior work, and allowed for better characterization of their exploratory activity in the maze. Our original findings were reproduced in the present study under these new task conditions, suggesting no role for visual cues during alternation, and emphasizing the robustness and generalizability of the corresponding interspecies differences in alternation performance. We also tested whether the lower alternation performance of C. sapidus also applied to another native crab species, Uca pugnax (fiddler crab). Spontaneous alternation performance of U. pugnax was significantly lower than C. maenas but indistinguishable from C. sapidus. Finally, we examined whether the potentially higher inherent risk-sensitivity of C. sapidus could have contributed to their lower alternation performance by testing C. maenas in the presence of a larger natural predator (stressor). Higher risk sensitivity presumably induced by the stressor led to locomotor activity patterns that better resembled those of C. sapidus, however the resultant reduction in alternation performance was not statistically significant. PsycINFO Database Record (c) 2014 APA, all rights reserved.

  3. Anatomy of virgin and mature externae of Loxothylacus texanus, parasitic on the dark blue crab Callinectes rathbunae (Crustacea

    DEFF Research Database (Denmark)

    Alvarez, Fernando; Bortolini, José Luis; Høeg, Jens Thorvald

    2010-01-01

    the reproductive biology and the taxonomy of these specialized parasites. We use scanning electron microscopy and histological methods to study the anatomy of juvenile and the mature externae of the rhizocephalan barnacle Loxothylacus texanus parasitizing the blue crab Callinectes rathbunae. We put emphasis......, as is characteristic for the genus Loxothylacus. The internal anatomy of the mature externa of L. texanus is in most features similar to that seen in other species of the Sacculinidae, which comprises the majority of rhizocephalan species. However, the single receptacle creates a situation where the two implanted...

  4. Evaluation of parenteral drugs for anesthesia in the blue crab (Callinectes sapidus).

    Science.gov (United States)

    Quesada, Rolando J; Smith, Christopher D; Heard, Darryl J

    2011-06-01

    The objective of this study was to evaluate the efficacy and safety of several parenteral anesthetics in blue crabs (Callinectes sapidus). Thirty-one animals were administered one or more of the following drugs by injection into the hemolymph (i.v.) through an arthrodial membrane: etomidate, ketamine, lidocaine, pentobarbital, propofol, tiletamine-zolazepam, xylazine, and ketamine-xylazine. A subset of crabs received intracardiac ketamine. Etomidate had no effect. Lidocaine effects were ultrashort (sapidus as well as in other crab species.

  5. Incidence of bacteremia in stressed and unstressed populations of the blue crab, Callinectes sapidus.

    Science.gov (United States)

    Welsh, P C; Sizemore, R K

    1985-01-01

    The incidence of bacteremia in the blue crab, Callinectes sapidus, is reported to be in excess of 80%. Because these results have been controversial, a field study was initiated to determine the effect of commercial capture and handling stresses on the incidence and levels of infection in blue crabs. The majority (75%) of "unstressed" crabs which were captured individually and bled immediately upon removal from the water were bacteremic, with a geometric mean level of infection of 14 CFU/ml of hemolymph. Crabs collected by crab pot, confined within these pots for as long as 24 h, and sampled immediately after removal from the water had a similar mean level of infection. Crabs subjected to the stresses of commercial capture, handling, and transport showed a higher incidence of infection (91%) and a mean infection level of 46 CFU/ml. Injuries sustained by crabs during commercial handling are thought to be associated with the higher incidence of infection. Vibrio spp. were primarily responsible for progressive infections in commercially stressed crabs and were the predominant bacterial type in heavily infected crabs. Our results indicated that uninjured healthy crabs do not have sterile hemolymph but instead harbor low-level bacterial infections. PMID:4051486

  6. Associations between dioxins/furans and dioxin-like PCBs in estuarine sediment and blue crab

    Science.gov (United States)

    Liebens, J.; Mohrherr, C.J.; Karouna-Renier, N. K.; Snyder, R.A.; Rao, K.R.

    2011-01-01

    The objective of the present study was to evaluate the relationships between the quantity, toxicity, and compositional profile of dioxin/furan compounds (PCDD/Fs) and dioxin-like polychlorinated biphenyls (DL-PCBs) in estuarine sediment and in the blue crab (Callinectes sapidus). Sediment and blue crab samples were collected in three small urban estuaries that are in relatively close proximity to each other. Results show that differences between PCDD/F and DL-PCB mass concentrations and total toxic equivalents (TEQ) toxicity in sediments of the three estuaries are reflected in those of the blue crab. TEQs are higher in the hepatopancreas of the crabs than in the sediment, but the concentration factor is inversely proportional to the TEQ in the sediments. Congener profiles in the crabs are systematically different from those in the sediments, and the difference is more pronounced for PCDD/Fs than for DL-PCBs, possibly due to differences in metabolization rates. Compared with sediment profiles, more lesser-chlorinated PCDD/Fs that have higher TEFs accumulate in crab hepatopancreas. This selective bioaccumulation of PCDD/Fs results in a TEQ augmentation in crab hepatopancreas compared with sediments. The bioaccumulation in the blue crab is also selective for PCDD/Fs over DL-PCBs. ?? 2011 Springer Science+Business Media B.V.

  7. Accumulation of contaminants from urban rainfall runoff in blue crabs: A pilot study

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — The objective of this pilot study was to determine the feasibility of using caged blue crabs Callinectes sapidus to monitor accumulation of contaminants in urban...

  8. Habitat selection of the pink shrimp Farfantepenaeus paulensis and the blue crab Callinectes sapidus in an estuary in southern Brazil: influence of salinity and submerged seagrass meadows

    Directory of Open Access Journals (Sweden)

    Vinicius Mendes Ruas

    Full Text Available This study was conducted in two estuarine inlets (Saco da Mangueira and Saco do Arraial at the Patos Lagoon estuary, southern Brazil. The changes in relative abundance and size of post-larvae and juvenile shrimp Farfantepenaeus paulensis and juvenile blue crab Callinectes sapidus were compared, considering the influence of salinity and the presence of submerged seagrass meadows. The analyses were performed using generalized linear models (GLM for abundance variations and ANOVA for variations on the size of individuals. The pink shrimp was more abundant at Saco da Mangueira, in seagrass meadows and areas of higher salinity. The blue crab was more abundant at Saco do Arraial and in lower levels of salinity. The importance of submerged vegetation for the blue crab lies in a preference of smaller crabs of the species for the seagrass meadows. It has been shown that these species choose different habitats in the estuary, and both the salinity and the presence of submerged seagrass meadows influence the selection of habitat.

  9. The importance of color in mate choice of the blue crab Callinectes sapidus.

    Science.gov (United States)

    Baldwin, Jamie; Johnsen, Sönke

    2009-11-01

    Visual displays often play a large role in animal communication, particularly in sexual interactions. The blue crab Callinectes sapidus is both colorful and highly visually responsive, yet almost all studies of their courtship have focused on chemical cues. In the blue crab's underwater environment, however, visual cues may function more rapidly and over a longer distance than chemical cues. Given that blue crabs are aggressive and cannibalistic, visual cues may therefore allow blue crabs to quickly evaluate potential mates from safer distances. In the present study we show that courtship and mate choice behavior in C. sapidus can be stimulated by visual cues alone. Further, we show that males have a preference for females with red claw dactyls. In binary choice experiments, males displayed more often to photographs of females with red claws than to those with white claws or to those with black claws that were isoluminant to the red ones. This strongly suggests that male blue crabs made their choices based on the hue of the red claws, further suggesting that blue crabs are capable of color vision and use color in mate choice.

  10. Metabolism of pectenotoxins in brown crabs Cancer pagurus fed with blue mussels Mytilus edulis

    Institute of Scientific and Technical Information of China (English)

    LI Zhaoxin

    2009-01-01

    We investigated the metabolism of pectenotoxins in brown crabs (Cancer pagurus). The crabs were fed with blue mussels (Mytilus edulis) for 21 d then depurated for 42 d. We extracted the toxins from the digestive glands of contaminated crabs, uncontaminated crabs (control group), and the meat of blue mussels using methanol. Extracts of the crab digestive glands were fractionated by liquid-liquid partitioning and solid phase extraction. The fractions were analyzed by liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS) and liquid chromatography coupled with ion-trap mass spectrometry (LC-MSn). We detected a new PTX-like compound, designated as metabolite-1. The MS2 mass spectrum of the metabolite-1 [M+Na]+ ion at m/z 897.5 revealed fragment ions at m/z 853.5 and 555.5, typical of those exhibited by other pectenotoxins.

  11. Disease, parasite, and commensal prevalences for blue crab Callinectes sapidus at shedding facilities in Louisiana, USA.

    Science.gov (United States)

    Rogers, Holly A; Taylor, Sabrina S; Hawke, John P; Schott, Eric J; Anderson Lively, Julie A

    2015-01-15

    Blue crab diseases, parasites, and commensals are not well studied in the Gulf of Mexico, and their prevalence rates have only been sporadically determined. Commercial soft shell shedding facilities in Louisiana experience high mortality rates of pre-molt crabs, and some of these deaths may be attributable to diseases or parasites. During the active shedding season in 2013, we determined the prevalence of shell disease, Vibrio spp., Lagenophrys callinectes, and Hematodinium perezi at 4 commercial shedding facilities along the Louisiana coast. We also detected Ameson michaelis and reo-like virus infections. Shell disease was moderately prevalent at rates above 50% and varied by shedding facility, collection month, and crab size. Vibrio spp. bacteria were prevalent in the hemolymph of 37% of the pre-molt crabs. Lagenophrys callinectes was highly prevalent in the pre-molt crabs, but because it is a commensal species, it may not cause high mortality rates. Hematodinium perezi was absent in all pre-molt crabs.

  12. Ontogenetic change of body color patterns in laboratory-raised juveniles of six terrestrial hermit crab species.

    Science.gov (United States)

    Hamasaki, Katsuyuki; Tsuru, Takuma; Sanda, Tetsuya; Fujikawa, Shunsuke; Dan, Shigeki; Kitada, Shuichi

    2017-01-30

    We examined the ontogenetic change of body color patterns in the laboratory-raised juveniles of six terrestrial hermit crab species, including Birgus latro, Coenobita brevimanus, C. cavipes, C. purpureus, C. rugosus, and C. violascens, which commonly occur in the southern islands, Japan. The body color patterns of coenobitid juveniles were species-specific. The diagnostic features of body color patterns enable identification of juveniles of coenobitid crab species in the wild, thereby helping to understand the precise habitats of each coenobitid species.

  13. Spatial distribution of juvenile and adult female Tanner crabs (Chionoecetes bairdi) in a glacial fjord ecosystem: Implications for recruitment processes

    Science.gov (United States)

    Nielsen, J.K.; Taggart, S.J.; Shirley, T.C.; Mondragon, J.

    2007-01-01

    A systematic pot survey in Glacier Bay, Alaska, was conducted to characterize the spatial distribution of juvenile and adult female Tanner crabs, and their association with depth and temperature. The information was used to infer important recruitment processes for Tanner crabs in glaciated ecosystems. High-catch areas for juvenile and adult female Tanner crabs were identified using local autocorrelation statistics. Spatial segregation by size class corresponded to features in the glacial landscape: high-catch areas for juveniles were located at the distal ends of two narrow glacial fjords, and high-catch areas for adults were located in the open waters of the central Bay. Juvenile female Tanner crabs were found at nearly all sampled depths (15-439 m) and temperatures (4-8??C), but the biggest catches were at depths crabs. ?? 2007 International Council for the Exploration of the Sea. Published by Oxford Journals. All rights reserved.

  14. The Effects of Season and Sex on the Nutritional Quality of Muscle Types of Blue Crab Callinectes sapidus and Swimming Crab Portunus segnis

    Directory of Open Access Journals (Sweden)

    Deniz Ayas

    2016-05-01

    Full Text Available The effects of season and sex on the nutritional quality of muscle types (lump crab meatLCM, claw crab meat-CCM of swimming crab (Portunus segnis and blue crab (Callinectes sapidus were investigated. Carapace width, carapace length and total weight of both crab species were measured. High protein content in spring and low protein content in autumn were observed for both crab species. The levels of lipid content of both crab species were found to be similar. Higher lipid contents in spring and winter, lower lipid contents in summer and autumn for both sexes were found. Although both crab species contain small amounts of fat, they are good sources of n-3 PUFA content (especially EPA and DHA for all seasons regardless of sex and muscle types.

  15. Timing and route of migration of mature female blue crabs in a tidal estuary.

    Science.gov (United States)

    Eggleston, David B; Millstein, Erika; Plaia, Gayle

    2015-05-01

    Information on migration patterns is critical to using no-take migratory corridors and marine reserves to protect the spawning stock of commercially exploited species. Both active and passive acoustic tracking methods quantified movement of commercially and ecologically important blue crabs in the White Oak River estuary, NC, USA. We targeted post-mating female crabs migrating down-estuary to oceanic spawning grounds. Crabs travelled approximately 14.1 km mainly in deeper channels and over 12-26 days from mating areas to spawning grounds. No crabs were detected migrating down-estuary in the autumn and only 30% were detected migrating down-estuary in spring. None of the crabs detected near spawning grounds were detected or recaptured back up-estuary, suggesting that they either (i) do not return to the estuary after a one to two week period in the spawning area or (ii) were captured by fishermen. The results from this study demonstrate that (1) acoustic transmitters coupled with passive acoustic receivers provided reliable and valuable data on migration patterns of mature female blue crabs and (2) mature female blue crabs are capable of migrating primarily within deep channels to spawning grounds shortly after insemination.

  16. Discovery of an opportunistic starfish pathogen, Orchitophrya stellarum, in captive blue crabs, Callinectes sapidus.

    Science.gov (United States)

    Small, H J; Miller, T L; Coffey, A H; Delaney, K L; Schott, E; Shields, J D

    2013-10-01

    Histophagous scuticociliate infections were discovered in blue crabs, Callinectes sapidus, held in research facilities at the Virginia Institute of Marine Science. Ciliates were observed infecting every tissue examined including the gills, heart, muscle, hepatopancreas, and epidermis. Hemolymph smears and histological tissue sections indicated a morphological similarity to Mesanophrys chesapeakensis, the only recorded histophagous ciliate infecting blue crabs. However, subsequent analysis of the ribosomal ITS region (ITS1-5.8S-ITS2) of the ciliate indicated the parasite was Orchitophrya stellarum, a parasitic ciliate previously reported infecting sea stars from Europe, Australia, and North America. A simple Polymerase Chain Reaction (PCR-RFLP) assay was developed to detect and differentiate between O. stellarum and M. chesapeakensis. Its application confirmed the presence of O. stellarum infecting blue crabs held in an additional research facility in Maryland. For growth studies, cultures of O. stellarum grew optimally on 10% blue crab serum in crustacean saline held at 10-20°C. A field survey of blue crabs collected during the winters of 2011-2012 and sea stars (Asterias forbesi) during the winter of 2010 from the Chesapeake Bay and eastern shore of Virginia did not identify additional infected individuals.

  17. The bioeconomic impact of different management regulations on the Chesapeake Bay blue crab fishery

    Science.gov (United States)

    Bunnell, David B.; Lipton, Douglas W.; Miller, Thomas J.

    2010-01-01

    The harvest of blue crabs Callinectes sapidus in Chesapeake Bay declined 46% between 1993 and 2001 and remained low through 2008. Because the total market value of this fishery has declined by an average of US $ 3.3 million per year since 1993, the commercial fishery has been challenged to maintain profitability. We developed a bioeconomic simulation model of the Chesapeake Bay blue crab fishery to aid managers in determining which regulations will maximize revenues while ensuring a sustainable harvest. We compared 15 different management scenarios, including those implemented by Maryland and Virginia between 2007 and 2009, that sought to reduce female crab harvest and nine others that used seasonal closures, different size regulations, or the elimination of fishing for specific market categories. Six scenarios produced the highest revenues: the 2008 and 2009 Maryland regulations, spring and fall closures for female blue crabs, and 152- and 165-mm maximum size limits for females. Our most important finding was that for each state the 2008 and 2009 scenarios that implemented early closures of the female crab fishery produced higher revenues than the 2007 scenario, in which no early female closures were implemented. We conclude that the use of maximum size limits for female crabs would not be feasible despite their potentially high revenue, given the likelihood that the soft-shell and peeler fisheries cannot be expanded beyond their current capacity and the potentially high mortality rate for culled individuals that are the incorrect size. Our model results support the current use of seasonal closures for females, which permit relatively high exploitation of males and soft-shell and peeler blue crabs (which have high prices) while keeping the female crab harvest sustainable. Further, our bioeconomic model allows for the inclusion of an economic viewpoint along with biological data when target reference points are set by managers.

  18. Development of Enzymes and In Vitro Digestibility during Metamorphosis and Molting of Blue Swimming Crab (Portunus pelagicus

    Directory of Open Access Journals (Sweden)

    Phanu Chamchuen

    2014-01-01

    Full Text Available The work focuses on development of digestive enzymes (amylase, total protease, trypsin, and chymotrypsin and activity ratio of trypsin to chymotrypsin (T/C ratio for digestive efficiency and growth, in blue swimming crab (Portunus pelagicus during metamorphosis and molting. Specific activities of all enzyme parameters studied were associated with growth during metamorphosis, while only those of trypsin and T/C ratio were associated during molting cycle where trypsin and chymotrypsin specific activities associated with consumption rate with especially high levels during late intermolt and early premolt stages. About 50% increased weight gain was observed with at least double increased T/C ratio at the end of molting period, compared to the stages prior to molting. Growth of carapace would be more significant after finishing molting. Carapace width gain and T/C ratio were highest at the first crab stage. Studies of in vitro protein digestibility of different feed raw materials indicated that Artemia, Rotifer, and Moina are the best for larval stages. Otherwise, the use of shrimp feed and Artemia flake could be the alternatives. Incorporating of cassava meal into the feed formula for early adult stage (juvenile could be an advantage. The proteins from animals are more beneficial for adult crab culture than the proteins from plants and bacteria. The digestible quality of dietary protein is very important during larval stages, while the protein level of diet is more important during adult stages with fully developed digestive enzymes.

  19. Infection of juvenile edible crabs, Cancer pagurus by a haplosporidian-like parasite.

    Science.gov (United States)

    Thrupp, Tara J; Lynch, Sharon A; Wootton, Emma C; Malham, Shelagh K; Vogan, Claire L; Culloty, Sarah C; Rowley, Andrew F

    2013-09-01

    This study aimed to examine the pathobiology of a haplosporidian-like infection in juvenile (pre-recruit) edible crabs (Cancer pagurus) from two locations in South West Wales, UK. Infected crabs showed no external symptoms of the disease but dissection revealed an infected and hypertrophic antennal gland. Histological examination showed extensive parasitisation of the antennal gland overlying the hepatopancreas. Heavily infected crabs also showed the presence of parasites with morphological similarities to Haplosporidia in the labyrinth of the antennal gland and in the gills. The spread of the infection from the antennal gland to the gills suggests that these parasites are released into the haemolymph. Attempts to characterise the haplosporidian-like organism using several primers previously shown to amplify members of the phylum Haplosporidia failed. The prevalence of infection in juvenile edible crabs varied throughout the sampling period of November 2011 to July 2012 with the lowest level of ca. 15% in November peaking at 70% in March. This parasite may represent a threat to the sustainability of edible crab fisheries in this region if the damage observed in the antennal gland and gills results in host mortality. The identification of these parasites as members of the phylum Haplosporidia based on morphology alone must be seen as tentative in the absence of sequence data.

  20. Identification of tropomyosin and arginine kinase as major allergens of Portunus pelagicus (blue swimming crab).

    Science.gov (United States)

    Rosmilah, M; Shahnaz, M; Zailatul, H M Y; Noormalin, A; Normilah, I

    2012-09-01

    Crab is an important source of food allergen. Tropomyosin represents the main crab allergen and is responsible for IgE cross-reactivity between various species of crustaceans. Recently, other new crab allergens including arginine kinase have been identified. However, information on allergens of the local Portunidcrab is not available. Thus, the aim of this study was to identify the major allergens of Portunus pelagicus (blue swimming crab) using the allergenomics approach. Raw and cooked extracts of the crab were prepared from the crab meat. Protein profile and IgE binding pattern were demonstrated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and immunoblotting using sera from 30 patients with crab allergy. The major allergens of the crab were then identified by two-dimensional electrophoresis (2-DE), followed by mass spectrometry analysis of the peptide digests. The SDS-PAGE of raw extract revealed approximately 20 protein fractions over a wide molecular weight range, while cooked extract demonstrated fewer protein bands. The raw extract also demonstrated a higher number of IgE reactive bands than the cooked extract. A heat-resistant protein of 36 kDa has been identified as the major allergen in both raw and cooked extracts. In addition, a heat-sensitive protein of 41 kDa was also recognized as a major allergen in raw crab. The 2-DE gel profile of the raw extract demonstrated about >100 distinct proteins spots and immunoblotting of the 2-DE profile demonstrated at least 12 different major IgE reactive spots with molecular masses between 13 to 250 kDa and isoelectric point (pI) values ranging from 4.0 to 7.0. The 36 and 41 kDa proteins were identified as the crab tropomyosin and arginine kinase, respectively by mass spectrometry. Therefore, this study confirmed that tropomyosin and arginine kinase are the major allergens of the local Portunid crab, P. pelagicus.

  1. Cadmium-binding proteins from blue crabs (Callinectes sapidus) environmentally exposed to cadmium

    Energy Technology Data Exchange (ETDEWEB)

    Wiedow, M.A.; Kneip, T.J.; Garte, S.J.

    1982-06-01

    Two heat-stable (90/sup 0/C) cadmium-binding proteins were isolated from the hepatopancreas of Hudson River blue crabs (Callinectes sapidus) by Sephadex G-75 gel filtration chromatography. These proteins have molecular weights of 10,600 and 9,400, and ultraviolet absorbance ratios at 250/280 nm of 12.4 and 5.4, respectively. Repeated freezing and thawing and prolonged (3-6 weeks) storage resulted in protein degradation or loss of Cd-binding activity. These proteins were induced by laboratory injection of CdCl/sub 2/ in blue crabs from pristine (Chesapeake Bay) areas; however, injection of CdCl/sub 2/ into Hudson River animals yielded anomalous chromatography profiles. Cadmium-binding proteins were also identified in blue crab thoracic muscle and gill. The possibility is discussed that these proteins are a type of metallothionein and could contribute to the human toxicity of this cadmium-contaminated edible crustacean.

  2. Concurrent protein synthesis is required for in vivo chitin synthesis in postmolt blue crabs

    Energy Technology Data Exchange (ETDEWEB)

    Horst, M.N. (Mercer Univ., Macon, GA (USA))

    1990-12-01

    Chitin synthesis in crustaceans involves the deposition of a protein-polysaccharide complex at the apical surface of epithelial cells which secrete the cuticle or exoskeleton. The present study involves an examination of in vivo incorporation of radiolabeled amino acids and amino sugars into the cuticle of postmolt blue crabs, Callinectes sapidus. Rates of incorporation of both 3H leucine and 3H threonine were linear with respect to time of incubation. Incorporation of 3H threonine into the endocuticle was inhibited greater than 90% in the presence of the protein synthesis inhibitor, puromycin. Linear incorporation of 14C glucosamine into the cuticle was also demonstrated; a significant improvement of radiolabeling was achieved by using 14C-N-acetylglucosamine as the labeled precursor. Incorporation of 3H-N-acetylglucosamine into the cuticle of postmolt blue crabs was inhibited 89% by puromycin, indicating that concurrent protein synthesis is required for the deposition of chitin in the blue crab. Autoradiographic analysis of control vs. puromycin-treated crabs indicates that puromycin totally blocks labeling of the new endocuticle with 3H glucosamine. These results are consistent with the notion that crustacean chitin is synthesized as a protein-polysaccharide complex. Analysis of the postmolt and intermolt blue crab cuticle indicates that the exoskeleton contains about 60% protein and 40% chitin. The predominant amino acids are arginine, glutamic acid, alanine, aspartic acid, and threonine.

  3. Molecular keys unlock the mysteries of variable survival responses of blue crabs to hypoxia.

    Science.gov (United States)

    Bell, Geoffrey W; Eggleston, David B; Noga, Edward J

    2010-05-01

    Hypoxia is a major stressor in coastal ecosystems, yet generalizing its impacts on fish and shellfish populations across hypoxic events is difficult due to variability among individuals in their history of exposure to hypoxia and related abiotic variables, and subsequent behavioral and survival responses. Although aquatic animals have diverse physiological responses to cope with hypoxia, we know little about how inter-individual variation in physiological state affects survival and behavioral decisions under hypoxic conditions. Laboratory experiments coupled with molecular techniques determined how extrinsic factors (e.g., water body and temperature) and respiratory physiology (hemocyanin concentration and structure) affected survival and behavior of adult blue crabs (Callinectes sapidus) exposed to different levels of hypoxia over a 30-h time period. Nearly 100% of crabs survived the 1.3 mg dissolved oxygen (DO) l(-1) treatment (18.4% air saturation), suggesting that adult blue crabs are tolerant of severe hypoxia. Probability of survival decreased with increasing hypoxic exposure time, lower DO, and increasing temperature. Individual-level differences in survival correlated with water body and crab size. Crabs collected from the oligo/mesohaline and hypoxic Neuse River Estuary (NRE), North Carolina, USA survived hypoxic exposures longer than crabs from the euhaline and normoxic Bogue and Back Sounds, North Carolina. Furthermore, small NRE crabs survived longer than large NRE crabs. Hemocyanin (Hcy) concentration did not explain these individual-level differences, however, hypoxia-tolerant crabs had Hcy structures indicative of a high-O(2)-affinity form of Hcy, suggesting Hcy "quality" (i.e., structure) may be more important for hypoxia survival than Hcy "quantity" (i.e., concentration). The geographic differences in survival we observed also highlight the importance of carefully selecting experimental animals when planning to extrapolate results to the population

  4. Transcriptome profiling of the eyestalk of precocious juvenile Chinese mitten crab reveals putative neuropeptides and differentially expressed genes.

    Science.gov (United States)

    Xu, Zhiqiang; Zhao, Muzi; Li, Xuguang; Lu, Quanping; Li, Yuehua; Ge, Jiachun; Pan, Jianlin

    2015-09-15

    Chinese mitten crabs that reach maturity 1 year earlier than normal crabs are known as precocious juvenile crabs. The molecular mechanisms underlying the precocity of the Chinese mitten crab are poorly understood. To identify the genes that may be involved in the control of precocity in Chinese mitten crab, we measured the expression profile of eyestalk genes in precocious and normally developed juvenile crabs using high-throughput sequencing on an Illumina HiSeq 2500 platform. We obtained 56,446,284 raw reads from the precocious crabs and 58,029,476 raw reads from the normally developed juvenile crabs. Reads from the two libraries were combined into a single data set. De novo assembly of the combined read set yielded 78,777 unigenes with an average length of 1563 bp. A total of 41,405 unigenes with predicted ORFs were selected for functional annotation. Among these genes, we identified three neuropeptide genes belonging to the crustacean hyperglycemic hormone family and two neuropeptide genes encoding the chromatophorotropic hormones. Transcriptome comparison between the two libraries revealed 42 genes that exhibited significant differential expression, of which 29 genes were up-regulated and 13 genes were down-regulated in the precocious crabs. To confirm the sequencing data, six differentially expressed genes with functional annotations were selected and validated by qRT-PCR. In conclusion, we obtained the comprehensive transcriptome of the eyestalk tissues of precocious juvenile crabs. The sequencing results may provide new insights into the biomolecular basis of precocity in the Chinese mitten crab.

  5. Transmission of the parasitic dinoflagellate Hematodinium sp. infection in blue crabs Callinectes sapidus by cannibalism.

    Science.gov (United States)

    Walker, Anna N; Lee, Richard F; Frischer, Marc E

    2009-07-23

    Infection with the parasitic dinoflagellate Hematodinium sp. can be devastating to blue crab Callinectes sapidus populations. Morbidity and mortality appear to depend on the burden of parasitic organisms. Heavily infected crabs become lethargic and, if not preyed upon, succumb to overwhelming infection. We report on the transmission of Hematodinium sp. into blue crabs that were fed pieces of infected tissues and examined for evidence of infection at time periods from 1 to 48 h and for the general state of their health after 4 d. During the first 16 h after feeding, Hematodinium sp. was found in the gut, followed by large increases in hemolymph hemocytes and the appearance of hemocytic nodules in tissues. By 16 h, the hemocytic nodules appeared poorly circumscribed and disorganized. No nodules were seen in a heavily infected crab after 24 h. By the end of the 48 h after feeding, 73% (11 of 15) of the crabs had shown evidence of infection with Hematodinium sp. Those crabs with infection intensities (Hematodinium sp. as percent of cells in hemolymph) higher than 20% were dead within 4 d.

  6. Uptake and survival of enteric viruses in the blue crab, Callinectes sapidus.

    Science.gov (United States)

    Hejkal, T W; Gerba, C P

    1981-01-01

    Uptake of poliovirus 1 by the blue crab, Callinectes sapidus, was measured to assess the likelihood of contamination by human enteric viruses. Virus was found in all parts of the crab within 2 h after the crab was placed in contaminated artificial seawater. The highest concentrations of virus were found in the hemolymph and digestive tract, but the meat also contained virus. The concentration of virus in the crabs was generally less than in the surrounding water. Changes in salinity did not substantially affect the rate of accumulation. An increase in temperature from 15 to 25 degrees C increased the rates of both uptake and removal. Poliovirus survived up to 6 days in crabs at a temperature of 15 degrees C and a salinity of 10 g/kg. When contaminated crabs were boiled, 99.9% of poliovirus 1, simian rotavirus SA11, and a natural isolate of echovirus 1 were inactivated within 8 min. These data demonstrate that viruses in crabs should not pose a serious health hazard if recommended cooking procedures are used. PMID:6261683

  7. Colonization of the gut of the blue crab (Callinectes sapidus) by Vibrio cholerae.

    Science.gov (United States)

    Huq, A; Huq, S A; Grimes, D J; O'Brien, M; Chu, K H; Capuzzo, J M; Colwell, R R

    1986-01-01

    Attachment of Vibrio cholerae to the mucosal surface of the intestine is considered to be an important virulence characteristic. Vibrio cholerae, an autochthonous member of brackish water and estuarine bacterial communities, also attaches to crustacea, a significant factor in multiplication and survival of V. cholerae in nature. The ability of V. cholerae to attach to the gut wall of the blue crab (Callinectes sapidus) was examined, and attachment was observed only in the hindgut and not the midgut of crabs, confirming a requirement for chitin in the attachment of V. cholerae to invertebrate and zooplankton surfaces. The new finding of attachment of V. cholerae to the hindgut of crabs may be correlated with the epidemiology and transmission of cholera in the aquatic environment. The crab model may also prove useful in elucidating the mechanism(s) of ion transport in crustacea. Images PMID:3767362

  8. Crabby Interactions: Fifth Graders Explore Human Impact on the Blue Crab Population

    Science.gov (United States)

    Jeffery, Tonya D.; McCollough, Cherie A.; Moore, Kim

    2016-01-01

    This article describes a two-day lesson in which fifth-grade students took on the role of marine biology scientists, using their critical-thinking and problem-solving skills to explore human impact on the blue crab ecosystem. The purpose of "Crabby Interactions" was to help students understand the impact of human activities on the local…

  9. TROPHIC ACCUMULATION AND DEPURATION OF MERCURY BY BLUE CRABS (CALLINECTES SAPIDUS) AND PINK SHRIMP (PENAEUS DUORARUM).

    Science.gov (United States)

    Mercury concentrations in blue crabs (Callinectes sapidus) collected from an area of mercury-contaminated sediments in Lavaca Bay, TX, USA, are more than an order of magnitude greater than concentrations in penaeid shrimp from the same area. Laboratory feeding experiments using ...

  10. Photo-induced toxicity of Deepwater Horizon slick oil to blue crab (Callinectes sapidus) larvae.

    Science.gov (United States)

    Alloy, Matthew M; Boube, Idrissa; Griffitt, Robert J; Oris, James T; Roberts, Aaron P

    2015-09-01

    The 2010 Deepwater Horizon oil spill resulted in the accidental release of approximately 700 million L of crude oil into the Gulf of Mexico. Photo-induced toxicity after co-exposure to ultraviolet (UV) radiation is 1 mechanism by which polycyclic aromatic hydrocarbons (PAHs) from oil spills may exert toxicity. Blue crab are an important commercial and ecological resource in the Gulf of Mexico, and their largely transparent larvae may make them sensitive to PAH photo-induced toxicity. The goal of the present study was to examine the sensitivity of early lifestage blue crab (Callinectes sapidus) zoea to slick oil collected during the Deepwater Horizon spill. Blue crab zoea were exposed to 1 of several dilutions of water accommodated fractions from 1 of 2 sources of oil and gradations of natural sunlight in a factorial design. Two 7-h solar exposures were carried out with a recovery period (dark) in between. Survival was found to be UV- and PAH-dependent. Toxicity was observed within the range of surface PAH concentrations reported in the Gulf of Mexico during the Deepwater Horizon spill. These findings indicate that early lifestage blue crab are sensitive to photo-induced toxicity from Deepwater Horizon slick oil. © 2015 SETAC.

  11. Crabby Interactions: Fifth Graders Explore Human Impact on the Blue Crab Population

    Science.gov (United States)

    Jeffery, Tonya D.; McCollough, Cherie A.; Moore, Kim

    2016-01-01

    This article describes a two-day lesson in which fifth-grade students took on the role of marine biology scientists, using their critical-thinking and problem-solving skills to explore human impact on the blue crab ecosystem. The purpose of "Crabby Interactions" was to help students understand the impact of human activities on the local…

  12. TROPHIC ACCUMULATION AND DEPURATION OF MERCURY BY BLUE CRABS (CALLINECTES SAPIDUS) AND PINK SHRIMP (PENAEUS DUORARUM).

    Science.gov (United States)

    Mercury concentrations in blue crabs (Callinectes sapidus) collected from an area of mercury-contaminated sediments in Lavaca Bay, TX, USA, are more than an order of magnitude greater than concentrations in penaeid shrimp from the same area. Laboratory feeding experiments using ...

  13. Analysis of metals in blue crabs, Callinectes sapidus, from two Connecticut estuaries

    Energy Technology Data Exchange (ETDEWEB)

    Jop, K.M. [Sciences Applications International Corp., Narragansett, RI (United States); Biever, R.C.; Hoberg, J.R.; Shepherd, S.P. [Springborn Labs., Inc., Wareham, MA (United States)

    1997-02-01

    Decisions involving the use and allocation of resources in the nation`s coastal and estuarine regions require reliable and continuous information about the status and trends of environmental quality in those areas. In recent years much attention has been focused on assessing environmental risks resulting from the manufacture, distribution, use and disposal of chemicals. Legislation and public concern have produced numerous regulations concerning the introduction of chemicals into surface waters which increase the potential for human exposure. There is considerable concern about the human health aspects of metal cycling especially in coastal and inland waters that are in proximity to large populations or industrial centers. Many of these compounds tend to remain in the ecosystem and eventually move from lower to higher trophic levels within the human food chain. Blue crabs, Callinectes sapidus Rathbun, are important members of the estuarine food chain due to high abundance and their multiple role as scavengers, predators and prey. Because of their omnivorous feeding characteristics and association with sediments, blue crabs are exposed and may potentially accumulate significant amount of pollutants above background seawater concentrations. This species represents one of the most valuable fishery resources in the southern states. According to Marcus and Mathews blue crabs ranked fifth in 1984 and fourth in 1985 behind shrimp, swordfish, oysters and hard clams in economic value, but first in total weight for both years in South Carolina. Although in Connecticut blue crabs are harvested mostly for personal consumption, their commercial value in other states makes the results from any environmental survey of great interest from the consideration of risk to human health. This study evaluated the level of contaminants in Blue crabs in the summer months by examining the concentration of selected metals in samples of muscle and hepatopancreas tissue. 12 refs., 3 tabs.

  14. American alligator digestion rate of blue crabs and its implications for stomach contents analysis

    Science.gov (United States)

    Nifong, James C.; Rosenblatt, Adam E.; Johnson, Nathan A.; Barichivich, William; Silliman, Brian; Heithaus, Michael R.

    2012-01-01

    Stomach contents analysis (SCA) provides a snap-shot observation of a consumer's diet. Interpretation of SCA data can be complicated by many factors, including variation in gastric residence times and digestion rates among prey taxa. Although some SCA methods are reported to efficiently remove all stomach contents, the effectiveness of these techniques has rarely been tested for large irregular shaped prey with hard exoskeletons. We used a controlled feeding trial to estimate gastric residency time and decomposition rate of a large crustacean prey item, the Blue Crab (Callinectes sapidus), which is consumed by American Alligators (Alligator mississippiensis), an abundant apex predator in coastal habitats of the southeastern United States. The decomposition rate of C. sapidus in the stomachs of A. mississippiensis followed a predictable pattern, and some crab pieces remained in stomachs for at least 14 days. We also found that certain portions of C. sapidus were prone to becoming caught within the stomach or esophagus, meaning not all crab parts are consistently recovered using gastric lavage techniques. However, because the state of decomposition of crabs was predictable, it is possible to estimate time since consumption for crabs recovered from wild alligators. This information, coupled with a detailed understanding of crab distributions and alligator movement tactics could help elucidate patterns of cross-ecosystem foraging by the American Alligator in coastal habitats

  15. The Influence of Diet Composition on Fitness of the Blue Crab, Callinectes sapidus.

    Science.gov (United States)

    Belgrad, Benjamin A; Griffen, Blaine D

    2016-01-01

    The physiological condition and fecundity of an organism is frequently controlled by diet. As changes in environmental conditions often cause organisms to alter their foraging behavior, a comprehensive understanding of how diet influences the fitness of an individual is central to predicting the effect of environmental change on population dynamics. We experimentally manipulated the diet of the economically and ecologically important blue crab, Callinectes sapidus, to approximate the effects of a dietary shift from primarily animal to plant tissue, a phenomenon commonly documented in crabs. Crabs whose diet consisted exclusively of animal tissue had markedly lower mortality and consumed substantially more food than crabs whose diet consisted exclusively of seaweed. The quantity of food consumed had a significant positive influence on reproductive effort and long-term energy stores. Additionally, seaweed diets produced a three-fold decrease in hepatopancreas lipid content and a simultaneous two-fold increase in crab aggression when compared to an animal diet. Our results reveal that the consumption of animal tissue substantially enhanced C. sapidus fitness, and suggest that a dietary shift to plant tissue may reduce crab population growth by decreasing fecundity as well as increasing mortality. This study has implications for C. sapidus fisheries.

  16. Accumulation of toxic organic pollutants in the blue crab Callinectes sapidus

    Energy Technology Data Exchange (ETDEWEB)

    Hale, R.C.

    1983-01-01

    Levels of toxic organic pollutants (TOP) were examined in the blue crabs, Callinectes sapidus, of Virginia waters. Alkyl substituted polynuclear aromatic hydrocarbons (ASPAH), thought derived from weathered petroleum, were the most common organic pollutants present. Unsubstituted aromatics, heterosubstituted aromatics, polychlorinated biphenyls (PCB), and DDT metabolites were also detected by the analytical procedure employed. Highest levels of ASPAH were found in crabs from the heavily industrialized Hampton Roads area of the James River. Lower concentrations were detected in crabs from the Pocomoke Sound, the upper James and the Rappahannock River sampling sites. PCB levels were elevated in samples taken from both James River stations. Levels of TOP were generally higher in crabs sampled in June than in September of 1981. Concentrations of pollutants in the tissues and tissue lipid content were correlated. Highest levels of both were detected in the hepatopancreas, followed by egg, ovary and muscle. TOP levels in field samples in in-vivo biotransformation of the model compound benzo(a)pyrene (B(a)P) in the hepatopancreas, during in-laboratory experiments, suggested that differences may exist in the uptake and elimination of pollutants as a function of the sex and maturity of the crabs. It appeared that the metabolism of aromatic hydrocarbons varied with the molt stage of the crabs.

  17. The Influence of Diet Composition on Fitness of the Blue Crab, Callinectes sapidus.

    Directory of Open Access Journals (Sweden)

    Benjamin A Belgrad

    Full Text Available The physiological condition and fecundity of an organism is frequently controlled by diet. As changes in environmental conditions often cause organisms to alter their foraging behavior, a comprehensive understanding of how diet influences the fitness of an individual is central to predicting the effect of environmental change on population dynamics. We experimentally manipulated the diet of the economically and ecologically important blue crab, Callinectes sapidus, to approximate the effects of a dietary shift from primarily animal to plant tissue, a phenomenon commonly documented in crabs. Crabs whose diet consisted exclusively of animal tissue had markedly lower mortality and consumed substantially more food than crabs whose diet consisted exclusively of seaweed. The quantity of food consumed had a significant positive influence on reproductive effort and long-term energy stores. Additionally, seaweed diets produced a three-fold decrease in hepatopancreas lipid content and a simultaneous two-fold increase in crab aggression when compared to an animal diet. Our results reveal that the consumption of animal tissue substantially enhanced C. sapidus fitness, and suggest that a dietary shift to plant tissue may reduce crab population growth by decreasing fecundity as well as increasing mortality. This study has implications for C. sapidus fisheries.

  18. High Connectivity among Blue Crab (Callinectes sapidus) Populations in the Western South Atlantic

    Science.gov (United States)

    Kersanach, Ralf; Cortinhas, Maria Cristina Silva; Prata, Pedro Fernandes Sanmartin; Dumont, Luiz Felipe Cestari; Proietti, Maíra Carneiro; Maggioni, Rodrigo; D’Incao, Fernando

    2016-01-01

    Population connectivity in the blue crab Callinectes sapidus was evaluated along 740 km of the Western South Atlantic coast. Blue crabs are the most exploited portunid in Brazil. Despite their economic importance, few studies report their ecology or population structure. Here we sampled four estuarine areas in southern Brazil during winter 2013 and summer 2014 in order to evaluate diversity, gene flow and structure of these populations. Nine microsatellite markers were evaluated for 213 adult crabs, with identification of seven polymorphic loci and 183 alleles. Pairwise FST values indicated low population structure ranging from -0.00023 to 0.01755. A Mantel test revealed that the geographic distance does not influence genetic (r = -0.48), and structure/migration rates confirmed this, showing that even the populations located at the opposite extremities of our covered region presented low FST and exchanged migrants. These findings show that there is a significant amount of gene flow between blue crab populations in South Brazil, likely influenced by local current dynamics that allow the transport of a high number of larvae between estuaries. Considering the elevated gene flow, the populations can be considered a single genetic stock. However, further information on population size and dynamics, as well as fishery demands and impacts at different regions, are necessary for harvest management purposes. PMID:27064977

  19. High Connectivity among Blue Crab (Callinectes sapidus Populations in the Western South Atlantic.

    Directory of Open Access Journals (Sweden)

    Ana Luzia Figueiredo Lacerda

    Full Text Available Population connectivity in the blue crab Callinectes sapidus was evaluated along 740 km of the Western South Atlantic coast. Blue crabs are the most exploited portunid in Brazil. Despite their economic importance, few studies report their ecology or population structure. Here we sampled four estuarine areas in southern Brazil during winter 2013 and summer 2014 in order to evaluate diversity, gene flow and structure of these populations. Nine microsatellite markers were evaluated for 213 adult crabs, with identification of seven polymorphic loci and 183 alleles. Pairwise FST values indicated low population structure ranging from -0.00023 to 0.01755. A Mantel test revealed that the geographic distance does not influence genetic (r = -0.48, and structure/migration rates confirmed this, showing that even the populations located at the opposite extremities of our covered region presented low FST and exchanged migrants. These findings show that there is a significant amount of gene flow between blue crab populations in South Brazil, likely influenced by local current dynamics that allow the transport of a high number of larvae between estuaries. Considering the elevated gene flow, the populations can be considered a single genetic stock. However, further information on population size and dynamics, as well as fishery demands and impacts at different regions, are necessary for harvest management purposes.

  20. High Connectivity among Blue Crab (Callinectes sapidus) Populations in the Western South Atlantic.

    Science.gov (United States)

    Lacerda, Ana Luzia Figueiredo; Kersanach, Ralf; Cortinhas, Maria Cristina Silva; Prata, Pedro Fernandes Sanmartin; Dumont, Luiz Felipe Cestari; Proietti, Maíra Carneiro; Maggioni, Rodrigo; D'Incao, Fernando

    2016-01-01

    Population connectivity in the blue crab Callinectes sapidus was evaluated along 740 km of the Western South Atlantic coast. Blue crabs are the most exploited portunid in Brazil. Despite their economic importance, few studies report their ecology or population structure. Here we sampled four estuarine areas in southern Brazil during winter 2013 and summer 2014 in order to evaluate diversity, gene flow and structure of these populations. Nine microsatellite markers were evaluated for 213 adult crabs, with identification of seven polymorphic loci and 183 alleles. Pairwise FST values indicated low population structure ranging from -0.00023 to 0.01755. A Mantel test revealed that the geographic distance does not influence genetic (r = -0.48), and structure/migration rates confirmed this, showing that even the populations located at the opposite extremities of our covered region presented low FST and exchanged migrants. These findings show that there is a significant amount of gene flow between blue crab populations in South Brazil, likely influenced by local current dynamics that allow the transport of a high number of larvae between estuaries. Considering the elevated gene flow, the populations can be considered a single genetic stock. However, further information on population size and dynamics, as well as fishery demands and impacts at different regions, are necessary for harvest management purposes.

  1. Movement patterns and trajectories of ovigerous blue crabs Callinectes sapidus during the spawning migration

    Science.gov (United States)

    Carr, Sarah D.; Tankersley, Richard A.; Hench, James L.; Forward, Richard B.; Luettich, Richard A.

    2004-08-01

    Female blue crabs ( Callinectes sapidus Rathbun) migrate from low salinity estuarine regions to high salinity regions near the ocean to release larvae. During this migration, ovigerous females use ebb-tide transport, a vertical migratory behavior in which they ascend into the water column during ebb tides, to move seaward to larval release areas. In order to determine the relationship of ebb-tide vertical migrations to local currents and the influence of these vertical migrations on the horizontal transport of blue crabs in the estuary, ovigerous females with mature embryos (˜1-3 days from hatching) were tracked near Beaufort Inlet, North Carolina (USA), in July and August 2001 and 2002. Crabs were tagged and tracked using ultrasonic telemetry, and currents near the crabs were measured simultaneously with a shipboard acoustic Doppler current profiler. During the two seasons, eight crabs were successfully tracked for periods ranging from 3.9-37.0 h and for distances ranging from 1.9-10.6 km. All crabs migrated seaward during the tracking periods. Crabs moved episodically during all tidal phases with periods of movement on the order of minutes to an hour. They moved with local currents in terms of both speed and direction during ebb tides, consistent with ebb-tide transport, and moved down-estuary (seaward) in opposition to local currents during flood tides. The percentage of time that crabs were active was higher during night ebb tides than during day ebb tides or flood tides and increased with increasing ebb-tide current speed. Mean migratory speeds were 0.11, 0.04, 0.08 and 0.02 m s -1 during night ebb, night flood, day ebb and day flood tides, respectively, and net migratory speeds were on the order of 5 km day -1. Due to the episodic nature of the crabs' movements, the total distances that crabs traveled during ebb tides ranged from 10-40% of the distances that passive particles could have traveled under the same conditions.

  2. Hemolymph ecdysteroids during the last three molt cycles of the blue crab, Callinectes sapidus: quantitative and qualitative analyses and regulation.

    Science.gov (United States)

    Chung, J Sook

    2010-01-01

    The profiles of circulating ecdysteroids during the three molt cycles prior to adulthood were monitored from the juvenile blue crab, Callinectes sapidus. Ecdysteroid patterns are remarkably similar in terms of peak concentrations ranging between 210-330 ng/ml hemolymph. Analysis of hemolymph at late premolt stage revealed six different types of ecdysteroids with ponasterone A (PoA) and 20-OH ecdysone (20-OH E) as the major forms. This ecdysteroid profile was consistent in all three molt cycles. Bilateral eyestalk ablation (EA) is a procedure that removes inhibitory neurohormones including crustacean hyperglycemic hormone (CHH) and molt-inhibiting hormone (MIH) and often results in precocious molting in crustaceans. However, the inhibitory roles of these neuropeptides in vivo have not yet been tested in C. sapidus. We determined the regulatory roles of CHH and MIH in the circulating ecdysteroid from ablated animals through daily injection. A daily administration of purified native CHH and MIH at physiological concentration maintained intermolt levels of ecdysteroids in the EA animals. This suggests that Y organs (YO) require a brief exposure to CHH and MIH in order to maintain the low level of ecdysteroids. Compared to intact animals, the EA crabs did not exhibit the level of peak ecdysteroids, and the major ecdysteroid turned out to be 20-OH E, not PoA. These results further underscore the important actions of MIH and CHH in ecdysteroidogenesis, as they not only inhibit, but also control the composition of output of the YO activity. (c) 2009 Wiley Periodicals, Inc.

  3. Risk of Handling as a Route of Exposure to Infectious Waterborne Cryptosporidium parvum Oocysts via Atlantic Blue Crabs (Callinectes sapidus)▿

    Science.gov (United States)

    Graczyk, Thaddeus K.; McOliver, Cynthia; Silbergeld, Ellen K.; Tamang, Leena; Roberts, Jennifer D.

    2007-01-01

    Commercial Atlantic blue crabs (Callinectes sapidus) were exposed to 2.0 × 104 infectious waterborne oocysts of Cryptosporidium parvum. The study demonstrated that blue crabs can transfer C. parvum oocysts to persons involved in handling or preparing crabs and that they may contaminate other surfaces or products during storage. PMID:17449680

  4. Effects of ocean acidification on juvenile red king crab (Paralithodes camtschaticus) and Tanner crab (Chionoecetes bairdi) growth, condition, calcification, and survival.

    Science.gov (United States)

    Long, William Christopher; Swiney, Katherine M; Harris, Caitlin; Page, Heather N; Foy, Robert J

    2013-01-01

    Ocean acidification, a decrease in the pH in marine waters associated with rising atmospheric CO2 levels, is a serious threat to marine ecosystems. In this paper, we determine the effects of long-term exposure to near-future levels of ocean acidification on the growth, condition, calcification, and survival of juvenile red king crabs, Paralithodes camtschaticus, and Tanner crabs, Chionoecetes bairdi. Juveniles were reared in individual containers for nearly 200 days in flowing control (pH 8.0), pH 7.8, and pH 7.5 seawater at ambient temperatures (range 4.4-11.9 °C). In both species, survival decreased with pH, with 100% mortality of red king crabs occurring after 95 days in pH 7.5 water. Though the morphology of neither species was affected by acidification, both species grew slower in acidified water. At the end of the experiment, calcium concentration was measured in each crab and the dry mass and condition index of each crab were determined. Ocean acidification did not affect the calcium content of red king crab but did decrease the condition index, while it had the opposite effect on Tanner crabs, decreasing calcium content but leaving the condition index unchanged. This suggests that red king crab may be able to maintain calcification rates, but at a high energetic cost. The decrease in survival and growth of each species is likely to have a serious negative effect on their populations in the absence of evolutionary adaptation or acclimatization over the coming decades.

  5. Effects of ocean acidification on juvenile red king crab (Paralithodes camtschaticus and Tanner crab (Chionoecetes bairdi growth, condition, calcification, and survival.

    Directory of Open Access Journals (Sweden)

    William Christopher Long

    Full Text Available Ocean acidification, a decrease in the pH in marine waters associated with rising atmospheric CO2 levels, is a serious threat to marine ecosystems. In this paper, we determine the effects of long-term exposure to near-future levels of ocean acidification on the growth, condition, calcification, and survival of juvenile red king crabs, Paralithodes camtschaticus, and Tanner crabs, Chionoecetes bairdi. Juveniles were reared in individual containers for nearly 200 days in flowing control (pH 8.0, pH 7.8, and pH 7.5 seawater at ambient temperatures (range 4.4-11.9 °C. In both species, survival decreased with pH, with 100% mortality of red king crabs occurring after 95 days in pH 7.5 water. Though the morphology of neither species was affected by acidification, both species grew slower in acidified water. At the end of the experiment, calcium concentration was measured in each crab and the dry mass and condition index of each crab were determined. Ocean acidification did not affect the calcium content of red king crab but did decrease the condition index, while it had the opposite effect on Tanner crabs, decreasing calcium content but leaving the condition index unchanged. This suggests that red king crab may be able to maintain calcification rates, but at a high energetic cost. The decrease in survival and growth of each species is likely to have a serious negative effect on their populations in the absence of evolutionary adaptation or acclimatization over the coming decades.

  6. Physicochemical properties of double-stranded RNA used to discover a reo-like virus from blue crab Callinectes sapidus.

    Science.gov (United States)

    Bowers, Holly A; Messick, Gretchen A; Hanif, Ammar; Jagus, Rosemary; Carrion, Lee; Zmora, Oded; Schott, Eric J

    2010-12-07

    Mortality among blue crab Callinectes sapidus in soft shell production facilities is typically 25% or greater. The harvest, handling, and husbandry practices of soft shell crab production have the potential to spread or exacerbate infectious crab diseases. To investigate the possible role of viruses in soft shell crab mortalities, we took advantage of the physicochemical properties of double-stranded RNA (dsRNA) to isolate a putative virus genome. Further characterization confirmed the presence of a reo-like virus that possesses 12 dsRNA genome segments. The virus was present in >50% of dead or dying soft shell crabs, but fewer than 5% of healthy hard crabs. Injection of the virus caused mortality and resulted in the appearance of viral RNA and virus inclusions in hemocytes. The genome of the virus was partially sequenced and the information used to develop a reverse transcription polymerase chain reaction (RT-PCR) assay that is able to detect the virus genome in as little as 7.5 pg of total RNA. The molecular tools developed during this study will allow us to quantify prevalence of the blue crab reo-like virus in captive (soft shell facilities, aquaculture operations) and wild populations and facilitate understanding of the role this virus has in blue crab life history.

  7. Assessment of metal concentrations in muscles of the blue crab, Callinectes danae S., from the Santos Estuarine System.

    Science.gov (United States)

    Bordon, Isabella C A C; Sarkis, Jorge E S; Tomás, Acácio R G; Scalco, Allan; Lima, Mariana; Hortellani, Marcos A; Andrade, Nathalia P

    2012-09-01

    This study determined the concentrations of eleven metals in the blue crab, Callinectes danae, from nine sites in the Santos Estuarine System of Sao Paulo State, Brazil. The results were compared to guidelines established in the United States, Europe and Brazil for the safety of human consumers. Muscles of blue crabs were removed by dissection and concentrations of Al, Cd, Co, Cr, Cu, Fe, Hg, Mn Ni, Pb and Zn were determined. In general, the concentrations of metals were low, and the crabs were regarded as safe for human consumption. Crabs from a single site (site 4) exceeded the guidelines established by the United States and Europe, but not Brazil, for Pb, with a mean tissue concentration of 1.725 μg g(-1). With the exception of Al, Fe and Ni, significant differences were noted between sites in the concentrations of each metal in crab tissue.

  8. Direct and indirect estimates of natural mortality for Chesapeake Bay blue crab

    Science.gov (United States)

    Hewitt, D.A.; Lambert, D.M.; Hoenig, J.M.; Lipcius, R.N.; Bunnell, D.B.; Miller, T.J.

    2007-01-01

    Analyses of the population dynamics of blue crab Callinectes sapidus have been complicated by a lack of estimates of the instantaneous natural mortality rate (M). We developed the first direct estimates of M for this species by solving Baranov's catch equation for M given estimates of annual survival rate and exploitation rate. Annual survival rates were estimated from a tagging study on adult female blue crabs in Chesapeake Bay, and female-specific exploitation rates for the same stock were estimated by comparing commercial catches with abundances estimated from a dredge survey. We also used eight published methods based on life history parameters to calculate indirect estimates of M for blue crab. Direct estimates of M for adult females in Chesapeake Bay for the years 2002–2004 ranged from 0.42 to 0.87 per year and averaged 0.71 per year. Indirect estimates of M varied considerably depending on life history parameter inputs and the method used. All eight methods yielded values for M between 0.99 and 1.08 per year, and six of the eight methods yielded values between 0.82 and 1.35 per year. Our results indicate that natural mortality of blue crab is higher than previously believed, and we consider M values between 0.7 and 1.1 per year to be reasonable for the exploitable stock in Chesapeake Bay. Remaining uncertainty about Mmakes it necessary to evaluate a range of estimates in assessment models.

  9. The male blue crab, Callinectes sapidus, uses both chromatic and achromatic cues during mate choice.

    Science.gov (United States)

    Baldwin, Jamie; Johnsen, Sönke

    2012-04-01

    In the blue crab, Callinectes sapidus, claw color varies by sex, sexual maturity and individual. Males rely in part on color cues to select appropriate mates, and these chromatic cues may be perceived through an opponent interaction between two photoreceptors with maximum wavelength sensitivities at 440 and 508 nm. The range of color discrimination of this dichromatic visual system may be limited, however, and it is unclear whether male blue crabs are capable of discriminating the natural variations in claw color that may be important in mate choice. By testing males' innate color preferences in binary choice tests between photographs of red-clawed females and six variations of orange-clawed females, we examined both the chromatic (opponent interaction) and achromatic (relative luminance) cues used in male mate choice. Males significantly preferred red-clawed females to orange-clawed females, except when the test colors were similar in both opponency and relative luminance. Our results are unusual in that they indicate that male mate choice in the blue crab is not guided solely by achromatic or chromatic mechanisms, suggesting that both color and intensity are used to evaluate female claw color.

  10. Extracellular digestion during hyposaline exposure in the Dungeness crab, Cancer magister, and the blue crab, Callinectes sapidus.

    Science.gov (United States)

    Curtis, Daniel L; van Breukelen, Frank; McGaw, Iain J

    2013-12-01

    Extracellular digestive processes were examined in the Dungeness crab, Cancer magister and the blue crab, Callinectes sapidus, during hyposaline exposure. Both species are found in estuaries as adults, but vary in their ability to balance the cardiovascular and respiratory demands of concurrent osmoregulation and digestion. The weak osmoregulator, C. magister, is unable to balance the demands of osmoregulation and digestion. Concordant with observed decreases in oxygen consumption and mechanical digestion, proteolytic digestion within the foregut and hepatopancreas was delayed, resulting in a relative reduction of circulating amino acids post-feeding in low salinity. In contrast, the efficient osmoregulator, C. sapidus, balances the demands of osmoregulation and digestion, and mechanical digestion continues unabated in low salinity. Protease activity in the gut fluid and hepatopancreas showed either no change or a reduction over time. The transport of amino acids into the cells post-feeding is opposed by an efflux of amino acids at the cellular level, and resulted in a build up of amino acids in the hemolymph. Despite differences in the extracellular responses to low salinity exposure following feeding, both species were able to maintain high digestive efficiencies. © 2013.

  11. Population ecology of the blue crab Callinectes danae (Crustacea: Portunidae) in a Brazilian tropical estuary.

    Science.gov (United States)

    Araújo, Marina S L C; Barreto, Aline V; Negromonte, Aurinete O; Schwamborn, Ralf

    2012-03-01

    This paper aims at describing the population ecology of the swimming crab Callinectes danae Smith, 1869 in one of the most productive estuaries of Brazil, the Santa Cruz Channel. These crabs were monthly collected from January to December/2009 at four stations along the channel, two in the upper and two in the lower estuary. A total of 2373 specimens of C. danae were collected during the study. Males had a larger average carapace width than non-ovigerous females (60.0 ± 15.6 mm and 52.9 ± 12.4 mm, respectively), an adaptation that gives greater protection for females during the copulation. Overall sex ratio did not differ significantly from 1:1. However, evaluating sex-ratio by sampling area, males and juveniles of both sexes occurred preferentially in the upper estuary (p < 0.05), while adult females, including ovigerous, inhabited the lower estuary, an area of major marine influence (p < 0.05). While juveniles look for estuarine waters due to the benefit from the shelter and abundance of food, ovigerous females migrate to areas of greater depth and higher salinity in order to provide a more favorable environment for embryonic and larval development and to enhance larval dispersal. Recruitment of juveniles was continuous along the year, but intensified from March to June and, with less intensity, from October to December.

  12. Changes during late-stage embryonic development from egg-juvenile to free-living hatchling in Chinese freshwater crab Sinopotamon yangtsekiense (Decapoda, Brachyura, Potamidae)

    Science.gov (United States)

    Xue, Junzeng; Liu, Yan; Cumberlidge, Neil; Wu, Huixian

    2013-05-01

    This study expands on recent reports that direct development in the Chinese potamid freshwater crab Sinopotamon yangtsekiense involves the completion of all brachyuran larval stages (nauplius, zoea, and megalopa) inside the egg case during embryonic development. Detailed studies of embryonic development in this species revealed the presence of an additional larval stage (the egg-juvenile) between the megalopa and the free-living hatchling crab. We described and compared the appendages of the head, thorax, and abdomen of the egg-juvenile with those of the hatchling crab in S. yangtsekiense. Significant differences were found between most of the appendages of these two stages with a soft exoskeleton in the egg-juvenile, no joint articulation, a slimmer appearance, and a lack of setae when compared with the newly emerged free-living hatchling crab. These modifications of the appendages are related to the confinement within the egg case of the egg-megalopa and egg-juvenile during direct development, and the need for the free-living hatchling freshwater crab to move, feed, and respire. In marine crabs, the megalopa gives rise to the first crab stage whereas in freshwater crabs the egg-juvenile follows the megalopa and immediately precedes the free-living first crab stage.

  13. Changes during late-stage embryonic development from egg-juvenile to free-living hatchling in Chinese freshwater crab Sinopotamon yangtsekiense (Decapoda, Brachyura,Potamidae)

    Institute of Scientific and Technical Information of China (English)

    XUE Junzeng; LIU Yan; Neil CUMBERLIDGE; WU Huixian

    2013-01-01

    This study expands on recent reports that direct development in the Chinese potamid freshwater crab Sinopotamon yangtsekiense involves the completion of all brachyuran larval stages (nauplius,zoea,and megalopa) inside the egg case during embryonic development.Detailed studies of embryonic development in this species revealed the presence of an additional larval stage (the egg-juvenile) between the megalopa and the free-living hatchling crab.We described and compared the appendages of the head,thorax,and abdomen of the egg-juvenile with those of the hatchling crab in S.yangtsekiense.Significant differences were found between most of the appendages of these two stages with a soft exoskeleton in the egg-juvenile,no joint articulation,a slimmer appearance,and a lack of setae when compared with the newly emerged free-living hatchling crab.These modifications of the appendages are related to the confinement within the egg case of the egg-megalopa and egg-juvenile during direct development,and the need for the free-living hatchling freshwater crab to move,feed,and respire.In marine crabs,the megalopa gives rise to the first crab stage whereas in freshwater crabs the egg-juvenile follows the megalopa and immediately precedes the free-living first crab stage.

  14. Effects of salinity on survival, feeding behavior and growth of the juvenile swimming crab, Portunus trituberculatus (Miers, 1876)

    Science.gov (United States)

    Shentu, Jikang; Xu, Yongjian; Ding, Zhangni

    2015-05-01

    Effect of salinity on survival, feeding behavior and growth of juvenile swimming crab Portunus trituberculatus was investigated under 5 salinity levels of 5, 10, 20, 30 and 40. The results show that the crab juveniles fed 2 or 3 times at the salinity 20 and 30, each lasted for about 25 minutes, for a total feeding time of 73.2±22.65 minutes per day. At these salinities, there were significantly higher in the frequency of feeding and in total feeding time than those at lower salinities of 5 and 10. All crab juveniles moulted when reared at a salinity of 20 during the 5 days duration of the experiment, which is significantly higher than those at other salinities. All juveniles survived at salinity 20, and the survivorship was not significantly different from that at 30, but was significantly higher than those at other salinities. The crab juveniles reared at a salinity of 20 had the highest value of food ration of 0.190 8±0.011 3 g/gBW, average body weight gain of 0.796±0.128 g, gain rate of 87%-96%, and food conversion ratio of 1.20±0.09. There was no significant difference in the values found between 20 and 30 but these values were significantly lower than that at the other salinities ( P >0.05). Highest activities of digestive enzymes (Amylase, Protease, Lipase) and lowest activities of protective enzymes (SOD, PO, CAT) were also obtained on crab juveniles reared at salinity of 20.

  15. Oesophageal chemoreceptors of blue crabs, Callinectes sapidus, sense chemical deterrents and can block ingestion of food.

    Science.gov (United States)

    Aggio, Juan F; Tieu, Ryan; Wei, Amy; Derby, Charles D

    2012-05-15

    Decapod crustaceans such as blue crabs possess a variety of chemoreceptors that control different stages of the feeding process. All these chemoreceptors are putative targets for feeding deterrents that cause animals to avoid or reject otherwise palatable food. As a first step towards characterizing the chemoreceptors that mediate the effect of deterrents, we used a behavioral approach to investigate their precise location. Data presented here demonstrate that chemoreceptors located on the antennules, pereiopods and mouthparts do not mediate the food-rejection effects of a variety of deterrents, both natural and artificial to crabs. Crabs always searched for deterrent-laced food and took it to their oral region. The deterrent effect was manifested as either rejection or extensive manipulation, but in both cases crabs bit the food. The biting behavior is relevant because the introduction of food into the oral cavity ensured that the deterrents gained access to the oesophageal taste receptors, and so we conclude that they are the ones mediating rejection. Additional support comes from the fact that a variety of deterrent compounds evoked oesophageal dilatation, which is mediated by oesophageal receptors and has been linked to food rejection. Further, there is a positive correlation between a compound's ability to elicit rejection and its ability to evoke oesophageal dilatation. The fact that deterrents do not act at a distance is in accordance with the limited solubility of most known feeding deterrents, and likely influences predator-prey interactions and their outcome: prey organisms will be attacked and bitten before deterrents become relevant.

  16. Bioaccumulation and depuration of metals in blue crabs (Callinectes sapidus Rathbun) from a contaminated and clean estuary

    Energy Technology Data Exchange (ETDEWEB)

    Reichmuth, Jessica M., E-mail: jreichmuth02@gmail.co [Department of Biological Sciences, Rutgers, State University of New Jersey, 195 University Avenue, Newark, NJ 07102 (United States); Weis, Peddrick, E-mail: weis@umdnj.ed [Department of Radiology, UMDNJ-Medical School of New Jersey, Newark, NJ 07101 (United States); Weis, Judith S., E-mail: jweis@andromeda.rutgers.ed [Department of Biological Sciences, Rutgers, State University of New Jersey, 195 University Avenue, Newark, NJ 07102 (United States)

    2010-02-15

    Blue crabs from a contaminated estuary (Hackensack Meadowlands-HM) and a cleaner reference site (Tuckerton-TK) were analyzed for Cr, Cu, Hg, Pb, and Zn in muscle and hepatopancreas. Crabs from each site were taken into the laboratory and fed food from the other site, or in another experiment, transplanted to the other site for eight weeks. All crabs were analyzed for metals. Overall, tissue concentrations reflected environmental conditions. Tissue differences were found for Cu, Pb and Zn (all higher in hepatopancreas), and Hg (higher in muscle). HM muscle had more Hg than TK muscle, but did not decrease after transplanting or consuming clean food. HM crabs lost Cu, Pb and Zn in hepatopancreas after being fed clean food or transplanted. TK crabs increased Hg in muscle and Cr and Zn in hepatopancreas after transplantation or being fed contaminated (HM) food. Concentrations were variable, suggesting that blue crabs may not be fully reliable bioindicators of polluted systems. - The accumulation of metals within the muscle and hepatopancreas of blue crabs was highly variable, but often followed environmental concentrations.

  17. Overwintering of the parasitic dinoflagellate Hematodinium perezi in dredged blue crabs (Callinectes sapidus) from Wachapreague Creek, Virginia.

    Science.gov (United States)

    Shields, Jeffrey D; Sullivan, Shelley E; Small, Hamish J

    2015-09-01

    Parasitic dinoflagellates in the genus Hematodinium cause disease and mortality in several commercially important marine decapod crustaceans. One species, Hematodinium perezi, occurs in blue crabs, Callinectes sapidus, along the eastern seaboard and Gulf coast of the USA. The parasite infects blue crabs, other decapods, and amphipods in the high salinity waters of coastal bays. Epizootics of the parasite often reach prevalence levels of 75-80% during outbreaks with diseased crabs dying from the infection. Prevalence of the parasite is bimodal, with a minor peak in late spring or summer, and a major peak in fall, and declining rapidly to nearly zero in late November and December. The rapid decline in infections in the late fall brings up the question of whether the parasite overwinters in crabs or whether it uses an unidentified resting stage, such as a cyst. We report observations on the prevalence of the parasite from winter dredge surveys undertaken in 2011 and 2012. Crabs were examined via hemolymph smears, histology, and PCR diagnosis for the presence of H. perezi and other pathogens. Active infections were observed from January through March in 2011 and 2012, indicating the parasite can overwinter in blue crabs. However, several crabs that were positive by PCR had presumptive effete infections that were difficult to diagnose in histological slides and hemolymph smears. These infections did not appear to be active and may have been in subsidence. Dredged crabs with light and moderate active infections were held at 15°C to determine if the parasite was capable of rapid progression. In 8 cases, infections exhibited logarithmic growth progressing rapidly over 8-12days. We present evidence that overwintering of H. perezi occurs in the blue crab hosts, that infections are capable of responding rapidly to increases in temperatures, and that overwintering provides a reservoir of infected animals for transmission to occur in the spring. Copyright © 2015 Elsevier Inc

  18. (1)H NMR metabolomic profiling of the blue crab (Callinectes sapidus) from the Adriatic Sea (SE Italy): A comparison with warty crab (Eriphia verrucosa), and edible crab (Cancer pagurus).

    Science.gov (United States)

    Zotti, Maurizio; De Pascali, Sandra Angelica; Del Coco, Laura; Migoni, Danilo; Carrozzo, Leonardo; Mancinelli, Giorgio; Fanizzi, Francesco Paolo

    2016-04-01

    The metabolomic profile of blue crab (Callinectes sapidus) captured in the Acquatina lagoon (SE Italy) was compared to an autochthonous (Eriphia verrucosa) and to a commercial crab species (Cancer pagurus). Both lipid and aqueous extracts of raw claw muscle were analyzed by (1)H NMR spectroscopy and MVA (multivariate data analysis). Aqueous extracts were characterized by a higher inter-specific discriminating power compared to lipid fractions. Specifically, higher levels of glutamate, alanine and glycine characterized the aqueous extract of C. sapidus, while homarine, lactate, betaine and taurine characterized E. verrucosa and C. pagurus. On the other hand, only the signals of monounsaturated fatty acids distinguished the lipid profiles of the three crab species. These results support the commercial exploitation and the integration of the blue crab in human diet of European countries as an healthy and valuable seafood. Copyright © 2015 Elsevier Ltd. All rights reserved.

  19. Prevalence of Vibrio parahaemolyticus, and Vibrio vulnificus in blue crabs (Callinectes sapidus), seawater and sediments of the Maryland Coastal Bays.

    Science.gov (United States)

    Rodgers, C; Parveen, S; Chigbu, P; Jacobs, J; Rhodes, M; Harter-Dennis, J

    2014-10-01

    To determine the prevalence of total and pathogenic Vibrio parahaemolyticus (Vp) and V. vulnificus (Vv) in blue crabs, water and sediment from the Maryland Coastal Bays (MCBs), USA. Crab, haemolymph, sediment and seawater samples were collected monthly from four sites in MCBs from February 2012 through October 2012 with environmental parameters recorded. The most-probable-number (MPN) methodology was used to enumerate Vp and Vv with presumptive colonies and the presence of virulence markers confirmed using polymerase chain reaction (PCR). Results indicate that blue crabs contained both Vp and Vv at densities (7·28 and 5·43 log MPN g(-1) , respectively) higher than those reported for bivalves. In addition, markers for clinically relevant strains of both species were detected in over 30% of samples. Haemolymph, sediment and seawater samples were also routinely positive for both species and clinically relevant strains, but generally at lower densities than found in crabs (4·27, 3·28, and 2·39 log MPN g(-1) per ml(-1) Vp, and 4·28, 2·49 and 2·38 log MPN g(-1) per ml(-1) Vv). Blue crabs concentrate Vp and Vv at levels greater than found in water or sediment. While changes in abundance associated with temperature are apparent, there is little evidence to support differences among sampling locations. These results highlight the potential for blue crab related vibriosis and the importance of proper handling, cooking and care of this popular seafood before consumption. © 2014 The Society for Applied Microbiology.

  20. Blue crabs Callinectes sapidus as potential biological reservoirs for white spot syndrome virus (WSSV).

    Science.gov (United States)

    Powell, James W B; Browdy, Craig L; Burge, Erin J

    2015-03-09

    White spot syndrome virus (WSSV) is a virulent pathogen of cultured shrimp and was first detected in farms in South Carolina (USA) in 1997 and subsequently in wild shrimp in 1999. We screened groups of 1808 wild Atlantic white shrimp Litopenaeus setiferus and 300 blue crabs Callinectes sapidus collected from South Carolina, Georgia, and Florida for the presence of WSSV using the Shrimple® immunoassay-strip test, with all positives and random subsets of negatives tested by TaqMan real-time PCR and in infectivity bioassays. Of 87 shrimp and 11 crabs that tested positive using the Shrimple® test, only a single C. sapidus was confirmed to be infected with WSSV by PCR and the infectivity bioassay. The data indicate that the prevalence of WSSV in these species is low in these southeastern US regions, but that C. sapidus may serve as a biological reservoir.

  1. Metallothionein-like proteins in the blue crab Callinectes sapidus: effect of water salinity and ions.

    Science.gov (United States)

    De Martinez Gaspar Martins, Camila; Bianchini, Adalto

    2009-03-01

    The effect of water salinity and ions on metallothionein-like proteins (MTLP) concentration was evaluated in the blue crab Callinectes sapidus. MTLP concentration was measured in tissues (hepatopancreas and gills) of crabs acclimated to salinity 30 ppt and abruptly subjected to a hypo-osmotic shock (salinity 2 ppt). It was also measured in isolated gills (anterior and posterior) of crabs acclimated to salinity 30 ppt. Gills were perfused with and incubated in an isosmotic saline solution (ISS) or perfused with ISS and incubated in a hypo-osmotic saline solution (HSS). The effect of each single water ion on gill MTLP concentration was also analyzed in isolated and perfused gills through experiments of ion substitution in the incubation medium. In vivo, MTLP concentration was higher in hepatopancreas than in gills, being not affected by the hypo-osmotic shock. However, MTLP concentration in posterior and anterior gills significantly increased after 2 and 24 h of hypo-osmotic shock, respectively. In vitro, it was also increased when anterior and posterior gills were perfused with ISS and incubated in HSS. In isolated and perfused posterior gills, MTLP concentration was inversely correlated with the calcium concentration in the ISS used to incubate gills. Together, these findings indicate that an increased gill MTLP concentration in low salinity is an adaptive response of the blue crab C. sapidus to the hypo-osmotic stress. This response is mediated, at least in part, by the calcium concentration in the gill bath medium. The data also suggest that the trigger for this increase is purely branchial and not systemic.

  2. Reproductive ecology of the blue crab, Callinectes danae Smith, 1869 in the Conceição Lagoon system, Santa Catarina Isle, Brazil.

    Science.gov (United States)

    Branco, J O; Masunari, S

    2000-02-01

    Abundance of ovigerous females, size of the first gonadal maturation and the possible migration, route of the blue crab Callinectes danae from the Conceição Lagoon system, Santa Catarina Isle, Brazil, are described. This lagoon is connected with the coastal area through a canal. A total of 1,124 crabs was caught during a 19 month sampling period. The reproduction and recruitment of juveniles occurred all year-round, with two peaks of abundance (February and September), correlated with the presence of ovigerous females (June and January). The mean carapace width at which the crabs attained gonadal maturity for the first time was 9.4 cm in males and 8.4 cm in females. The Conceição Lagoon is a growth, reproduction, and spawning area for the species. However, egg eclosion occurs outside the lagoon following migration of ovigerous females to the open sea. After hatching the eggs, some females return to the lagoon, but males stay there for most of their life cycle.

  3. Climate Change Effects on Respiration Rates of Blue Crab (Callinectes sapidus) from the Patuxent River, Chesapeake Bay

    Science.gov (United States)

    Nyffeler, A.

    2016-02-01

    A rise in atmospheric CO2 induces a greenhouse effect that also causes ocean temperatures and CO2 levels to rise. These environmental changes may represent an additional energetic cost for blue crabs because they rely on the concentration of CO2 in the water to deposit calcium carbonate in their shells. We conducted a respiration experiment to measure the effect of climate change on crab metabolism. Crabs were collected from the Chesapeake Bay and exposed to different heated and acidified conditions. After crabs had been exposed to the environmental conditions in the chambers for two molts, they were placed in respiration chambers to measure rates of oxygen consumption. Results indicated different trends in respiration rates between the treatments, although the patterns were not statistically significant. Crabs exposed to higher temperatures showed elevated respiration rates, while crabs exposed to high CO2 demonstrated decreased respiration rates. The two factors of climate change (high temperature and high CO2) did not demonstrate the highest respiration rate, but rather the crabs exposed to high temperatures and ambient CO2 showed the highest mean respiration rate. These data suggest that crab metabolism may not change as much as expected due to climate changes.

  4. In vitro culture and developmental cycle of the parasitic dinoflagellate Hematodinium sp. from the blue crab Callinectes sapidus.

    Science.gov (United States)

    Li, Caiwen; Miller, Terrence L; Small, Hamish J; Shields, Jeffrey D

    2011-12-01

    Hematodinium is a genus of parasitic dinoflagellates whose species have caused significant mortalities in marine crustacean fisheries worldwide. A species of Hematodinium infects the blue crab, Callinectes sapidus on the eastern seaboard of the USA. The mode of transmission of the parasite in blue crabs is unknown. We established several continuous in vitro cultures of Hematodinium sp. isolated from the haemolymph of infected blue crabs. One isolate has been continuously maintained in our laboratory through serial subcultivation for over 12 months, and is capable of infecting new hosts when inoculated into healthy crabs. Cells of the parasite undergo characteristic developmental changes in vitro consistent with the identifiable stages of Hematodinium sp.: filamentous trophonts, amoeboid trophonts, arachnoid trophonts and sporonts, sporoblasts, prespores and dinospores (macrospores and microspores). Additionally, we describe an unusual shunt in the life cycle wherein presumptive schizonts derived from arachnoid sporonts developed into filamentous and arachnoid trophonts that can then initiate arachnoid sporonts in new cultures. This may explain the rapid proliferation of the parasite in blue crab hosts. We also found that temperature and light intensity affected the growth and development of the parasite in vitro.

  5. Reproductive performance and larval quality of blue swimming crab (Portunus pelagicus broodstock, fed with different feeds

    Directory of Open Access Journals (Sweden)

    Vutthichai Oniam

    2012-09-01

    Full Text Available Fecundity, hatching rate and crab larvae quality of blue swimming crab, Portunus pelagicus, broodstock reared inearthen ponds, fed with different feeds, were studied for about 150 days. Results showed that average fecundity ofP. pelagicus broodstock fed with trash fish (569,842±243,173 eggs, shrimp feed (464,098±188,884 eggs, mixed feeds(544,875.3±169,357.3 eggs and hatching rate (50.78±25.19%, 62.33±26.79% and 50.86±20.76% were not significantly different(P>0.05. Zoea produced by female broodstock fed with mixed feeds had a significantly higher survival rate (89.47±5.03%,P<0.05 compared to those produced by female broodstock fed with trash fish (73.40±14.61% and shrimp feeds (67.33±12.80%, but the survival rate of megalopa and first crab stages was not affected. This study recommends that the mixed feedwas suitable feed for rearing of P. pelagicus broodstock in an earthen pond as evidenced by the quality of zoea I or 1 dayafter hatching and growth of female broodstock.

  6. Ecdysteriod titers during the molt cycle of the blue crab resemble those of other crustacea

    Energy Technology Data Exchange (ETDEWEB)

    Soumoff, C.; Skinner, D.M.

    1983-08-01

    Callinectes sapidus is the only true crab (brachyuran) whose pattern of ecdysteroid titers has been described as departing from the pattern seen in other decapods. While ecdysteroids in other crabs reach a peak just prior to ecdysis, those of C. sapidus were claimed to reach their maxima after ecdysis. The data reported here challenge these findings. Ecdysteroids were measured in hemolymph, ovaries, and whole animal extracts of blue crabs using a radioimmunoassay. In hemolymph and whole animals, ecdysteroid levels rose during premolt to a maximum at stage D/sub 3/. Ecdysteroids declined rapidly from late premolt stage D/sub 4/ through postmolt stage A/sub 2/, increased slightly at postmolt stage B, and returned to low levels where they remained during intermolt stage C. Ecdysteroid levels in males and immature females were not significantly different but mature females, having reached a terminal anecdysis, had signifincatly lower ecdysteroid levels. Ovaries of mature females accumulated ecdysteroids during vitellogenesis while the concentration of ecdysteroids in hemolymph was low.

  7. Vertical distribution of first stage larvae of the blue crab, Callinectes sapidus, at the mouth of Chesapeake Bay

    Science.gov (United States)

    Provenzano, Anthony J.; McConaugha, John R.; Philips, Kathleen B.; Johnson, David F.; Clark, John

    1983-05-01

    The vertical distribution of stage I blue crab larvae, near the mouth of Chesapeake Bay, was examined over four diurnal cycles. Each of two stations was occupied for 30 hours twice during the summer of 1979. On each of the four cruises, peak larval abundance occurred after a night time high slack tide, suggesting a synchronized hatch of blue crab larvae. 90-99% of all larvae collected were taken in the neuston layer. The apparent timing of the hatches to coincide with the beginning of an ebb tide and the concentration of larvae in the neuston layer strongly suggests seaward transport of these early stage larvae and the probability of offshore development.

  8. Locomotory fatigue during moderate and severe hypoxia and hypercapnia in the Atlantic blue crab, Callinectes sapidus.

    Science.gov (United States)

    Stover, Kristin K; Burnett, Karen G; McElroy, Eric J; Burnett, Louis E

    2013-04-01

    The Atlantic blue crab, Callinectes sapidus (Rathbun), is a highly mobile crustacean that must locomote to find food, evade predators, find mates, and avoid adverse conditions such as hypoxia. In this study we tested the effects of two levels of hypoxia (10.4 kPa, 50% air saturation = moderate hypoxia; 4 kPa, 20% air saturation = severe hypoxia) and hypercapnic hypoxia (50% air saturation O(2) with Pco(2) = 2 kPa) on fatigue during sustained continuous exercise. Fatigue was induced by an exercise trial that entailed continuous sideways hexapedal walking on an underwater treadmill. Fatigue was quantified using two methods: (1) a pull force test that measures the holding strength of the legs, and (2) the number of fatigue-resisting behaviors (180° turns and stopping). Fatigue was defined as a pull force of 67% or less of the initial pre-exercise pull force and was reached after 6.12 h of walking for crabs in well-aerated normoxic seawater, 4 h in 50% air saturation, 2.07 h in 20% air saturation, and 4.58 h in 50% air saturation and hypercapnia. The number of fatigue-resisting behaviors increased with walking time in all treatments. Performance decreased in hypoxia, with fatigue being reached more quickly as the level of hypoxia intensified. Hypercapnia in moderate hypoxia did not have a deleterious influence on behavior and lengthened slightly the time it took crabs to fatigue. In addition, severe hypoxia exacerbated changes in gait kinematics as crabs became fatigued, by significantly increasing stride length and decreasing stride frequency.

  9. Effects of molting on the visual acuity of the blue crab, Callinectes sapidus.

    Science.gov (United States)

    Baldwin, Jamie; Johnsen, Sönke

    2011-09-15

    In crustaceans with compound eyes, the corneal lens of each facet is part of the exoskeleton and thus shed during molting. Here we used an optomotor assay to evaluate the impact of molting on visual acuity (as measured by the minimum resolvable angle, α(min)) in the female blue crab, Callinectes sapidus. We found that visual acuity decreases substantially in the days prior to molting and is gradually recovered after molting. Four days prior to molting, α(min) was 1.8 deg (N=5), a value approximating the best possible acuity in this species. In the 24 h before ecdysis occurred, α(min) increased to 15.0 deg (N=12), corresponding to an eightfold drop in visual acuity. Within 6 days after molting, α(min) returned to the pre-molting value. Micrographs of C. sapidus eyes showed that a gap between the corneal lens and the crystalline cone first appeared approximately 5 days prior to shedding and increased in width as the process progressed. This separation was likely responsible for the loss of visual acuity observed in behavioral tests. In blue crabs, mating is limited to the period of the female's pubertal molt, and a reduction in acuity during this time may have an effect on the sensory cues used in female mate choice. The results described here may be broadly applicable to all arthropods that molt and have particular importance for crustaceans that molt multiple times in their lifetime or have mating cycles that are paired with molting.

  10. POP levels in blue crab (Callinectes sapidus) and edible fish from the eastern Mediterranean coast.

    Science.gov (United States)

    Tekin, Serkan; Pazi, Idil

    2017-01-01

    Organochlorinated pesticides and Aroclors were measured in the muscle of two edible fish species (gray mullet, sea bream) and blue crab, collected from eastern Mediterranean coast in 2013. The concentration of organochlorinated pesticides (OCPs) and Aroclors in biota samples which were collected at six sites ranged from 1.0-8.6 and 9-47.5 ng g(-1) wet weight, respectively. Total DDT concentrations in seafood samples were compared to tolerance level established by the US Food and Drug Administration (FDA); the concentrations were detected below the tolerence level. Health risk assessment was conducted related to the consumption of chemically contaminated seafood. The estimated daily intake of OCPs calculated by using the estimated daily fish consumption in Turkey was far below the acceptable daily intake as established by FAO/WHO. Our data indicated that consumption of blue crab, gray mullet, and sea bream collected from the Mediterranean coast of Turkey could pose "no risk" for human health in terms of OCPs.

  11. Tolerance, bioenergetics, and biochemical composition of the blue crab, Callinectes sapidus rathbun, exposed to the water-soluble fraction of South Louisiana crude oil

    Energy Technology Data Exchange (ETDEWEB)

    Wang, S.Y.

    1986-01-01

    Blue crabs were highly tolerant to petroleum hydrocarbons. Rates of energy intake decreased with increasing hydrocarbon concentration. Although energy expenditure rates of crabs exposed to 2504 ppb were not significantly higher than that of control crabs, they were significantly higher than those of crabs exposed to 820 and 1476 ppb. Molting was delayed in crabs exposed to 1476 and 2504 ppb. Crab growth was significantly reduced in a dose-dependent manner. The correlation between scope for growth and tissue growth was highly significant, indicating a bioenergetic basis for the decreased growth in crabs exposed to petroleum hydrocarbons. RNA content of crabs exposed to crude oil was significantly reduced on all sampling dates. Protein content of crabs exposed to crude oil was lower than that of control crabs on days 14 and 21. DNA content was not significantly different from that of control crabs. RNA:DNA and protein:DNA ratio were significantly reduced in crabs exposed to crude oil. The significant correlations suggest the possibility of their use as indicators of physiological condition. Significant differences in lipid content and concentration were observed. Analysis of five lipid classes indicate that structural lipids were less affected than lipids used for energy storage among crabs exposed to crude oil. The observed changes growth pattern and biochemical composition suggest that the pattern of energy utilization was altered. Among crabs exposed to petroleum hydrocarbons, growth in size took place despite little increase in tissue content. Available energy was used for growth with little being stored in lipid reserves.

  12. Variations in prevalence of viral, bacterial, and rhizocephalan diseases and parasites of the blue crab (Callinectes sapidus).

    Science.gov (United States)

    Rogers, Holly A; Taylor, Sabrina S; Hawke, John P; Anderson Lively, Julie A

    2015-05-01

    Prevalence of blue crab diseases and parasites has not been consistently monitored in the Gulf of Mexico. To establish current prevalence levels and to more fully understand population dynamics, commercial landing trends, and effects of future natural and anthropogenic disasters on animal health, we measured the prevalence of white spot syndrome virus (WSSV), Loxothylacus texanus, shell disease, and Vibrio spp. in blue crabs collected from Louisiana in 2013 and the beginning of 2014. We used PCR to detect WSSV and L. texanus infections, visual gross diagnosis for L. texanus externae and shell disease, and standard microbiological culture techniques and biochemical testing for Vibrio spp. We found no crabs infected with WSSV or L. texanus. Absence of L. texanus parasitization was expected based on the sampled salinities and the sampling focus on large crabs. Shell disease was present at a level of 54.8% and was most prevalent in the winter and summer and least prevalent in the spring. Vibrio spp. were found in the hemolymph of 22.3% of the crabs and prevalence varied by site, season, and sex. Additionally, three of 39 crabs tested were infected with reo-like virus. Copyright © 2015 Elsevier Inc. All rights reserved.

  13. Accumulation and retention of No. 2 fuel-oil compounds in the blue crab, Callinectes sapidus' rathbun

    Energy Technology Data Exchange (ETDEWEB)

    Melzian, B.D.; Lake, J.

    1987-01-01

    In order to determine if Blue Crabs (Callinectes sapidus) can bioaccumulate and retain complex mixtures of petroleum hydrocarbons, adult crabs were exposed for 14 days or 30-35 days in continuous flow-through seawater systems to three sublethal concentrations, nominally 0.00 (control), 0.01, or 1.0 ppm (mg/liter), of the water-accomodated fraction (WAF) of Number (No.) 2 fuel oil. Crabs exposed for 14 days were subsequently exposed to clean running seawater for a 30 day depuration period. Gill, hepatopancreas, and muscle tissue samples were collected from control, WAF exposed, and depurated crabs and analyzed by gas chromatography and/or gas chomatography-mass spectrometry. No. 2 fuel-oil compounds were not detected in any of the tissues of the control crabs. Trace amounts of fuel-oil compounds were detected in gill and hepatopancreas tissues collected from crabs exposed to the 0.01 ppm WAF and no fuel-oil compounds were detected in muscle tissues. All tissues of crabs exposed to the 1.0 ppm WAF accumulated No. 2 fuel-oil compounds and considerable amounts remained in hepatopancreas and gill tissues following depuration for 30 days in clean seawater.

  14. Mercury, lead, and cadmium in blue crabs, Callinectes sapidus, from the Atlantic coast of Florida, USA: a multipredator approach.

    Science.gov (United States)

    Adams, Douglas H; Engel, Marc E

    2014-04-01

    Blue crabs, Callinectes sapidus, from the Atlantic coast of Florida were analyzed for total mercury, methylmercury, lead, and cadmium. Paired samples of two tissue types were analyzed for each crab, (1) muscle tissue (cheliped and body muscles) and (2) whole-body tissue (all organs, muscle tissue and connective tissue), for evaluation of the concentration of metals available to human consumers as well as estuarine predators. There were clear patterns of tissue-specific partitioning for each metal. Total mercury was significantly greater in muscle tissue (mean=0.078 µg/g) than in whole-body tissue (mean=0.055 µg/g). Conversely, whole-body concentrations of lead and cadmium (means=0.131 and 0.079 µg/g, respectively) were significantly greater than concentrations in muscle (means=0.02 and 0.029 µg/g, respectively). There were no significant correlations between any metal contaminant and crab size. Cadmium levels were significantly greater in the muscle tissue of females, but, no other sex-related differences were seen for other metals or tissue types. Methylmercury composed 93-100% of the total mercury in tissues. Compared to previous blue crab studies from different regions of the United States, mean concentrations of mercury, lead, and cadmium were relatively low, although isolated groups or individual blue crabs accumulated high metal concentrations. © 2013 Published by Elsevier Inc.

  15. Efficacy of alfaxalone for intravascular anesthesia and euthanasia in blue crabs (Callinectes sapidus).

    Science.gov (United States)

    Minter, Larry J; Harms, Craig A; Archibald, Kate E; Broadhurst, Heather; Bailey, Kate M; Christiansen, Emily F; Lewbart, Gregory A; Posner, Lysa P

    2013-09-01

    The objective of this study was to characterize the behavioral effects and changes in heart rate of four doses of alfaxalone delivered by intravascular injection to blue crabs (Callinectes sapidus). Thirty (male, n = 27; female, n = 3) blue crabs were randomly assigned to one of four treatment groups of alfaxalone: eight animals were assigned to each of the 5-, 10-, and 15-mg/kg treatment groups, and the remaining six animals were assigned to the 100-mg/kg group. Times for anesthetic induction and recovery periods were recorded. Righting reflex, defensive posturing, and heart rate were evaluated before, during, and after the anesthetic trial. Anesthesia was induced in all 14 animals consolidated into the high-dosage group (15 mg/kg [n = 8] and 100 mg/kg [n = 6]), which was significantly greater than 8 of 16 animals in the low-dosage group (5 mg/kg [n = 2] and 10 mg/kg [n = 6]). Median anesthesia induction time for all crabs was 0.4 min, with no significant difference in induction time between groups observed. Median recovery time was 9.4 min (n = 2), 6.1 min (n = 5), 11.3 min (n = 8), and 66.1 min (n = 5) for the 5-, 10-, 15-, and 100-mg/kg groups, respectively. Recovery times were significantly longer for crabs exposed to an induction dose of 100 mg/kg compared with the 10- and 15-mg/kg induction doses. A significant decrease in the median heart rate was observed between the baseline value and that observed at both induction and 5 min postinjection in the 100-mg/kg dose trial. Two mortalities were observed during the anesthesia trials (n = 1, 10 mg/kg; n = 1, 100 mg/kg), both associated with the autotomization of limbs. In summary, the intravascular administration of alfaxalone at 15 mg/kg provided rapid and reliable sedation, whereas alfaxalone administered at 100 mg/kg produced rapid and long lasting anesthesia.

  16. Application of Artificial Neural Networks (ANNs for Weight Predictions of Blue Crabs (Callinectes sapidus RATHBUN, 1896 Using Predictor Variables

    Directory of Open Access Journals (Sweden)

    C. TURELI BILEN

    2012-12-01

    Full Text Available An evaluation of the performance of artificial networks (ANNs to estimate the weights of blue crab (Callinectes sapidus catches in Yumurtalık Cove (Iskenderun Bay that uses measured predictor variables is presented, including carapace width (CW, sex (male, female and female with eggs, and sampling month. Blue crabs (n=410 were collected each month between 15 September 1996 and 15 May 1998. Sex, CW, and sampling month were used and specified in the input layer of the network. The weights of the blue crabs were utilized in the output layer of the network. A multi-layer perception architecture model was used and was calibrated with the Levenberg Marguardt (LM algorithm. Finally, the values were determined by the ANN model using the actual data. The mean square error (MSE was measured as 3.3, and the best results had a correlation coefficient (R of 0.93. We compared the predictive capacity of the general linear model (GLM versus the Artificial Neural Network model (ANN for the estimation of the weights of blue crabs from independent field data. The results indicated the higher performance capacity of the ANN to predict weights compared to the GLM (R=0.97 vs. R=0.95, raw variable when evaluated against independent field data.

  17. Application of Artificial Neural Networks (ANNs for Weight Predictions of Blue Crabs (Callinectes sapidus RATHBUN, 1896 Using Predictor Variables

    Directory of Open Access Journals (Sweden)

    C. TURELI BILEN

    2011-10-01

    Full Text Available An evaluation of the performance of artificial networks (ANNs to estimate the weights of blue crab (Callinectes sapidus catches in Yumurtalık Cove (Iskenderun Bay that uses measured predictor variables is presented, including carapace width (CW, sex (male, female and female with eggs, and sampling month. Blue crabs (n=410 were collected each month between 15 September 1996 and 15 May 1998. Sex, CW, and sampling month were used and specified in the input layer of the network. The weights of the blue crabs were utilized in the output layer of the network. A multi-layer perception architecture model was used and was calibrated with the Levenberg Marguardt (LM algorithm. Finally, the values were determined by the ANN model using the actual data. The mean square error (MSE was measured as 3.3, and the best results had a correlation coefficient (R of 0.93. We compared the predictive capacity of the general linear model (GLM versus the Artificial Neural Network model (ANN for the estimation of the weights of blue crabs from independent field data. The results indicated the higher performance capacity of the ANN to predict weights compared to the GLM (R=0.97 vs. R=0.95, raw variable when evaluated against independent field data.

  18. Spatial Dynamics of the Blue Crab Spawning Stock in the Gulf of Mexico: Local Processes Driving Regional Patterns.

    Science.gov (United States)

    Darnell, M. Z.

    2016-02-01

    Female blue crabs undertake a critical spawning migration seaward, migrating from low-salinity mating habitat to high-salinity waters of the lower estuaries and coastal ocean, where larval survival is highest. This migration occurs primarily through ebb tide transport, driven by an endogenous circatidal rhythm in vertical swimming that is modulated by behavioral responses to environmental cues. Blue crabs are typically considered an estuarine species and fisheries are managed on a state-by-state basis. Yet recent evidence from state and regional fishery independent survey programs suggests that the spawning migration can take females substantial distances offshore (>150 km), and that offshore waters are important spawning grounds for female blue crabs in the Gulf of Mexico. This is especially true in areas where freshwater inflow is high, resulting in low estuarine and coastal salinities. In low-salinity, high-inflow areas (e.g., Louisiana), spawning occurs further offshore while in high-salinity, low-inflow areas (e.g., South Texas), spawning takes place primarily within the estuary. Regional patterns in spawning locations both inshore and offshore are driven by interactions between behavioral mechanisms and local oceanographic conditions during the spawning migration. These environmentally driven differences in spawning locations have implications for larval survival and population connectivity, and emphasize the need for interjurisdictional assessment and management of the blue crab spawning stock.

  19. The Muskrat. The Not-So-Common Oyster. The Horseshoe Crab. The Blue Crab. Learning Experiences for Coastal and Oceanic Awareness Studies, Nos. 108, 109, 111, 201. [Project COAST].

    Science.gov (United States)

    Delaware Univ., Newark. Coll. of Education.

    Included are four units related to coastal and oceanic awareness. The units are: (1) The Muskrat; (2) The Not-So-Common Oyster; (3) The Horseshoe Crab; and (4) The Blue Crab. All four units are designed for elementary school students. Each unit contains teacher background materials, student activity materials, evaluation materials, transparency…

  20. Comparison of metal concentrations in tissues of blue crab, Callinectes sapidus from Mediterranean Lagoons.

    Science.gov (United States)

    Mutlu, Cengiz; Türkmen, Mustafa; Türkmen, Aysun; Tepe, Yalçın

    2011-09-01

    This study was performed to investigate the metal concentrations in muscle and gill of blue crab, Callinectes sapidus from Dörtyol Lake, Akyatan Lagoon, Paradeniz Lagoon and Çamlık Lagoon from the northeastern coastal area of Mediterranean Sea. So, the levels of cadmium, chromium, copper, iron, manganese, nickel, aluminum and zinc in tissues of specimens from the lagoons were determined by inductively coupled plasma optical emission spectrometer. The metal concentrations found in muscle tissue varied for Cd: 0.03-0.08, Cr: 0.05-0.13, Cu: 5.38-11.7, Fe: 21.1-38.2, Mn: 0.15-2.98, Ni: 0.24-0.45, Zn: 13.9-20.1 and Al: 1.2-13.7 mg/kg wet weight. Iron showed the highest levels in both tissues, and generally followed by zinc except gills. On the other hand, cadmium showed the lowest levels from all sites. Followed cadmium; chromium had the second lowest levels. The differences between mean metal concentrations from different sampling sites were statistically significant. Regional changes in metal concentration were observed in the tissues of the crabs, but these variations may not influence consumption advisories.

  1. Cardiac frequency compensation responses of adult blue crabs exposed to moderate temperature increases

    Energy Technology Data Exchange (ETDEWEB)

    Burton, D.T.; Richardson, L.B.; Moore, C.J.

    1980-01-01

    Cardiac frequency patterns of Callinectes sapidus Rathbun were used to evaluate potential thermal stress after exposure to 5/sup 0/C increases over a range of acclimation temperatures from 5/sup 0/ to 30/sup 0/C. An acclimated rate-temperature curve (R-T curve), acute R-T curves of the stabilized rates at the increased temperatures and Q/sub 10/ temperature coefficients were used to assess the significance of the changes in rate frequency. The acclimated R-T curve showed that blue crabs go through a series of seasonal adaptation types characterized by a plateau of perfect adaptation for both cold and warm adapted organisms. Paradoxical adaptation occurred between the transition from cold to warm acclimation temperatures. The acute R-T curves showed that cardiac frequency was highly responsive to a 5/sup 0/C increase when the organisms were acclimated to low temperatures. The Q/sub 10/'s of the acute R-T curves at the warm acclimation temperatures approximated those values derived for the acclimated R-T curve. This suggests that the temperature increase had a negligible effect on the warm adapted crabs, that is, little or no thermal stress occurred.

  2. Properties of bacteria that trigger hemocytopenia in the Atlantic blue crab, Callinectes sapidus.

    Science.gov (United States)

    Johnson, Nathaniel G; Burnett, Louis E; Burnett, Karen G

    2011-10-01

    In the blue crab Callinectes sapidus, injection with the bacterial pathogen Vibrio campbellii causes a decrease in oxygen consumption. Histological and physiological evidence suggests that the physical obstruction of hemolymph flow through the gill vasculature, caused by aggregations of bacteria and hemocytes, underlies the decrease in aerobic function associated with bacterial infection. We sought to elucidate the bacterial properties sufficient to induce a decrease in circulating hemocytes (hemocytopenia) as an indicator for the initiation of hemocyte aggregation and subsequent impairment of respiration. Lipopolysaccharide (LPS), the primary component of the gram-negative bacterial cell wall, is known to interact with crustacean hemocytes. Purified LPS was covalently bound to the surfaces of polystyrene beads resembling bacteria in size. Injection of these "LPS beads" caused a decrease in circulating hemocytes comparable to that seen with V. campbellii injection, while beads alone failed to do so. These data suggest that in general, gram-negative bacteria could stimulate hemocytopenia. To test this hypothesis, crabs were injected with different bacteria--seven gram-negative and one gram-positive species--and their effects on circulating hemocytes were assessed. With one exception, all gram-negative strains caused decreases in circulating hemocytes, suggesting an important role for LPS in the induction of this response. However, LPS is not necessary to provoke the immune response given that Bacillus coral, a gram-positive species that lacks LPS, caused a decrease in circulating hemocytes. These results suggest that a wide range of bacteria could impair metabolism in C. sapidus.

  3. Changes in ecdysteroids during embryogenesis of the blue crab, callinectes sapidus rathbun

    Energy Technology Data Exchange (ETDEWEB)

    McCarthy, J.F.; Skinner, D.M.

    1979-01-01

    Total ecdysteroid titers (estimated by radioimmunoassay (RIA)) in embryos of the blue crab increased from approx. 6 ng 20-hydroxyecdysone equivalents/g in the immature embryo to a maximum of approx. 500 ng 20-hydroxyecdysone equivalents/g in maturing embryos; titers dropped to approx. 300 ng 20-hydroxyecydsone equivalents/g in prehatch embryos. High-pressure reverse-phase chromatography of the embryo extracts resolved five RIA-active components, ..cap alpha..-Ecdysone and the polar conjugate of 20-hydroxyecdysone were present in low quantities. The concentration of 20-hydroxyecdysone increased during embryogenesis to a maximum of approx. 160 ng/g in maturing embryos and decreased only slightly in the prehatch embryos. Two unidentified components were also detected and the changes in their concentrations were estimated. One, an apolar component (peak III), accounted for as much as 63% of the total RIA activity as the embryos matured. The estimated concentration of this component increased from 85 ng/g in early embryos to 475 ng/g in maturing embryos, then decreased by 50% in the prehatch embryos. The level of the other, more polar component (peak II) increased from 7.5 to 75 ng/g as the embryos developed. The increase in the concentration of ecdysteroids during embryogenesis indicates that crab embryos have the capacity to synthesize ecdysteroids and suggests that these hormones may have a physiological role in the embryonic development of crustaceans.

  4. Association of bioluminescent bacteria from blue swimmer crab Portunus pelagicus (Linneaus, 1758

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    Chinnavenkataraman Govindasamy

    2012-10-01

    Full Text Available Objective: To screen the bioluminescent bacteria from Portunus pelagicus (P. pelagicus at Thondi coast, Palk Strait, Bay of Bengal, India. Methods: Physico-chemical parameter including atmospheric and surfacewater temperature, pH, salinity and dissolved oxygen were analyzed. The population of bioluminescent bacterium was screened in ambient water and blue swimmer crab of P. pelagicus (muscle, gill, hemolymph, shell and colony forming unit (CFU was calculated. Result: Atmospheric and surface water temperatures varied from 26.1 and 27.3 °C to 33.4 and 32.6 °C, respectively; salinity varied from 28.4% to 34.3%, pH varied from 7.6 to 8.6, and dissolved oxygen varied from 4.8 to 6.9 O2 ml/l. In addition, the maximum CFU value was identified (12.63 x104 CFU/ml during postmonsoon season and the minimum level (1.09 x104 CFU/ml identified during summer season. Further, based on the phenotypic characterizations the isolated strain were identified as Vibrio harveyi (V. harveyi. Conclusions: It is concluded from that the incidence of V. harveyi infections was frequently identified with edible crab of P. pelagicus, throughout the study periods in different seasons.

  5. Patterns of juvenile habitat use by the spider crab Maja brachydactyla as revealed by stable isotope analyses

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    Juan Freire

    2009-03-01

    Full Text Available Patterns of habitat use by spider crab juveniles, Maja brachydactyla, from two geographic areas on the NW coast of the Iberian Peninsula were studied through the analysis of carbon and nitrogen stable isotope relations in muscle and hepatopancreas. Main potential preys of spider crab juveniles in rocky and sandy habitats and different organic matter sources in coastal food webs were also analysed. Isotopic ratios showed no difference between rocky and sandy habitats. The use of carapace colour and epibiosis as an indicator of habitat use was not supported by our data. These results suggest that movements between the two habitats are much more frequent than suggested in previous studies. In the coastal food web, two main trophic compartments were identified according to their organic matter source: one based on plankton and seaweeds (rocky habitats, and one based on sedimentary particulate organic matter (sandy bottoms. By means of the model of Phillips and Gregg (2003, it was found that juveniles of Maja brachydactyla from both habitats consumed approximately two thirds of the preys in rocky habitats and one third in sedimentary habitats. The results indicate that in exposed environments large juveniles spend most of the time on sedimentary bottoms, where they find more refuge, moving frequently to nearby rocky substrates to feed.

  6. Silicification of the medial tooth in the blue crab Callinectes sapidus.

    Science.gov (United States)

    Nesbit, Katherine T; Roer, Robert D

    2016-12-01

    Observations of cuticular structures mineralized with silica within the Crustacea have been limited to the opal teeth of copepods, mandibles of amphipods, and recently the teeth of the gastric mill in the blue crab Callinectes sapidus. Copepod teeth are deposited during premolt, with sequential elaboration of organic materials followed by secretion of silica into the tooth mold. The timing of mineralization is in stark contrast to that of the general integument of crustaceans in which calcification is completely restricted to the postmolt period. To determine the timing of molt-related deposition and silicification of the teeth of the gastric mill, the medial tooth of the blue crab C. sapidus was examined histologically and ultrastructurally across the molt cycle. Histological data revealed deposition of the organic matrix of the epicuticle and exocuticle during premolt. No evidence of postmolt changes in the thickness of the epicuticle and exocuticle, or any deposition of endocuticle, was observed. Scanning electron microscopy revealed degradation of the outer surface of the old tooth during premolt. During premolt, epithelial structures resembling papilla appeared to secrete a fibrous web that coalesces to become the matrix of the new tooth. Semi-quantitative elemental analyses indicated simultaneous deposition of silica and organic matrix, and demonstrated a homogeneous distribution of silicon throughout the epicuticle of the tooth at all stages. However, there is evidence of deposition (presumably silicification) during postmolt as spaces between the papillae become filled in. Thus, the pattern and timing of deposition and silicification of the tooth are different from both teeth of copepods and the general exoskeleton of decapods, and may facilitate rapid resumption of feeding and consumption of the exuvia in early postmolt. J. Morphol. 277:1648-1660, 2016. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

  7. The Involvement of Hemocyte Prophenoloxidase in the Shell-Hardening Process of the Blue Crab, Callinectes sapidus.

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    Javier V Alvarez

    Full Text Available Cuticular structures of arthropods undergo dramatic molt-related changes from being soft to becoming hard. The shell-hardening process of decapod crustaceans includes sclerotization and mineralization. Hemocyte PPO plays a central role in melanization and sclerotization particularly in wound healing in crustaceans. However, little is known about its role in the crustacean initial shell-hardening process. The earlier findings of the aggregation of heavily granulated hemocytes beneath the hypodermis during ecdysis imply that the hemocytes may be involved in the shell-hardening process. In order to determine if hemocytes and hemocyte PPO have a role in the shell-hardening of crustaceans, a knockdown study using specific CasPPO-hemo-dsRNA was carried out with juvenile blue crabs, Callinectes sapidus. Multiple injections of CasPPO-hemo-dsRNA reduce specifically the levels of CasPPO-hemo expression by 57% and PO activity by 54% in hemocyte lysate at the postmolt, while they have no effect on the total hemocyte numbers. Immunocytochemistry and flow cytometry analysis using a specific antiserum generated against CasPPO show granulocytes, semigranulocytes and hyaline cells as the cellular sources for PPO at the postmolt. Interestingly, the type of hemocytes, as the cellular sources of PPO, varies by molt stage. The granulocytes always contain PPO throughout the molt cycle. However, semigranulocytes and hyaline cells become CasPPO immune-positive only at early premolt and postmolt, indicating that PPO expression in these cells may be involved in the shell-hardening process of C. sapidus.

  8. The Involvement of Hemocyte Prophenoloxidase in the Shell-Hardening Process of the Blue Crab, Callinectes sapidus.

    Science.gov (United States)

    Alvarez, Javier V; Chung, J Sook

    2015-01-01

    Cuticular structures of arthropods undergo dramatic molt-related changes from being soft to becoming hard. The shell-hardening process of decapod crustaceans includes sclerotization and mineralization. Hemocyte PPO plays a central role in melanization and sclerotization particularly in wound healing in crustaceans. However, little is known about its role in the crustacean initial shell-hardening process. The earlier findings of the aggregation of heavily granulated hemocytes beneath the hypodermis during ecdysis imply that the hemocytes may be involved in the shell-hardening process. In order to determine if hemocytes and hemocyte PPO have a role in the shell-hardening of crustaceans, a knockdown study using specific CasPPO-hemo-dsRNA was carried out with juvenile blue crabs, Callinectes sapidus. Multiple injections of CasPPO-hemo-dsRNA reduce specifically the levels of CasPPO-hemo expression by 57% and PO activity by 54% in hemocyte lysate at the postmolt, while they have no effect on the total hemocyte numbers. Immunocytochemistry and flow cytometry analysis using a specific antiserum generated against CasPPO show granulocytes, semigranulocytes and hyaline cells as the cellular sources for PPO at the postmolt. Interestingly, the type of hemocytes, as the cellular sources of PPO, varies by molt stage. The granulocytes always contain PPO throughout the molt cycle. However, semigranulocytes and hyaline cells become CasPPO immune-positive only at early premolt and postmolt, indicating that PPO expression in these cells may be involved in the shell-hardening process of C. sapidus.

  9. Respiratory, acid-base, and metabolic responses of the Christmas Island blue crab, Cardisoma hirtipes (Dana), during simulated environmental conditions.

    Science.gov (United States)

    Dela-Cruz, J; Morris, S

    1997-01-01

    The dependency of the Christmas Island blue crab, Cardisoma hirtipes, on fresh water for respiratory gas exchange and transport was investigated in laboratory simulations. The gas exchange rates of air-breathing C. hirtipes were similar to those of other land crabs but decreased to 20% in submerged crabs. Crabs with access to air maintained arterial and pulmonary O2 content (CO2) and partial pressure (PO2), while in submerged crabs the PO2 and CO2 rapidly decreased (by 50%). There was no anaerobiosis, but haemolymph glucose concentration and cardiac output decreased when crabs were submersed, which suggests a hypometabolic state. Submersion induced a metabolic rather than a respiratory alkalosis, and since respiratory gas exchange was low, CO2 excretion to water was unimportant. Cardisoma hirtipes haemocyanin (Hc) has high O2 affinity but low pH sensitivity, which facilitates O2 uptake from hypoxic environments. The high Hc-O2 affinity supports O2 loading but may prevent access to a venous O2 reserve. Calcium, magnesium, and urate, but not L-lactate, were effectors of Hc-O2 affinity. In submerged crabs increased circulating urate maintained haemolymph O2 content. The CO2 capacitance and nonbicarbonate buffering of the haemolymph were relatively low. A significant Haldane effect seemed important for CO2 excretion but would require CO2 and O2 exchange to occur at the same organ (gills or lungs). Submersion interferes with respiration and is not needed for haemolymph acid-base balance; thus; C. hirtipes is an air-breathing crab.

  10. Induced thermal stress on serotonin levels in the blue swimmer crab, Portunus pelagicus

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    Saravanan Rajendiran

    2016-03-01

    Full Text Available The temperature of habitat water has a drastic influence on the behavioral, physiological and biochemical mechanisms of crustaceans. Hyperglycemia is a typical response of many aquatic animals to harmful physical and chemical environmental changes. In crustaceans increased circulating crustacean hyperglycemic hormone (CHH and hyperglycemia are reported to occur following exposure to several environmental stress. The biogenic amine, serotonin has been found to modulate the CHH levels and oxidation of serotonin into its metabolites is catalysed by monoamine oxidase. The blue swimmer crab, Portunus pelagicus is a dominant intertidal species utilized throughout the indo-pacific region and is a particularly important species of Palk bay. It has high nutritional value and delicious taste and hence their requirements of capture and cultivation of this species are constantly increasing. This species experiences varying and increasing temperature levels as it resides in an higher intertidal zone of Thondi coast. The present study examines the effect of thermal stress on the levels of serotonin and crustacean hyperglycemic hormone in the hemolymph of P. pelagicus and analyzes the effect of the monoamine oxidase inhibitor, pargyline on serotonin and CHH level after thermal stress. The results showed increased levels of glucose, CHH and serotonin on exposure to 26 °C in control animals. Pargyline injected crabs showed highly significant increase in the levels of CHH and serotonin on every 2 °C increase or decrease in temperature. A greater CHH level of 268.86±2.87 fmol/ml and a greater serotonin level of 177.69±10.10 ng/ml was observed at 24 °C. This could be due to the effect of in maintaining the level of serotonin in the hemolymph and preventing its oxidation, which in turn induces hyperglycemia by releasing CHH into hemolymph. Thus, the study demonstrates the effect of thermal stress on the hemolymph metabolites studied and the role of

  11. Primary structure and tissue-specific expression of blue crab (Callinectes sapidus) metallothionein isoforms.

    Science.gov (United States)

    Brouwer, M; Enghild, J; Hoexum-Brouwer, T; Thogersen, I; Truncali, A

    1995-01-01

    In aquatic animals, synthesis of the metal-binding protein metallothionein (MT) can be induced through exposure to elevated levels of metals in food or water. Whether the different routes of exposure lead to expression of different metallothionein isoforms in different tissues in unknown. In this study we examined the induction of metallothionein isoforms in the hepatopancreas and gills of the blue crab Callinectes sapidus. When blue crabs are exposed to cadmium in their diet, the metal accumulates in the hepatopancreas. Size-exclusion and anion-exchange chromatography show the presence of five low-molecular-mass cadmium-binding proteins. All of the observed cadmium-binding proteins belong to the class I MT family. They are designated as MT-Ia, MT-Ib, MT-Ic, MT-IIa and MT-IIb. All purified proteins run as single peaks upon rechromatography on anion-exchange HPLC, except for MT-Ic, which segregates into two peaks corresponding to MT-Ia and MT-Ic. The amino acid sequence of MT-Ia and MT-Ic is identical. MT-Ib differs from MT-Ia and MT-Ic only in having an extra N-terminal methionine. The 18 cysteine residues in MT-Ia and MT-IIa occur in identical positions; however, of the remaining 40 amino acids, 15 are found to be different. MT-IIb is identical with MT-IIa, except for an extra methionine residue at its N-terminal position. It appears therefore that, of the five observed CdMTs, only two are the products of distinct genes. CdMT-Ia and -IIa are posttranslationally modified forms of Ib and IIb, respectively, and CdMT-Ia and -Ic appear to be conformational isomers. Cadmium-induced expression of the two genes is tissue-specific. When crabs are exposed to cadmium in water, the metal accumulates in the gills, where it is bound to MT-II. MT-I is virtually absent. PMID:7487904

  12. The identification and structure-activity relations of a cardioactive FMRFamide-related peptide from the blue crab Callinectes sapidus.

    Science.gov (United States)

    Krajniak, K G

    1991-01-01

    The pericardial organs and thoracic ganglia of the blue crab Callinectes sapidus were resected and extracted. The extracts were fractionated by HPLC and the fractions analyzed by a radioimmunoassay (RIA) to FMRFamide. Multiple peaks of immunoreactivity were present and one of these, upon fast atom bombardment mass spectrometry (FAB-ms) and microsequencing, yielded the sequence GYNRSFLRFamide. The amount of this peptide in each crab is between 7 and 13 pmol. Several incomplete sequences were also characterized, suggesting a precursor with multiple copies of peptides related to GYNRSFLRFamide might occur. The peptide caused a dose-dependent increase in heart rate; threshold was 10 to 30 nM, and the EC50 was 323 +/- 62 nM. A structure-activity study of GYNRSFLRFamide on the crab heart suggests that, for full potency, a peptide should be at least a heptapeptide with the sequence XXZFLRFamide, where X is any amino acid and Z is either asparagine or serine.

  13. Clearance of Vibrio campbellii injected into the hemolymph of Callinectes sapidus, the Atlantic blue crab: the effects of prior exposure to bacteria and environmental hypoxia.

    Science.gov (United States)

    Macey, Brett M; Rathburn, Charles K; Thibodeaux, Lindy K; Burnett, Louis E; Burnett, Karen G

    2008-12-01

    The Atlantic blue crab, Callinectes sapidus (Rathbun), lives in a bacteria-rich environment that experiences daily fluctuations in water quality. In the present study, we tested the hypothesis that crustaceans with prior or ongoing exposure to bacteria in their hemolymph have an increased susceptibility to subsequent infections, and that acute exposure to low dissolved oxygen (hypoxia) and elevated carbon dioxide levels (hypercapnia) may further confound the ability of blue crabs to counter a subsequent infection. Adult male blue crabs held in well-aerated (normoxic; P O2=20.7 kPA; CO(2)sapidus to a second, sublethal dose of V. campbellii. In fact, a recent exposure to V. campbellii enhances the ability of blue crabs to render bacteria non-culturable and the immune mechanisms/effectors responsible for this are short lived and appear to be sensitive to low dissolved oxygen and high carbon dioxide concentrations in the environment.

  14. Occurrence of the blue crab Callinectes sapidus, Rathbun, 1896, and its fisheries biology in Bardawil Lagoon, Sinai Peninsula, Egypt

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    Fatma A. Abdel Razek

    2016-06-01

    Full Text Available This study reports the yearly occurrence and the biology of fisheries belonging to the blue crab Callinectes sapidus (Rath. in the catch yield of Bardawil Lagoon (BL in Sinai Peninsula, Egypt over the past 15 years. The study shows that between the years 2000–2015 the crustacean fishery increased (pooling both shrimp and crabs with fluctuations from 40% to 63% of the total production of the lagoon. The crab yield, during this period, increased from 19% to 42% of the total lagoon production. Moreover, the results show that the crab catch of BL is composed mainly of two crab species Portunus pelagicus (L. and C. sapidus (Rath.. The latter is considered the most dominant in the crab yield with 85% of the total crab production, while C. sapidus is only 15%. The size of C. sapidus ranged between 65 and 155 mm (carapace width with a dominance of the class size 105 mm. Furthermore, the ratio of C. sapidus males to females was in favor of males. The regression of width–length relationship showed a marked deviation from the isometric growth. Length–width and body weight regressions also showed deviations from the isometric growth and the analysis of the covariance. This indicates the significant difference between sexes in respect to length weight relationship. The interrelationships between width–length and propodus length and depth of males and with abdomen in females of C. sapidus suggested that in most conditions the relationships were positive and highly significant. This study shows the first insights on the status of C. sapidus in Bardawil Lagoon, Egypt.

  15. The Effects of Acute Copper and Ammonia Challenges on Ammonia and Urea Excretion by the Blue Crab Callinectes sapidus.

    Science.gov (United States)

    Zimmer, Alex M; Jorge, Marianna Basso; Wood, Chris M; Martins, Camila M G; Bianchini, Adalto

    2017-04-01

    Copper (Cu) is a persistent environmental contaminant that elicits several physiological disturbances in aquatic organisms, including a disruption in ammonia regulation. We hypothesized that exposure to Cu in a model crustacean (blue crab, Callinectes sapidus) acclimated to brackish water (2 ppt) would lead to hyperammonemia by stimulating an increase in ammonia production and/or by inhibiting ammonia excretion. We further hypothesized that urea production would represent an ammonia detoxification strategy in response to Cu. In a pilot experiment, exposure to 0, 100, and 200 µg/L Cu for 6 h caused significant concentration-dependent increases in ammonia excretion (J amm). Based on these results, an acute 24-h 100 µg/L Cu exposure was conducted and this similarly caused an overall stimulation of J amm during the 24-h period, indicative of an increase in ammonia production. Terminal haemolymph total ammonia content (T amm) was unchanged, suggesting that while ammonia production was increased, there was no inhibition of the excretion mechanism. In support of our second hypothesis, urea excretion (J urea) increased in response to Cu exposure; haemolymph [urea] was unaffected. This suggested that urea production also was increased. To further test the hypothesis that J urea increased to prevent hyperammonemia during Cu exposure, crabs were exposed to high environmental ammonia (HEA; 2.5 mmol/L NH4HCO3) for 12 h in a separate experiment. This led to a fourfold increase in haemolymph T amm, whereas J urea increased only transiently and haemolymph [urea] was unchanged, indicating that urea production likely does not contribute to the attenuation of hyperammonemia in blue crabs. Overall, Cu exposure in blue crabs led to increased ammonia and urea production, which were both eliminated by excretion. These results may have important implications in aquaculture systems where crabs may be exposed to elevated Cu and/or ammonia.

  16. Prevalence, serovars, and antimicrobial susceptibility of Salmonella isolated from blue land crabs (Cardisoma guanhumi) in Grenada, West Indies.

    Science.gov (United States)

    Peterson, Ross; Hariharan, Harry; Matthew, Vanessa; Chappell, Sam; Davies, Rob; Parker, Regina; Sharma, Andravindra

    2013-07-01

    Samples of intestine and hepatopancreas from 65 blue land crabs (Cardisoma guanhumi), a crustacean commonly consumed as a food item in Grenada, were collected from six geographic sites in Grenada and tested for Salmonella by enrichment and selective culture. The individual animal prevalence of Salmonella based on isolation was 17% (11 of 65), and all infected crabs were from three of the six sampled locations. Isolates were identified by serotyping as Salmonella enterica serovars Saintpaul (n = 6), Montevideo (n = 4), and Newport (n = 1). The intestines of all 11 infected crabs were positive for Salmonella, but only 7 of 11 hepatopancreas samples were positive for Salmonella, and these isolates were the same serovar as isolated from the matching intestine. These three Salmonella serovars are known to cause human illness in many countries, and in the Caribbean Salmonella Saintpaul has been frequently isolated from humans. In a disc diffusion assay, all isolates were susceptible to all 11 drugs tested: amoxicillin-clavulanic acid, ampicillin, cephalothin, chloramphenicol, ciprofloxacin, gentamicin, imipenem, neomycin, streptomycin, tetracycline, and trimethoprim-sulfamethoxazole. To our knowledge, this report is the first concerning isolation and antimicrobial susceptibilities of Salmonella serotypes from the blue land crab.

  17. Acute toxicity, histopathology, and bioconcentration-retention studies with No. 2 fuel oil and the blue crab, Callinectes sapidus Rathbun

    Energy Technology Data Exchange (ETDEWEB)

    Melzian, B.D.

    1982-01-01

    Adult male blue crabs (Callinectes sapidus Rathbun) were exposed in a flow-through system to five concentrations, nominally 0.0 (control), 1.0, 5.0, 10.0, or 20.0 ppm of the water accommodated fraction (WAF) of No. 2 fuel oil. The 96-hour LC/sub 5//sup 0/ was 14.1 ppm. All crabs in the 5.0, 10.0, and 20.0 ppm tanks exhibited abnormal behavior prior to death including periodic beating of the maxillipedal flagella, hyperactivity, ataxia, and equilibrium loss. The ability of adult male and female blue crabs to bioconcentrate and retain No. 2 fuel oil compounds was examined after crabs were exposed for two weeks or 30-35 days in flow-through systems to three sublethal No. 2 fuel oil WAF concentrations, nominally 0.00 (control), 0.01, or 1.0 ppm. Gill, hepatopancreas, and muscle tissues were analyzed by gas chromatography/mass spectrometry. Trace amounts of fuel oil hydrocarbons were detected in gill and hepatopancreas at 0.01 ppm exposures. All tissues bioconcentrated fuel oil compounds during 1.0 ppm WAF exposure periods, and with the exception of the gills, little depuration or metabolism of the bioconcentrated compounds occurred during a period of 30 days in clean, running seawater.

  18. Heavy Metals in the Blue Crab (Callinectes sapidus) in Mersin Bay, Turkey.

    Science.gov (United States)

    Çoğun, H Y; Firat, Ö; Aytekin, T; Firidin, G; Firat, Ö; Varkal, H; Temiz, Ö; Kargin, F

    2017-06-01

    The concentrations of four metals (copper, cadmium, zinc and lead) were quantified in blue crabs (Callinectes sapidus) tissues collected in January, April, June and September at two stations in Mersin Bay, northeastern Mediterranean Sea, using ICP-MS. The metal concentrations in crabs from the two stations differed significantly. The hepatopancreas was the major organ accumulating metals, followed by gill and muscle tissues. Except for lead, the highest concentrations of metals were measured in the hepatopancreas. The hepatopancreas had higher concentrations of all heavy metals (Cu 321.1 ± 4.30; Zn 182.2 ± 3.40; Cd 48.2 ± 2.00) compared to gill (Cu 90.2 ± 1.35; Zn 104.3 ± 2.30; Cd 22.3 ± 3.40) and muscle (Cu 19.1 ± 1.10; Zn 55.1 ± 3.25; Cd 2.5 ± 0.20). Among the metals analyzed, Cu, Zn and Pb were the most abundant in the different tissues while Cd was the least abundant in C. sapidus. Seasonality in the levels of the four metals was determined.The highest concentrations of all metals were observed in the June (Zn 55.1 ± 3.25; Cu 19.1 ± 1.10; Cd 2.5 ± 0.20; Pb 5.1 ± 0.18) compared to all other months (Zn 34.1 ± 3.23; Cu 11.1 ± 1.15; Cd 0.9 ± 0.20; Pb 3.1 ± 0.21).

  19. Parasitization of juvenile edible crabs (Cancer pagurus) by the dinoflagellate, Hematodinium sp.: pathobiology, seasonality and its potential effects on commercial fisheries.

    Science.gov (United States)

    Smith, Amanda L; Hirschle, Lucy; Vogan, Claire L; Rowley, Andrew F

    2015-03-01

    This study reports on the prevalence and severity of infections caused by the parasitic dinoflagellate, Hematodinium in juvenile edible crabs (Cancer pagurus) found in 2 intertidal survey sites (Mumbles Head and Oxwich Bay) in the Bristol Channel, UK. Crabs were assessed for the presence and severity of Hematodinium infections by the histological examination of infected tissues. Such infections were found to exhibit a seasonal trend in the 2 study areas with high numbers of animals (ca. 30%) infected in the spring to summer but with low severity. Conversely, in November only ca. 10% of crabs were infected but these animals had large numbers of parasites in their haemolymph and other tissues. At this time, the carapace and underlying tissues of infected crabs had the chalky, pinkish-orange appearance that is characteristic of this disease. Hematodinium-infected crabs ranged in size from 12 to 74 mm carapace width. Overall, it is concluded that the high prevalence of infection of juvenile crabs in this area may have implications for the sustainability of the edible crab fishery in the Bristol Channel.

  20. BIOCHEMICAL AND ULTRASTRUCTURAL ASPECTS OF CA2+ TRANSPORT BY MITOCHONDRIA OF THE HEPATOPANCREAS OF THE BLUE CRAB CALLINECTES SAPIDUS

    Science.gov (United States)

    Chen, Chung-Ho; Greenawalt, John W.; Lehninger, Albert L.

    1974-01-01

    Mitochondria isolated from the hepatopancreas of the blue crab Callinectes sapidus show up to 12-fold stimulation of respiration on addition of Ca2+, which is accompanied by Ca2+ accumulation (Ca2+:site = 1.9) and H+ ejection (H+:Ca2+ = 0.85). Sr2+ and Mn2+ are also accumulated; Mg2+ is not. A strongly hypertonic medium (383 mosM), Mg2+, and phosphate are required for maximal Ca2+ uptake. Ca2+ uptake takes precedence over oxidative phosphorylation of ADP for respiratory energy. Once Ca2+ is accumulated by the crab mitochondria, it is stable and only very slowly released, even by uncoupling agents. ATP hydrolysis also supports Ca2+ uptake. Respiration-inhibited crab hepatopancreas mitochondria show both high-affinity and low-affinity Ca2+-binding sites, which are inactive in the presence of uncoupling agents. Crab hepatopancreas mitochondria have an enormous capacity for accumulation of Ca2+, up to 5,500 ng-atoms Ca2+ per mg protein, with an equivalent amount of phosphate. Freshly isolated mitochondria contain very large amounts of Ca2+, Mg2+, phosphate, K+, and Na+; their high Ca2+ content is a reflection of the vary large amount of extra-mitochondrial Ca2+ in the whole tissue. Electron microscopy of crab mitochondria loaded with Ca2+ and phosphate showed large electron-dense deposits, presumably of precipitated calcium phosphate. They consisted of bundles of needle-like crystals, whereas Ca2+-loaded rat liver mitochondria show only amorphous deposits of calcium phosphate under similar conditions. The very pronounced capacity of crab hepatopancreas mitochondria for transport of Ca2+ appears to be adapted to a role in the storage and release of Ca2+ during the molting cycle of this crustacean. PMID:4827906

  1. Biochemical and ultrastructural aspects of Ca2+ transport by mitochondria of the hepatopancreas of the blue crab Callinectes sapidus.

    Science.gov (United States)

    Chen, C H; Greenawalt, J W; Lehninger, A L

    1974-05-01

    Mitochondria isolated from the hepatopancreas of the blue crab Callinectes sapidus show up to 12-fold stimulation of respiration on addition of Ca(2+), which is accompanied by Ca(2+) accumulation (Ca(2+):site = 1.9) and H(+) ejection (H(+):Ca(2+) = 0.85). Sr(2+) and Mn(2+) are also accumulated; Mg(2+) is not. A strongly hypertonic medium (383 mosM), Mg(2+), and phosphate are required for maximal Ca(2+) uptake. Ca(2+) uptake takes precedence over oxidative phosphorylation of ADP for respiratory energy. Once Ca(2+) is accumulated by the crab mitochondria, it is stable and only very slowly released, even by uncoupling agents. ATP hydrolysis also supports Ca(2+) uptake. Respiration-inhibited crab hepatopancreas mitochondria show both high-affinity and low-affinity Ca(2+)-binding sites, which are inactive in the presence of uncoupling agents. Crab hepatopancreas mitochondria have an enormous capacity for accumulation of Ca(2+), up to 5,500 ng-atoms Ca(2+) per mg protein, with an equivalent amount of phosphate. Freshly isolated mitochondria contain very large amounts of Ca(2+), Mg(2+), phosphate, K(+), and Na(+); their high Ca(2+) content is a reflection of the vary large amount of extra-mitochondrial Ca(2+) in the whole tissue. Electron microscopy of crab mitochondria loaded with Ca(2+) and phosphate showed large electron-dense deposits, presumably of precipitated calcium phosphate. They consisted of bundles of needle-like crystals, whereas Ca(2+)-loaded rat liver mitochondria show only amorphous deposits of calcium phosphate under similar conditions. The very pronounced capacity of crab hepatopancreas mitochondria for transport of Ca(2+) appears to be adapted to a role in the storage and release of Ca(2+) during the molting cycle of this crustacean.

  2. Evaluation of Blue Crab, Callinectes sapidus, Megalopal Settlement and Condition during the Deepwater Horizon Oil Spill.

    Directory of Open Access Journals (Sweden)

    Erin K Grey

    Full Text Available The Blue Crab, Callinectes sapidus, is a commercially, culturally, and ecologically significant species in the Gulf of Mexico (GOM, whose offshore stages were likely impacted by the Deepwater Horizon oil spill (DWH. To test for DWH effects and to better understand the planktonic ecology of this species, we monitored Callinectes spp. megalopal settlement and condition at sites within and outside of the spill extent during and one year after the DWH. We tested for DWH effects by comparing 2010 settlement against baseline data available for two sites, and by testing for differences in settlement and condition inside and outside of the spill extent. We also developed time series models to better understand natural drivers of daily settlement variation (seasonal and lunar trends, hydrodynamics, wind during 2010 and 2011. Overall, we found that neither megalopal settlement nor body weight were significantly reduced at oiled sites, but that high unexplained variation and low statistical power made detection of even large effects unlikely. Time series models revealed remarkably consistent and relatively strong seasonal and lunar trends within sites (explaining on average 28% and 9% of variation, respectively, while wind and hydrodynamic effects were weak (1-5% variation explained and variable among sites. This study provides insights into DWH impacts as well as the natural drivers of Callinectes spp. megalopal settlement across the northern GOM.

  3. Evaluation of Blue Crab, Callinectes sapidus, Megalopal Settlement and Condition during the Deepwater Horizon Oil Spill.

    Science.gov (United States)

    Grey, Erin K; Chiasson, Susan C; Williams, Hannah G; Troeger, Victoria J; Taylor, Caz M

    2015-01-01

    The Blue Crab, Callinectes sapidus, is a commercially, culturally, and ecologically significant species in the Gulf of Mexico (GOM), whose offshore stages were likely impacted by the Deepwater Horizon oil spill (DWH). To test for DWH effects and to better understand the planktonic ecology of this species, we monitored Callinectes spp. megalopal settlement and condition at sites within and outside of the spill extent during and one year after the DWH. We tested for DWH effects by comparing 2010 settlement against baseline data available for two sites, and by testing for differences in settlement and condition inside and outside of the spill extent. We also developed time series models to better understand natural drivers of daily settlement variation (seasonal and lunar trends, hydrodynamics, wind) during 2010 and 2011. Overall, we found that neither megalopal settlement nor body weight were significantly reduced at oiled sites, but that high unexplained variation and low statistical power made detection of even large effects unlikely. Time series models revealed remarkably consistent and relatively strong seasonal and lunar trends within sites (explaining on average 28% and 9% of variation, respectively), while wind and hydrodynamic effects were weak (1-5% variation explained) and variable among sites. This study provides insights into DWH impacts as well as the natural drivers of Callinectes spp. megalopal settlement across the northern GOM.

  4. Ultrastructure, Histochemistry, and Mineralization Patterns in the Ecdysial Suture of the Blue Crab, Callinectes sapidus

    Science.gov (United States)

    Priester, Carolina; Dillaman, Richard M.; Gay, D. Mark

    2005-12-01

    The ecdysial suture is the region of the arthropod exoskeleton that splits to allow the animal to emerge during ecdysis. We examined the morphology and composition of the intermolt and premolt suture of the blue crab using light microscopy and scanning electron microscopy. The suture could not be identified by routine histological techniques; however 3 of 22 fluorescein isothiocyanate-labeled lectins tested (Lens culinaris agglutinin, Vicia faba agglutinin, and Pisum sativum agglutinin) differentiated the suture, binding more intensely to the suture exocuticle and less intensely to the suture endocuticle. Back-scattered electron (BSE) and secondary electron observations of fracture surfaces of intermolt cuticle showed less mineralized regions in the wedge-shaped suture as did BSE analysis of premolt and intermolt resin-embedded cuticle. The prism regions of the suture exocuticle were not calcified. X-ray microanalysis of both the endocuticle and exocuticle demonstrated that the suture was less calcified than the surrounding cuticle with significantly lower magnesium and phosphorus concentrations, potentially making its mineral more soluble. The presence or absence of a glycoprotein in the organic matrix, the extent and composition of the mineral deposited, and the thickness of the cuticle all likely contribute to the suture being removed by molting fluid, thereby ensuring successful ecdysis.

  5. TURNING WASTE INTO USABLE PRODUCTS: A CASE STUDY OF EXTRACTING CHITOSAN FROM BLUE CRAB

    Directory of Open Access Journals (Sweden)

    Camille Webster

    2014-01-01

    Full Text Available The purpose of this project was to develop a practical and cost efficient alternative to the current disposal of seafood waste in the North Florida region. Fortuitously, due to an unusually high turnover rate, this reconceptualization study may have turned seafood waste into a hot commodity. At least that is one conclusion one can draw from these findings. Indeed, over the past decades, under the pressure of volume and environmental concerns, Blue Crab (Callinectes sapidus Rathbun waste, usually considered a nuisance in North Florida, has seen a historical shift in its disposal and utilization. From the 10 million lbs generated in the region last year, almost 30%, compared to 10% the year before, has been processed into usable products. These products have found use in biotechnology, food, biomedical and environmental and agricultural industries. The latter was mainly processed in the form of chitosan, a chemical known to promote seed germination and control economically destructive fungal diseases. This reconceptualization of seafood waste could represent a new market or economic opportunity for limited-land owners in coastal areas all over the world.

  6. Extraction and Characterization of Chitin and Chitosan from Blue Crab and Synthesis of Chitosan Cryogel Scaffolds

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    Nimet Bölgen

    2016-08-01

    Full Text Available Polymeric scaffolds produced by cryogelation technique have attracted increasing attention for tissue engineering applications. Cryogelation is a technique which enables to produce interconnected porous matrices from the frozen reaction mixtures of polymers or monomeric precursors. Chitosan is a biocompatible, biodegradable, nontoxic, antibacterial, antioxidant and antifungal natural polymer that is obtained by deacetylation of chitin, which is mostly found in the exoskeleton of many crustacean. In this study, chitin was isolated from the exoskeleton of blue crap (Callinectes sapidus using a chemical method. Callinectes sapidus samples were collected from a market, as a waste material after it has been consumed as food. Demineralization, deproteinization and decolorization steps were applied to the samples to obtain chitin. Chitosan was prepared from isolated chitin by deacetylation at high temperatures. The chemical compositon of crab shell, extracted chitin and chitosan were characterized with FTIR analyses. And also to determine the physicochemical and functional properties of the produced chitosan; solubility, water binding and fat binding analysis were performed. Chitosan cryogel scaffolds were prepared by crosslinking reaction at cryogenic conditions at constant amount of chitosan (1%, w/v with different ratios of glutaraldehyde (1, 3, and 6%, v/v as crosslinker. The chemical structure of the scaffolds were examined by FTIR. Also, the water uptake capacity of scaffolds have been determined. Collectively, the results suggested that the characterized chitosan cryogels can be potential scaffolds to be used in tissue engineering applications.

  7. Mercury (Hg2+) effect on enzyme activities and hepatopancreas histostructures of juvenile Chinese mitten crab Eriocheir sinensis

    Science.gov (United States)

    Zhao, Yanmin; Wang, Xinhua; Qin, Yanwen; Zheng, Binghui

    2010-05-01

    We studied the effects of mercury (Hg2+) on antioxidant and digestive enzyme activities in terms of LC50 value and on hepatopancreas histostructures of juvenile Chinese mitten crabs Eriocheir sinensis in 40-day exposure to various concentrations of Hg2+ (0, 0.01, 0.05, 0.10, 0.20, and 0.30 mg/L). The results show that the activities of superoxide dismutase (SOD), glutathione peroxidase (GPX) and catalase (CAT) significantly increased in the concentrations of 0.01 and 0.05 mg/L, while that of enzyme decreased in 0.10, 0.20 and 0.30 mg/L treatments. Meanwhile, Hg2+ disrupted the histostructures of the hepatopancreas, causing decreases in activities of pepsin, tryptase, amylase, and cellulose, which are synthesized in the hepatopancreas. Moreover, as the Hg2+ concentration increased, the survival rate of the crabs decreased, worst at 56.57% in 0.30 mg/L. Therefore, although crabs are able to tolerate low levels of mercury pollution, high levels lead to cellular injury and tissue damage in hepatopancreas, which then loses some of its vital physiological functions such as absorption, storage, and secretion.

  8. Calcium phosphate granules in the hepatopancreas of the blue crab Callinectes sapidus.

    Science.gov (United States)

    Becker, G L; Chen, C H; Greenawalt, J W; Lehninger, A L

    1974-05-01

    The hepatopancreas of the adult male blue crab Callinectes sapidus in intermolt was found to contain substantial amounts of calcium, magnesium, and inorganic phosphorus, averaging about 260, 20, and 250 microg-atoms per g wet tissue, respectively, accounting for over 10% of the tissue dry weight. Electron microscopy of the intact tissue showed three qualitatively different granular structures having electron densities suggestive of high mineral content. After fractionation of the tissue using centrifugal techniques, almost 95% of the total mineral was found to reside in a heavy, nonmitochondrial particulate fraction(s). The bulk of the low-speed pellet consisted of relatively dense, roughly spherical granules 1-5 microm in diameter, which could be considerably purified by repeated suspension in water and low-speed sedimentation. In the electron microscope the isolated granules appeared basically similar to one of the three characteristic types of electron-dense granules seen in the intact tissue. Although the freshly isolated granules lost approximately 50% of their wet weight when dried at 105 degrees C, only 10% more was lost upon dry ashing at 450 degrees C, suggesting a fairly low content of organic material. Chemical analysis revealed calcium, magnesium, and inorganic phosphate at 5.7, 2.1, and 4.4 microg-atoms per mg dried granules, respectively, accounting for 69% of the dry weight of the fraction. By specific enzymatic assays, the freshly isolated granules were found to contain ATP, ADP, and AMP at levels of 0.13, 0.03, and 0.01 micromol/mg, or 8% of their total dry weight. The remainder of the total phosphorus contributed an additional 3%, whereas carbonate, citrate, oxalate, and protein each constituted no more than 1%. The mineral granules of the crab hepatopancreas appear to function as storage forms of calcium and phosphate during the intermolt period. This tissue appears promising as a model for study of the cellular events associated with biological

  9. CALCIUM PHOSPHATE GRANULES IN THE HEPATOPANCREAS OF THE BLUE CRAB CALLINECTES SAPIDUS

    Science.gov (United States)

    Becker, Gerald L.; Chen, Chung-Ho; Greenawalt, John W.; Lehninger, Albert L.

    1974-01-01

    The hepatopancreas of the adult male blue crab Callinectes sapidus in intermolt was found to contain substantial amounts of calcium, magnesium, and inorganic phosphorus, averaging about 260, 20, and 250 µg-atoms per g wet tissue, respectively, accounting for over 10% of the tissue dry weight. Electron microscopy of the intact tissue showed three qualitatively different granular structures having electron densities suggestive of high mineral content. After fractionation of the tissue using centrifugal techniques, almost 95% of the total mineral was found to reside in a heavy, nonmitochondrial particulate fraction(s). The bulk of the low-speed pellet consisted of relatively dense, roughly spherical granules 1–5 µm in diameter, which could be considerably purified by repeated suspension in water and low-speed sedimentation. In the electron microscope the isolated granules appeared basically similar to one of the three characteristic types of electron-dense granules seen in the intact tissue. Although the freshly isolated granules lost approximately 50% of their wet weight when dried at 105°C, only 10% more was lost upon dry ashing at 450°C, suggesting a fairly low content of organic material. Chemical analysis revealed calcium, magnesium, and inorganic phosphate at 5.7, 2.1, and 4.4 µg-atoms per mg dried granules, respectively, accounting for 69% of the dry weight of the fraction. By specific enzymatic assays, the freshly isolated granules were found to contain ATP, ADP, and AMP at levels of 0.13, 0.03, and 0.01 µmol/mg, or 8% of their total dry weight. The remainder of the total phosphorus contributed an additional 3%, whereas carbonate, citrate, oxalate, and protein each constituted no more than 1%. The mineral granules of the crab hepatopancreas appear to function as storage forms of calcium and phosphate during the intermolt period. This tissue appears promising as a model for study of the cellular events associated with biological calcification, since

  10. A second copper zinc superoxide dismutase (CuZnSOD) in the blue crab Callinectes sapidus: cloning and up-regulated expression in the hemocytes after immune challenge.

    Science.gov (United States)

    Sook Chung, J; Bachvaroff, T R; Trant, J; Place, A

    2012-01-01

    The full-length cDNA (1362 nucleotides, GenBank JF736621) encoding an extracellular copper zinc superoxide dismutase initially isolated from an EST library of the blue crab Callinectes sapidus was characterized using 3' RACE and named Cas-ecCuZnSOD-2. The open reading frame of Cas-ecCuZnSOD-2 contains 203 deduced amino acids with the conserved active catalytic center for copper and zinc binding and the post-translational modification at two putative N-glycosylation and nine phosphorylation sites. Overall, the deduced amino acids of Cas-ecCuZnSOD-2 shared only 35% sequence identity with that of Cas-ecCuZnSOD (GenBank AF264031) which was previously found in C. sapidus, while it showed ∼75% sequence identity to Scylla paramamosain ecCuZnSOD (GenBank FJ774661). The expression profile of Cas-ecCuZnSOD-2 and the other three C. sapidus SODs: ecCuZn, cytMn- and mitMn SODs was largely ubiquitous among the tested tissues obtained from a juvenile female at intermolt: brain, eyestalk ganglia, pericardial organs, and thoracic ganglia complex (nervous system); hepatopancreas (digestive system); heart, artery and hemocytes (circulatory system); gill and antennal gland (excretory system), hypodermis, and Y-organ (endocrine organ). Our study reports, for the first time in the crustaceans, expression analyses for all four Cas-SODs in hemocytes after immune challenges. Crabs challenged with lipopolysaccharides (LPS) injection had a remarkable induction of Cas-ecCuZnSOD-2 expression along with three other SODs in hemocytes, suggesting that Cas-SODs including Cas-ecCuZnSOD-2 are involved in the defense system, possibly innate immunity and immunocompetency of C. sapidus. Copyright © 2011 Elsevier Ltd. All rights reserved.

  11. Population ecology of the blue crab Callinectes danae (Crustacea: Portunidae in a Brazilian tropical estuary

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    Marina S.L.C. Araújo

    2012-03-01

    Full Text Available This paper aims at describing the population ecology of the swimming crab Callinectes danae Smith, 1869 in one of the most productive estuaries of Brazil, the Santa Cruz Channel. These crabs were monthly collected from January to December/2009 at four stations along the channel, two in the upper and two in the lower estuary. A total of 2373 specimens of C. danae were collected during the study. Males had a larger average carapace width than non-ovigerous females (60.0 ± 15.6 mm and 52.9 ± 12.4 mm, respectively, an adaptation that gives greater protection for females during the copulation. Overall sex ratio did not differ significantly from 1:1. However, evaluating sex-ratio by sampling area, males and juveniles of both sexes occurred preferentially in the upper estuary (p O presente trabalho tem por objetivo descrever a estrutura populacional do siri Callinectes danae Smith, 1869 em um dos estuários mais produtivos do Brasil, o Canal de Santa Cruz. As coletas foram realizadas mensalmente de Janeiro a Dezembro/ 2009 em quatro estações ao longo do canal, duas no estuário superior e duas no estuário inferior. Um total de 2373 exemplares de C. danae foi coletado. Os machos apresentaram média de largura de carapaça superior à das fêmeas não-ovígeras (60,0 ± 15,6 mm e 5,9 ± 12,4 mm, respectivamente, uma adaptação que confere maior proteção às fêmeas durante a cópula. A proporção sexual total não diferiu significativamente de 1:1. Porém, avaliando a 'sex-ratio' por área de coleta, os machos e os juvenis residem preferencialmente no estuário superior (p < 0, 05, enquanto as fêmeas adultas e ovígeras habitam no estuário inferior, área de maior influência marinha (p < 0, 05. Enquanto os juvenis procuram águas estuarinas devido a abundância de abrigos e comida, as fêmeas ovígeras migram para áreas de maior profundidade e maior salinidade visando prover um ambiente mais favorável ao desenvolvimento embrionário e

  12. Respiratory and digestive responses of postprandial Dungeness crabs, Cancer magister, and blue crabs, Callinectes sapidus, during hyposaline exposure.

    Science.gov (United States)

    Curtis, Daniel L; McGaw, Iain J

    2010-02-01

    Respiratory responses and gastric processing were examined during hyposaline exposure in two crab species of differing osmoregulatory ability. The efficient osmoregulator, Callinectes sapidus, displayed an immediate increase in oxygen uptake when exposed to low salinity in isolation. In contrast, the weak osmoregulator, Cancer magister, showed no change in oxygen uptake upon acute exposure (sapidus were able to sum the demands of osmoregulation and digestion. Thus, gastric processes continued unabated in low salinity. Conversely, postprandial C. magister prioritized responses to low salinity over those of digestion, resulting in a decrease in oxygen uptake when exposed to low salinity. This decrease in oxygen uptake corresponded to a reduction in the rate of contraction of the pyloric stomach and a subsequent doubling of gastric evacuation time. The current study is one of the few to illustrate how summation or prioritization of competing physiological systems is manifested in digestive processes.

  13. Acute toxicity of current and alternative oil spill chemical dispersants to early life stage blue crabs (Callinectes sapidus).

    Science.gov (United States)

    Pie, Hannah V; Mitchelmore, Carys L

    2015-06-01

    The aim of this study was to examine the acute toxicity of five oil spill chemical dispersants on the ecologically and economically important coastal and estuarine species, blue crab Callinectes sapidus. Static, non-renewal 48 h acute toxicity tests were performed on stage-II blue crab zoea. The median lethal concentration (LC50) was calculated for each dispersant at 24 h and 48 h using nominal concentrations for each dispersant tested. The 48 h LC50 values from the most to the least toxic ranged from 10.1 mg L(-1) for Dispersit SPC 1000 to 76.5 mg L(-1) for Orca. For all dispersants, the swimming activity and mobility of larvae decreased with increasing dispersant concentration within 24h of exposure and reached relative immobility at concentrations below LC50 values. These results show that the dispersants examined in this study are only slightly toxic after 48 h exposure to the earliest life stage of blue crabs that might likely be exposed to dispersants in the environment, with the exception of Dispersit SPC 1000 that bordered between slightly and moderately toxic. Although the dispersants themselves appear to not cause substantial acute toxicity, sublethal and potentially delayed impacts, such as, reduced mobility or food source availability could indirectly remove larvae from the population and need to be further examined, as do larval responses in standard chronic toxicity tests. Furthermore, dispersants are not released into the environment in isolation and so the impact of dispersed-oil using these dispersant formulations also needs to be investigated to translate into real-world situations. Copyright © 2015 Elsevier Ltd. All rights reserved.

  14. Heat shock response of the blue crab Portunus pelagicus:thermal stress and acclimation

    Institute of Scientific and Technical Information of China (English)

    Suhaila Qari

    2014-01-01

    Objective:To determine the effect of prior heat shock on the CTMax of differently acclimated Portunus pelagicus (P. pelagicus) as well as the time course of the changes in CTMax post heat shock. Methods: Crabs P. pelagicus were held in laboratory aquaria in tanks, which were supplied with filtered and aerated seawater. Crabs were acclimated at 20 °C, 25 °C, 30 °C and 35 °C for 3 weeks before their CTMax was determined. The CTMax was recorded for each crab as the median temperature during the 5 min period when a crab was not able to right itself, the average CTMax was calculated. The effect of heat shock on subsequent CTMax was measured. Crabs were heat shocked at temperature 1 °C lower than the CTMax for 20 min, followed by either 0.5 h, 1 h or 1.5 h recovery at 20 °C. The same procedure was repeated at other acclimation temperatures (25 °C, 30 °C and 35 °C). Results: Temperature acclimation of P. pelargicus from 20-35 °C progressively increased the CTMax. Acclimation at 35 °C the CTMax was 42.66 °C, whereas acclimation at 20 °C the CTMax was 39.8 °C. In P. pelagicus acclimated, at 20 °C the CTMax values after heat shock were significantly higher than crabs in control for 30 min, 1 h and 1.5 h after heat shock. In the 25 °C and 30 °C acclimated crabs, the CTMax values after heat shock were significantly higher than control only in 30 min and 1 h after heat shock. No significant differences in 35 °C acclimated crabs between control and heat shocked crabs were found after recovery for 30 min, 1 h, or 1.5 h. Conclusions: Heat shock caused significant rises in the CTMax, however, this increase was progressively reduced with longer recovery times at the acclimation temperature. For 20 °C acclimated crabs, the increased CTMax was still evident after 90 min, but for 25 °C and 30 °C crabs, the response was over after 90 min. Heat shock of 35 °C crabs was problematical, the CTMax gave no increased thermotolerance. It must be concluded that the

  15. Some aspects of the biology of the female blue crab Callinectes amnicola (De Rocheburne) from the Cross River estuary, Nigeria

    Institute of Scientific and Technical Information of China (English)

    Eyo Victor Oscar; Akpan Michael Mfon; Udoh Ifiok Solomon

    2015-01-01

    Objective: To investigate some important aspects of the biology of Callinectes amnicola (C. amnicola) such as fecundity, carapace length-weight relationship, condition factor and carapace length frequency distribution from the Cross River estuary, Nigeria. Methods: A total of one hundred and twenty ovigerous females of C. amnicola, freshly caught with basket traps, lift net trap, and gill net were collected from the catches of the artisanal fisheries in the study area between June 2012 and May 2013. Fecundity, carapace length-weight relationship, condition factor and carapace length frequency distribution were determined and analyzed following standard methods. Results: Fecundity (F) ranged between 73090 eggs for crab of carapace length 8.1 cm and total weight 34 g and 809450 eggs for crab of carapace length 16.1 cm and total weight 395 g with a mean of 311808.93±17693.94 eggs. There was a positive significant relationship between fecundity and carapace length, total weight and condition factor as follows: F=6839.7CL1.4403 (r2=0.2145, P<0.05), F=15302TW0.5798 (r2=0.4079, P<0.05), F=147255K0.2788 (r=0.2717, r2=0.0738, P<0.05). A significant linear relationship between carapace length and weight of C. amnicola is given by the equation: Log W=2.0447LogL – 0.1389 (r2=0.3357, P<0.05). The crab exhibited a negative allometric growth pattern (b=2.0447). Condition factor ranged between 21.48 to 104.95 with a mean value of 47.21±2.17. The carapace length frequency distribution showed a unimodal class size distribution. Conclusions: Findings of this study is crucial in assessing the population dynamics and development of management strategies of the the Blue crab, C. amnicola from the estuary such as mesh size regulation, fishing season and fishing ground regulation in the Cross River estuary. Also, findings of this study will be useful in evaluation of the aquaculture potential of the Blue crab C. amnicola, which is a valuable shell fish for the inhabitants estuary.

  16. Some aspects of the biology of the female blue crab Callinectes amnicola (De Rocheburne from the Cross River estuary, Nigeria

    Directory of Open Access Journals (Sweden)

    Eyo Victor Oscar

    2015-04-01

    Full Text Available Objective: To investigate some important aspects of the biology of Callinectes amnicola (C. amnicola such as fecundity, carapace length-weight relationship, condition factor and carapace length frequency distribution from the Cross River estuary, Nigeria. Methods: A total of one hundred and twenty ovigerous females of C. amnicola, freshly caught with basket traps, lift net trap, and gill net were collected from the catches of the artisanal fisheries in the study area between June 2012 and May 2013. Fecundity, carapace length-weight relationship, condition factor and carapace length frequency distribution were determined and analyzed following standard methods. Results: Fecundity (F ranged between 73090 eggs for crab of carapace length 8.1 cm and total weight 34 g and 809450 eggs for crab of carapace length 16.1 cm and total weight 395 g with a mean of 311808.93±17 693.94 eggs. There was a positive significant relationship between fecundity and carapace length, total weight and condition factor as follows: F=6839.7CL1.4403 (r 2 =0.2145, P<0.05, F=15302TW0.5798 (r 2 =0.4079, P<0.05, F=147255K0.2788 (r=0.2717, r 2 =0.0738, P<0.05. A significant linear relationship between carapace length and weight of C. amnicola is given by the equation: Log W=2.0447LogL – 0.1389 (r 2 =0.3357, P<0.05. The crab exhibited a negative allometric growth pattern (b=2.0447. Condition factor ranged between 21.48 to 104.95 with a mean value of 47.21±2.17. The carapace length frequency distribution showed a unimodal class size distribution. Conclusions: Findings of this study is crucial in assessing the population dynamics and development of management strategies of the the Blue crab, C. amnicola from the estuary such as mesh size regulation, fishing season and fishing ground regulation in the Cross River estuary. Also, findings of this study will be useful in evaluation of the aquaculture potential of the Blue crab C. amnicola, which is a valuable shell fish for the

  17. Energy metabolism and metabolic depression during exercise in Callinectes sapidus, the Atlantic blue crab: effects of the bacterial pathogen Vibrio campbellii.

    Science.gov (United States)

    Thibodeaux, Lindy K; Burnett, Karen G; Burnett, Louis E

    2009-11-01

    Callinectes sapidus (Rathbun), the Atlantic blue crab, commonly harbors low to moderate amounts of bacteria in hemolymph and other tissues. These bacteria are typically dominated by Vibrio spp., which are known to cause mortality in the blue crab. The dose-dependent lethality of an isolate of Vibrio campbellii was determined in crabs; the mean 48 h LD(50) (half-maximal lethal dose) was 6.2 x 10(5) colony forming units g(-1) crab. Injection of a sublethal dose of V. campbellii into the hemolymph of the crab resulted in a rapid and large depression (30-42%) of metabolic rate, which persisted for 24 h. Because gills are an organ of immune function as well as respiration, we were interested in how bacteria injected into the crab would affect the energetic costs associated with walking. Overall metabolism (aerobic and anaerobic) more than doubled in crabs walking for 30 min at 8 m min(-1). The metabolic depression resulting from bacterial injection persisted throughout the exercise period and patterns of phosphagen and adenylate consumption within walking leg muscle were not affected by treatment. The ability of crabs to supply required energy for walking is largely unaffected by exposure to Vibrio; however, Vibrio-injected crabs are less aerobic while doing so. This depressed metabolic condition in response to bacteria, present during moderate activity, could be a passive result of mounting an immune response or may indicate an actively regulated metabolic depression. A compromised metabolism can affect the performance of daily activities, such as feeding and predator avoidance or affect the ability to cope with environmental stressors, such as hypoxia.

  18. The effects of predation by wading birds (Ardeidae) and blue crabs ( Callinectes sapidus) on the population size structure of the common mummichog, Fundulus heteroclitus

    Science.gov (United States)

    Kneib, R. T.

    1982-02-01

    Preliminary observations suggested that predation by herons and egretsaffected the size structure of a mummichog ( Fundulus heteroclitus) population in Tar Landing Marsh, North Carolina. The hypothesis was tested by placing 300 mummichogs represented equally in three size classes into each half of an enclosed, divided, high marsh pool. Nylon cord was strung in a grid over one side to inhibit predation by wading birds. Although mummichog losses were higher in the side of the pool which was open to bird predation, the same trend in size-specific losses also occurred in the bird-exclusion side. Repeating the experiment after the removal of several blue crabs ( Callinectes sapidus) improved mummichog survivorship and suggested that crabs and not birds were responsible for the fish losses previously observed. In a final experiment, birds were excluded and crabs were removed from one side but added to the other side of the pool. After 24 days losses due to C. sapidus occurred in all mummichog size classes, but size-specific predation by blue crabs produced the highest losses (90%) among the largest (>70 mm total length) fish. Blue crab predation on mummichog populations may influence the community structure of salt marsh infauna and may also function in the movement of marsh production to open coastal waters.

  19. mRNA Expression and activity of ion-transporting proteins in gills of the blue crab Callinectes sapidus: effects of waterborne copper.

    Science.gov (United States)

    Martins, Camila M G; Almeida, Daniela Volcan; Marins, Luis Fernando Fernandes; Bianchini, Adalto

    2011-01-01

    Waterborne Cu effects on the transcription of genes encoding ion-transporting proteins and the activities of these proteins were evaluated in gills of the blue crab Callinectes sapidus acclimated to diluted (2‰) and full (30‰) seawater. Crabs were exposed (96 h) to an environmentally relevant concentration of dissolved Cu (0.78 µM) and had their posterior (osmoregulating) gills dissected for enzymatic and molecular analysis. Endpoints analyzed were the activity of key enzymes involved in crab osmoregulation (sodium-potassium adenosine triphosphatase [Na(+)/K(+)-ATPase], hydrogen adenosine triphosphatase [H(+)-ATPase], and carbonic anhydrase [CA]) and the mRNA expression of genes encoding these enzymes and the sodium-potassium-chloride (Na(+)/K(+)/2Cl⁻) cotransporter. Copper effects were observed only in crabs acclimated to diluted seawater (hyperosmoregulating crabs) and were associated with an inhibition of the expression of mRNA of genes encoding the Na(+)/K(+)-ATPase and the Na(+)/K(+)/2Cl⁻ cotransporter. However, Cu did not affect Na(+)/K(+)-ATPase activity, indicating that the gene transcription is downregulated before a significant inhibition of the enzyme activity can be observed. This also suggests the existence of a compensatory response of this enzyme to prevent osmoregulatory disturbances after short-term exposure to environmentally relevant Cu concentrations. These findings suggest that Cu is a potential ionoregulatory toxicant in blue crabs C. sapidus acclimated to low salinity. The lack of Cu effect on blue crabs acclimated to full seawater would be due to the reduced ion uptake needed for the regulation of the hemolymph osmotic concentration in full seawater (30‰). Also, this could be explained considering the lower bioavailability of toxic Cu (free ion) associated with the higher ionic content and dissolved organic matter concentration in high salinity (30‰) than in diluted seawater (2‰). © 2010 SETAC.

  20. Inter-cohort cannibalism of early benthic phase blue king crabs (Paralithodes platypus): alternate foraging strategies in different habitats lead to different functional responses.

    Science.gov (United States)

    Daly, Benjamin; Long, W Christopher

    2014-01-01

    Blue king crabs (Paralithodes platypus) are commercially and ecologically important in Alaska, USA, but population abundances have fluctuated over the past several decades likely resulting from a combination of environmental and biological factors, including recruitment variability. Cannibalism between cohorts may be a source of mortality limiting recruitment success in the wild, but the degree of inter-cohort cannibalism is unknown for early benthic phase blue king crabs. In laboratory experiments, we evaluated the effects of habitat type (sand and shell) on the predator functional response and foraging behavior of year-1 blue king crabs as predators of year-0 conspecifics and examined the effects of predator presence on crypsis of prey crabs. In sand, consumption rates increased with predator size and prey density until satiation, while predation rates in shell were low regardless of predator size or prey density. These differential predation rates yielded a type III functional response in sand but a type I functional response in shell habitat. Crypsis of prey crabs was generally high and did not change in the presence of predators. Predator foraging activity was reduced in shell and may be an adaptive behavior to balance foraging efficiency and susceptibility to larger predators. Our results demonstrate that early benthic phase blue king crabs are cannibalistic between cohorts in the laboratory and that shell material is extremely effective for reducing encounter rates with conspecific predators. The distribution and abundance of such habitat may be important for recruitment success in some populations. Future studies should compare benthic habitat and species assemblages in areas with variable abundances, such as the Pribilof Islands and Saint Matthew Island in the eastern Bering Sea, to better understand possible mechanisms for recruitment variability.

  1. Inter-cohort cannibalism of early benthic phase blue king crabs (Paralithodes platypus: alternate foraging strategies in different habitats lead to different functional responses.

    Directory of Open Access Journals (Sweden)

    Benjamin Daly

    Full Text Available Blue king crabs (Paralithodes platypus are commercially and ecologically important in Alaska, USA, but population abundances have fluctuated over the past several decades likely resulting from a combination of environmental and biological factors, including recruitment variability. Cannibalism between cohorts may be a source of mortality limiting recruitment success in the wild, but the degree of inter-cohort cannibalism is unknown for early benthic phase blue king crabs. In laboratory experiments, we evaluated the effects of habitat type (sand and shell on the predator functional response and foraging behavior of year-1 blue king crabs as predators of year-0 conspecifics and examined the effects of predator presence on crypsis of prey crabs. In sand, consumption rates increased with predator size and prey density until satiation, while predation rates in shell were low regardless of predator size or prey density. These differential predation rates yielded a type III functional response in sand but a type I functional response in shell habitat. Crypsis of prey crabs was generally high and did not change in the presence of predators. Predator foraging activity was reduced in shell and may be an adaptive behavior to balance foraging efficiency and susceptibility to larger predators. Our results demonstrate that early benthic phase blue king crabs are cannibalistic between cohorts in the laboratory and that shell material is extremely effective for reducing encounter rates with conspecific predators. The distribution and abundance of such habitat may be important for recruitment success in some populations. Future studies should compare benthic habitat and species assemblages in areas with variable abundances, such as the Pribilof Islands and Saint Matthew Island in the eastern Bering Sea, to better understand possible mechanisms for recruitment variability.

  2. Temperature correlates with annual changes in Hematodinium perezi prevalence in blue crab Callinectes sapidus in Florida, USA.

    Science.gov (United States)

    Gandy, Ryan; Schott, Eric J; Crowley, Claire; Leone, Erin H

    2015-04-08

    Blue crabs Callinectes sapidus were monitored biannually throughout Florida, USA, for 2 yr using a highly sensitive, quantitative polymerase chain reaction (qPCR) to determine the spatial and temporal changes in prevalence and intensity of Hematodinium perezi infections during drought years. Despite persistent drought conditions, H. perezi infections were not universally found. Overall prevalence was 25.3% (95% CI: 22.8-28.1%) in 1066 crabs sampled from 6 locations (Jacksonville, Ormond Beach, Everglades City, Tampa Bay, Steinhatchee, and Panama City) from 2011 to 2012. Presence of H. perezi was consistently highest in winter season samples, ranging from 4.2-51.1% (3 locations) in 2011, to 32-83% (5 locations) in 2012. The highest prevalence and intensities were observed in the winter samples from Everglades City. Previous studies have found that the prevalence of H. perezi in C. sapidus in temperate regions of the US East Coast shows seasonal peaks in early winter in Maryland and South Carolina and in fall and spring in Georgia. The seasonality of infections in the subtropical waters of Florida reinforces the concept that temperature is a strong factor that may override other drivers, such as drought. Seasonal H. perezi infections in Florida appear to be triggered by the parasite responding to an optimal temperature during the annual rise from the low temperature of winter when salinity is elevated. However, salinity alone is not sufficient to trigger an increase in prevalence of H. perezi in Florida.

  3. The Atlantic blue crab Callinectes sapidus in southern European coastal waters: Distribution, impact and prospective invasion management strategies.

    Science.gov (United States)

    Mancinelli, Giorgio; Chainho, Paula; Cilenti, Lucrezia; Falco, Silvia; Kapiris, Kostas; Katselis, George; Ribeiro, Filipe

    2017-06-15

    The native distribution of the blue crab Callinectes sapidus in the western Atlantic extends from Nova Scotia to Argentina. Introduced to Europe at the beginning of the 20th century, it is currently recorded almost ubiquitously in the Mediterranean and in the Black Sea. An overview of the occurrence, abundance, and ecological impact of the species in southern European waters is provided; additionally, we present a pragmatic assessment of its management scenarios, explicitly considering the dual nature of C. sapidus as both an invasive species and a fishery resource. We emphasise that the ongoing expansion of C. sapidus in the region may represent a stimulating challenge for the identification and implementation of future strategies in the management of invasive crustaceans. The impact of the invader could be converted into an enhancement of the services delivered by southern European coastal ecosystems, while mitigation costs could be transformed into profits for local populations. Copyright © 2017 Elsevier Ltd. All rights reserved.

  4. Distribution and Size of Barnacle Chelonibia patula Fouling Blue Crab Callinectes amnicola in Southeast Nigeria

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    Udoh James Philip

    2016-09-01

    Full Text Available The distribution and occurrence of epibionts on the dorsal carapace, ventral carapace and chela of 325 specimens of Callinectes amnicola (De Rocheburne, 1883 (103.4 - 138.7 mm carapace width from the Qua Iboe (QIRE and Imo River (IRE estuaries in southeast Nigeria was determined. The only ectosymbiont observed was cirriped barnacle, Chelonibia patula, mostly of smaller sizes (2.25 mm, infesting only 25-29% of intermoult crabs, more on females and in the Imo River estuary, with an average of four barnacles per crab, presupposing low level of epibiont-host interaction. There was no significant difference (P>0.05 in spatial distribution but epibionts were highest in the dry season in low salinity IRE (0.53‰ and in wet season in the medium-salinity QIRE (17.4‰. No public health risk has been reported among crab consumers in the study area. This study highlights epibiont-host interaction in the study area largely unknown for proper management of the fishery.

  5. Anatomy of virgin and mature externae of Loxothylacus texanus, parasitic on the dark blue crab Callinectes rathbunae (Crustacea: Cirripedia: Rhizocephala: Sacculinidae).

    Science.gov (United States)

    Alvarez, Fernando; Bortolini, José Luis; Høeg, Jens T

    2010-02-01

    Rhizocephalan parasites are dioecious organisms, in that one or several dwarf males are implanted into the external part of the female parasite soon after it emerges from the interior of the host animal. The structure of the female externa and its resident males is crucial for understanding both the reproductive biology and the taxonomy of these specialized parasites. We use scanning electron microscopy and histological methods to study the anatomy of juvenile and the mature externae of the rhizocephalan barnacle Loxothylacus texanus parasitizing the blue crab Callinectes rathbunae. We put emphasis on the implantation of males and the histology of the female reproductive organs. In the virgin externae, male cyprids attach around a cuticular hood covering the mantle aperture, which is partially blocked by a plug of cuticle so only trichogon larvae, not cyprids, can access the mantle cavity. This resembles the situation known from Sacculina carcini. The mature externa is characterized by a visceral mass that contains the ovary, paired colleteric glands, a single male receptacle, but paired receptacle ducts. The proximal attachment of the visceral mass is located at some distance from the basal stalk, as is characteristic for the genus Loxothylacus. The internal anatomy of the mature externa of L. texanus is in most features similar to that seen in other species of the Sacculinidae, which comprises the majority of rhizocephalan species. However, the single receptacle creates a situation where the two implanted males cannot be kept separate as in most other rhizocephalans, but pass through spermatogenesis in a common chamber. This may have unknown effects on the reproductive biology such as male-male competition.

  6. Predation of the ribbed mussel geukensia demissa by the blue crab callinectes sapidus

    Science.gov (United States)

    Seed, R.

    Callinectes sapidus fed extensively on Geukensia demissa in laboratory aquaria. Several predation techniques used by Callinectes to open its prey are reported. Prey value decreases monotonically with increasing mussel size. Crabs consumed mussels over a wide size range but were generally reluctant to feed on larger mussels whilst smaller, more profitably prey was available. The relative importance of 'energy maximization' and 'time minimization' could not be distinguished. The distribution and population structure of Geukensia at Beaufort, N. Carolina are briefly considered in terms of the foraging strategy of Callinectes.

  7. Population biology and color patterns of the blue land crab, Cardisoma guanhumi (Latreille 1828) (Crustacea: Gecarcinidae) in the Northeastern Brazil.

    Science.gov (United States)

    Silva, C C; Schwamborn, R; Lins Oliveira, J E

    2014-11-01

    The objective of this study was to analyze the population biology and color patterns of Cardisoma guanhumi Latreille, 1828 in a mangrove area in Natal, Rio Grande do Norte, Brazil. Crabs were collected monthly between February 2010 and January 2012 and totaled 1,837 individuals. Sex ratios were similar between males and females in the first year and differed in the second. Sex ratios by size class differed statistically in the extremes of the distribution, with an abundance of males in the large size classes. There was no difference (p > 0.05) in carapace width between males and females in the first year, but in the second year, males were larger than females (p = 0.003), showing the importance of considering interannual variation in such studies. Both sexes presented a unimodal distribution. The size of first maturing of the females was 6.00 cm. Asymptotic carapace width for males was 9.4 cm and females for 9.2 cm, using the Wetherall method. There was no defined modal progression, which made the determination of the Von Bertalanffy growth parameter K impossible. Juveniles were found throughout all months of the year, demonstrating that there was no defined period of recruiting, although slightly fewer juveniles were found in the dry season. Four color patterns were observed, the three first patterns were the same for both sexes, while the fourth pattern was observed in females only. The four color patterns identified could be clearly related to the stage of development (size) and sexual maturity of the animal.

  8. A Stock Assessment of the Blue Swimming Crab Portunus pelagicus (Linnaeus, 1758) for Sustainable Management in Kung Krabaen Bay, Gulf of Thailand.

    Science.gov (United States)

    Kunsook, Chutapa; Gajaseni, Nantana; Paphavasit, Nittharatana

    2014-08-01

    A stock assessment of blue swimming crabs, Portunus pelagicus was conducted with crab gill nets and collapsible crab traps at Kung Krabaen Bay, in the eastern Gulf of Thailand, from 2008 to 2009. Several key indicators show that P. pelagicus population is in crisis. Fishing mortality shows an increase to 4.14. The exploitation rate is 0.71, higher than the optimal value of 0.38. The size of the mature females has also decreased from 8.10±0.39 cm to 7.52±1.14 cm. The average fecundity is 0.572×10(6)±0.261×10(6) eggs per batch, and the sex ratio (male:female) is 1:0.92. Based on these results, a sustainable management program for P. pelagicus was proposed as follows: (i) closing the bay during the spawning season, (ii) restoration of the Enhalus acoroides seagrass beds, (iii) restocking crab larvae in the bay and (iv) educating and networking all stakeholders to develop a better understanding of the ecology of the crab to support sustainable fishery management in Kung Krabaen Bay.

  9. IgE Reactivity of Blue Swimmer Crab (Portunus pelagicus Tropomyosin, Por p 1, and Other Allergens; Cross-Reactivity with Black Tiger Prawn and Effects of Heating.

    Directory of Open Access Journals (Sweden)

    Jodie B Abramovitch

    Full Text Available Shellfish allergy is a major cause of food-induced anaphylaxis, but the allergens are not well characterized. This study examined the effects of heating on blue swimmer crab (Portunus pelagicus allergens in comparison with those of black tiger prawn (Penaeus monodon by testing reactivity with shellfish-allergic subjects' serum IgE. Cooked extracts of both species showed markedly increased IgE reactivity by ELISA and immunoblotting, and clinical relevance of IgE reactivity was confirmed by basophil activation tests. Inhibition IgE ELISA and immunoblotting demonstrated cross-reactivity between the crab and prawn extracts, predominantly due to tropomyosin, but crab-specific IgE-reactivity was also observed. The major blue swimmer crab allergen tropomyosin, Por p 1, was cloned and sequenced, showing strong homology with tropomyosin of other crustacean species but also sequence variation within known and predicted linear IgE epitopes. These findings will advance more reliable diagnosis and management of potentially severe food allergy due to crustaceans.

  10. The smell of moulting: N-acetylglucosamino-1,5-lactone is a premoult biomarker and candidate component of the courtship pheromone in the urine of the blue crab, Callinectes sapidus.

    Science.gov (United States)

    Kamio, Michiya; Schmidt, Manfred; Germann, Markus W; Kubanek, Julia; Derby, Charles D

    2014-04-15

    Female blue crabs (Callinectes sapidus) in their pubertal moult stage release unidentified sex pheromone molecules in their urine, causing males to respond with courtship behaviours including a display called courtship stationary paddling and a form of precopulatory guarding called cradle carry. We hypothesized that pheromones are mixtures of molecules and are more concentrated in urine of pubertal premoult females compared with other moulting stages and thus that these molecules are biomarkers (i.e. metabolites that can be used as an indicator of some biological state or condition) of pubertal premoult females. We tested this hypothesis by combining bioassay-guided fractionation and biomarker targeting. To evaluate the molecular mass of the putative pheromone by bioassay-guided fractionation, we separated urine from pubertal premoult females and intermoult males by ultrafiltration into three molecular mass fractions. The 1000 Da fraction of female urine induced male courtship stationary paddling, but none of the fractions of male urine did. Thus, female urine contains molecules of <1000 Da that stimulate courtship behaviours in males. Biomarker targeting using nuclear magnetic resonance (NMR) spectral analysis of the 500-1000 Da fraction of urine from premoult and postmoult males and females revealed a premoult biomarker. Purification, nuclear magnetic resonance, mass spectrometry and high pressure liquid chromatography analysis of this premoult biomarker identified it as N-acetylglucosamino-1,5-lactone (NAGL) and showed that it is more abundant in urine of premoult females and males than in urine of either postmoult or juvenile females and males. NAGL has not been reported before as a natural product or as a molecule of the chitin metabolic pathway. Physiological and behavioural experiments demonstrated that blue crabs can detect NAGL through their olfactory pathway. Thus, we hypothesize that NAGL is a component of the sex pheromone and that it acts in

  11. Toxicity of the organophosphate insecticide fenitrothion and its metabolism by blue crabs, Callinectes sapidus

    Energy Technology Data Exchange (ETDEWEB)

    Johnston, J.J.

    1986-01-01

    The LC/sub 50/ for Callinectes sapidus exposed to fenitrothion for 96 hours at 22/sup 0/C and a salinity of 34 ppt (parts per thousand) was estimated to be 8.6 ..mu..g/liter. Acute toxicity was shown to decrease with decreasing salinity and decreasing temperature. Exposure to a simulated tidal cycle increased the acute toxicity of fenitrothion to Callinectes. The autotomization response in Callinectes was shown to be affected at subacute exposure levels as low as 0.1 ..mu..g/liter. In vitro studies showed that the rates of formation of 3-methyl-4-nitrophenol and desmethyl fenitrothion were greater and the rate of formation of fenitrooxon was less in subcellular fractions prepared from the hepatopancreas of crabs which had been acclimated to lower salinity seawater. All three of these metabolites were formed at faster rates in subcellular fractions prepared from crabs which had been acclimated to and incubated at 22/sup 0/C than at 17/sup 0/C. Tissue distribution of aniline hydroxylase and glutathione-S-transferase activity was also determined. The uptake of /sup 14/C-fenitrothion at a level in a seawater of 5.2 ..mu..g/liter was greater at 22/sup 0/C than at 17/sup 0/C and from 34 ppt than from 17 ppt seawater. Tissue distribution of radioactivity was determined as well as the nature of radiolabelled metabolites in the hepatopancreas and in seawater. There was no significant difference in the overall level of metabolites detected in the 22/sup 0/C than in the 17/sup 0/C seawater. The rate of uptake of fenitrothion by Callinectes also affects the toxicity as the uptake of fenitrothion was more rapid at the higher salinity as well as at the higher temperature.

  12. Cloning of aquaporin-1 of the blue crab, Callinectes sapidus: its expression during the larval development in hyposalinity.

    Science.gov (United States)

    Chung, J Sook; Maurer, Leah; Bratcher, Meagan; Pitula, Joseph S; Ogburn, Matthew B

    2012-09-03

    Ontogenetic variation in salinity adaptation has been noted for the blue crab, Callinectes sapidus, which uses the export strategy for larval development: females migrate from the estuaries to the coast to spawn, larvae develop in the ocean, and postlarvae (megalopae) colonize estuarine areas. We hypothesized that C. sapidus larvae may be stenohaline and have limited osmoregulatory capacity which compromises their ability to survive in lower salinity waters. We tested this hypothesis using hatchery-raised larvae that were traceable to specific life stages. In addition, we aimed to understand the possible involvement of AQP-1 in salinity adaptation during larval development and during exposure to hyposalinity. A full-length cDNA sequence of aquaporin (GenBank JQ970426) was isolated from the hypodermis of the blue crab, C. sapidus, using PCR with degenerate primers and 5' and 3' RACE. The open reading frame of CasAQP-1 consists of 238 amino acids containing six helical structures and two NPA motifs for the water pore. The expression pattern of CasAQP-1 was ubiquitous in cDNAs from all tissues examined, although higher in the hepatopancreas, thoracic ganglia, abdominal muscle, and hypodermis and lower in the antennal gland, heart, hemocytes, ovary, eyestalk, brain, hindgut, Y-organs, and gill. Callinectes larvae differed in their capacity to molt in hyposalinity, as those at earlier stages from Zoea (Z) 1 to Z4 had lower molting rates than those from Z5 onwards, as compared to controls kept in 30 ppt water. No difference was found in the survival of larvae held at 15 and 30 ppt. CasAQP-1 expression differed with ontogeny during larval development, with significantly higher expression at Z1-2, compared to other larval stages. The exposure to 15 ppt affected larval-stage dependent CasAQP-1 expression which was significantly higher in Z2- 6 stages than the other larval stages. We report the ontogenetic variation in CasAQP-1 expression during the larval development

  13. Explosive development of pectoral muscle fibres in large juvenile blue catfish Ictalurus furcatus.

    Science.gov (United States)

    Lahiri, S; Fine, M L

    2015-11-01

    As part of an effort on scaling of pectoral spines and muscles, the basis for growth was examined in six pectoral muscles in juvenile blue catfish Ictalurus furcatus, the largest catfish in North America. Fibre number increases slowly in fish from 13.0 to 26.4 cm in total length, doubles by 27.0 cm and remains stable in larger individuals. Simultaneously, mean fibre diameter decreases by half, caused by the addition of new small fibres, before increasing non-linearly in larger fish. The orders of magnitude disparity between the size at hatching and the size of large adults may have selected for rapid muscle fibre addition at a threshold size.

  14. Structure, molting, and mineralization of the dorsal ossicle complex in the gastric mill of the blue crab, Callinectes sapidus.

    Science.gov (United States)

    Vatcher, Hayley E; Roer, Robert D; Dillaman, Richard M

    2015-11-01

    This study examined the mesocardiac and urocardiac ossicles in the gastric mill of the blue crab to describe its structure, mineralization, and dynamics throughout the molt cycle, and to assess its possible utility in age determination. Morphologically, the mineralized ossicles are similar to the calcified dorsal carapace having a lamellate structure comprised of sheets of chitin/protein fibrils. Staining with acridine orange showed the same arrangement of an epicuticle, exocuticle, and endocuticle. In much of the mesocardiac and urocardiac ossicles, the endocuticle is very reduced, with the exocuticle predominating; the reverse of the dimensions of the exoskeleton. The lamellate structure of the ossicles was confirmed with scanning electron microscopy; however, elemental mapping by energy-dispersive analysis of X-rays revealed that the ossicles are mineralized with calcium phosphate, in contrast to the calcium carbonate biomineral of the exoskeleton. The medial tooth of the urocardiac ossicle is not calcified, but the epicuticle is highly elaborated and impregnated with silica. Histological examination of the ossicles demonstrated that they are molted during ecdysis, so despite the appearance of bands in the mesocardiac ossicle, it is difficult to hypothesize how the bands could represent a record of chronological age. © 2015 Wiley Periodicals, Inc.

  15. Total mercury and its distribution in blue crab and deep water pink shrimp from Alexandria coast

    Energy Technology Data Exchange (ETDEWEB)

    Moustafa, E.K.; Moharram, Y.G.; El-Sokkary, I.; Telb, A.I.

    1987-01-01

    Total mercury content and its distribution in muscles and viscera of male and female blue grab (Callinectes sapidus Rothbum) and deep water pink shrimp (Parapenacus longirostris) collected from the 3 main fishing grounds near the Alexandria coast in the Mediterranean sea was estimated. The results indicate that the mercury content in the muscles of both species differ according to fishing areas, size, sex, and species. More than 75% of total mercury were accumulated in the viscera of both species which indicates that the mercury entered in these organisms via the feed chain.

  16. PCR-based prevalence of a fatal reovirus of the blue crab, Callinectes sapidus (Rathbun) along the northern Atlantic coast of the USA.

    Science.gov (United States)

    Flowers, E M; Simmonds, K; Messick, G A; Sullivan, L; Schott, E J

    2016-06-01

    There is a need for more information on the relationship between diseases and fluctuations of wild populations of marine animals. In the case of Callinectes sapidus reovirus 1 (CsRV1, also known as RLV), there is a lack of baseline information on range, prevalence and outbreaks, from which to develop an understanding of population-level impacts. An RT-qPCR assay was developed that is capable of detecting 10 copies of the CsRV1 genome. In collaboration with state, federal and academic partners, blue crabs were collected from sites throughout the north-eastern United States to assess the northern range of this pathogen. In addition, archived crab samples from the Chesapeake Bay were assessed for CsRV1 by RT-qPCR and histology. PCR-based assessments indicate that CsRV1 was present at all but one site. Prevalence of CsRV1 as assessed by RT-qPCR was highly variable between locations, and CsRV1 prevalence varied between years at a given location. Mean CsRV1 prevalence as assessed by RT-qPCR was >15% each year, and peak prevalence was 79%. The wide geographic range and highly variable prevalence of CsRV1 indicate that more study is needed to understand CsRV1 dynamics and the role the virus plays in blue crab natural mortality. © 2015 The Authors Journal of Fish Diseases Published by John Wiley & Sons Ltd.

  17. Genome Sequence Analysis of CsRV1: A Pathogenic Reovirus that Infects the Blue Crab Callinectes sapidus Across Its Trans-Hemispheric Range.

    Science.gov (United States)

    Flowers, Emily M; Bachvaroff, Tsvetan R; Warg, Janet V; Neill, John D; Killian, Mary L; Vinagre, Anapaula S; Brown, Shanai; Almeida, Andréa Santos E; Schott, Eric J

    2016-01-01

    The blue crab, Callinectes sapidus Rathbun, 1896, which is a commercially important trophic link in coastal ecosystems of the western Atlantic, is infected in both North and South America by C. sapidus Reovirus 1 (CsRV1), a double stranded RNA virus. The 12 genome segments of a North American strain of CsRV1 were sequenced using Ion Torrent technology. Putative functions could be assigned for 3 of the 13 proteins encoded in the genome, based on their similarity to proteins encoded in other reovirus genomes. Comparison of the CsRV1 RNA-dependent RNA polymerase (RdRP) sequence to genomes of other crab-infecting reoviruses shows that it is similar to the mud crab reovirus found in Scylla serrata and WX-2012 in Eriocheir sinensis, Chinese mitten crab, and supports the idea that there is a distinct "Crabreo" genus, different from Seadornavirus and Cardoreovirus, the two closest genera in the Reoviridae. A region of 98% nucleotide sequence identity between CsRV1 and the only available sequence of the P virus of Macropipus depurator suggests that these two viruses may be closely related. An 860 nucleotide region of the CsRV1 RdRP gene was amplified and sequenced from 15 infected crabs collected from across the geographic range of C. sapidus. Pairwise analysis of predicted protein sequences shows that CsRV1 strains in Brazil can be distinguished from those in North America based on conserved residues in this gene. The sequencing, annotation, and preliminary population metrics of the genome of CsRV1 should facilitate additional studies in diverse disciplines, including structure-function relationships of reovirus proteins, investigations into the evolution of the Reoviridae, and biogeographic research on the connectivity of C. sapidus populations across the Northern and Southern hemispheres.

  18. Detection and Discovery of Crustacean Parasites in Blue Crabs (Callinectes sapidus) by Using 18S rRNA Gene-Targeted Denaturing High-Performance Liquid Chromatography▿ †

    Science.gov (United States)

    Troedsson, Christofer; Lee, Richard F.; Walters, Tina; Stokes, Vivica; Brinkley, Karrie; Naegele, Verena; Frischer, Marc E.

    2008-01-01

    Recently, we described a novel denaturing high-performance liquid chromatography (DHPLC) approach useful for initial detection and identification of crustacean parasites. Because this approach utilizes general primers targeted to conserved regions of the 18S rRNA gene, a priori genetic sequence information on eukaryotic parasites is not required. This distinction provides a significant advantage over specifically targeted PCR assays that do not allow for the detection of unknown or unsuspected parasites. However, initial field evaluations of the DHPLC assay suggested that because of PCR-biased amplification of dominant host genes it was not possible to detect relatively rare parasite genes in infected crab tissue. Here, we describe the use of a peptide nucleic acid (PNA) PCR hybridization blocking probe in association with DHPLC (PNA-PCR DHPLC) to overcome inherent PCR bias associated with amplification of rare target genes by use of generic primers. This approach was utilized to detect infection of blue crabs (Callinectes sapidus) by the parasitic dinoflagellate Hematodinium sp. Evaluation of 76 crabs caught in Wassaw Sound, GA, indicated a 97% correspondence between detection of the parasite by use of a specific PCR diagnostic assay and that by use of PNA-PCR DHPLC. During these studies, we discovered one crab with an association with a previously undescribed protist symbiont. Phylogenetic analysis of the amplified symbiont 18S rRNA gene indicated that it is most closely related to the free-living kinetoplastid parasite Procryptobia sorokini. To our knowledge, this is the first report of this parasite group in a decapod crab and of this organism exhibiting a presumably parasitic life history. PMID:18502913

  19. Genome sequence analysis of CsRV1, a pathogenic reovirus that infects the blue crab Callinectes sapidus across its trans-hemispheric range

    Directory of Open Access Journals (Sweden)

    Emily Maya Flowers

    2016-02-01

    Full Text Available The blue crab, Callinectes sapidus (Rathbun 1896, which is a commercially important trophic link in coastal ecosystems of the western Atlantic, is infected in both North and South America by C. sapidus Reovirus 1 (CsRV1, a double stranded RNA virus. The 12 genome segments of a North American strain of CsRV1 were sequenced using Ion Torrent technology. Putative functions could be assigned for 3 of the 13 proteins encoded in the genome, based on their similarity to proteins encoded in other reovirus genomes. Comparison of the CsRV1 RNA dependent RNA polymerase (RdRP sequence to genomes of other crab-infecting reoviruses shows that it is similar to the MCRV virus found in Scylla serrata, mud crab, and WX-2012 in Eriocheir sinensis, Chinese mitten crab, and supports the idea that there is a distinct Crabreo genus, different from Seadornavirus and Cardoreovirus, the two closest genera in the Reoviridae. A region of 98% nucleotide sequence identity between CsRV1 and the only available sequence of the P virus of Macropipus depurator suggests that these two viruses may be closely related. An 860 nucleotide region of the CsRV1 RdRP gene was amplified and sequenced from 15 infected crabs collected from across the geographic range of C. sapidus. Pairwise analysis of predicted protein sequences shows that CsRV1 strains in Brazil can be distinguished from those in North America based on conserved residues in this gene. The sequencing, annotation, and preliminary population metrics of the genome of CsRV1 should facilitate additional studies in diverse disciplines, including structure-function relationships of reovirus proteins, investigations into the evolution of the Reoviridae, and biogeographic research on the connectivity of C. sapidus populations across the Northern and Southern hemispheres.

  20. Detection and discovery of crustacean parasites in blue crabs (Callinectes sapidus) by using 18S rRNA gene-targeted denaturing high-performance liquid chromatography.

    Science.gov (United States)

    Troedsson, Christofer; Lee, Richard F; Walters, Tina; Stokes, Vivica; Brinkley, Karrie; Naegele, Verena; Frischer, Marc E

    2008-07-01

    Recently, we described a novel denaturing high-performance liquid chromatography (DHPLC) approach useful for initial detection and identification of crustacean parasites. Because this approach utilizes general primers targeted to conserved regions of the 18S rRNA gene, a priori genetic sequence information on eukaryotic parasites is not required. This distinction provides a significant advantage over specifically targeted PCR assays that do not allow for the detection of unknown or unsuspected parasites. However, initial field evaluations of the DHPLC assay suggested that because of PCR-biased amplification of dominant host genes it was not possible to detect relatively rare parasite genes in infected crab tissue. Here, we describe the use of a peptide nucleic acid (PNA) PCR hybridization blocking probe in association with DHPLC (PNA-PCR DHPLC) to overcome inherent PCR bias associated with amplification of rare target genes by use of generic primers. This approach was utilized to detect infection of blue crabs (Callinectes sapidus) by the parasitic dinoflagellate Hematodinium sp. Evaluation of 76 crabs caught in Wassaw Sound, GA, indicated a 97% correspondence between detection of the parasite by use of a specific PCR diagnostic assay and that by use of PNA-PCR DHPLC. During these studies, we discovered one crab with an association with a previously undescribed protist symbiont. Phylogenetic analysis of the amplified symbiont 18S rRNA gene indicated that it is most closely related to the free-living kinetoplastid parasite Procryptobia sorokini. To our knowledge, this is the first report of this parasite group in a decapod crab and of this organism exhibiting a presumably parasitic life history.

  1. D1-like dopamine receptors downregulate Na+-K+-ATPase activity and increase cAMP production in the posterior gills of the blue crab Callinectes sapidus.

    Science.gov (United States)

    Arnaldo, Francis B; Villar, Van Anthony M; Konkalmatt, Prasad R; Owens, Shaun A; Asico, Laureano D; Jones, John E; Yang, Jian; Lovett, Donald L; Armando, Ines; Jose, Pedro A; Concepcion, Gisela P

    2014-09-15

    Dopamine-mediated regulation of Na(+)-K(+)-ATPase activity in the posterior gills of some crustaceans has been reported to be involved in osmoregulation. The dopamine receptors of invertebrates are classified into three groups based on their structure and pharmacology: D1- and D2-like receptors and a distinct invertebrate receptor subtype (INDR). We tested the hypothesis that a D1-like receptor is expressed in the blue crab Callinectes sapidus and regulates Na(+)-K(+)-ATPase activity. RT-PCR, using degenerate primers, showed the presence of D1βR mRNA in the posterior gill. The blue crab posterior gills showed positive immunostaining for a dopamine D5 receptor (D5R or D1βR) antibody in the basolateral membrane and cytoplasm. Confocal microscopy showed colocalization of Na(+)-K(+)-ATPase and D1βR in the basolateral membrane. To determine the effect of D1-like receptor stimulation on Na(+)-K(+)-ATPase activity, intact crabs acclimated to low salinity for 6 days were given an intracardiac infusion of the D1-like receptor agonist fenoldopam, with or without the D1-like receptor antagonist SCH23390. Fenoldopam increased cAMP production twofold and decreased Na(+)-K(+)-ATPase activity by 50% in the posterior gills. This effect was blocked by coinfusion with SCH23390, which had no effect on Na(+)-K(+)-ATPase activity by itself. Fenoldopam minimally decreased D1βR protein expression (10%) but did not affect Na(+)-K(+)-ATPase α-subunit protein expression. This study shows the presence of functional D1βR in the posterior gills of euryhaline crabs chronically exposed to low salinity and highlights the evolutionarily conserved function of the dopamine receptors on sodium homeostasis. Copyright © 2014 the American Physiological Society.

  2. Ecdysteroids regulate the levels of Molt-Inhibiting Hormone (MIH) expression in the blue crab, Callinectes sapidus.

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    Techa, Sirinart; Chung, J Sook

    2015-01-01

    Arthropod molt is coordinated through the interplay between ecdysteroids and neuropeptide hormones. In crustaceans, changes in the activity of Y-organs during the molt cycle have been regulated by molt-inhibiting hormone (MIH) and crustacean hyperglycemic hormone (CHH). Little has been known of the mode of direct effects of ecdysteroids on the levels of MIH and CHH in the eyestalk ganglia during the molt cycle. This study focused on a putative feedback of ecdysteroids on the expression levels of MIH transcripts using in vitro incubation study with ecdysteroids and in vivo RNAi in the blue crab, Callinectes sapidus. Our results show a specific expression of ecdysone receptor (EcR) in which EcR1 is the major isoform in eyestalk ganglia. The initial elevation of MIH expression at the early premolt stages is replicated by in vitro incubations of eyestalk ganglia with ecdysteroids that mimic the intrinsic conditions of D0 stage: the concentration (75 ng/ml) and composition (ponasterone A and 20-hydroxyecdysone at a 3:1 (w:w) ratio). Additionally, multiple injections of EcR1-dsRNA reduce MIH expression by 67%, compared to the controls. Our data provide evidence on a putative feedback mechanism of hormonal regulation during molting cycle, specifically how the molt cycle is repeated during the life cycle of crustaceans. The elevated concentrations of ecdysteroids at early premolt stage may act positively on the levels of MIH expression in the eyestalk ganglia. Subsequently, the increased MIH titers in the hemolymph at postmolt would inhibit the synthesis and release of ecdysteroids by Y-organs, resulting in re-setting the subsequent molt cycle.

  3. An insulin-like growth factor found in hepatopancreas implicates carbohydrate metabolism of the blue crab Callinectes sapidus.

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    Chung, J Sook

    2014-04-01

    Hyperglycemia that is caused by the release of crustacean hyperglycemic hormone (CHH) from the sinus gland to hemolymph is one of the hallmark physiological phenomena, occurring in decapod crustaceans experiencing stressful conditions. However, the mechanism(s) by which such elevated glucose levels return to resting levels is still unknown. Interestingly, noted is a difference in the clearance rate of hemolymph glucose between adult females and adult males of the blue crab, Callinectes sapidus: the former with more rapid clearance than the latter. The presence of an endogenous-insulin-like molecule is suggested in C. sapidus because an injection of bovine insulin, significantly reduces the levels of hemolymph glucose that were previously elevated by emersion stress or the glucose injection. Using 5' and 3' RACE, the full-length cDNA of an insulin-like molecule is isolated from the hepatopancreas of an adult female C. sapidus and shows the same putative sequence of an insulin-like androgenic gland factor (IAG) but differs in 5' and 3' UTR sequences. A knock-down study using five injections of double-stranded RNA of CasIAG-hep (dsRNA-CasIAG-hep, 10μg/injection) over a 10-day period reduces CasIAG-hep expression by ∼50%. The levels of hemolymph glucose are also kept higher in dsRNA-CasIAG-hep injected group than those treated with dsRNA-green fluorescent protein (dsRNA-IAG-hep) or saline. Most importantly, the hepatopancreas of dsRNA-CasIAG-hep injected animals contains amounts of carbohydrate (glucose, trehalose, and glycogen) significantly lower than those of control groups, indicating that the function of CasIAG-hep in carbohydrate metabolism in crustaceans is similar to carbohydrate metabolism in vertebrates. Copyright © 2014 Elsevier Inc. All rights reserved.

  4. Epidermal carbonic anhydrase activity and exoskeletal metal content during the molting cycle of the blue crab, Callinectes sapidus.

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    Calhoun, Stacy; Zou, Enmin

    2016-03-01

    During the crustacean molting cycle, the exoskeleton is first mineralized in postmolt and intermolt and then presumably demineralized in premolt in order for epidermal retraction to occur. The mineralization process calls for divalent metal ions, such as Ca(2+) and Mg(2+) , and bicarbonate ions whereas protons are necessary for dissolution of carbonate salts. Carbonic anhydrase (CA) has been suggested to be involved in exoskeletal mineralization by providing bicarbonate ions through catalyzing the reaction of carbon dioxide hydration. However, results of earlier studies on the role of epidermal CA in metal incorporation in crustacean exoskeleton are not consistent. This study was aimed to provide further evidence to support the notion that epidermal CA is involved in exoskeletal mineralization using the blue crab, Callinectes sapidus (Rathbun 1896), as the model crustacean. Significant increases first in calcium and magnesium then in manganese post-ecdysis indicate significant metal deposition during postmolt and intermolt. Significant positive correlation between calcium or magnesium content and epidermal CA activity in postmolt and intermolt constitutes evidence that CA is involved in the mineralization of the crustacean exoskeleton. Additionally, we proposed a hypothetical model to describe the role of epidermal CA in both mineralization and demineralization of the exoskeleton based on the results of epidermal CA activity and exoskeletal metal content during the molting cycle. Furthermore, we found that the pattern of epidermal CA activity during the molting cycle of C. sapidus is similar to that of ecdysteroids reported for the same species, suggesting that epidermal CA activity may be under control of the molting hormones. © 2016 Wiley Periodicals, Inc.

  5. Ecdysteroids regulate the levels of Molt-Inhibiting Hormone (MIH expression in the blue crab, Callinectes sapidus.

    Directory of Open Access Journals (Sweden)

    Sirinart Techa

    Full Text Available Arthropod molt is coordinated through the interplay between ecdysteroids and neuropeptide hormones. In crustaceans, changes in the activity of Y-organs during the molt cycle have been regulated by molt-inhibiting hormone (MIH and crustacean hyperglycemic hormone (CHH. Little has been known of the mode of direct effects of ecdysteroids on the levels of MIH and CHH in the eyestalk ganglia during the molt cycle. This study focused on a putative feedback of ecdysteroids on the expression levels of MIH transcripts using in vitro incubation study with ecdysteroids and in vivo RNAi in the blue crab, Callinectes sapidus. Our results show a specific expression of ecdysone receptor (EcR in which EcR1 is the major isoform in eyestalk ganglia. The initial elevation of MIH expression at the early premolt stages is replicated by in vitro incubations of eyestalk ganglia with ecdysteroids that mimic the intrinsic conditions of D0 stage: the concentration (75 ng/ml and composition (ponasterone A and 20-hydroxyecdysone at a 3:1 (w:w ratio. Additionally, multiple injections of EcR1-dsRNA reduce MIH expression by 67%, compared to the controls. Our data provide evidence on a putative feedback mechanism of hormonal regulation during molting cycle, specifically how the molt cycle is repeated during the life cycle of crustaceans. The elevated concentrations of ecdysteroids at early premolt stage may act positively on the levels of MIH expression in the eyestalk ganglia. Subsequently, the increased MIH titers in the hemolymph at postmolt would inhibit the synthesis and release of ecdysteroids by Y-organs, resulting in re-setting the subsequent molt cycle.

  6. Detecting selection in the blue crab, Callinectes sapidus, using DNA sequence data from multiple nuclear protein-coding genes.

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    Yednock, Bree K; Neigel, Joseph E

    2014-01-01

    The identification of genes involved in the adaptive evolution of non-model organisms with uncharacterized genomes constitutes a major challenge. This study employed a rigorous and targeted candidate gene approach to test for positive selection on protein-coding genes of the blue crab, Callinectes sapidus. Four genes with putative roles in physiological adaptation to environmental stress were chosen as candidates. A fifth gene not expected to play a role in environmental adaptation was used as a control. Large samples (n>800) of DNA sequences from C. sapidus were used in tests of selective neutrality based on sequence polymorphisms. In combination with these, sequences from the congener C. similis were used in neutrality tests based on interspecific divergence. In multiple tests, significant departures from neutral expectations and indicative of positive selection were found for the candidate gene trehalose 6-phosphate synthase (tps). These departures could not be explained by any of the historical population expansion or bottleneck scenarios that were evaluated in coalescent simulations. Evidence was also found for balancing selection at ATP-synthase subunit 9 (atps) using a maximum likelihood version of the Hudson, Kreitmen, and Aguadé test, and positive selection favoring amino acid replacements within ATP/ADP translocase (ant) was detected using the McDonald-Kreitman test. In contrast, test statistics for the control gene, ribosomal protein L12 (rpl), which presumably has experienced the same demographic effects as the candidate loci, were not significantly different from neutral expectations and could readily be explained by demographic effects. Together, these findings demonstrate the utility of the candidate gene approach for investigating adaptation at the molecular level in a marine invertebrate for which extensive genomic resources are not available.

  7. Detecting selection in the blue crab, Callinectes sapidus, using DNA sequence data from multiple nuclear protein-coding genes.

    Directory of Open Access Journals (Sweden)

    Bree K Yednock

    Full Text Available The identification of genes involved in the adaptive evolution of non-model organisms with uncharacterized genomes constitutes a major challenge. This study employed a rigorous and targeted candidate gene approach to test for positive selection on protein-coding genes of the blue crab, Callinectes sapidus. Four genes with putative roles in physiological adaptation to environmental stress were chosen as candidates. A fifth gene not expected to play a role in environmental adaptation was used as a control. Large samples (n>800 of DNA sequences from C. sapidus were used in tests of selective neutrality based on sequence polymorphisms. In combination with these, sequences from the congener C. similis were used in neutrality tests based on interspecific divergence. In multiple tests, significant departures from neutral expectations and indicative of positive selection were found for the candidate gene trehalose 6-phosphate synthase (tps. These departures could not be explained by any of the historical population expansion or bottleneck scenarios that were evaluated in coalescent simulations. Evidence was also found for balancing selection at ATP-synthase subunit 9 (atps using a maximum likelihood version of the Hudson, Kreitmen, and Aguadé test, and positive selection favoring amino acid replacements within ATP/ADP translocase (ant was detected using the McDonald-Kreitman test. In contrast, test statistics for the control gene, ribosomal protein L12 (rpl, which presumably has experienced the same demographic effects as the candidate loci, were not significantly different from neutral expectations and could readily be explained by demographic effects. Together, these findings demonstrate the utility of the candidate gene approach for investigating adaptation at the molecular level in a marine invertebrate for which extensive genomic resources are not available.

  8. The role of alternate hosts in the ecology and life history of Hematodinium sp., a parasitic dinoflagellate of the blue crab (Callinectes sapidus).

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    Lohan, Katrina M Pagenkopp; Reece, Kimberly S; Miller, Terrence L; Wheeler, Kersten N; Small, Hamish J; Shields, Jeffrey D

    2012-02-01

    Hematodinium sp. infections are relatively common in some American blue crab (Callinectes sapidus) populations in estuaries of the western Atlantic Ocean. Outbreaks of disease caused by Hematodinium sp. can be extensive and can cause substantial mortalities in blue crab populations in high salinities. We examined several species of crustaceans to determine if the same species of Hematodinium that infects C. sapidus is found in other crustaceans from the same localities. Over a 2-yr period, 1,829 crustaceans were collected from the Delmarva Peninsula, Virginia, examined for the presence of infections. A portion of the first internal transcribed spacer (ITS1) region of the ribosomal RNA (rRNA) gene complex from Hematodinium sp. was amplified and sequences were compared among 35 individual crustaceans putatively infected with the parasite, as determined by microscopic examination, and 4 crustaceans putatively infected based only on PCR analysis. Of the 18 crustacean species examined, 5 were infected with Hematodinium sp. after microscopic examination and PCR analysis, including 3 new host records, and an additional species was positive only via PCR analysis. The ITS1 rRNA sequences of Hematodinium sp. from the infected crustaceans were highly similar to each other and to that reported from C. sapidus (>98%). The similarity among these ITS1 sequences and similarities in the histopathology of infected hosts is evidence that the same species of Hematodinium found in C. sapidus infects a broad range of crustaceans along the Delmarva Peninsula. Our data indicate that the species of Hematodinium found in blue crabs from estuaries along the east coast of North America is a host generalist, capable of infecting hosts in different families within the Order Decapoda. Additionally, evidence indicates that it may be capable of infecting crustaceans within the Order Amphipoda.

  9. Molecular cloning, characterization and expression analysis of two juvenile hormone esterase-like carboxylesterase cDNAs in Chinese mitten crab, Eriocheir sinensis.

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    Xu, Yu; Zhao, Muzi; Deng, Yanfei; Yang, Yuanjie; Li, Xuguang; Lu, Quanping; Ge, Jiachun; Pan, Jianlin; Xu, Zhiqiang

    2017-03-01

    Precise regulation of methyl farnesoate (MF) titer is of prime importance throughout the crustacean life-cycle. Although the synthetic pathway of MF is well-documented, little is known about its degradation and recycling in crustaceans. Juvenile hormone esterase-like (JHE-like) carboxylesterase (CXE) is a key enzyme in MF degradation, thus playing a significant role in regulating the MF titer. We identified and characterized two cDNAs, Es-CXE1 and Es-CXE2, encoding JHE-like CXEs in Chinese mitten crab. Full-length cDNAs of Es-CXE1 and Es-CXE2 encode proteins composed of 584 and 597 amino acids, respectively, both of which contain a typical carboxylesterase domain. Alignment and phylogenetic analyses revealed that the Es-CXEs are highly similar to those of other crustaceans. To further validate their functions, we evaluated the mRNA expression patterns of the Es-CXEs in various tissues and in different physiological conditions. Tissue-specific expression analysis showed that the two Es-CXEs were predominantly expressed in the hepatopancreas and ovaries, which are the major tissues for MF metabolism. Es-CXE2 expression levels in the hepatopancreas and ovaries were about 100 and 25-fold higher, than the respective Es-CXE1 expressions. During ovarian rapid development stage, the global expressions of Es-CXEs were up-regulated in the hepatopancreas and down-regulated in the ovaries. After eyestalk ablation (ESA), the mRNA expressions of the two Es-CXEs were up-regulated in the hepatopancreas, further indicating their potential in degrading MF. Taken together, our results suggest that Es-CXEs, the key component of the juvenile hormone degradation pathway, may play vital roles in the development and reproduction of the Chinese mitten crab.

  10. Impact of molt-disrupting BDE-47 on epidermal ecdysteroid signaling in the blue crab, Callinectes sapidus, in vitro.

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    Booth, Ashley; Zou, Enmin

    2016-08-01

    Polybrominated diphenyl ethers (PBDEs) are environmentally pervasive flame retardants that have been linked with endocrine disruption in a variety of organisms. BDE-47, one of the most prevalent congeners found in aquatic environments, has recently been shown to inhibit crustacean molting, but little is known about the specific mechanism through which molt-inhibition occurs. This study examined whether the inhibitory effect on molting arises from the disruption of hormone signaling in the epidermis using the blue crab, Callinectes sapidus, as the model crustacean. First, we partially sequenced cDNA of N-acetyl-β-glucosaminidase (NAG) from the epidermis, a terminal enzyme in the molting hormone-signaling cascades that is commonly used as the biomarker for ecdysteroid signaling. This partial cDNA sequence was then used to create primers for quantification of NAG gene expression. Then, a new tissue culture technique was developed and dubbed the epidermis-with-exoskeleton (EWE) method, wherein epidermal tissue, along with the overlying exoskeleton, is immersed in a medium of physiologically relevant osmolarity. Using this EWE tissue culture method, we assessed the inducibility of NAG mRNA by 20-hydroxyecdysone (20-HE) in vitro. Exposures to 1μM 20-HE were found to induce NAG mRNA at a significantly higher level than the control. Using NAG expression as a biomarker for ecdysteroid signaling, the effects of BDE-47 were measured. BDE-47 alone at 100nM and a combination of 1μM BDE-47 and 1μM 20-HE were found to significantly increase NAG mRNA. A trend of increasing NAG gene expression in the binary BDE-47 exposure as compared to 1μM BDE-47 and 1μM 20-HE alone is suggestive of a synergistic effect of these two chemicals on ecdysteroid signaling in the cultured epidermis. Discussion on the mechanism for inhibition of crustacean molting by BDE-47 is presented. Copyright © 2016 Elsevier B.V. All rights reserved.

  11. Effects of Hypoxia and Hypercapnic Hypoxia on Oxygen Transport and Acid-Base Status in the Atlantic Blue Crab, Callinectes sapidus, During Exercise.

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    Lehtonen, Mark P; Burnett, Louis E

    2016-11-01

    The responses of estuarine invertebrates to hypoxic conditions are well established. However, many studies have investigated hypoxia as an isolated condition despite its frequent co-occurrence with hypercapnia (elevated CO2 ). Although many studies suggest deleterious effects, hypercapnia has been observed to improve blue crab walking performance in hypoxia. To investigate the physiological effects of combined hypercapnic hypoxia, we measured Po2 , pH, [l-lactate], Pco2 , and total O2 in pre- and postbranchial hemolymph sampled from blue crabs during walking exercise. Crabs walked at 8 m min(-1) on an aquatic treadmill in normoxic (100% air saturation), moderately hypoxic (50%), and severely hypoxic (20%) seawater with and without the addition of hypercapnia (about 2% CO2 ). Respiration was almost completely aerobic in normoxic conditions, with little buildup of lactate. During exercise under severe hypoxia, lactate increased from 1.4 to 11.0 mM, indicating a heavy reliance on anaerobic respiration. The O2 saturation of arterial hemocyanin was 47% in severe hypoxia after 120 min, significantly lower than in normoxia (80%). However, the addition of hypercapnia significantly increased the percentage saturation of arterial hemocyanin in severe hypoxia to 92% after 120 min of exercise, equivalent to normoxic levels. Hypercapnia in severe hypoxia also caused a marked increase in hemolymph Pco2 (around 1.1 kPa), but caused only a minor decrease in pH of 0.1 units. We suggest that the improved O2 saturation at the gills results from a specific effect of molecular CO2 on hemocyanin oxygen binding affinity, which works independently of and counter to the effects of decreased pH. © 2016 Wiley Periodicals, Inc.

  12. Mitochondrial DNA Variation Reveals a Sharp Genetic Break within the Distribution of the Blue Land Crab Cardisoma guanhumi in the Western Central Atlantic

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    Maria Rosimere Xavier Amaral

    2015-08-01

    Full Text Available The blue land crab Cardisoma guanhumi is widely distributed throughout tropical and subtropical estuarine regions in the Western Central Atlantic (WCA. Patterns of population genetic structure and historical demographics of the species were assessed by mtDNA control region sequence analysis to examine the connectivity among five populations (n = 97 within the region for future conservation strategies and decision-making of fishery management. A total of 234 polymorphic nucleotides were revealed within the sequence region, which have defined 93 distinct haplotypes. No dominant mtDNA haplotypes were found but instead a distribution of a few low-frequency recurrent haplotypes with a large number of singletons. A NJ-tree and a median-joining haplotype network revealed two distinct clusters, corresponding to individuals from estuaries located along the Caribbean Sea and Brazilian waters, respectively. AMOVA and FST statistics supported the hypothesis that two main geographic regions exists. Phylogeographical discontinuity was further demonstrated by the Bayesian assignment analysis and a significant pattern of isolation-by-distance. Additionally, tests of neutral evolution and analysis of mismatch distribution indicate a complex demographic history in the WCA, which corresponds to bottleneck and subsequent population growth. Overall, a sharp genetic break between Caribbean and Brazilian populations raised concerns over the conservation status of the blue land crab.

  13. Mitochondrial DNA Variation Reveals a Sharp Genetic Break within the Distribution of the Blue Land Crab Cardisoma guanhumi in the Western Central Atlantic.

    Science.gov (United States)

    Amaral, Maria Rosimere Xavier; Albrecht, Marc; McKinley, Alan Shane; de Carvalho, Adriana Márcia Ferreira; de Sousa Junior, Severino Cavalcante; Diniz, Fabio Mendonça

    2015-08-19

    The blue land crab Cardisoma guanhumi is widely distributed throughout tropical and subtropical estuarine regions in the Western Central Atlantic (WCA). Patterns of population genetic structure and historical demographics of the species were assessed by mtDNA control region sequence analysis to examine the connectivity among five populations (n = 97) within the region for future conservation strategies and decision-making of fishery management. A total of 234 polymorphic nucleotides were revealed within the sequence region, which have defined 93 distinct haplotypes. No dominant mtDNA haplotypes were found but instead a distribution of a few low-frequency recurrent haplotypes with a large number of singletons. A NJ-tree and a median-joining haplotype network revealed two distinct clusters, corresponding to individuals from estuaries located along the Caribbean Sea and Brazilian waters, respectively. AMOVA and FST statistics supported the hypothesis that two main geographic regions exists. Phylogeographical discontinuity was further demonstrated by the Bayesian assignment analysis and a significant pattern of isolation-by-distance. Additionally, tests of neutral evolution and analysis of mismatch distribution indicate a complex demographic history in the WCA, which corresponds to bottleneck and subsequent population growth. Overall, a sharp genetic break between Caribbean and Brazilian populations raised concerns over the conservation status of the blue land crab.

  14. Effects of gamma irradiation on the physical and sensory quality and inactivation of Listeria monocytogenes in blue swimming crab meat (Portunas pelagicus)

    Science.gov (United States)

    Suklim, Kannapha; Flick, George J.; Vichitphan, Kanit

    2014-10-01

    Blue swimming crab lump (backfin) meat were exposed to 2, 4, and 6 kGy doses of Co60 irradiation and evaluated for changes in physical, sensory properties, and Listeria monocytogenes inactivation. Irradiation up to 6 kGy resulted in no textural changes (p>0.05) in maximum shear forces; however, these exposures resulted in sensory quality changes (p0.05) on L* color value. Irradiation at 4 and 6 kGy resulted in listericidal reductions greater than 6.65 (Department of Medical Science, Ministry of Health, Thailand, [DMST] 1783) and 7.56 logs (DMST 4553). Irradiation doses of 1 and 2 kGy resulted in a reduction of 2.10 and 5.35 logs respectively of L. monocytogenes DMST 1783 and 1.56 and 4.19 logs respectively of L. monocytogenes DMST 4553. The D10 values of L. monocytogenes DMST 1783 and 4553 were 0.35 and 0.45 kGy. The study indicated that low-dose gamma irradiation would increase the safety of blue swimming crab meat without unacceptable changes in texture and L* color value.

  15. Two incidents of venomous snakebite on juvenile blue and Sykes monkeys (Cercopithecus mitis stuhlmanni and C. m. albogularis).

    Science.gov (United States)

    Foerster, Steffen

    2008-10-01

    Although rarely observed, predation is thought to be an important factor in the evolution of primate life histories and behavior. Here I describe two incidents of snake predation on Cercopithecus mitis guenons from Kenya. The first case involved a juvenile blue monkey (Cercopithecus mitis stuhlmanni) in the Kakamega Forest, which died following a bite by a Gaboon viper (Bitis gabonica gabonica). The snake's attempts to ingest its prey were unsuccessful. In the second incident, a juvenile Sykes monkey (Cercopithecus mitis albogularis) at Gede Ruins National Monument died suddenly after suffering symptoms that are characteristic of bites inflicted by black mambas (Dendroaspis polylepis). In both cases circumstantial evidence suggests that attacks occurred during extended play sessions in dense vegetation on or near the ground. If so, the observations support the hypothesis that play may be a costly activity.

  16. Spatial dynamics of large-scale, multistage crab (Callinectes sapidus) dispersal: Determinants and consequences for recruitment

    Science.gov (United States)

    Etherington, L.L.; Eggleston, D.B.

    2003-01-01

    We assessed determinants and consequences of multistage dispersal on spatial recruitment of the blue crab, Callinectes sapidus, within the Croatan, Albemarle, Pamlico Estuarine System (CAPES), North Carolina, U.S.A. Large-scale sampling of early juvenile crabs over 4 years indicated that spatial abundance patterns were size-dependent and resulted from primary post-larval dispersal (pre-settlement) and secondary juvenile dispersal (early post-settlement). In general, primary dispersal led to high abundances within more seaward habitats, whereas secondary dispersal (which was relatively consistent) expanded the distribution of juveniles, potentially increasing the estuarine nursery capacity. There were strong relationships between juvenile crab density and specific wind characteristics; however, these patterns were spatially explicit. Various physical processes (e.g., seasonal wind events, timing and magnitude of tropical cyclones) interacted to influence dispersal during multiple stages and determined crab recruitment patterns. Our results suggest that the nursery value of different habitats is highly dependent on the dispersal potential (primary and secondary dispersal) to and from these areas, which is largely determined by the relative position of habitats within the estuarine landscape.

  17. Seasonal variations in reproductive activity of the blue crab, Callinectes sapidus: Vitellogenin expression and levels of vitellogenin in the hemolymph during ovarian development.

    Science.gov (United States)

    Thongda, Willawan; Chung, J Sook; Tsutsui, Naoaki; Zmora, Nilli; Katenta, Anna

    2015-01-01

    In general, season affects the physiology and behavior of most animals. Warmer temperatures accelerate growth and reproduction of ectotherms, whereas these processes are slowed or halted in colder temperatures. Female blue crabs, Callinectes sapidus inhabiting the Chesapeake Bay, exhibit a seasonal migratory behavior that is closely tied with spawning and the release of larvae. To better understand reproductive activities of the migratory adult females, we examined two reproductive parameters of these crabs sampled monthly (April-December, 2006): the levels of vitellogenin (VtG) in the hemolymph and VtG expression in the hepatopancreas and ovary. The full-length cDNA of VtG (CasVtG-ova) has been isolated from the ovary. The putative CasVtG sequence found in the ovary is >99% identical to that of the hepatopancreas and is related most closely to the sequences reported in other crab species. In female C. sapidus, the hepatopancreas produces over 99% of the total VtG toward the ovarian development. Ovarian stages 2 and 3 in the sampled females are characterized by significant high levels of VtG in hemolymph and VtG expression in both the hepatopancreas and ovary. However, during the southbound migration in fall, females at ovarian stages 2 and 3 have decreased VtG levels, compared to those in spring and summer. The decreased vitellogenesis activity during the fall migration suggests seasonal adaptation to ensure successful spawning and the larval release. Copyright © 2014 Elsevier Inc. All rights reserved.

  18. Cloning of an insulin-like androgenic gland factor (IAG) from the blue crab, Callinectes sapidus: implications for eyestalk regulation of IAG expression.

    Science.gov (United States)

    Chung, J Sook; Manor, R; Sagi, A

    2011-08-01

    In malacostracan crustaceans, sex differentiation is uniquely regulated by a hormone secreted by the male-specific androgenic gland (AG). An isopod AG hormone was the first to be structurally elucidated and was found to belong to the insulin superfamily of proteins. Recently, it has been found that the AGs of several decapod crustaceans express insulin-like androgenic gland factors (IAGs), whose function is believed to be similar to that of the isopod AG hormone. Here we report the isolation from the blue crab Callinectes sapidus of the full-length cDNA encoding a candidate insulin-like AG hormone, termed Cas-IAG. The predicted protein Cas-IAG was encoded as a precursor consisting of a signal peptide, the B chain, the C peptide, and the A chain in that order. While the AG was the main source of Cas-IAG expression, as found in other decapod species, the hepatopancreas of male Callinectes sapidus crabs displayed minor Cas-IAG expression. Eyestalk ablation confirmed the presence of a possible endocrine axis between the eyestalk ganglia and the AG, implying that Cas-IAG expression is negatively regulated by (a) substance(s) present in the eyestalk ganglia. Copyright © 2011 Elsevier Inc. All rights reserved.

  19. Dietary Methionine Requirement of Juvenile Swimming Crab ( Portunus trituberculatus)%三疣梭子蟹幼蟹的蛋氨酸需要量

    Institute of Scientific and Technical Information of China (English)

    金敏; 王猛强; 霍雅文; 黄文文; 候迎梅; 丁立云; 周歧存

    2015-01-01

    An 8-week growth trial was conducted to determine the dietary methionine requirement of juvenile swimming crabs ( Portunus trituberculatus) . Six isonitrogenous and isoenergetic diets ( 49. 5% crude protein and 18. 2 MJ/kg gross energy) were formulated with dietary methionine supplement levels of 0, 0. 25%, 0.50%, 0.75%, 1. 00% and 1. 25%, respectively, and the measured values of dietary methionine contents were 0.61%, 0.77%, 0.97%, 1.18%, 1.44% and 1.64%, respectively. Each diet was randomly assigned to 3 replicates of 60 juvenile swimming crabs, and each replicate had 20 crabs with the average body weight of (11.27±0.13) g which were stocked in rectangle plastic baskets. The results showed that dietary methionine content had significant effects on weight gain ratio ( WGR) , specific growth rate ( SGR) , protein productive value ( PPV) , feed efficiency ( FE) and protein efficiency ratio ( PER) ( P0. 05 ) , but when dietary methionine content increased from 1.44% to 1.64%, the WGR and SGR decreased significantly ( P0.05), and there were no significant differences in the amino acid composition of muscle among all groups ( P>0. 05 ) . The dietary methionine requirement is 1. 07% of diet (2.16% of dietary protein) of juvenile swimming crabs estimated by broken-line model base on SGR as an e-valuation index. Considering the dissolve-loss of crystalline amino acids in seawater, make the methionine dis-solve-loss rate of diet immersed in seawater within 60 min is 10.21%, the determined methionine requirement of juvenile swimming crabs is 0.96% of diet (1.94% of dietary protein).%为确定三疣梭子蟹幼蟹对蛋氨酸的需要量,进行了为期8周的生长试验. 试验设计6种等氮等能饲料(粗蛋白质49. 5%,总能18. 2 MJ/kg) ,饲料中蛋氨酸的添加水平分别为 0、0.25%、0.50%、0.75%、1.00%和1.25%,实测各饲料蛋氨酸含量分别为0.61%、0.77%、0.97%、1.18%、1.44%和 1. 64%. 每种饲料饲喂 60 只蟹,设成 3 个重复,每个

  20. Effects of salinity on the accumulation of hemocyte aggregates and bacteria in the gills of Callinectes sapidus, the Atlantic blue crab, injected with Vibrio campbellii.

    Science.gov (United States)

    Ikerd, Jennifer L; Burnett, Karen G; Burnett, Louis E

    2015-05-01

    In addition to respiration and ion regulation, crustacean gills accumulate and eliminate injected particles, along with hemocyte aggregates that form in response to those particles. Here we report that the dose of Vibrio campbellii previously shown to induce a decrease in respiration and hemolymph flow across the gill in the Atlantic blue crab, Callinectes sapidus, also triggered the formation of aggregates containing four or more hemocytes in the gills, compared with saline-injected controls. More bacteria were trapped and rendered non-culturable per unit weight by anterior respiratory gills than posterior gills specialized for ion regulation. Further, more bacteria accumulated in the anterior gills of animals held at 30 ppt than those at 10 ppt. Thus, the role of the gills in immune defense comes at an energetic cost to this and likely to other crustaceans; this cost is influenced by acclimation salinity and the position and specialized function of individual gills. Copyright © 2014 Elsevier Inc. All rights reserved.

  1. Effects of cadmium on survival and bioenergetics of juvenile Callinectes sapidus at different salinities

    Energy Technology Data Exchange (ETDEWEB)

    Guerin, J.L. [Environmental Protection Agency, Gulf Breeze, FL (United States). Gulf Breeze Environmental Research Lab.; Stickle, W.B. [Louisiana State Univ., Baton Rouge, LA (United States). Dept. of Zoology and Physiology

    1995-12-31

    Juvenile blue crabs, Callinectes sapidus, from the Barataria estuary (Louisiana, USA) were exposed to a range of dissolved cadmium concentrations at 2.5 and 25{degree}/ooS to determine their response to cadmium. 21-day LC{sub 50}`s were an order of magnitude lower at 2.5{degree}/oo (19ppb) than at 25{degree}/oo (186ppb). Crabs were exposed to Cd levels of 0, 50 and 100ppb for measurements of physiological rates. Respiration was the primary component (x = 86.2%) of the energy expenditure budget in all cases, relative to excretion. Rates of energy expenditure did not vary with cadmium concentration at either salinity and were much lower than those of energy consumption and absorption. Scope for growth paralleled energy consumption and absorption. Scope for growth did not vary as a function of cadmium concentration at 25{degree}/ooS; at 2.5{degree}/ooS, however, scope for growth was significantly lower in crabs exposed to 50 and 100ppb Cd relative to control crabs. Cadmium levels of up to 100ppb do not stress juvenile blue crabs at 25{degree}/ooS; but at 2.5{degree}/ooS, these same levels of Cd result in mortality and sub-lethal stress. This finding is important since nursery grounds for juveniles of this species often lie in low salinity, estuarine waters, and dissolved cadmium levels as high as 50ppb have been reported in Louisiana estuaries.

  2. Transport of Blue Crab Larvae in the Northern Gulf of Mexico During the Deepwater Horizon Oil Spill

    Science.gov (United States)

    2015-05-11

    Woods Hole Oceanographic Institution, Woods Hole, Massachusetts 02543, USA lDepartment of Ecology and Evolutionary Biology , Tulane University, New...Coast Shelf Sci 60: 611-617 Martin PJ, Barron CN, Smedstad LF, Campbell TJ and oth- ers (2009) Users manual for the Navy Coastal Ocean Model (NCOM...stock in North Carolina. In: Kruse GH, Eckert GL, Foy RJ, Upcius RN, Sainte-Marie B, Stram DL, Woodby D (eds) Biology and management of exploited crab

  3. Good Crab, Bad Crab

    Science.gov (United States)

    Are crabs friends or foes of marsh grass, benefit or detriment to the salt marsh system? We examined Uca pugilator (sand fiddler) and Sesarma reticulatum (purple marsh crab) with Spartina patens (salt marsh hay) at two elevations (10 cm below MHW and 10 cm above MHW) in mesocosms...

  4. Elevated water temperature increases the levels of reo-like virus and selected innate immunity genes in hemocytes and hepatopancreas of adult female blue crab, Callinectes sapidus.

    Science.gov (United States)

    Chung, J Sook; Pitula, J S; Schott, E; Alvarez, J V; Maurer, L; Lycett, K A

    2015-11-01

    Seasonal changes in water temperature directly affect the aquatic ecosystem. The blue crab, Callinectes sapidus, inhabiting the Chesapeake Bay has been adapted to seasonal changes of the environmental conditions. In this, the animals halt their physiological process of the growth and reproduction during colder months while they resume these processes as water temperatures increase. We aimed to understand the effect of the elevated temperatures on a disease progression of reo-like virus (CsRLV) and innate immunity of adult female C. sapidus. Following a rise in water temperature from 10 to 23 °C, CsRLV levels in infected crabs rose significantly in hemocytes and multiple organs. However, in hemocytes, the elevated temperature had no effect on the levels of three innate immune genes: Cas-ecCuZnSOD-2, CasPPO and CasLpR three carbohydrate metabolic genes: CasTPS, CasGlyP; and CasTreh and the total hemocyte counts (THC). Interestingly, the hemocytes of CsRLV infected animals exposed to 23 °C for 10 days had significantly elevated levels of Cas-ecCuZnSOD-2 and CasTPS, compared to those of the uninfected ones also exposed to the same condition and compared to hatchery-raised females kept at 23 °C. Despite the lack of changes in THC, the types of hemocytes from the animals with high CsRLV levels differed from those of uninfected ones and from hatchery animals kept at 23 °C: CsRLV-infected crabs had hemocytes of smaller size with less cytosolic complexity than uninfected crabs. It therefore appears that the change in temperature influences rapid replication of CsRLV in all internal tissues examined. This implies that CsRLV may have broad tissue tropism. Interestingly, the digestive tract (mid- and hindgut) contains significantly higher levels of CsRLV than hemocytes while hepatopancreas and ovary have lower levels than hemocytes. Innate immune responses differ by tissue: midgut and hepatopancreas with upregulated Cas-ecCuZnSOD-2 similar to that found in hemocytes. By

  5. The trophic position of the Atlantic blue crab Callinectes sapidus Rathbun 1896 in the food web of Parila Lagoon (South Eastern Adriatic, Croatia: a first assessment using stable isotopes.

    Directory of Open Access Journals (Sweden)

    G. MANCINELLI

    2016-09-01

    Here, carbon and nitrogen isotopic signatures were measured in C. sapidus and other representative taxa of the benthic flora and fauna sampled in summer in the Parila Lagoon, a coastal basin located in the Neretva River estuary area (Croatia. d15N values of individual blue crab specimens were used to calculate their trophic position (TP , using the filter feeder mussel Mytilus galloprovincialis as the isotopic baseline. In general, the isotopic signature of C. sapidus was comparable with those characterizing invertebrate and fish predators (e.g., Hexaplex trunculus, Gobius niger. An average  trophic position of 3.73 was estimated for the blue crab population. However, a considerable inter-individual variation was observed in TP values, significantly related with the size of the specimens. Interestingly, a hump-shaped quadratic polynomial resulted the best fitting model for the data, characterized for small-size individuals by a positive body size-TP relationship, leveling or even turning negative for larger adult crabs. The interplay between environmental factors and ontogenetic diet shifts in determining the trophic position of the blue crab and, ultimately, its ecological impact on the benthic community of the Parila Lagoon is discussed.

  6. 七种捕食性鱼类对中华绒螯蟹幼蟹捕食风险的评估%ASSESSMENT OF PREDATION RISKS OF SEVEN PREDACIOUS FISH ON JUVENILE CHINESE MITTEN CRAB (ERIOCHEIR SINENSIS)

    Institute of Scientific and Technical Information of China (English)

    罗鸣钟; 张堂林; 张超文; 李钟杰; 刘家寿; 吴小平

    2012-01-01

    分别以鲤、鳜、斑点叉尾鲴、黄颡鱼、瓦氏黄颡鱼、大口鲇和乌鳢作为捕食者,以中华绒螯蟹幼蟹作为猎物,在室内水泥池(2.4 m3)进行捕食试验.以日捕获率和日摄食率为指标,评估这些鱼类对幼蟹的捕食作用和危害程度,为提高湖泊幼蟹放流效果、建立蟹—鱼复合的优质高效养殖模式提供科学依据.在幼蟹完全暴露的条件下,经过多次(至少9次)重复的试验(短期1d和长期7d),鳜对不同大小的硬壳和软壳(刚蜕壳的)幼蟹没有任何捕食作用;黄颡鱼对硬壳和软壳幼蟹也没有捕食作用,但还需做进一步观察;虽然鲤、瓦氏黄颡鱼对硬壳蟹的捕获率低,但对软壳的幼蟹有较大的危害性,对幼蟹的日摄食率分别为0.070%、0.012%;大口鲇、斑点叉尾鲴、乌鳢对幼蟹具有较强的捕食能力,对幼蟹的日摄食率分别为0.122%、0.188%和0.284%.根据这些研究结果,可以建议:(1)在池塘和湖泊河蟹养殖中,完全可以将鳜作为套养或混养对象,以期提高养殖效益;(2)在河蟹放养的湖泊,需要抑制乌鳢和大口鲇种群,适当减少鲤和瓦氏黄颡鱼丰度,以期减少这些鱼类的捕食作用,提高幼蟹存活率;(3)在河蟹养殖池塘,不能放养乌鳢、大口鲇、斑点叉尾鲴、瓦氏黄颡鱼和鲤.%The lake and pond cultures of Chinese mitten crab (Eriocheir sinensis) are two main farming modes with high commercial benefits in the Changjiang River basin. Unfortunately, recapture rates of the released crabs are often considerably lower mainly due to the predation of predacious fish. In order to provide scientific bases for improving the survival of the crab stocked in lakes and establishing a crab-fish polyculture mode with high returns on investment, a series of predation experiments of indoor cement pools were conducted to assess predation risks on juvenile E. sinensis by Cyprinus carpio, Siniperca chuatsi, Ictalurus punctatu

  7. Sexual maturity and reproductive period of the swimming blue crab Callinectes danae Smith, 1869 (Brachyura: Portunidae from Guaratuba Bay, Paraná State, southern Brazil

    Directory of Open Access Journals (Sweden)

    Murilo Zanetti Marochi

    Full Text Available This work aims to estimate the average size at the onset of morphological and physiological sexual maturity and the reproductive period of Callinectes danae. Specimens were captured from a shrimp fishing boat equipped with a trawl net from March 2009 to February 2010. After sorting, crabs were sexed, and the following morphometric dimensions were measured: carapace width (CW, length and height of the major (MAP and HMAP, and the minor cheliped propodus (MIP and HMIP for both sexes, and the abdominal width for females (AW. The onset of morphological maturity was estimated with the REGRANS program, in which the inflection point is calculated. The size at the onset of physiological maturity was determined by logistic regressions fitted to the relationships between the percentages of juvenile and adult individuals of each CW. A total of 893 individuals were sampled. Of these individuals, 389 were males, 472 non-ovigerous females, and 32 ovigerous females. The CW ranged from 19.81 to 117.17 mm for males, 19.91 to 113.11 mm for non-ovigerous females, and 70.55 to 88.60 mm for ovigerous females. Morphological sexual maturity was attained at 86.47 mm CW (males and 67.87 mm CW (females. The size at the onset of physiological maturity was calculated to be 86.50 mm CW (males and 67.00 mm CW (females. Due to the closeness of these values, both techniques were deemed suitable for determination of the onset of sexual maturity in C. danae. This species reproduces throughout the year, but reproduction is more intense during the winter. Mature males are present throughout the year. Data from this investigation will help resource managers to develop strategies that will ensure a sustainable harvest of this important species of swimming crab in southern Brazil.

  8. Gill (Na+,K+)-ATPase from the blue crab Callinectes danae: modulation of K+-phosphatase activity by potassium and ammonium ions.

    Science.gov (United States)

    Masui, D C; Furriel, R P M; Mantelatto, F L M; McNamara, J C; Leone, F A

    2003-04-01

    The kinetic properties of a microsomal gill (Na(+),K(+))-ATPase from the blue crab Callinectes danae were analyzed using the substrate p-nitrophenylphosphate. The (Na(+),K(+))-ATPase hydrolyzed PNPP obeying cooperative kinetics (n=1.5) at a rate of V=125.4+/-7.5 U mg(-1) with K(0.5)=1.2+/-0.1 mmol l(-1); stimulation by potassium (V=121.0+/-6.1 U mg(-1); K(0.5)=2.1+/-0.1 mmol l(-1)) and magnesium ions (V=125.3+/-6.3 U mg(-1); K(0.5)=1.0+/-0.1 mmol l(-1)) was cooperative. Ammonium ions also stimulated the enzyme through site-site interactions (n(H)=2.7) to a rate of V=126.1+/-4.8 U mg(-1) with K(0.5)=13.7+/-0.5 mmol l(-1). However, K(+)-phosphatase activity was not stimulated further by K(+) plus NH(4)(+) ions. Sodium ions (K(I)=36.7+/-1.7 mmol l(-1)), ouabain (K(I)=830.3+/-42.5 micromol l(-1)) and orthovanadate (K(I)=34.0+/-1.4 nmol l(-1)) completely inhibited K(+)-phosphatase activity. The competitive inhibition by ATP (K(I)=57.2+/-2.6 micromol l(-1)) of PNPPase activity suggests that both substrates are hydrolyzed at the same site on the enzyme. These data reveal that the K(+)-phosphatase activity corresponds strictly to a (Na(+),K(+))-ATPase in C. danae gill tissue. This is the first known kinetic characterization of K(+)-phosphatase activity in the portunid crab C. danae and should provide a useful tool for comparative studies.

  9. Avaliação de contaminação por metais pesados em amostras de siris azuis Assessment of heavy metal contamination in blue crab specimens

    Directory of Open Access Journals (Sweden)

    Rossana Helena Pitta Virga

    2007-12-01

    Full Text Available Metais pesados por não serem biodegradáveis podem se acumular nos tecidos vivos ao longo da cadeia alimentar chegando ao ser humano principalmente por meio da alimentação. Siris e outros organismos que se alimentam de matéria orgânica existente em sistemas aquáticos, podem absorver uma carga maior destes elementos tóxicos e assim, representar um risco potencial à saúde da população da região. Neste trabalho, foram realizados estudos quantitativos sobre o teor de Pb, Cd, Cr, Zn e Cu em amostras (n = 144 de siris azuis do gênero Callinectes sp., coletados ao longo do rio Cubatão, utilizando um Espectrofotômetro de Absorção Atômica por Chama (FSAA. Exceto para o Cr, onde o valor médio obtido neste trabalho ficou acima do estabelecido para qualquer tipo de alimento pela legislação brasileira, todos os outros resultados estiveram abaixo dos limites máximos recomendados por agências de saúde. Uma discussão é apresentada sobre a contribuição ao valor provisório de ingestão diária tolerável (PTDI, sugerido pela Organização Mundial de Saúde, devido ao consumo de carne de siri pela população.Because they are nonbiodegradable, heavy metals can accumulate in the living tissues along the food chain, reaching humans mainly through food. Swimming crabs and other organisms which feed on organic matter that is present in aquatic systems can ingest high loads of these toxic elements; hence, they pose a potential risk to the health of regional populations. This work involved a quantitative analysis of Pb, Cd, Cr, Zn and Cu in blue crab specimens of the genus Callinectes sp. (n = 144 collected along the Cubatão river, using Flame Atomic Absorption Spectrophotometry (FAAS. Except for Cr, whose average value exceeded the limit allowed for any type of food by Brazilian regulations, all the other elements fell below the maximum content recommended by health agencies. This paper also discusses the contribution of crab meat consumed

  10. Ecology and Population Dynamics of Juvenile Dungeness Crab in Grays Harbor Estuary and Adjacent Nearshore Waters of the Southern Washington Coast

    Science.gov (United States)

    1989-10-01

    132 ii LIST OF TABLES Table 4.1. Temporal range of occurrence of laral Dungeness crab...1986 there was no major crab settlement observed on the outer coast between Bodega Bay, California and Tofino, B.C. From May to July, sustained...Dungeness crab occur nearshore of San Francisco Bay and north to Bodega Bay in early May in accord with evidence of timing of occurrence in the same

  11. Capture and commercialization of blue land crabs ("guaiamum" Cardisoma guanhumi (Lattreille, 1825 along the coast of Bahia State, Brazil: an ethnoecological approach

    Directory of Open Access Journals (Sweden)

    Firmo Angélica MS

    2012-03-01

    Full Text Available Abstract Background Blue Land Crab (Cardisoma guanhumi is one of the most important crustacean species captured and commercialized in Brazil. Although this species is not considered to be threatened with extinction, populations of C. guanhumi are known to be rapidly diminishing due to heavy harvesting pressures and degradation of their natural habitats, highlighting the necessity of developing and implanting management and protection strategies for their populations. There have been no ethnozoological publications that have focused specifically on C. guanhumi, in spite of importance of this type of information for developing efficient management plans of resource utilization. So, the present work describes the ethnoecological aspects of the capture and commercialization of C. guanhumi by a fishing community in northeastern Brazil. Methods Field work was carried out in the municipality of Mucuri, Bahia in Brazil, between the months of January and March/2011 through the use of open semi-structured interviews with all of the crustacean harvesters in city who acknowledged their work in capturing this species, totaling 12 interviewees. The informants were identified through the use of the "snowball" sampling technique. In addition to the interviews themselves, the "guided tour" technique and direct observations was employed. Results According all the interviewees, the C. guanhumi is popularly called "guaiamum" and is collected in "apicum" zones. They recognize sexual dimorphism in the species based on three morphological characteristics and the harvesters also pointed two stages in the reproductive cycle during the year and another phase mentioned by the interviewees was ecdysis. All of the interviewed affirmed that the size and the quantities C. guanhumi stocks in Mucuri have been diminishing. All of the interviewees agreed that the species and other mangrove resources constituted their principal source of income. The harvesters dedicated three to

  12. Characterization of cholinesterases present in brain and muscle tissues of juvenile blue shark (Prionace glauca

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    Luís Miguel Fonseca Alves

    2014-06-01

    Regarding the in vitro exposure to chlorpyrifos-oxon, we have observed a dose-response pattern showing higher ChE inhibitions with increasing pesticide concentrations and with more than 90% inhibition in the highest concentrations, which reveals the potential of this biomarker for biomonitoring studies and contaminant effect assessment in the blue shark.

  13. Acute toxicity, accumulation and tissue distribution of copper in the blue crab Callinectes sapidus acclimated to different salinities: In vivo and in vitro studies

    Energy Technology Data Exchange (ETDEWEB)

    De Martinez Gaspar Martins, Camila [Programa de Pos-Graduacao em Ciencias Fisiologicas - Fisiologia Animal Comparada, Instituto de Ciencias Biologicas, Universidade Federal do Rio Grande (FURG), Campus Carreiros, Av. Italia km 8, 96201-900, Rio Grande, RS (Brazil); Barcarolli, Indianara Fernanda; Menezes, Eliana Jaime de; Mussoi Giacomin, Marina [Instituto de Ciencias Biologicas, Universidade Federal do Rio Grande (FURG), Campus Carreiros, Av. Italia km 8, 96201-900, Rio Grande, RS (Brazil); Wood, Chris M. [McMaster University, Department of Biology, 1280 Main Street West, Hamilton, ON, L8S 4K1 (Canada); Bianchini, Adalto, E-mail: adaltobianchini@furg.br [Programa de Pos-Graduacao em Ciencias Fisiologicas - Fisiologia Animal Comparada, Instituto de Ciencias Biologicas, Universidade Federal do Rio Grande (FURG), Campus Carreiros, Av. Italia km 8, 96201-900, Rio Grande, RS (Brazil); Instituto de Ciencias Biologicas, Universidade Federal do Rio Grande (FURG), Campus Carreiros, Av. Italia km 8, 96201-900, Rio Grande, RS (Brazil)

    2011-01-17

    In vivo and in vitro studies were performed to evaluate acute toxicity, organ-specific distribution, and tissue accumulation of copper in Callinectes sapidus acclimated to two different experimental salinities (2 and 30 ppt). Blue crabs were quite tolerant to copper. Acute dissolved copper toxicity (96-h LC{sub 50} and its corresponding 95% confident interval) was higher at salinity 2 ppt (5.3 (3.50-8.05) {mu}M Cu) than at 30 ppt (53.0 (27.39-102.52) {mu}M Cu). The difference between salinities can be completely explained based on the water chemistry because it disappeared when 96-h LC{sub 50} values were expressed as the free Cu{sup 2+} ion (3.1 (1.93-4.95) {mu}M free Cu at 2 ppt versus 5.6 (2.33-13.37) {mu}M free Cu at 30 ppt) or the Cu{sup 2+} activity (1.4 (0.88-2.26) {mu}M Cu activity at 2 ppt versus 1.7 (0.71-4.07) {mu}M Cu activity at 30 ppt). The relationships between gill Cu burden and % mortality were very similar at 2 and 30 ppt, in accord with the Biotic Ligand Model. In vivo experiments showed that copper concentration in the hemolymph is not dependent on metal concentration in the surrounding medium at either experimental salinity. They also showed that copper flux into the gills is higher than into other tissues analyzed, and that anterior and posterior gills are similarly important sites of copper accumulation at both experimental salinities. In vitro experiments with isolated-perfused gills showed that there is a positive relationship between copper accumulation in this tissue and the metal concentration in the incubation media for both anterior and posterior gills. A similar result was observed at both low and high salinities. Furthermore, in vitro experiments showed that copper accumulation in posterior gills is also positively and strongly dependent on the incubation time with copper. Gill copper accumulation occurred at a lower rate in the first 2 h of metal exposure, increasing markedly after this 'steady-state' period. This finding

  14. Acute toxicity, accumulation and tissue distribution of copper in the blue crab Callinectes sapidus acclimated to different salinities: in vivo and in vitro studies.

    Science.gov (United States)

    Martins, Camila De Martinez Gaspar; Barcarolli, Indianara Fernanda; de Menezes, Eliana Jaime; Giacomin, Marina Mussoi; Wood, Chris M; Bianchini, Adalto

    2011-01-17

    In vivo and in vitro studies were performed to evaluate acute toxicity, organ-specific distribution, and tissue accumulation of copper in Callinectes sapidus acclimated to two different experimental salinities (2 and 30 ppt). Blue crabs were quite tolerant to copper. Acute dissolved copper toxicity (96-h LC(50) and its corresponding 95% confident interval) was higher at salinity 2 ppt (5.3 (3.50-8.05) μM Cu) than at 30 ppt (53.0 (27.39-102.52) μM Cu). The difference between salinities can be completely explained based on the water chemistry because it disappeared when 96-h LC(50) values were expressed as the free Cu(2+) ion (3.1 (1.93-4.95) μM free Cu at 2 ppt versus 5.6 (2.33-13.37) μM free Cu at 30 ppt) or the Cu(2+) activity (1.4 (0.88-2.26) μM Cu activity at 2 ppt versus 1.7 (0.71-4.07) μM Cu activity at 30 ppt). The relationships between gill Cu burden and % mortality were very similar at 2 and 30 ppt, in accord with the Biotic Ligand Model. In vivo experiments showed that copper concentration in the hemolymph is not dependent on metal concentration in the surrounding medium at either experimental salinity. They also showed that copper flux into the gills is higher than into other tissues analyzed, and that anterior and posterior gills are similarly important sites of copper accumulation at both experimental salinities. In vitro experiments with isolated-perfused gills showed that there is a positive relationship between copper accumulation in this tissue and the metal concentration in the incubation media for both anterior and posterior gills. A similar result was observed at both low and high salinities. Furthermore, in vitro experiments showed that copper accumulation in posterior gills is also positively and strongly dependent on the incubation time with copper. Gill copper accumulation occurred at a lower rate in the first 2h of metal exposure, increasing markedly after this "steady-state" period. This finding was corroborated by a significant

  15. An individual-based modeling approach to spawning-potential per-recruit models: An application to blue crab (Callinectes sapidus) in Chesapeake Bay

    Science.gov (United States)

    Bunnell, D.B.; Miller, T.J.

    2005-01-01

    An individual-based modeling approach to estimate biological reference points for blue crabs (Callinectes sapidus) in Chesapeake Bay offered several advantages over conventional models: (i) known individual variation in size and growth rate could be incorporated, (ii) the underlying discontinuous growth pattern could be simulated, and (iii) the complexity of the fishery, where vulnerability is based on size, shell status (e.g., soft, hard), maturity, and sex could be accommodated. Across a range of natural mortality (M) scenarios (0.375-1.2??year-1), we determined the exploitation fraction (??) and fishing mortality (F) that protected 20% of the spawning potential of an unfished population, the current target. As M increased, ??20% and F-20% decreased. Assuming that M = 0.9??year-1, our models estimated ??20% = 0.45, which is greater than field-based estimates of ?? in 64% of the years since 1990. Hence, the commercial fishery has likely contributed to the recent population decline in Chesapeake Bay. Comparisons of our results with conventional per-recruit approaches indicated that incorporating the complexity of the fishery was the most important advantage in our individual-based modeling approach. ?? 2005 NRC.

  16. Use of DNA strand damage (Comet assay) and embryo hatching effects to assess contaminant exposure in blue crab (Callinectes sapidus) embryos

    Energy Technology Data Exchange (ETDEWEB)

    Lee, R.F.; Steinert, S.A.; Nakayama, K.; Oshima, Y.

    1999-07-01

    After fertilization, blue crab eggs are embedded in a sponge which is attached to the female abdomen during embryo development. Embryos after 9 stages in the egg sac hatch into a swimming zoea stage (stage 10). The authors have developed a bioassay where embryo development is monitored in culture plates with and without toxicants in the water. Toxicant effects are based on determining the percentage of embryos which hatch to zoea. Hatching EC{sub 50} (toxicant concentration at which 50% of the embryos fail to hatch) for a number of pesticides, organometallics and metals were determined. The test takes from 2 to 6 days depending on the embryo stage selected for the study. In addition to embryo development effects the prevalence of DNA single-strand breaks in individual embryo cells were determined using the single cell gel electrophoresis method (Comet assay). A good correlation between DNA strand breakage and embryo defects was found after exposure to genotoxic contaminants. Thus, the bioassay linking DNA damage to embryo hatching effects is rapid, sensitive and mechanistically relevant.

  17. A trehalose 6-phosphate synthase gene of the hemocytes of the blue crab, Callinectes sapidus: cloning, the expression, its enzyme activity and relationship to hemolymph trehalose levels.

    Science.gov (United States)

    Chung, J Sook

    2008-12-12

    Trehalose in ectoderms functions in energy metabolism and protection in extreme environmental conditions. We structurally characterized trehalose 6-phosphate synthase (TPS) from hemocytes of the blue crab, Callinectes sapidus. C. sapidus Hemo TPS (CasHemoTPS), like insect TPS, encodes both TPS and trehalose phosphate phosphatase domains. Trehalose seems to be a major sugar, as it shows higher levels than does glucose in hemocytes and hemolymph. Increases in HemoTPS expression, TPS enzyme activity in hemocytes, and hemolymph trehalose levels were determined 24 h after lipopolysaccharide challenge, suggesting that both TPS and TPP domains of CasHemoTPS are active and functional. The TPS gene has a wide tissue distribution in C. sapidus, suggesting multiple biosynthetic sites. A correlation between TPS activity in hemocytes and hemolymph trehalose levels was found during the molt cycle. The current study provides the first evidence of presence of trehalose in hemocytes and TPS in tissues of C. sapidus and implicates its functional role in energy metabolism and physiological adaptation.

  18. Systematic investigation of factors controlling supercritical fluid extraction (SFE) of spiked and aged PCBs from edible tissues of the blue crab (Callinectes sapidus).

    Science.gov (United States)

    Gaylor, Michael O; Harvey, Ellen; Hale, Robert C

    2015-01-01

    Systematic investigation of factors controlling supercritical fluid extraction (SFE) of spiked and naturally incurred (aged) PCBs from edible tissues of the Blue Crab (Callinectes sapidus) was undertaken. Effects of extraction pressure, temperature and time, CO2 flow rate and total volume, and collection temperature were assessed. Temperature dramatically impacted extraction efficiency, especially at lower pressures. Surprisingly, extraction of both spiked and aged PCBs was flow rate dependent, counter to prevailing views regarding the relative ease of SFE of spiked versus aged contaminants from environmental matrices. PCBs were optimally trapped on a 1:1 mixture of C18-modified and porous silica at 0°C and eluted with <2 mL isooctane at 90°C. A combined 10 min static/30 min dynamic extraction at 35.5 MPa and 150°C with a CO2 flow rate of 3 mL min(-1) yielded maximum (quantitative) recoveries of spiked and aged PCBs. Resulting solvent extracts required no cleanup and could be analyzed directly by halogen-selective GC with MS confirmation.

  19. Seasonal and Inter-annual Variability in Modeled Larval Dispersal and Population Connectivity of Blue Crabs (Callinectes sapidus) in the Northern Gulf of Mexico

    Science.gov (United States)

    Gyory, J.; Jones, B.; Ko, D. S.; Taylor, C.

    2016-02-01

    Larval dispersal trajectories and their resulting population connectivity patterns are known to be key drivers of population dynamics for many marine organisms. However, few studies to date have examined the temporal variability in population connectivity. Here, we model the larval dispersal and population connectivity of blue crabs in the northern Gulf of Mexico from 2003-2012 and use network analyses to understand how they vary over seasonal and inter-annual scales. We found that in all years, the Mississippi River Delta is a barrier to dispersal. Few larvae cross it and settle successfully. In some years (2004, 2007, 2008, and 2009), 1-2 locations (Adams Bay and Chandeleur Sound) had high (> 0.3) betweenness centrality. These locations are likely to be important for maintaining population connectivity in the region, since more than 30% of larval pathways are predicted to pass through them. Connectivity matrices suggest that some estuaries have consistently high larval retention rates. These include West Cote Blanche Bay, Chandeleur Sound, and, in some years, Pensacola Bay and Atchafalaya Bay. Within the spawning season, we observe a decline in average vertex degree and average source strength in every year. This suggests that seasonal declines in the strength of along-shore currents produce consistent reductions in population connectivity through the spawning season.

  20. Investigation of Petroleum and Wastewater Contaminants in Blue Crab, Callinectes sapidus, Megalopae in the Northern Gulf of Mexico using GC-MS

    Science.gov (United States)

    Chiasson, S. C.; Taylor, C.

    2016-02-01

    We collected blue crab, Callinectes sapidus, megalopae five days per week over a six-month period in 2010 and 2011 at multiple sites across the Northern Gulf of Mexico, and one site in 2013. We used GC-MS to investigate if we could detect evidence of petroleum hydrocarbons in megalopae, and if detected hydrocarbons could be linked to the DWH oil spill. We made a comparison between the distance from the oil slick to our collection sites and the concentration of long straight chain alkanes found in megalopae. We also compared levels of alkanes in megalopae between years. We then scanned the megalopae for presence of other contaminants using GC-MS. We detected long straight chain alkanes in megalopae in 2010 but not in 2011 or 2013. The highest levels of alkanes were found in Grand Isle, suggesting that the alkanes could possibly be sourced from the DWH oil spill. No Polycyclic Aromatic Hydrocarbons (PAHs) were detected, and we found no significant relationship between distance of oil slick to collection sites. Other componds were also detected, of which 4-nonylphenol, butylated hydroxytoluene, 2,4,6-tri-tertbutylphenol, and 2,4-di-tertbutylphenol exceeded the quantification limit.

  1. K+-Phosphatase activity of gill (Na+, K+)-ATPase from the blue crab, Callinectes danae: low-salinity acclimation and expression of the alpha-subunit.

    Science.gov (United States)

    Masui, D C; Furriel, R P M; Mantelatto, F L M; McNamara, J C; Leone, F A

    2005-04-01

    The kinetic properties of a microsomal gill (Na(+), K(+)) ATPase from the blue crab, Callinectes danae, acclimated to 15 per thousand salinity for 10 days, were analyzed using the substrate p-nitrophenylphosphate. The (Na(+), K(+))-ATPase hydrolyzed the substrate obeying Michaelian kinetics at a rate of V=102.9+/-4.3 U.mg(-1) with K(0.5)=1.7+/-0.1 mmol.L(-1), while stimulation by magnesium (V=93.7+/-2.3 U.mg(-1); K(0.5)=1.40+/-0.03 mmol.L(-1)) and potassium ions (V=94.9+/-3.5 U.mg(-1); K(0.5)=2.9+/-0.1 mmol.L(-1)) was cooperative. K(+)-phosphatase activity was also stimulated by ammonium ions to a rate of V=106.2+/-2.2 U. mg(-1) with K(0.5)=9.8+/-0.2 mmol.L(-1), following cooperative kinetics (n(H)=2.9). However, K(+)-phosphatase activity was not stimulated further by K(+) plus NH(4) (+) ions. Sodium ions (K(I)=22.7+/-1.7 mmol.L(-1)), and orthovanadate (K(I)=28.1+/-1.4 nmol.L(-1)) completely inhibited PNPPase activity while ouabain inhibition reached almost 75% (K(I)=142.0+/-7.1 micromol.L(-1)). Western blotting analysis revealed increased expression of the (Na(+), K(+))-ATPase alpha-subunit in crabs acclimated to 15 per thousand salinity compared to those acclimated to 33 per thousand salinity. The increase in (Na(+), K(+))-ATPase activity in C. danae gill tissue in response to low-salinity acclimation apparently derives from the increased expression of the (Na(+), K( (+) ))-ATPase alpha-subunit; phosphate-hydrolyzing enzymes other than (Na(+), K(+))-ATPase are also expressed. These findings allow a better understanding of the kinetic behavior of the enzymes that underlie the osmoregulatory mechanisms of euryhaline crustaceans. (c) 2005 Wiley-Liss, Inc.

  2. New functions of arthropod bursicon: inducing deposition and thickening of new cuticle and hemocyte granulation in the blue crab, Callinectes sapidus.

    Directory of Open Access Journals (Sweden)

    J Sook Chung

    Full Text Available Arthropod growth requires molt-associated changes in softness and stiffness of the cuticle that protects from desiccation, infection and injury. Cuticle hardening in insects depends on the blood-borne hormone, bursicon (Burs, although it has never been determined in hemolymph. Whilst also having Burs, decapod crustaceans reiterate molting many more times during their longer life span and are encased in a calcified exoskeleton, which after molting undergoes similar initial cuticle hardening processes as in insects. We investigated the role of homologous crustacean Burs in cuticular changes and growth in the blue crab, Callinectes sapidus. We found dramatic increases in size and number of Burs cells during development in paired thoracic ganglion complex (TGC neurons with pericardial organs (POs as neurohemal release sites. A skewed expression of Burs β/Burs α mRNA in TGC corresponds to protein contents of identified Burs β homodimer and Burs heterodimer in POs. In hemolymph, Burs is consistently present at ∼21 pM throughout the molt cycle, showing a peak of ∼89 pM at ecdysis. Since initial cuticle hardness determines the degree of molt-associated somatic increment (MSI, we applied recombinant Burs in vitro to cuticle explants of late premolt or early ecdysis. Burs stimulates cuticle thickening and granulation of hemocytes. These findings demonstrate novel cuticle-associated functions of Burs during molting, while the unambiguous and constant presence of Burs in cells and hemolymph throughout the molt cycle and life stages may implicate further functions of its homo- and heterodimer hormone isoforms in immunoprotective defense systems of arthropods.

  3. Cloning of prophenoloxidase from hemocytes of the blue crab, Callinectes sapidus and its expression and enzyme activity during the molt cycle.

    Science.gov (United States)

    Alvarez, Javier V; Chung, J Sook

    2013-11-01

    The arthropods cuticle undergoes dramatic morphological and biochemical changes from being soft to hardness through each molting process. Prophenoloxidase (PPO) known as a key enzyme in the arthropod innate immune system involved in the melanization reaction, has been related with the initial shell-hardening process, specifically in the sclerotization of the protein matrix in the new cuticle. Since hemocytes have been reported as the main PPO source in arthropods, the transport of hemocyte PPO into the newly laid, soft cuticle has been proposed for shell-hardening occurring during and immediately after ecdysis. In order to define the role of hemocyte PPO in the shell-hardening of crustaceans, the full-length cDNA sequence (2806 nt) of hemocytes PPO of the blue crab Callinectes sapidus (CasPPO-hemo) is isolated using degenerate PCR and 5'-3' RACE. CasPPO-hemo encodes a putative PPO (672 aa) showing three hemocyanin domains: N, M, and C in order and two copper binding sites (CuA & CuB). The sequence analysis identifies the putative CasPPO-hemo as zymogen which requires the cleavage at the N-terminus for its activation. Hemocyte extract (CasHLS) contains the PO, the activity of which depends on the in vitro activation of trypsin. The expression levels of CasPPO-hemo are kept constant during the molt cycle. The increase in the number of hemocytes at early premolt correlates with the elevated PO activity, while at late premolt, the increment in hemocyte numbers does not reflect on the PO activity. The functional importance of the changes in the levels of CasHLS-PO activity during molt cycle is discussed in relation to cuticle hardening process. Copyright © 2013 Elsevier Ltd. All rights reserved.

  4. New functions of arthropod bursicon: inducing deposition and thickening of new cuticle and hemocyte granulation in the blue crab, Callinectes sapidus.

    Science.gov (United States)

    Chung, J Sook; Katayama, Hidekazu; Dircksen, Heinrich

    2012-01-01

    Arthropod growth requires molt-associated changes in softness and stiffness of the cuticle that protects from desiccation, infection and injury. Cuticle hardening in insects depends on the blood-borne hormone, bursicon (Burs), although it has never been determined in hemolymph. Whilst also having Burs, decapod crustaceans reiterate molting many more times during their longer life span and are encased in a calcified exoskeleton, which after molting undergoes similar initial cuticle hardening processes as in insects. We investigated the role of homologous crustacean Burs in cuticular changes and growth in the blue crab, Callinectes sapidus. We found dramatic increases in size and number of Burs cells during development in paired thoracic ganglion complex (TGC) neurons with pericardial organs (POs) as neurohemal release sites. A skewed expression of Burs β/Burs α mRNA in TGC corresponds to protein contents of identified Burs β homodimer and Burs heterodimer in POs. In hemolymph, Burs is consistently present at ∼21 pM throughout the molt cycle, showing a peak of ∼89 pM at ecdysis. Since initial cuticle hardness determines the degree of molt-associated somatic increment (MSI), we applied recombinant Burs in vitro to cuticle explants of late premolt or early ecdysis. Burs stimulates cuticle thickening and granulation of hemocytes. These findings demonstrate novel cuticle-associated functions of Burs during molting, while the unambiguous and constant presence of Burs in cells and hemolymph throughout the molt cycle and life stages may implicate further functions of its homo- and heterodimer hormone isoforms in immunoprotective defense systems of arthropods.

  5. Trehalose metabolism in the blue crab Callinectes sapidus: isolation of multiple structural cDNA isoforms of trehalose-6-phosphate synthase and their expression in muscles.

    Science.gov (United States)

    Shi, Q; Chung, J Sook

    2014-02-15

    Adult blue crab Callinectes sapidus exhibit behavioral and ecological dimorphisms: females migrating from the low salinity water to the high salinity area vs. males remaining in the same areas. The flesh basal muscle of the swimming paddle shows a dimorphic color pattern in that levator (Lev) and depressor (Dep) of females tend to be much darker than those of males, while both genders have the same light colored remoter (Rem) and promoter (Pro). The full-length cDNA sequence of four structural isoforms of trehalose-6-phosphate synthase (TPS) is isolated from chela muscles of an adult female, C. sapidus. Two isoforms of the C. sapidus TPS encode functional domains of TPS and trehalose-6-phosphorylase (TPP) in tandem as a fused gene product of Escherichia coli Ost A and Ost B. The other two isoforms contain only a single TPS domain. In both males and females, the darker (Lev+Dep) muscles exhibit greater amounts of trehalose, TPS and trehalase activities than the light colored (Rem+Pro). The fact that adult females show higher levels of trehalase activity in the basal muscles and of glucose in Lev+Dep than those of adult males suggests that there may be a metabolic dimorphism. Moreover, the involvement of trehalose in energy metabolism that was examined under the condition of strenuous swimming activity mimicked in adult females demonstrates the intrinsic trehalose metabolism in Lev+Dep, which subsequently results in hemolymphatic hyperglycemia and hyperlactemia. Our data support that trehalose serves as an additional carbohydrate source of hemolymphatic hyperglycemia in this species. Behavioral and ecological dimorphisms of C. sapidus adults may be supported by a functional dimorphism in energy metabolism. Copyright © 2013 Elsevier B.V. All rights reserved.

  6. Production and characterization of films based on blends of chitosan from blue crab (Callinectes sapidus) waste and pectin from Orange (Citrus sinensis Osbeck) peel.

    Science.gov (United States)

    Baron, Ricardo Duran; Pérez, Latife Lúquez; Salcedo, Jesús Mejía; Córdoba, Luis Pérez; Sobral, Paulo José do Amaral

    2017-05-01

    The objective of this study was to develop and characterize films based on blends of chitosan and pectin, produced in laboratory scale, from industrial wastes. The chitosan was obtained by termoalcaline deacetylation of chitin, extracted from blue crab (Callinectes sapidus) waste and characterized according to degree of deacetylation (DD) and viscosimetric molecular weight (Mw); and pectin was extracted by conventional heating, from orange (Citrus sinensis Osbeck) peel and characterized according to degree of esterification (DE) and molecular weight (Mw). The Ch:P based films were prepared by the casting method in different Ch:P ratios [0: 100, 25:75, 50:50, 75:25 and 100:0], and compared to two controls [0:100 and 100:0], of commercial pectin and chitosan. Glycerol was used as a plasticizer at concentrations of 0.2g/g macromolecules. The addition of high concentrations of pectin in the formulations resulted in films with high solubility and an increase in moisture. No significant difference (P>0.05) in the degree of swelling (DS) and water vapor permeability (WVP) of the films was observed. Ch:P blend films were less stiff and therefore more elastic and flexible than films based on only one biopolymer. The control films presented better results in terms of color, being brighter and less opaque than other film formulations. These data suggest that chitosan or pectin obtained from agro-industrial waste is a potential matrix to produce biodegradable films for future food applications. Copyright © 2017 Elsevier B.V. All rights reserved.

  7. Dietary Vitamin C Requirement of Juvenile Swimming Crab ( Portunus trituberculatus)%三疣梭子蟹幼蟹的维生素C需要量

    Institute of Scientific and Technical Information of China (English)

    侯迎梅; 金敏; 张稳; 霍雅文; 周歧存

    2015-01-01

    本试验通过研究饲料中维生素C含量对三疣梭子蟹幼蟹生长、抗氧化性能以及非特异性免疫的影响,旨在确定三疣梭子蟹幼蟹的维生素C需要量. 试验配制维生素C含量分别为1.91、18.89、36.76、78.42、156.49和315.97 mg/kg的6种等能等氮的试验饲料,以初始体重为(5.65±0.25) g的三疣梭子蟹幼蟹为试验对象,饲养于室外水泥池的长方形塑料筐中,进行为期8周的养殖试验. 每种试验饲料投喂60只幼蟹,每20只幼蟹作为1个重复. 结果显示:当饲料中维生素C含量从1. 91 mg/kg 增加到36. 76 mg/kg 时,增重率和特定生长率显著上升( P0.05) ,随着饲料中维生素C含量的增加,全蟹粗脂肪含量基本上呈升高的趋势, 315.97 mg/kg组显著高于其他各组( P0.05). 1.91 mg/kg组血清中总胆固醇含量显著高于其他各组(P0.05). 血清中碱性磷酸酶活性随着饲料中维生素C含量的增加而升高, 315.97 mg/kg组显著高于其他各组( P0.05). 1.91 mg/kg组血清中丙二醛含量显著高于其他各组( P0.05). With the dietary vitamin C content increasing, the crude lipid content in whole-body showed an increased trend, and that in 315.97 mg/kg group was significantly higher than that in other groups ( P0.05). Serum total cholesterol content in 1.91 mg/kg group was significantly higher than that in other groups ( P0.05) . Alkaline phosphatase activity in serum was increased with the increase of di-etary vitamin C content and it in 315.97 mg/kg group was significantly higher than that in other groups ( P0.05). Serum malondialdehyde content in 1.91 mg/kg group was significantly higher than that in other groups (P<0.05). Base on broken-line model analysis of the SGR as an evaluation index, the vitamin C requirement of juvenile swimming crab is 42.60 mg/kg dry matter of diet.

  8. Ecdysone and retinoid-X receptors of the blue crab, Callinectes sapidus: cloning and their expression patterns in eyestalks and Y-organs during the molt cycle.

    Science.gov (United States)

    Techa, Sirinart; Chung, J Sook

    2013-09-15

    Crustacean molting is known to be regulated largely by ecdysteroids and crustacean hyperglycemic hormone (CHH) neuropeptide family including molt-inhibiting hormone (MIH) and CHH. The surge of 20-OH ecdysone and/or ponasterone A initiates the molting process through binding to its conserved heterodimeric nuclear receptor: Ecdysone Receptor (EcR) and Ultraspiracle (USP)/Retinoid-X Receptor (RXR). To better understand the role of ecdysteroids in the molt regulation, the full-length cDNAs of the blue crab, Callinectes sapidus EcR1 and RXR1 were isolated from the Y-organs and their expression levels were determined in both Y-organs and eyestalks at various molt stages. Y-organs show the expression of four putative isoforms of CasEcRs and CasRXRs which differ in the length of the open reading frame but share the same domain structures as in typical nuclear receptors: AF1, DBD, HR, LBD, and AF2. The putative CasEcR isoforms are derived from a 27-aa insert in the HR and a 49-aa residue substitution in the LBD. In contrast, an insertion of a 5-aa and/or a 45-aa in the DBD and LBD gives rise to CasRXR isoforms. The eyestalks and Y-organs show the co-expression of CasEcRs and CasRXRs but at the different levels. In the eyestalks, the expression levels of CasRXRs are 3-5 times higher than those of CasEcRs, while in Y-organs, CasRXRs are 2.5-4 times higher than CasEcRs. A tissue-specific response to the changes in the levels of hemolymphatic ecdysteroids indicates that these tissues may have differences in the sensitivity or responsiveness to ecdysteroids. The presence of upstream open reading frame and internal ribosome entry site in 5' UTR sequences of C. sapidus and other arthropod EcR/RXR/USP analyzed by in silico indicates a plausible, strong control(s) of the translation of these receptors. Copyright © 2013 Elsevier B.V. All rights reserved.

  9. Evaluation of lactic acid bacterium fermentation products and food-grade chemicals to control Listeria monocytogenes in blue crab (Callinectes sapidus) meat.

    Science.gov (United States)

    Degnan, A J; Kaspar, C W; Otwell, W S; Tamplin, M L; Luchansky, J B

    1994-01-01

    Fresh blue crab (Callinectes sapidus) meat was obtained from retail markets in Florida and sampled for viable Listeria monocytogenes. The pathogen was found in crabmeat in three of four different lots tested by enrichment and at levels of 75 CFU/g in one of the same four lots by direct plating. Next, crabmeat was steam sterilized, inoculated with a three-strain mixture of L. monocytogenes (ca. 5.5 log10 CFU/g), washed with various lactic acid bacterium fermentation products (2,000 to 20,000 arbitrary units [AU]/ml of wash) or food-grade chemicals (0.25 to 4 M), and stored at 4 degrees C. Counts of the pathogen remained relatively constant in control samples during storage for 6 days, whereas in crabmeat washed with Perlac 1911 or MicroGard (10,000 to 20,000 AU), numbers initially decreased (0.5 to 1.0 log10 unit/g) but recovered to original levels within 6 days. Numbers of L. monocytogenes cells decreased 1.5 to 2.7 log10 units/g of crabmeat within 0.04 day when washed with 10,000 to 20,000 AU of Alta 2341, enterocin 1083, or Nisin per ml. Thereafter, counts increased 0.5 to 1.6 log10 units within 6 days. After washing with food-grade chemicals, modest reductions (0.4 to 0.8 log10 unit/g) were observed with sodium acetate (4 M), sodium diacetate (0.5 or 1 M), sodium lactate (1 M), or sodium nitrite (1.5 M). However, Listeria counts in crabmeat washed with 2 M sodium diacetate decreased 2.6 log10 units/g within 6 days. In addition, trisodium phosphate reduced L. monocytogenes counts from 1.7 (0.25 M) to > 4.6 (1 M) log10 units/g within 6 days.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:7944362

  10. Accumulation and depuration of pectenotoxins in brown crab Cancer pagurus

    Institute of Scientific and Technical Information of China (English)

    LI Zhaoxin

    2009-01-01

    Pectenotoxins (PTXs) are a group of marine algal toxins. In this study, the accumulation and depuration of pectenotoxins in brown crab Cancer pagurus were investigated. Crabs were fed with toxic blue mussels Mytilus edulis for 21 days and then depurated for 42 days. Toxins were extracted with methanol from the digestive glands of contaminated crabs, uncontaminated crabs (control group) and from blue mussels for comparison. Extracts were analyzed by liquid chromatograph coupled with tandem mass spectrometry (LC-MS-MS). The concentrations of PTX-2, PTX-2 SA, 7-epi-PTX-2 SA, and PTX-12 were analyzed in two batches of toxic blue mussels and the crabs. A one-compartment model was applied to describe the depuration of PTXs. The half-life of PTXs was estimated to be 6-7.5 days. After depuration for 42 days, the amount of PTXs measured in the crab digestive glands was less than 1 μg/kg.

  11. Evaluation and management of blue crab Callinectes sapidus (Rathbun, 1896 (Decapoda - Portunidae fishery in the Estuary of Cananéia, Iguape and Ilha Comprida, São Paulo, Brazil

    Directory of Open Access Journals (Sweden)

    JT. Mendonça

    Full Text Available The Estuary of Cananéia, Iguape and Ilha Comprida is a part of the Estuarine Lagoon System of Cananéia, Iguape and Paranaguá , on the south coast of São Paulo State, Brazil. It has been recognised for its high standards of environmental conservation. The objective of this paper was to assess the blue crab (Callinectes sapidus fishing in the region, from January 1998 to December 2006, and obtain supportive data to implement technical rules for the rational exploitation and resulting conservation of this resource. The results show a remarkable decrease in the fisheries' abundance index (CPUE up to 2005, from 9.4 to 4.0 kg/hour, mainly caused by an increase in fishing effort, from 1,960 to 13,776 hours on a yearly basis. With the decrease in the fishing effort in 2005 and 2006, the abundance index reacted positively, indicating a recovery of the exploited population. Due to the lack of appropriate regulation limiting the fishing effort and organising the fluctuating admission rates of new fishermen, there is a noticeable increase of the effort, above the sustainable level. Therefore, there is a need for measures to limit and control the admission of fishermen in this activity. One of the measures to be considered is the establishment of regular periods where fishing the species is prohibited (called "defeso", each year, especially from September to January. Another measure is to create a fishermen registry and special licenses, to limit the number of new entrants. Such actions require, for their implementation, a co-managed initiative, involving the blue crab fishermen themselves, governmental agencies and resource management researchers, and the integration of ecological, socioeconomic and cultural dimensions.

  12. Evaluation and management of blue crab Callinectes sapidus (Rathbun, 1896) (Decapoda-Portunidae) fishery in the Estuary of Cananéia, Iguape and Ilha Comprida, São Paulo, Brazil.

    Science.gov (United States)

    Mendonça, J T; Verani, J R; Nordi, N

    2010-02-01

    The Estuary of Cananéia, Iguape and Ilha Comprida is a part of the Estuarine Lagoon System of Cananéia, Iguape and Paranaguá, on the south coast of São Paulo State, Brazil. It has been recognised for its high standards of environmental conservation. The objective of this paper was to assess the blue crab (Callinectes sapidus) fishing in the region, from January 1998 to December 2006, and obtain supportive data to implement technical rules for the rational exploitation and resulting conservation of this resource. The results show a remarkable decrease in the fisheries' abundance index (CPUE) up to 2005, from 9.4 to 4.0 kg/hour, mainly caused by an increase in fishing effort, from 1,960 to 13,776 hours on a yearly basis. With the decrease in the fishing effort in 2005 and 2006, the abundance index reacted positively, indicating a recovery of the exploited population. Due to the lack of appropriate regulation limiting the fishing effort and organising the fluctuating admission rates of new fishermen, there is a noticeable increase of the effort, above the sustainable level. Therefore, there is a need for measures to limit and control the admission of fishermen in this activity. One of the measures to be considered is the establishment of regular periods where fishing the species is prohibited (called 'defeso'), each year, especially from September to January. Another measure is to create a fishermen registry and special licenses, to limit the number of new entrants. Such actions require, for their implementation, a co-managed initiative, involving the blue crab fishermen themselves, governmental agencies and resource management researchers, and the integration of ecological, socioeconomic and cultural dimensions.

  13. Species Profiles. Life Histories and Environmental Requirements of Coastal Fishes and Invertebrates (Pacific Northwest). Dungeness Crab.

    Science.gov (United States)

    1986-08-01

    analyze some of the original data in this report was provided by Washington Sea Grant. vii 1 II ’ 1 . w. Figure 1. Dungeness crab. - DUNGENESS CRAB 5 -4...Lough Poole 1967). After 1 year of growth 1976; Armstrong 1983). beyond hatching, most crabs in Bodega Bay, California, are in their 8th, Juveniles...Stevens 1982). Grays Harbor, while the range is 63-94 After molting, the juveniles are mm in Bodega Bay (Poole 1967; Stevens found in shallow coastal

  14. Dietary choline requirements of juvenile Chinese mitten crab, Eri-ocheir sinensis at two dietary phospholipid levels%不同磷脂水平下中华绒螯蟹幼蟹的胆碱需要量

    Institute of Scientific and Technical Information of China (English)

    齐霁; 陈立侨; 孙盛明; 姜海波; 李二超; 禹娜

    2013-01-01

    A 42-day feeding trial was conducted to investigate the effects of dietary phospholipids on the choline requirement of the juvenile Chinese mitten crab, Eriocheir sinensis. Twelve purified diets were formulated con-taining two phospholipid levels (1% and 2%) and six choline chloride levels (0, 250, 500, 1 000, 2 000 and 4 000 mg/kg diet), and were fed to E. sinensis juveniles (0.22g±0.01g) with four replicates in each treatment. The results showed that dietary choline and phospholipids had a significant interaction on survival, weight gain, specific growth rate and feed conversion ratio (P0.05);各试验组的全蟹粗脂肪含量、肝胰腺的甘油三酯含量、总胆固醇含量、谷草转氨酶和谷丙转氨酶活性,均随着饲料中胆碱量的增加而显著下降(P<0.05).综上所述,中华绒螯蟹幼蟹饲料中磷脂和胆碱存在显著的交互作用,饲料中适量添加胆碱和磷脂,可以显著提高幼蟹的增重率和特定生长率,降低饲料系数以及蟹体脂肪含量.以增重率为判据,采用折线回归法进行分析,得出饲料中不同磷脂水平下幼蟹的胆碱适宜需要量分别为1429.65 mg/kg 饲料(磷脂水平1%时)和529.65 mg/kg 饲料(磷脂水平2%).

  15. Population biology of the portunid crab Callinectes arcuatus Ordway in the Gulf of Nicoya, Costa Rica, Central America

    Science.gov (United States)

    Dittel, Ana I.; Epifanio, C. E.; Chavarria, Juan Bautista

    1985-05-01

    Tropical blue crabs Callinectes arcuatus were collected by trawling in the Gulf of Nicoya on the Pacific coast of Costa Rica, Central America. The gulf population was generally dominated by females. Adult females were common in the upper, more estuarine regions of the gulf during rainy season, but appeared to migrate to the lower gulf during dry season for spawning. Biomass varied with seasonal changes in abundance, but was generally similar to biomass of C. sapidus in Chesapeake Bay. Analysis of size frequency indicated that the population is numerically dominated by adults during January and February and that juveniles are common during the remainder of the year. Extrapolation of available data suggests that female crabs reach maturity in approximately one year after hatching.

  16. Cloning of the crustacean hyperglycemic hormone and evidence for molt-inhibiting hormone within the central nervous system of the blue crab Portunus pelagicus.

    Science.gov (United States)

    Stewart, Michael J; Stewart, Praphaporn; Sroyraya, Morakot; Soonklang, Nantawan; Cummins, Scott F; Hanna, Peter J; Duan, Wei; Sobhon, Prasert

    2013-02-01

    The crustacean X-organ-sinus gland (XO-SG) complex controls molt-inhibiting hormone (MIH) production, although extra expression sites for MIH have been postulated. Therefore, to explore the expression of MIH and distinguish between the crustacean hyperglycemic hormone (CHH) superfamily, and MIH immunoreactive sites (ir) in the central nervous system (CNS), we cloned a CHH gene sequence for the crab Portunus pelagicus (Ppel-CHH), and compared it with crab CHH-type I and II peptides. Employing multiple sequence alignments and phylogenic analysis, the mature Ppel-CHH peptide exhibited residues common to both CHH-type I and II peptides, and a high degree of identity to the type-I group, but little homology between Ppel-CHH and Ppel-MIH (a type II peptide). This sequence identification then allowed for the use of MIH antisera to further confirm the identity and existence of a MIH-ir 9kDa protein in all neural organs tested by Western blotting, and through immunohistochemistry, MIH-ir in the XO, optic nerve, neuronal cluster 17 of the supraesophageal ganglion, the ventral nerve cord, and cell cluster 22 of the thoracic ganglion. The presence of MIH protein within such a diversity of sites in the CNS, and external to the XO-SG, raises new questions concerning the established mode of MIH action. Copyright © 2012 Elsevier Inc. All rights reserved.

  17. HUBBLE CAPTURES DYNAMICS OF CRAB NEBULA (color)

    Science.gov (United States)

    2002-01-01

    A new sequence of Hubble Space Telescope images of the remnant of a tremendous stellar explosion is giving astronomers a remarkable look at the dynamic relationship between the tiny Crab Pulsar and the vast nebula that it powers. This colorful photo shows a ground-based image of the entire Crab Nebula, the remnant of a supernova explosion witnessed over 900 years ago. The nebula, which is 10 light-years across, is located 7,000 light-years away in the constellation Taurus. The green, yellow and red filaments concentrated toward the edges of the nebula are remnants of the star that were ejected into space by the explosion. At the center of the Crab Nebula lies the Crab Pulsar -- the collapsed core of the exploded star. The Crab Pulsar is a rapidly rotating neutron star -- an object only about six miles across, but containing more mass than our Sun. As it rotates at a rate of 30 times per second the Crab Pulsar's powerful magnetic field sweeps around, accelerating particles, and whipping them out into the nebula at speeds close to that of light. The blue glow in the inner part of the nebula -- light emitted by energetic electrons as they spiral through the Crab's magnetic field -- is powered by the Crab Pulsar. Credit: Jeff Hester and Paul Scowen (Arizona State University), and NASA

  18. Bioenergetic model predictions of actual growth and allometric transitions during ontogeny of juvenile blue mussels Mytilus edulis

    DEFF Research Database (Denmark)

    Larsen, Poul Scheel; Lundgreen, Kim; Riisgård, Hans Ulrik

    2013-01-01

    rate (μL ≡ dlnL/dt = αLβ) by which data on shell length was well correlated, including the influence of chla concentration. Supplementary growth data from mussels in suspended net-bags at the same site illustrated differences ascribed to lack of competition for space and food, and literature data...... on shell length from cage-growth of mussels in the brackish Baltic Sea support the present correlations. It is argued that the allometric transitions that take place around W ≈ 10 mg and L ≈ 10 mm during the ontogeny of M. edulis is most likely universal and not restricted to first year growth of juvenile...

  19. Molecular cloning of a putative crustacean hyperglycemic hormone (CHH) isoform from extra-eyestalk tissue of the blue crab (Callinectes sapidus), and determination of temporal and spatial patterns of CHH gene expression.

    Science.gov (United States)

    Zheng, Junying; Chen, Hsiang-Yin; Choi, Cheol Young; Roer, Robert D; Watson, R Douglas

    2010-11-01

    Crustacean hyperglycemic hormone (CHH) is a polypeptide neurohormone involved in regulation of multiple physiological processes. We report here the cloning from thoracic ganglia of the blue crab (Callinectes sapidus) a cDNA (CsCHH-2) encoding a putative CHH isoform (CsCHH-2). CsCHH-2 is structurally similar to a putative preproCHH (CsCHH-1) previously cloned from eyestalk ganglia of C. sapidus. The two preprohormones possess an identical signal peptide and CHH precursor related peptide, but differ in the mature CHH polypeptide. An analysis by RT-PCR of the tissue distribution of CsCHH-1 and CsCHH-2 revealed the former is restricted to eyestalk neural ganglia, while the latter is widely distributed among tissues. The type of CHH transcript present in eyestalk and thoracic ganglia did not vary as a function of the molt cycle. An assessment of transcript abundance in tissues of intermolt crabs showed the abundance of the CsCHH-1 transcript in eyestalk ganglia far exceeds the abundance of the CsCHH-2 transcript in extra-eyestalk tissue. An assessment of transcript abundance during a molt cycle showed CsCHH-1 transcript abundance in eyestalk ganglia was low during intermolt, rose during premolt, reaching a peak in D(3), then fell prior to molting, and remained low during postmolt. By contrast, CsCHH-2 transcript abundance in thoracic ganglia was low during intermolt, rose sharply during D(2), then dropped in D(3) and remained low during postmolt. The results are consistent with the hypothesis that CsCHH-1 and CsCHH-2 differ with respect to physiological function. Copyright © 2010 Elsevier Inc. All rights reserved.

  20. Investigação dos teores de metais pesados em espécies de siris azuis do gênero Callinectes sp. Heavy metals content investigation in blue crab species of the genus Callinectes sp.

    Directory of Open Access Journals (Sweden)

    Rossana Helena Pitta Virga

    2008-12-01

    Full Text Available A ocorrência de metais pesados em sistemas aquáticos, usualmente, é resultante de processos naturais geoquímicos. Entretanto, a presença destes elementos químicos tem aumentado consideravelmente nas últimas décadas, como no caso da bacia do rio Cubatão, em conseqüência das atividades humanas na região. Neste trabalho, foi realizada uma análise quantitativa do conteúdo de Pb, Cd, Cr, Zn e Cu, em quatro espécies de siris azuis do gênero Callinectes sp., coletadas ao longo do rio Cubatão, utilizando a técnica da espectrometria de absorção atômica por chama (FAAS. Foram analisadas 144 amostras de siris azuis das seguintes espécies: C. danae (63%; C. sapidus (23%; C. bocourti (10.5%; e C. ornatus (3.5%. A espécie C. Sapidus foi a que apresentou os maiores níveis de concentração para os metais estudados. Com exceção do Cu, cuja concentração média obtida foi 40% maior para as fêmeas (p Usually, heavy metals occurrence in aquatic systems is resulting from natural geochemical processes. However, the presence of these chemical elements has considerably increased in the last decades . An example is the case of the Cubatão river basin caused by human activities in that region. In this work, a quantitative analysis of Pb, Cd, Cr, Zn, and Cu content of four blue crab species of the genus Callinectes sp., sampled along the Cubatão river, was carried out using a flame atomic absorption spectrometer (FAAS. 144 blue crab samples from the following species were analyzed: C. danae (63%, C. sapidus (23%, C. bocourti (10.5%, and C. ornatus (3.5%. The C. Sapidus species presented the highest concentration levels for the studied metals. With the exception of Cu, for which the average concentration was 40% higher for the females (p < 0,05, there was no significant variation in the heavy metal content regarding sex and the size of the animals. Except for Cr, for which the average values interval obtained for the 4 species was above the

  1. Na+, K+-ATPase activity in gill microsomes from the blue crab, Callinectes danae, acclimated to low salinity: novel perspectives on ammonia excretion.

    Science.gov (United States)

    Masui, Douglas C; Mantelatto, Fernando L M; McNamara, John C; Furriel, Rosa P M; Leone, Francisco A

    2009-06-01

    This investigation provides an extensive characterization of the modulation by ATP, Mg(2+), Na(+), K(+) and NH(4)(+) of a gill microsomal (Na(+),K(+))-ATPase from Callinectes danae acclimated to 15 per thousand salinity. Novel findings are the lack of high-affinity ATP-binding sites and a 10-fold increase in enzyme affinity for K(+) modulated by NH(4)(+), discussed regarding NH(4)(+) excretion in benthic marine crabs. The (Na(+),K(+))-ATPase hydrolyzed ATP at a maximum rate of 298.7+/-16.7 nmol Pi min(-1) mg(-1) and K(0.5)=174.2+/-9.8 mmol L(-1), obeying cooperative kinetics (n(H)=1.2). Stimulation by sodium (V=308.9+/-15.7 nmol Pi min(-1) mg(-1), K(0.5)=7.8+/-0.4 mmol L(-1)), magnesium (299.2+/-14.1 nmol Pi min(-1) mg(-1), K(0.5)=767.3+/-36.1 mmol L(-1)), potassium (300.6+/-15.3 nmol Pi min(-1) mg(-1), K(0.5)=1.6+/-0.08 mmol L(-1)) and ammonium (V=345.1+/-19.0 nmol Pi min(-1) mg(-1), K(0.5)=6.0+/-0.3 mmol L(-1)) ions showed site-site interactions. Ouabain inhibited (Na(+),K(+))-ATPase activity with K(I)=45.1+/-2.5 micromol L(-1), although affinity for the inhibitor increased (K(I)=22.7+/-1.1 micromol L(-1)) in 50 mmol L(-1) NH(4)(+). Inhibition assays using ouabain plus oligomycin or ethacrynic acid suggest mitochondrial F(0)F(1)- and K(+)-ATPase activities, respectively. Ammonium and potassium ions synergistically stimulated specific activity up to 72%, inferring that these ions bind to different sites on the enzyme molecule, each modulating stimulation by the other.

  2. Bacterial septicaemia in prerecruit edible crabs, Cancer pagurus L.

    Science.gov (United States)

    Smith, A L; Whitten, M M A; Hirschle, L; Pope, E C; Wootton, E C; Vogan, C L; Rowley, A F

    2014-08-01

    Juvenile edible crabs, Cancer pagurus L., were surveyed from Mumbles Head and Oxwich Bay in South Wales, UK, and the number of heterotrophic bacteria and vibrios in the hemolymph was determined. The percentage of crabs with hemolymph containing bacteria was variable over the survey with higher numbers of animals affected in summer than in winter. Post-moult crabs contained significantly higher numbers of heterotrophic bacteria in the hemolymph than pre- and intermoult animals. Crabs with cuticular damage to the gills also had significantly higher numbers of bacteria in the hemolymph. Crabs were found to have a high prevalence of infection by the dinoflagellate, Hematodinium. Such animals had significantly fewer bacteria in the blood in comparison with Hematodinium-free animals. Of the 463 crabs surveyed, only 3 individuals had hemolymph containing 2000 + CFU mL(-1). Based on 16S rRNA gene sequences, two of these crabs contained a Vibrio pectenicida-like isolate, while the other had a mixed assemblage of vibrios. Although 59% of the crabs surveyed had culturable bacteria in the hemolymph, the majority only had small numbers (crab fishery in this region.

  3. Rapid evolution to terrestrial life in Jamaican crabs

    Science.gov (United States)

    Schubart, Christoph D.; Diesel, Rudolf; Hedges, S. Blair

    1998-05-01

    Crabs of the family Grapsidae are abundant organisms in most intertidal communities. However, relatively few species live in complete independence of the sea. Of those species that do, Jamaica's nine endemic species of land crabs are unique in their exceptional adaptations to terrestrial life, which include the only active brood-care for larvae and juveniles known in crabs. These adaptations, and the morphological similarity to a group of southeast Asian land-dwelling crabs, have raised the question of the number and age of land invasions of the Jamaican species. Here we present molecular evidence that Jamaican land crabs represent a single adaptive radiation from a marine ancestor that invaded terrestrial habitats only 4 million years (Myr) ago. A Late-Tertiary origin has also been found for lizards and frogs of Jamaica and probably reflects the Mid-Tertiary inundation of that island.

  4. Mitigating by-catch of diamondback terrapins in crab pots

    Science.gov (United States)

    Hart, Kristen M.; Crowder, Larry B.

    2011-01-01

    Chronic by-catch of diamondback terrapins (Malaclemys terrapin) in blue crab (Callinectes sapidus) pots is a concern for terrapin conservation along the United States Atlantic and Gulf of Mexico coasts. Despite the availability of by-catch reduction devices (BRDs) for crab pots, adoption of BRDs has not been mandated and by-catch of terrapins continues. We conducted experimental fishing studies in North Carolina's year-round blue crab fishery from 2000 to 2004 to evaluate the ability of various BRDs to reduce terrapin by-catch without a concomitant reduction in the catch of blue crabs. In 4,822 crab pot days fished, we recorded only 21 terrapin captures. Estimated capture rates were 0.003 terrapins/pot per day in hard crab experimental fishing and 0.008 terrapins/pot per day in peeler experimental fishing. All terrapin captures occurred from April to mid-May within 321.4 m of the shoreline. Longer soak times produced more dead terrapins, with 4 live and 4 dead during hard crab experimental fishing and 11 live and 2 dead during peeler experimental fishing. The 4.0-cm BRDs in fall and 4.5-cm and 5.0-cm BRDs in spring reduced the catch of legal-sized male hard crabs by 26.6%, 21.2%, and 5.7%, respectively. Only the 5.0-cm BRDs did not significantly affect the catch of legal-sized hard male crabs. However, BRDs had no measurable effect on catch of target crabs in the peeler crab fishery. Our results identify 3 complementary and economically feasible tools for blue crab fishery managers to exclude terrapins from commercially fished crab pots in North Carolina: 1) gear modifications (e.g., BRDs); 2) distance-to-shore restrictions; and 3) time-of-year regulations. These measures combined could provide a reduction in terrapin by-catch of up to 95% without a significant reduction in target crab catch.

  5. Biomagnification of mercury and selenium in blue shark Prionace glauca from the Pacific Ocean off Mexico.

    Science.gov (United States)

    Escobar-Sánchez, Ofelia; Galván-Magaña, Felipe; Rosíles-Martínez, René

    2011-12-01

    The aim of this study was to determine the biomagnification of mercury through the principal prey of the blue shark, Prionace glauca, off the western coast of Baja California Sur, Mexico, as well as the relationship between mercury and selenium in blue sharks. High levels of mercury were found in shark muscle tissues (1.39 ± 1.58 μg/g wet weight); these values are above the allowed 1.0 μg/g for human consumption. The mercury to selenium molar ratio was 1:0.2. We found a low correlation between mercury bioaccumulation and shark size. Juveniles have lower concentrations of mercury than adults. Regarding the analyzed prey, the main prey of the blue shark, pelagic red crab, Pleuroncodes planipes, bioaccumulated 0.04 ± 0.01 μg/g Hg wet weight, but the prey with higher bioaccumulation was the bullet fish Auxis spp. (0.20 ± 0.02 μg/g wet weight). In terms of volume, the red crab P. planipes can be the prey that provides high levels of mercury to the blue shark.

  6. Gene transcripts encoding hypoxia-inducible factor (HIF) exhibit tissue- and muscle fiber type-dependent responses to hypoxia and hypercapnic hypoxia in the Atlantic blue crab, Callinectes sapidus.

    Science.gov (United States)

    Hardy, Kristin M; Follett, Chandler R; Burnett, Louis E; Lema, Sean C

    2012-09-01

    Hypoxia inducible factor (HIF) is a transcription factor that under low environmental oxygen regulates the expression of suites of genes involved in metabolism, angiogenesis, erythropoiesis, immune function, and growth. Here, we isolated and sequenced partial cDNAs encoding hif-α and arnt/hif-β from the Atlantic blue crab, Callinectes sapidus, an estuarine species that frequently encounters concurrent hypoxia (low O(2)) and hypercapnia (elevated CO(2)). We then examined the effects of acute exposure (1h) to hypoxia (H) and hypercapnic hypoxia (HH) on relative transcript abundance for hif-α and arnt/hif-β in different tissues (glycolytic muscle, oxidative muscle, hepatopancreas, gill, and gonads) using quantitative real-time RT-PCR. Our results indicate that hif-α and arnt/hif-β mRNAs were constitutively present under well-aerated normoxia (N) conditions in all tissues examined. Further, H and HH exposure resulted in both tissue-specific and muscle fiber type-specific effects on relative hif-α transcript abundance. In the gill and glycolytic muscle, relative hif-α mRNA levels were significantly lower under H and HH, compared to N, while no change (or a slight increase) was detected in oxidative muscle, hepatopancreas and gonadal tissues. H and HH did not affect relative transcript abundance for arnt/hif-β in any tissue or muscle fiber type. Thus, in crustaceans the HIF response to H and HH appears to involve changes in hif transcript abundance, with variation in hif-α and arnt/hif-β transcriptional dynamics occurring in both a tissue- and muscle fiber type-dependent manner. Copyright © 2012 Elsevier Inc. All rights reserved.

  7. Molecular cloning of a plasma membrane Ca²⁺ ATPase (PMCA) from Y-organs of the blue crab (Callinectes sapidus), and determination of spatial and temporal patterns of PMCA gene expression.

    Science.gov (United States)

    Chen, Hsiang-Yin; Roer, Robert D; Watson, R Douglas

    2013-06-10

    Existing data indicate that a stage-specific increase in intracellular free Ca(2+) stimulates ecdysteroid production by crustacean molting glands (Y-organs). The concentration of Ca(2+) in cytosol is controlled mainly by proteins intrinsic to the plasma membrane and to the membranes of organelles. Several families of proteins are involved, including Ca(2+) channels, Ca(2+) pumps (ATPases), and Ca(2+) exchangers. The family of Ca(2+) pumps includes plasma membrane calcium ATPases (PMCAs). As a step toward understanding the involvement of calcium signaling in regulation of ecdysteroidogenesis, we used a PCR-based cloning strategy (RT-PCR followed by 3'- and 5'-RACE) to clone from Y-organs of the blue crab (Callinectes sapidus) a cDNA encoding a putative PMCA. The 4292 base pair (bp) cDNA includes a 3510 bp open reading frame encoding a 1170-residue protein (Cas-PMCA). The conceptually translated protein has a relative molecular mass of 128.8×10(3) and contains all signature domains of an authentic PMCA, including ten transmembrane domains and a calmodulin binding site. The predicted membrane topography of Cas-PMCA is as expected for an authentic PMCA protein. A phylogenetic analysis of nonredundant amino acid sequences of PMCA proteins from different species showed Cas-PMCA clusters with other arthropod PMCA proteins. An assessment of tissue distribution showed the Cas-PMCA transcript to be broadly distributed in both neural and non-neural tissues. Studies using quantitative real-time PCR revealed stage-specific changes in Cas-PMCA abundance during the molting cycle, with peak expression occurring during premolt stage D2, a pattern consistent with the hypothesis that Cas-PMCA functions to maintain cellular Ca(2+) homeostasis in Y-organs. Copyright © 2013 Elsevier B.V. All rights reserved.

  8. Crab Rationalization Permit Program

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Crab Rationalization Program (Program) allocates BSAI crab resources among harvesters, processors, and coastal communities. The North Pacific Fishery Management...

  9. Changes in ecdysteroid levels and expression patterns of ecdysteroid-responsive factors and neuropeptide hormones during the embryogenesis of the blue crab, Callinectes sapidus.

    Science.gov (United States)

    Techa, Sirinart; Alvarez, Javier V; Sook Chung, J

    2015-04-01

    Embryogenesis requires the involvement and coordination of multiple networks of various genes, according to a timeline governing development. Crustacean embryogenesis usually includes the first molt, a process that is known to be positively controlled by ecdysteroids. We determined the amounts of ecdysteroids, as well as other related factors: the ecdysone receptor (CasEcR), the retinoid X receptor (CasRXR), the molt-inhibiting hormone (CasMIH), and crustacean hyperglycemic hormone (CasCHH) during the ovarian and embryonic developments of Callinectes sapidus. In summary, the ovaries at stages 1-4 have expression levels of maternal CasEcR and CasRXR 10-50 times higher than levels seen in embryos at the yolk stage. This large difference in the amount of the these factors in C. sapidus ovaries suggests that these maternal ecdysteroid-responsive factors may be utilized at the initiation of embryogenesis. During embryogenesis, the changes in total ecdysteroids and levels of CasEcR and CasRXR expression are similar to those observed in juvenile molts. The full-length cDNA sequence of the C. sapidus BTB domain protein (CasBTBDP) initially isolated from Y-organ cDNA, contains only Broad-Complex, Tramtrack, and Bric a brac (BTB) domains. The levels of CasBTBDP are kept constant throughout embryogenesis. The expression profiles of CasMIH and CasCHH are similar to the titers of ecdysteroids. However, the timing of their appearance is followed by increases in CasEcRs and CasRXRs, implying that the expressions of these neuropeptides may be influenced by ecdysteroids. Moreover, the ecdysteroid profile during embryogenesis may track directly with the timing of organogenesis of Y-organs and their activity. Our work reports, for first time, the observed expression and changes of ecdysteroid-responsive factors, along with CasCHH and CasMIH, during embryogenesis in the crustacean C. sapidus. Copyright © 2014 Elsevier Inc. All rights reserved.

  10. Crab Cavity Development

    CERN Document Server

    Calaga, R; Burt, G; Ratti, A

    2015-01-01

    The HL-LHC upgrade will use deflecting (or crab) cavities to compensate for geometric luminosity loss at low β* and non-zero crossing angle. A local scheme with crab cavity pairs across the IPs is used employing compact crab cavities at 400 MHz. Design of the cavities, the cryomodules and the RF system is well advanced. The LHC crab cavities will be validated initially with proton beam in the SPS.

  11. Juvenile angiofibroma

    Science.gov (United States)

    Nasal tumor; Angiofibroma - juvenile; Benign nasal tumor; Juvenile nasal angiofibroma; JNA ... Juvenile angiofibroma is not very common. It is most often found in adolescent boys. The tumor contains ...

  12. Effects of dietary peppermint (Mentha piperita) essential oil on survival, growth, cannibalism and hepatopancreatic histopathology of Portunus pelagicus juveniles.

    Science.gov (United States)

    Roslan, Syahirah; Taher, Sofea; Ehteshamei, Fariborz; Arshad, Aziz; Romano, Nicholas

    2016-07-01

    A two-part experiment was performed to determine whether dietary peppermint oil could improve the growth and/or decrease aggression among blue swimmer crab, Portunus pelagicus early juveniles. A total of five isonitrogenous diets were made that contained increasing peppermint oil levels of 0.00, 0.05, 0.10, 0.50 or 1.00%.? These diets were fed to 45 replicate crabs in each treatment (total of 225 crabs) for 12 days, the final sizes and weights were measured, and then placed in 3 replicate containers (30 in total/treatment) to allow the opportunity for cannibalism over 10 days.? After 10 days, the remaining crabs were examined for any histopathological changes in gills or hepatopancreas.? Results showed dietary peppermint oil, at the tested levels, had no effect on the growth or cannibalism, in either experiments (p > 0.05).? However, there were substantial changes in the hepatopancreatic histopathology that included thinner tubules and significantly less B- and R-cells from 0.10% dietary peppermint oil and above.? The unaffected growth or cannibalism indicate that the levels of dietary peppermint oil used were insufficient and further investigations are required, particularly on the implications to the hepatopancreatic changes. ?

  13. Cuticular proteins from the horseshoe crab, Limulus polyphemus

    DEFF Research Database (Denmark)

    Ditzel, Nicholas; Andersen, Svend Olav; Højrup, Peter

    2003-01-01

    Proteins were purified from the carapace cuticle of a juvenile horseshoe crab, Limulus polyphemus, and several of them were characterized by amino acid sequence determination. The proteins are small (7-16 kDa) and their isoelectric points range from 6.5 to 9.2. They have high contents of tyrosine...

  14. Metals in crab, oyster and sediment in two South Carolina estuaries

    Energy Technology Data Exchange (ETDEWEB)

    1984-04-01

    The blue crab Callinectes sapidus and the eastern oyster Crassostrea virginica have the ability to concentrate metals from the marine environment. From August 1979 to May 1981, cadmium, copper, lead and zinc concentrations were determined quarterly for crab, oyster, and bottom sediment from two estuarine areas in the vicinity of Charleston, South Carolina. The results of the analyses indicate that crab muscle and oyster meats obtained from locations nearest domestic and industrial activities have the highest Cu and Zn concentrations.

  15. Dermatomyositis (Juvenile)

    Science.gov (United States)

    ... Am A Patient / Caregiver Diseases & Conditions Dermatomyositis (Juvenile) Dermatomyositis (Juvenile) Fast Facts Patients with JDM have varying ... What are common signs and symptoms of juvenile dermatomyositis? The most common signs and symptoms of JDM ...

  16. Retinoschisis (Juvenile)

    Science.gov (United States)

    ... here Home › Eye Conditions Listen Retinoschisis What is Juvenile Retinoschisis? Juvenile retinoschisis is an inherited disease diagnosed in childhood ... degeneration of the retina. What are the symptoms? Juvenile retinoschisis, also known as X-linked retinoschisis, occurs ...

  17. Dungeness crab survey for the Southwest Ocean Disposal Site off Grays Harbor, Washington, June 1990

    Energy Technology Data Exchange (ETDEWEB)

    Higgins, B.J.; Pearson, W.H. (Battelle/Marine Sciences Lab., Sequim, WA (United States))

    1991-09-01

    As part of the Grays Harbor Navigation Improvement Project, the Seattle District of the US Army Corps of Engineers has begun active use of the Southwest Ocean Disposal Site off Grays Harbor, Washington. This survey was to verify that the location of the area of high crab density observed during site selection surveys has not shifted into the Southeast Ocean Disposal Site. In June 1990, mean densities of juvenile Dungeness crab were 146 crab/ha within the disposal site and 609 crab/ha outside ad north of the disposal site. At nearshore locations outside the disposal site, juvenile crab density was 3275 crab/ha. Despite the low overall abundance, the spatial distribution of crab was such that the high crab densities in 1990 have remained outside the Southwest Ocean Disposal Site. The survey data have confirmed the appropriateness of the initial selection of the disposal site boundaries and indicated no need to move to the second monitoring tier. 8 refs., 9 figs., 2 tabs.

  18. Proximate causes of sexual size dimorphism in horseshoe crabs (Limulus Polyphemus) of the Delaware Bay

    Science.gov (United States)

    Smith, D.R.; Mandt, M.T.; Macdonald, P.D.M.

    2009-01-01

    The unresolved status of the proximate cause for sexual size dimorphism in horseshoe crabs has practical consequence, because harvest recommendations rely on assumptions about sex-specific growth and maturity. We propose and evaluate competing hypotheses for the proximate cause of sexual size dimorphism in horseshoe crabs (Limulus polyphemus) by comparing size and estimated age frequencies from spring-captured juveniles (n = 9,075) and adults (n = 36,274) to predictions from the competing hypotheses. We found that the number of identifiable juvenile size distributions was greater for females than males and the probability of remaining a juvenile was higher for females than males among older juveniles. These findings are consistent with males maturing earlier than females. Molt increments and mean sizes were similar for male and female juveniles, which is not consistent with differential growth. Among adults, one size distribution accounted for ???90% of females regardless of carapace wear. Also, size ratio of adult females to males was 1.26, and size ratio of the largest adult to largest juvenile female was 1.28. These observations are not consistent with females continuing to molt as adults. Differential-maturity is the most parsimonious explanation for sexual size dimorphism in Delaware Bay horseshoe crabs. In addition, because of a low frequency of juvenile females >195 mm relative to adult females and male-biased sex ratios starting at 105 mm, we hypothesize that females, more than males, migrate as older juveniles and mature in the ocean. Management implications include that (1) minimum size limits, as previously suggested, would not allocate harvest to older adults as intended because size does not indicate age among adult horseshoe crabs in the Delaware Bay population, and (2) the Shuster Horseshoe Crab Reserve, which has reduced harvest on the continental shelf, could be protecting older juveniles and newly mature females from harvest prior to their first

  19. Preference alters consumptive effects of predators: top-down effects of a native crab on a system of native and introduced prey.

    Directory of Open Access Journals (Sweden)

    Emily W Grason

    Full Text Available Top-down effects of predators in systems depend on the rate at which predators consume prey, and on predator preferences among available prey. In invaded communities, these parameters might be difficult to predict because ecological relationships are typically evolutionarily novel. We examined feeding rates and preferences of a crab native to the Pacific Northwest, Cancer productus, among four prey items: two invasive species of oyster drill (the marine whelks Urosalpinx cinerea and Ocenebra inornata and two species of oyster (Crassostrea gigas and Ostrea lurida that are also consumed by U. cinerea and O. inornata. This system is also characterized by intraguild predation because crabs are predators of drills and compete with them for prey (oysters. When only the oysters were offered, crabs did not express a preference and consumed approximately 9 juvenile oysters crab(-1 day(-1. We then tested whether crabs preferred adult drills of either U. cinerea or O. inornata, or juvenile oysters (C. gigas. While crabs consumed drills and oysters at approximately the same rate when only one type of prey was offered, they expressed a strong preference for juvenile oysters over drills when they were allowed to choose among the three prey items. This preference for oysters might negate the positive indirect effects that crabs have on oysters by crabs consuming drills (trophic cascade because crabs have a large negative direct effect on oysters when crabs, oysters, and drills co-occur.

  20. Dieta natural do siri-azul Callinectes sapidus (Decapoda, Portunidae na região estuarina da Lagoa dos Patos, Rio Grande, Rio Grande do Sul, Brasil Natural diet of the blue crab Callinectes sapidus (Decapoda, Portunidae in the Patos Lagoon estuary area, Rio Grande, Rio Grande do Sul, Brazil

    Directory of Open Access Journals (Sweden)

    Alexandre Oliveir

    Brazil blue crab Callinectes sapidus Rathbun, 1869 is the most abundant crab of the genus Callinectes in Patos Lagoon estuary. Although this species is widely distributed throughout the Patos Lagoon estuary area, there is little information about its natural diet. This species is an important predator and has a significant influence on its prey populations. The aim of this study was to check the natural diet of blue crab through the foregut contents analysis. Crabs were collected using an otter trawl net from March 2003 to March 2004. After collected, crabs were preserved immediately in 10% formaldehyde. The carapace width, weight and sex were measured for each individual. The foregut of each crab was removed and stored in 70% ethanol. Blue crab feeds on a wide variety of sessile and slow moving invertebrates. The main item was Detritus, followed by the suspension-feeder mollusk Erodona mactroides Bosc, 1802 (Erodonidae. Sand grains and the small crustaceans of class Ostracoda, were an important component of the foregut contents, but sand grains were not considered food. Setae and pieces of Polychaeta and some seeds of submersed higher vegetation of Ruppia maritima L. (Potamogatonaceae (beaked tasselweed, and Zannichellia palustris L. (Potamogatonaceae (homed pondweed, were also found. This study has as purpose to provide information for a long-term protection and conservation of blue crab population and also to characterize its relationship with the macrobenthic communities in the Patos Lagoon estuary.

  1. Chinese mitten crab surveys of San Joaquin River basin and Suisun Marsh, California, 2000

    Science.gov (United States)

    May, Jason T.; Brown, Larry R.

    2001-01-01

    Juvenile Chinese mitten crabs (Eriocheir sinensis) are known to use both brackish and freshwater habitats as rearing areas. The objectives of this study were to examine the habitat use and potential effects of mitten crabs in the freshwater habitats of the San Joaquin River drainage up-stream of the Sacramento-San Joaquin Delta. After several unsuccessful attempts to catch or observe mitten crabs by trapping, electrofishing, and visual observations, the study was redirected to determine the presence of crabs in the San Joaquin River (in the vicinity of Mossdale) and Suisun Marsh. Monthly surveys using baited traps in the San Joaquin River were done from June through November 2000 and in the Suisun Marsh from August through October 2000. No mitten crabs were caught in the San Joaquin River Basin and only one mitten crab was caught in Suisun Marsh. Surveys were conducted at 92 locations in the San Joaquin River Basin by deploying 352 traps for 10,752 hours of trapping effort; in Suisun Marsh, 34 locations were investigated by deploying 150 traps for 3,600 hours of trapping effort. The baited traps captured a variety of organisms, including catfishes (Ictularidae), yellowfin gobies (Acantho-gobius flavimanus), and crayfish (Decapoda). It is unclear whether the failure to capture mitten crabs in the San Joaquin River Basin and Suisun Marsh was due to ineffective trapping methods, or repre-sents a general downward trend in populations of juvenile mitten crabs in these potential rearing areas or a temporary decline related to year-class strength. Available data (since 1998) on the number of mitten crabs entrained at federal and state fish salvage facilities indicate a downward trend in the number of crabs, which may indicate a declining trend in use of the San Joaquin River Basin by juvenile mitten crabs. Continued monitoring for juvenile Chinese mitten crabs in brackish and freshwater portions of the Sacramento-San Joaquin River Basins is needed to better assess the

  2. EFFECTS OF FISHES ON THE GROWTH AND SURVIVAL OF CHINESE MITTEN CRAB, ERIOCHEIR SINENSIS

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    This experiment on the effects of fishes (Pelteobagrus fulvidraco, Channa argus, Cyprinus carpio) on growth and survival of juvenile Chinese mitten crab, Eriocheir sinensis was conducted in cages placed in Bao'an Lake. T-tests showed that effects of fishes on the carapace width growth were not significant as compared with the control (no fish). But the effects of these fishes on crab survival were negative. The causes of negative effects of fishes on crab survival were simply discussed on the basis of food habits.

  3. Crab Meat with Potherb Mustard

    Institute of Scientific and Technical Information of China (English)

    1996-01-01

    Ingredients: Eight fresh crab. 75 grams of potherb mustard, two egg whites, scallions, ginger and cooking wine. Salt to the taste. Directions: 1. Slice and deep fry the potherb mustard till crisp. Place fried mustard on plate. 2. Steam the crab and remove meat. Stir fry meat with scallions, ginger, cooking wine and salt, Return meat to crab shells. 3. Beat egg white until stiff. Cover the crab meat with mixture and garnish. Steam meat for a few minutes. 4. Place the crab shells on fried mustard and serve. This attractive red and white dish features delicious crab meat with savory crisp mustard leaves.

  4. Effects of Dietary Vitamin E Level on Growth Performance, Serum Non?Specific Immune and Anti?Oxidant Indices of Juvenile Swimming Crab ( Portunus tribueculatus)%饲料中维生素 E水平对三疣梭子蟹幼蟹生长性能、血清非特异性免疫及抗氧化指标的影响

    Institute of Scientific and Technical Information of China (English)

    李弋; 张稳; 金敏; 霍雅文; 邱红; 侯迎梅; 周歧存

    2015-01-01

    An 8?week feeding trial was conducted to evaluate the effects of dietary vitamin E level on growth performance, serum non?specific immune anti?oxidant indices of juvenile swimming crab ( Portunus tribuecula?tus). Juvenile swimming crab with an average body weight about of (5.94±0.17) g were used as test object. Six iso?nitrogenous and iso?energetic diets were formulated to contain 8. 9, 19. 6, 27. 0, 39. 7, 77. 6 and 156.9 mg/kg vitamin E, respectively. Each experimental diet fed 60 crab, and per 20 crab as a replicate. Re?sults showed that weight gain rate ( WGR) and specific growth rate ( SGR) were significantly increased with dietary vitamin E level increasing from 8.9 to 39.7 mg/kg ( P0.05) . Dietary vitamin E level had no sig?nificant effects on the feed conversion ratio, survival rate and molting rate of juvenile crab among all groups ( P>0.05) . Crude protein, moisture and ash contents in whole body and total protein, triglyceride and glucose contents in serum were not significantly affected by dietary vitamin E level ( P>0.05) , while crude lipid con?tent in whole body was significantly influenced by dietary vitamin E level (P0.05), however, serum malondialdehyde (MDA) content was gradually de?creased with dietary vitamin E level increasing, and crabs fed the diet containing 156.9 mg/kg vitamin E had the lowest serum MDA content which significantly lower than that in 8.9 mg/kg group (P0.05). 饲料中维生素E水平对幼蟹的饲料系数、成活率和蜕壳率均没有显著影响( P>0.05). 饲料中维生素E水平对三疣梭子蟹全蟹粗蛋白质、水分和粗灰分含量以及血清中总蛋白、甘油三酯和葡萄糖含量均没有显著影响(P>0.05),但对全蟹粗脂肪含量有显著影响( P0.05). 血清中丙二醛含量随着饲料中维生素E水平的增加逐渐降低,当饲料中维生素E水平增加到156.9 mg/kg时,血清中丙二醛含量最低,显著低于对照组( P<0.05). 以特定生长率为评价指标,通过折线模

  5. Desenvolvimento "in vitro" de larvas e juvenis de Emerita brasiliensis Schmitt (Crustacea, Decapoda, Hippidae sob diferentes condições de temperatura, salinidade e regime alimentar "In vitro" development of larvae and juveniles of the sand crab Emerita brasiliensis Schmitt (Crustacea, Decapoda, Hippidae under different conditions of temperature, salinity and food diet

    Directory of Open Access Journals (Sweden)

    Ana Clara P. Otegui

    2007-06-01

    Full Text Available Larvas eclodidas em laboratório e juvenis coletados em campo do tatuí Emeritabrasiliensis (Hippidae foram cultivados em diferentes temperaturas e regime alimentar com a finalidade de avaliar as melhores condições para a manutenção da espécie em laboratório. O efeito da freqüência da substituição da água de cultivo sobre o desenvolvimento larvar também foi estudado avaliando-se a sobrevivência, o crescimento e a duração dos estádios larvares. A duração das fases larvares e o crescimento das três últimas fases de zoea correlacionaramse positivamente com a temperatura. As temperaturas testadas, entre 18 e 26ºC não influenciaram a sobrevivência das larvas. Não houve influencia da alimentação e nem da troca de água no desenvolvimento, crescimento e sobrevivência das larvas, bem como das dietas de microalgas na sobrevivência e desenvolvimento dos juvenis.Hatched larvae and field sampled juveniles of the sand crab Emeritabrasiliensis were reared at different temperatures and food diet in order to evaluate the best conditions for laboratory maintenance. The effects of frequency of changing the aquarium seawater on larval development was also studied evaluating the survival, growth and duration of larval stages. The duration of larval stage and growth of the last three zoes phases correlate positively with temperature. Temperatures between 18 and 26ºC did not influence the larval survival. The kind of food and frequency of water exchange did not influence the development, growth, and survival of larvae, as well as the development, and survival of juveniles.

  6. First field record of mangrove crab Ucides cordatus (Crustacea: Decapoda: Ucididae recruits co-inhabiting burrows of conspecific crabs

    Directory of Open Access Journals (Sweden)

    Anders Jensen Schmidt

    2009-12-01

    Full Text Available Recruits of the mangrove crab Ucides cordatus (Linnaeus, 1763, rarely encountered in the field were found co-inhabiting burrows of larger male and female conspecifics in the mangrove forest. They were located in the sediment of the inner walls and burrow plugs. Average carapace width (CW of the hosting and co-inhabiting crabs was 3.8 ± 0.20 and 0.9 ± 0.03, respectively. As shown by the size-frequency distribution, while most recruits leave the conspecific burrows after reaching 1.0 cm CW, some stay until they reach a size of 2.5 cm CW. The results of this study contribute to a better understanding of recruitment patterns in this ecologically and economically important mangrove crab species. Follow-up studies are however needed to fully determine the role of conspecific burrows for juvenile habitat choice and survivorship in U. cordatus.

  7. Juvenile Scleroderma

    Science.gov (United States)

    Juvenile Scleroderma INTRODUCTION Every parent will experience a moment of panic when told their child has scleroderma. ... in all their family members as well. CONCLUSION Juvenile scleroderma can be unsettling for the child and ...

  8. The variable Crab Nebula

    CERN Document Server

    Tavani, Marco

    2011-01-01

    The remarkable Crab Nebula is powered by an energetic pulsar whose relativistic wind interacts with the inner parts of the Supernova Remnant SN1054. Despite low-intensity optical and X-ray variations in the inner Nebula, the Crab has been considered until now substantially stable at X-ray and gamma-ray energies. This paradigm has been shattered by the AGILE discovery in September 2010 of a very intense transient gamma-ray flare of nebular origin. For the first time, the Crab Nebula was "caught in the act" of accelerating particles up to 10^15 eV within the shortest timescale ever observed in a cosmic nebula (1 day or less). Emission between 50 MeV and a few GeV was detected with a quite hard spectrum within a short timescale. Additional analysis and recent Crab Nebula data lead to identify a total of four major flaring gamma-ray episodes detected by AGILE and Fermi during the period mid-2007/mid-2011. These observations challenge emission models of the pulsar wind interaction and particle acceleration process...

  9. 水体 pH 对中华绒螯蟹幼蟹蜕壳生长及其相关基因表达的影响%The effect of pH on the molting, growth and related gene expression in juvenile mitten crab, Eriocheir sinensis

    Institute of Scientific and Technical Information of China (English)

    刘金生; 王军; 岳武成; 陈娇; 黄姝; 慈元吉; 王成辉

    2016-01-01

    为了解养殖水体 pH 值对中华绒螯蟹(Eriocheir sinensis)蜕壳生长及其相关基因表达的影响,在试验室水槽条件下,设定 pH =7、8、9、10(均无水草)为实验组,以种植适量水草(pH 值为8.2~9.1)为对照组,研究中华绒螯蟹幼蟹(均重0.43 g ±0.09 g)在不同 pH 值水体中饲养一个蜕壳周期(37 d)的蜕壳生长及其相关基因(蜕皮抑制激素 MIH,蜕皮激素受体 EcR,维甲类 X 受体 RXR,胰岛素样生长因子 IGF2)表达情况。结果显示,对照组河蟹的成活率和增重率均显著高于实验组,其中, pH10的河蟹成活率和增重率最低。荧光定量 PCR 检测显示, MIH、 EcR 和 RXR 基因在不同 pH 水体的表达存在显著差异, IGF2基因在不同 pH 水体中的表达无显著差异;不同 pH 水体幼蟹的增重率与成活率之间存在显著正相关, EcR、 RXR 与 IGF2基因相互间的表达量存在显著正相关,表明这三个基因的表达具有协同作用。通过对成活率、增重率和基因表达的综合分析认为幼蟹生长的最适pH 为8~9。%In order to investigate the effect of pH on the molting , growth and expression of related genes (MIH, EcR, RXR, IGF2) in juvenile mitten crabs, Eriocheir sinensis, with the average weight of (0.43 ±0.09)g cultured in the in-door experiment closets, tests were conducted with four experimental group of pH =7, 8, 9 and 10 (no water grass) and one control group (water grass) for one inter-molting period (37 days).The results indicated that the survival rate and weight gain in the control group were significantly higher than those in the experimental groups , while the lowest survival rate and weight gain existed in the pH 10 group.The quantitative real-time PCR showed there were significant expression difference in MIH, EcR and RXR genes.Among the different water pH groups , however, there was no significant expres-sion difference in IGF2

  10. Larval spirurida (Nematoda) from the crab Macrophthalmus hirtipes in New Zealand

    DEFF Research Database (Denmark)

    Moravec, Frantisek; Fredensborg, Brian Lund; Latham, A David M;

    2003-01-01

    Previously undescribed third-stage larvae of two species of Spirurida were found in the haemocoel of the stalk-eyed mud crab Macrophthalmus hirtipes (Heller) (Ocypodidae) in New Zealand. Examinations by light and scanning electron microscopy showed that the larger larvae (about 7 mm long) belonged...... from Papanui Inlet, on Otago Peninsula, South Island, 74 crabs (90.2%) were infected with larval nematodes with an intensity of 1-18 (mean 4.6) nematodes per crab; no distinction between nematode species was made in these estimates, although juvenile Acuariidae greatly outnumbered larval Ascarophis....... Apparently, crabs play a role as intermediate hosts of these nematode species. This is the first record of larval representatives of Cystidicolidae and Acuariidae from invertebrates in the Australasian Region....

  11. Juvenile Judge

    Institute of Scientific and Technical Information of China (English)

    1997-01-01

    SHANG Xiuyun was among the first sitting judges when the juvenile court was set up in Beijing 10 years ago. With enriched experience she has altered the way judges ask questions in court. She began the practice of inviting juvenile offenders, their parents, relatives, friends and teachers to the juvenile court to work hand in hand in dealing with cases: Facing their relatives and friends and hearing their heartfelt words, juvenile offenders would often be touched, thus bringing forth a positive attitude toward life.

  12. Preliminary assessment of the effects of Delaware Bay water and a known endocrine disrupting compound on horseshoe crabs (Limulus polyphemus) using proteomics and observation of embryonic development and survival

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — The eggs, larvae, and juveniles of horseshoe crabs (L. polyphemus) contribute significantly to the forage base of many species in Delaware Bay. The eggs also provide...

  13. Juvenile Arthritis

    Science.gov (United States)

    Juvenile arthritis (JA) is arthritis that happens in children. It causes joint swelling, pain, stiffness, and loss of motion. It can affect any joint, but ... of JA that children get is juvenile idiopathic arthritis. There are several other forms of arthritis affecting ...

  14. [Juvenile scleroderma].

    Science.gov (United States)

    de Mâcedo, Patrícia Andrade; Shinjo, Samuel Katsuyuki; Goldenstein-Schainberg, Cláudia

    2008-01-01

    Juvenile scleroderma is a rare childhood condition characterized by fibrosis of the skin and internal organs. Clinical manifestations of childhood scleroderma are different from adult disease and early recognition, correct classification and treatment can improve long-term outcome. This review explores the most recent actualizations on clinical manifestations, classification criteria, treatment options and prognosis of juvenile scleroderma. There are two main forms of the disease: localized scleroderma and systemic sclerosis. Localized scleroderma is the most common form in children and mostly restricted to the skin. Juvenile diffuse systemic sclerosis is related to visceral involvement and cardiac disease which is the main cause of death in these patients. The outcome of juvenile systemic sclerosis is better compared with the adult form. Treatment remains a medical challenge and the EULAR task force proposed an approach to juvenile scleroderma treatment based on expert's opinion and guidelines used for the treatment of adults. Larger studies on childhood scleroderma are warranted.

  15. 50 CFR Table 9 to Part 680 - Initial Issuance of Crab PQS by Crab QS Fishery

    Science.gov (United States)

    2010-10-01

    ... 50 Wildlife and Fisheries 9 2010-10-01 2010-10-01 false Initial Issuance of Crab PQS by Crab QS... EXCLUSIVE ECONOMIC ZONE OFF ALASKA Pt. 680, Table 9 Table 9 to Part 680—Initial Issuance of Crab PQS by Crab QS Fishery Column A:For each crab QS fishery: Column B:The Regional Administrator shall calculate...

  16. 50 CFR Table 7 to Part 680 - Initial Issuance of Crab QS by Crab QS Fishery

    Science.gov (United States)

    2010-10-01

    ... 50 Wildlife and Fisheries 9 2010-10-01 2010-10-01 false Initial Issuance of Crab QS by Crab QS... EXCLUSIVE ECONOMIC ZONE OFF ALASKA Pt. 680, Table 7 Table 7 to Part 680—Initial Issuance of Crab QS by Crab QS Fishery Column A: Crab QS Fisheries Column B: Qualifying Years for QS Column C: Eligibility...

  17. Molt-inhibiting hormone stimulates vitellogenesis at advanced ovarian developmental stages in the female blue crab, Callinectes sapidus 2: novel specific binding sites in hepatopancreas and cAMP as a second messenger

    Science.gov (United States)

    Zmora, Nilli; Sagi, Amir; Zohar, Yonathan; Chung, J Sook

    2009-01-01

    The finding that molt-inhibiting hormone (MIH) regulates vitellogenesis in the hepatopancreas of mature Callinectes sapidus females, raised the need for the characterization of its mode of action. Using classical radioligand binding assays, we located specific, saturable, and non-cooperative binding sites for MIH in the Y-organs of juveniles (J-YO) and in the hepatopancreas of vitellogenic adult females. MIH binding to the hepatopancreas membranes had an affinity 77 times lower than that of juvenile YO membranes (KD values: 3.22 × 10-8 and 4.19 × 10-10 M/mg protein, respectively). The number of maximum binding sites (BMAX) was approximately two times higher in the hepatopancreas than in the YO (BMAX values: 9.24 × 10-9 and 4.8 × 10-9 M/mg protein, respectively). Furthermore, MIH binding site number in the hepatopancreas was dependent on ovarian stage and was twice as high at stage 3 than at stages 2 and 1. SDS-PAGE separation of [125I] MIH or [125I] crustacean hyperglycemic hormone (CHH) crosslinked to the specific binding sites in the membranes of the J-YO and hepatopancreas suggests a molecular weight of ~51 kDa for a MIH receptor in both tissues and a molecular weight of ~61 kDa for a CHH receptor in the hepatopancreas. The use of an in vitro incubation of hepatopancreas fragments suggests that MIH probably utilizes cAMP as a second messenger in this tissue, as cAMP levels increased in response to MIH. Additionally, 8-Bromo-cAMP mimicked the effects of MIH on vitellogenin (VtG) mRNA and heterogeneous nuclear (hn) VtG RNA levels. The results imply that the functions of MIH in the regulation of molt and vitellogenesis are mediated through tissue specific receptors with different kinetics and signal transduction. MIH ability to regulate vitellogenesis is associated with the appearance of MIH specific membrane binding sites in the hepatopancreas upon pubertal/final molt. PMID:19583849

  18. Hairy Crab Arrives at Zen

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    The best time for feasting on hairy crab is only for a short period of time in autumn,so don’t miss out on this unparalleled delicacy. Zen has prepared a variety of dishes made from the crab. Gift boxes and gift vouchers are also available for your friends and family.

  19. Crab Cavities for Linear Colliders

    Energy Technology Data Exchange (ETDEWEB)

    Burt, G.; Ambattu, P.; Carter, R.; Dexter, A.; Tahir, I.; /Cockcroft Inst. Accel. Sci. Tech. /Lancaster U.; Beard, C.; Dykes, M.; Goudket, P.; Kalinin, A.; Ma, L.; McIntosh, P.; /Daresbury; Shulte, D.; /CERN; Jones, Roger M.; /Cockcroft Inst. Accel. Sci. Tech. /Manchester U.; Bellantoni, L.; Chase, B.; Church, M.; Khabouline, T.; Latina, A.; /Fermilab; Adolphsen, C.; Li, Z.; Seryi, Andrei; /SLAC

    2011-11-08

    Crab cavities have been proposed for a wide number of accelerators and interest in crab cavities has recently increased after the successful operation of a pair of crab cavities in KEK-B. In particular crab cavities are required for both the ILC and CLIC linear colliders for bunch alignment. Consideration of bunch structure and size constraints favour a 3.9 GHz superconducting, multi-cell cavity as the solution for ILC, whilst bunch structure and beam-loading considerations suggest an X-band copper travelling wave structure for CLIC. These two cavity solutions are very different in design but share complex design issues. Phase stabilisation, beam loading, wakefields and mode damping are fundamental issues for these crab cavities. Requirements and potential design solutions will be discussed for both colliders.

  20. Crab cavities for linear colliders

    CERN Document Server

    Burt, G; Carter, R; Dexter, A; Tahir, I; Beard, C; Dykes, M; Goudket, P; Kalinin, A; Ma, L; McIntosh, P; Shulte, D; Jones, Roger M; Bellantoni, L; Chase, B; Church, M; Khabouline, T; Latina, A; Adolphsen, C; Li, Z; Seryi, Andrei; Xiao, L

    2008-01-01

    Crab cavities have been proposed for a wide number of accelerators and interest in crab cavities has recently increased after the successful operation of a pair of crab cavities in KEK-B. In particular crab cavities are required for both the ILC and CLIC linear colliders for bunch alignment. Consideration of bunch structure and size constraints favour a 3.9 GHz superconducting, multi-cell cavity as the solution for ILC, whilst bunch structure and beam-loading considerations suggest an X-band copper travelling wave structure for CLIC. These two cavity solutions are very different in design but share complex design issues. Phase stabilisation, beam loading, wakefields and mode damping are fundamental issues for these crab cavities. Requirements and potential design solutions will be discussed for both colliders.

  1. Juvenile Prostitution.

    Science.gov (United States)

    Csapo, Marg

    1986-01-01

    Recent research and Canadian government committee reports concerning juvenile prostitution are reviewed. Proposals are made in the realms of law and social policy; and existing programs are described. (DB)

  2. Juvenile Prostitution.

    Science.gov (United States)

    Csapo, Marg

    1986-01-01

    Recent research and Canadian government committee reports concerning juvenile prostitution are reviewed. Proposals are made in the realms of law and social policy; and existing programs are described. (DB)

  3.  The diversity of horseshoe crabs - protecting an endangered resource

    DEFF Research Database (Denmark)

    Funch, Peter; Cong, Nguyen Van; Intanai, Itsara

    Horseshoe crabs are fascinating inhabitants of the sea represented by four living species, where three species live in Asia, while the fourth species lives on the East coast of North America. Ancient fossils, dating back to Ordovician 445 million years ago looks so similar to recent horseshoe crabs...... that people often call them "living fossils". Unfortunately, the existing populations are threatened by overfishing of the adults as well as by destruction and pollution of the beaches where they mate and deposit their eggs. All four extant species are on IUCN Red List of Threatened Species. The blue blood...... for eel and conch on the Atlantic Coast, and migrating shorebirds depend on their eggs for food. We recently initiated a research project to investigate and compare the physiology and genetic variation in all four species of horseshoe crabs worldwide. We intend to analyze the DNA of the horseshoe crabs...

  4. Juvenile myasthenia

    Directory of Open Access Journals (Sweden)

    Knežević-Pogančev Marija

    2011-01-01

    Full Text Available Introduction. Juvenile myasthenia is a chronic autoimmune neuromuscular disease characterized by varying degrees of fluctuating, painless muscle weakness and rapid fatigue of any muscles under voluntary control. Juvenile myasthenia is a form of myasthenia appearing in adolescent age, representing 10% to 15% of all cases of myasthenia gravis. Juvenile myasthenia is presented by a defect in the transmission of nerve impulses to muscles, resulting from a breakdown in the normal communication between nerves and muscles. In myasthenia, antibodies produced by the body’s own immune system block, alter, or destroy the receptors for acetylcholine. Juvenile myasthenia is neither directly inherited nor is it contagious. Signs and Symptoms. The first noticeable symptoms may be eye muscle weakness, difficulty in swallowing, or slurred speech. Juvenile myasthenia usually affects muscles innervated by the cranial nerves (face, lips, tongue, neck and throat, but it can affect any muscle group. Symptoms vary in type and severity with typical periods of exacerbation interspersed with periods of remission. When the muscles necessary for breathing are affected, a patient is said to be in a myasthenic crisis, which is a life-threatening situation. Disease Outcome and Treatment. Juvenile myasthenia produces sporadic but progressive weakness and abnormal fatigability of striated (skeletal muscles, exacerbated by exercise and repeated movement, but improved by rest and anticholinesterase drugs. Juvenile myasthenia follows an unpredictable course of recurring exacerbations and periodic remissions. With current therapies, however, most cases of juvenile myasthenia are not as serious as the name implies. Although there is no known cure, drug treatment has improved prognosis and allows patients to lead relatively normal lives, except during exacerbations.

  5. 纯化饲料、活饵料及其混合投喂对三疣梭子蟹幼蟹生长性能、肝胰腺指数和生化组成的影响%Effects of purified diet, fresh foods and mixed diets on the survival, growth performance and biochemical composition of juvenile swimming crab,Portunus trituberculatus

    Institute of Scientific and Technical Information of China (English)

    杨印蹼; 吴旭干; 王伟; 刘智俊; 楼宝; 成永旭

    2013-01-01

    采用单个体养殖实验和生化分析技术,研究了纯化饲料(A组)、活饵料(章鱼和缢蛏,B组)和混合投喂(纯化饲料和活饵料有规律地交替使用,C组)对三疣梭子蟹幼蟹(初体重0.5g左右)成活、生长性能、肝胰腺指数(HSI)和生化组成的影响.结果表明:(1)3组幼蟹的成活率并无显著差异,均在70%~80%之间;(2)A组和B组幼蟹的增重率、蜕壳周期、特定增长率和饲料系数无显著差异,C组幼蟹的第二次蜕壳周期和饲料系数显著低于其它两组,其特定增长率显著高于其它两组;(3)3种投喂方式的饵料对幼蟹的肝胰腺指数及其蛋白和脂肪含量影响显著,A组幼蟹肝胰腺指数及其脂肪含量显著高于其它两组,但蛋白含量显著低于其它两组;(4)就脂肪酸组成而言,A组肝胰腺和躯体中的饱和脂肪酸和单不饱和脂肪酸均高于其它两组,多不饱和脂肪酸和高度不饱和脂肪酸显著低于其它两组.因此,研制的纯化饲料可以使三疣梭子蟹幼蟹获得较好的生长性能,为进一步开展梭子蟹幼蟹营养需求研究奠定了良好的基础.%By the individual culture technique and biochemical analysis, this study is to investigate the effects of purified diet (group A), fresh foods (Octopus variabilis and Sinonovacula constricta, group B) and mixed diets ( purified diets and fresh foods, group C) on the survival, growth performance and biochemical composition of juvenile swimming crab Portunus trituberculatus (initial mean wet weight was 0. 5g). The results are as follows: ( 1 ) The survival of juvenile swimming crab ranged from 70% to 80% , and no significant effects caused by survival were observed among three groups. (2) There were no significant differences in the WGR (weight gain ratio), molting period, SGR ( specific growth rate) and FCR (feed conversion ratio) of juvenile swimming crab between group A and B. The second molting cycle of group C was significantly

  6. Species profiles: Life histories and environmental requirements of coastal fishes and invertebrates (North and Mid-Atlantic): Blue mussel

    Energy Technology Data Exchange (ETDEWEB)

    Newell, R.I.E.

    1989-06-01

    The blue mussel, Mytilus edulis L. is a widely distributed and locally abundant bivalve mollusc in the North and Mid-Atlantic Regions. It is a valuable commercial species; regional landings in 1986 were worth nearly $4 million. It is a semi-sessile species, anchored by byssus threads to firm surfaces in littoral and sub-littoral environments at salinities ranging from 5 to 35 ppt. It is a suspension feeder, ingesting phytoplankton and detrital particles in the size range of 3--30 /mu/m. The geographical range of the species is limited by lethal water temperatures above 27/degree/C in the south and by temperatures too low for growth and reproduction in the north. Animals from the northern end of the range are stressed by temperatures above 20/degree/C, whereas those near the southern distributional limit are not severely stressed by temperatures as high as 25/degree/C. The blue mussel is diecious and oviparous. The planktotrophic larvae take about 3 weeks to develop and metamorphose. The environmental tolerances of larvae are more restricted than those of adults. The juveniles grow to approximately 1.5 mm while attached to filamentous algae before being carried by water currents to reattach to a firm substrate, often close to adult mussels. Larval and adult blue mussels are important prey items for many animals, including crabs, fishes, and birds. 95 refs., 5 figs., 2 tabs.

  7. Juvenile idiopathic arthritis

    Science.gov (United States)

    Juvenile rheumatoid arthritis (JRA); Juvenile chronic polyarthritis; Still disease; Juvenile spondyloarthritis ... The cause of juvenile idiopathic arthritis (JIA) is not known. It ... illness . This means the body attacks and destroys healthy body ...

  8. Juvenile Polyposis Syndrome

    Science.gov (United States)

    ... Types of Cancer > Juvenile Polyposis Syndrome Request Permissions Juvenile Polyposis Syndrome Approved by the Cancer.Net Editorial Board , 12/2015 What is juvenile polyposis syndrome? Juvenile polyposis syndrome (JPS) is a ...

  9. Habitat shifts and spatial distribution of the intertidal crab Neohelice ( Chasmagnathus ) granulata Dana

    Science.gov (United States)

    Casariego, Agustina Mendez; Alberti, Juan; Luppi, Tomás; Daleo, Pedro; Iribarne, Oscar

    2011-08-01

    Intertidal zones of estuaries and embayments of the SW Atlantic are dominated by the semiterrestrial burrowing grapsid crab, Neohelice ( Chasmagnathus) granulata, and characterized by extensive mud flats surrounded by salt marshes. In this work we examined spatial patterns of distribution of N. granulata during two years to explain their movement patterns. The results of the population sampling showed segregation by sex and size throughout the intertidal, with seasonal variations in densities and different condition indices for adults and juveniles at the different zones. The comparison of seasonal activity (ambulatory activity outside burrows) between marshes and mudflats shows that short term (e.g. daily) variations in activity were controlled by tides. Crabs were active at high tides but increased their activity on days with higher tidal amplitude. Seasonal activity showed that at both areas, females remain with low activity except for a peak in winter, while males showed the highest activity during summer in the mudflat zone, but not so in the marsh. This pattern can be the response to differences in stress tolerance, suggesting that high temperatures are limiting the performance of adult crabs during summer, especially at the marsh where physical conditions can be more critical. The spatial size segregation can be explained by differential mortality in each zone (estimated with tethered crabs), and by the juvenile movement between these zones (estimated with movement traps). Juvenile mortality is higher at the mudflat, while adult mortality is higher in the marsh. Smaller juveniles moved to the marsh, where the mortality is lower, and the larger juveniles moved towards the mudflat. This mortality is due almost exclusively to cannibalism, so our results suggest that this movement of different size classes between zones is controlled, at least in part, by intraspecific predation.

  10. Offspring production in three freshwater crab species (Brachyura: Pseudothelphusidae from the Amazon region and Central America

    Directory of Open Access Journals (Sweden)

    Ingo S. Wehrtmann

    2010-01-01

    Full Text Available Freshwater crabs are an important component of the fauna of limnic environments, and out of the two true freshwater crab families present in the Neotropics, Pseudothelphusidae is the most diverse. Considering the lack of information regarding reproductive features of neotropical freshwater crabs, we studied, for the first time, the fecundity and the presence of juveniles carried by females of two pseudothelphusids from the Amazon region - Kingsleya latifrons (Randall, 1840 and Kingsleya ytupora Magalhães, 1986 - and one from Central America - Potamocarcinus magnus (Rathbun, 1896. The two Kingsleya species produced relatively few (56-114 and large eggs (1.9-3.7 mm, typical for species with an abbreviated or direct development. Recently produced eggs were substantially larger in K. latifrons (mean 2.83 mm when compared to those of K. ytupora (mean 1.87 mm; however, at the end of the embryogenesis, mean egg diameter was similar in both species. Therefore, it is assumed that hatchlings in both species should have a similar size. A brief description of attached juveniles of K. ytupora is provided. The number of juveniles varied between 30 (K. ytupora and 179 (P. magnus; two size groups of juveniles were found, which indicates that the offspring cling to their mother for a prolonged period of time. There was no significant loss of eggs and juveniles; it is assumed that parental care diminishes the loss of their offspring. We compiled the available information of reproductive aspects from freshwater crabs: egg diameter was in the range of 2-3 mm, independent of female size and fecundity, and reported egg number varied between 9 and 417 eggs.

  11. A novel putative lipoprotein receptor (CasLpR) in the hemocytes of the blue crab, Callinectes sapidus: cloning and up-regulated expression after the injection of LPS and LTA.

    Science.gov (United States)

    Tsutsui, Naoaki; Chung, J Sook

    2012-03-01

    The full-length cDNA encoding a putative lipoprotein receptor (CasLpR) was isolated from the hemocytes of Callinectes sapidus using 5' and 3' RACEs. The open reading frame for CasLpR contains a precursor of putative CasLpR consisting of 1710 amino acid residues including 22 amino acid residues of the signal peptide (22 amino acids). Mature CasLpR (1688 amino acids with 5.6% of phosphorylation sites) has multiple, putative functional domains: five low-density lipoprotein receptor domains in the N-terminus, and a G-protein-coupled receptor proteolysis site domain and a 7 transmembrane receptor (secretin family) domain in the C-terminus. To date, there are no proteins with a similar domain structure in the GenBank. The expression pattern of CasLpR was exclusive in hemocytes among all tested tissues obtained from a juvenile female at intermolt stage: brain, eyestalk ganglia, pericardial organs, and thoracic ganglia complex (nervous system); hepatopancreas (digestive system); heart, artery and hemocytes (circulatory system); gill and antennal gland (excretory system), hypodermis; and Y-organ (endocrine organ). There was no CasLpR expression in the ovary of an adult female. A putative function of CasLpR was examined after challenges of lipopolysaccharides (LPS) and lipoteichoic acid (LTA) in vivo using qRT-PCR assays. Animals at 24 h after injection of LPS or LTA up-regulated the expression of CasLpR in hemocytes by ∼3.5 and 1.4 folds, respectively, compared to the controls that received saline injection. LPS challenge also caused the greatest increment (∼55 folds) of heat shock protein 90 (Hsp90) expression in these samples. These data indicate that putative CasLpR and CasHsp90 may be involved in the defense system or the stress response of C. sapidus. Copyright © 2011 Elsevier Ltd. All rights reserved.

  12. 饲料中镁添加量对中华绒螯蟹幼蟹生长、体成分及抗氧化能力的影响%Effects of Magnesium Supplementation on Growth, Body Composition and Antioxidant Ability of Juvenile Chinese Mitten Crab (Eriocheir sinensis)

    Institute of Scientific and Technical Information of China (English)

    田文静; 魏建军; 李二超; 禹娜; 吴强强; 陈立侨

    2015-01-01

    with the Mg supplementation of 7.5 g/kg and the group without Mg supplementation, re-spectively (P<0.05). The content of malonaldehyde (MDA) in hepatopancreas and serum was firstly de-creased and then increased with the increase of dietary Mg supplementation, and the lowest values were found in the group with the Mg supplementation of 3. 0 g/kg, which was significantly lower than that in the other groups ( P<0.05) . In conclusion, the L-aspartic acid magnesium as Mg source, the juvenile Chinese mitten crab have the better growth effect when Mg supplementation is 3.0 g/kg;the GSH content in hepatopancreas as criterion, base on the quadratic regression model fitting, the juvenile Chinese mitten crab have the best antioxi-dant ability when Mg supplementation is 3.76 g/kg ( dietary Mg content is 4.39 g/kg) .

  13. Abundance of non-native crabs in intertidal habitats of New England with natural and artificial structure

    Directory of Open Access Journals (Sweden)

    Christina M. Lovely

    2015-09-01

    Full Text Available Marine habitats containing complex physical structure (e.g., crevices can provide shelter from predation for benthic invertebrates. To examine effects of natural and artificial structure on the abundance of intertidal juvenile crabs, 2 experiments were conducted in Kingston Bay, Massachusetts, USA, from July to September, 2012. In the first experiment, structure was manipulated in a two-factor design that was placed in the high intertidal for 3 one-week periods to test for both substrate type (sand vs. rock and the presence or absence of artificial structure (mesh grow-out bags used in aquaculture, ∼0.5 m2 with 62 mm2 mesh openings. The Asian shore crab, Hemigrapsus sanguineus, and small individuals of the green crab, Carcinus maenas, were observed only in the treatments of rocks and mesh bag plus rocks. Most green crabs were small (<6 mm in carapace width whereas H. sanguineus occurred in a wide range of sizes. In the second experiment, 3 levels of oyster-shell treatments were established using grow-out bags placed on a muddy sand substrate in the low intertidal zone: mesh grow-out bags without shells, grow-out bags with oyster shells, and grow-out bags containing live oysters. Replicate bags were deployed weekly for 7 weeks in a randomized complete block design. All crabs collected in the bags were juvenile C. maenas (1–15 mm carapace width, and numbers of crabs differed 6-fold among treatments, with most crabs present in bags with live oysters (29.5 ± 10.6 m−2 [mean ± S.D.] and fewest in bags without shells (4.9 ± 3.7 m−2. Both C. maenas and H. sanguineus occurred in habitats with natural structure (cobble rocks. The attraction of juvenile C. maenas to artificial structure consisting of plastic mesh bags containing both oyster shells and living oysters could potentially impact oyster aquaculture operations.

  14. Population biology and distribution of the portunid crab Callinectes ornatus (Decapoda: Brachyura in an estuary-bay complex of southern Brazil

    Directory of Open Access Journals (Sweden)

    Timoteo T. Watanabe

    2014-08-01

    Full Text Available Trawl fisheries are associated with catches of swimming crabs, which are an important economic resource for commercial as well for small-scale fisheries. This study evaluated the population biology and distribution of the swimming crab Callinectes ornatus (Ordway, 1863 in the Estuary-Bay of São Vicente, state of São Paulo, Brazil. Crabs were collected from a shrimp fishing boat equipped with a semi-balloon otter-trawl net, on eight transects (four in the estuary and four in the bay from March 2007 through February 2008. Specimens caught were identified, sexed and measured. Samples of bottom water were collected and the temperature and salinity measured. A total of 618 crabs were captured (332 males, 267 females and 19 ovigerous females, with a sex ratio close to 1:1. A large number of juveniles were captured (77.67%. Crab spatial distributions were positively correlated with salinity (Rs = 0.73, p = 0.0395 and temperature (Rs = 0.71, p = 0.0092. Two peaks of recruitment occurred, in summer and autumn, and ovigerous females were mostly captured during summer, showing a seasonal reproductive pattern. The results showed that C. ornatus uses the bay as a nursery area for juvenile development. Callinectes ornatus is not yet a legally protected species, and the minimum allowed size of crabs caught in the area, although already restricted, should be carefully evaluated since the removal of large numbers of juveniles could negatively impact the local population.

  15. Golden Crab Logbook Survey (Vessels)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — In November 1995, a voluntary logbook program for the golden crab fishery in the waters under the jurisdiction of the South Atlantic Fishery Management Council...

  16. Antarctic crabs: invasion or endurance?

    Science.gov (United States)

    Griffiths, Huw J; Whittle, Rowan J; Roberts, Stephen J; Belchier, Mark; Linse, Katrin

    2013-01-01

    Recent scientific interest following the "discovery" of lithodid crabs around Antarctica has centred on a hypothesis that these crabs might be poised to invade the Antarctic shelf if the recent warming trend continues, potentially decimating its native fauna. This "invasion hypothesis" suggests that decapod crabs were driven out of Antarctica 40-15 million years ago and are only now returning as "warm" enough habitats become available. The hypothesis is based on a geographically and spatially poor fossil record of a different group of crabs (Brachyura), and examination of relatively few Recent lithodid samples from the Antarctic slope. In this paper, we examine the existing lithodid fossil record and present the distribution and biogeographic patterns derived from over 16,000 records of Recent Southern Hemisphere crabs and lobsters. Globally, the lithodid fossil record consists of only two known specimens, neither of which comes from the Antarctic. Recent records show that 22 species of crabs and lobsters have been reported from the Southern Ocean, with 12 species found south of 60 °S. All are restricted to waters warmer than 0 °C, with their Antarctic distribution limited to the areas of seafloor dominated by Circumpolar Deep Water (CDW). Currently, CDW extends further and shallower onto the West Antarctic shelf than the known distribution ranges of most lithodid species examined. Geological evidence suggests that West Antarctic shelf could have been available for colonisation during the last 9,000 years. Distribution patterns, species richness, and levels of endemism all suggest that, rather than becoming extinct and recently re-invading from outside Antarctica, the lithodid crabs have likely persisted, and even radiated, on or near to Antarctic slope. We conclude there is no evidence for a modern-day "crab invasion". We recommend a repeated targeted lithodid sampling program along the West Antarctic shelf to fully test the validity of the "invasion hypothesis".

  17. On the Crab Proper Motion

    CERN Document Server

    Caraveo, P A; Caraveo, Patrizia A; Mignani, Roberto

    1998-01-01

    Owing to the dramatic evolution of telescopes as well as optical detectors in the last 20 yrs, we are now able to measure anew the proper motion of the Crab pulsar, after the classical result of Wyckoff and Murray (1977) in a time span 40 times shorter. The proper motion is aligned with the axis of symmetry of the inner Crab nebula and, presumably, with the pulsar spin axis.

  18. Juvenile Spondyloarthritis

    Science.gov (United States)

    Gmuca, Sabrina; Weiss, Pamela F.

    2015-01-01

    Purpose of review To provide a comprehensive update of the pathogenesis, diagnostic imaging, treatments, and disease activity measurements of juvenile spondyloarthritis (JSpA). Recent findings Genetic and microbiome studies have provided new information regarding possible pathogenesis of JSpA. Recent work suggests that children with JSpA have decreased thresholds for pain in comparison to healthy children. Additionally, pain on physical examination and abnormalities on ultrasound of the entheses are not well correlated. Treatment guidelines for juvenile arthritis, including JSpA, were published by the American College of Rheumatology and are based on active joint count and presence of sacroiliitis. Recent studies have established the efficacy of tumor necrosis factor inhibitors in the symptomatic treatment of axial disease, though their efficacy for halting progression of structural damage is less clear. Newly developed disease activity measures for JSpA include the Juvenile Arthritis Disease Activity Score and the JSpA Disease Activity index. In comparison to other categories of juvenile arthritis, children with JSpA are less likely to attain and sustain inactive disease. Summary Further microbiome and genetic research may help elucidate JSpA pathogenesis. More randomized therapeutic trials are needed and the advent of new composite disease activity measurement tools will hopefully allow for the design of these greatly needed trials. PMID:26002028

  19. Use of Hyperspectral Imagery to Assess Cryptic Color Matching in Sargassum Associated Crabs.

    Science.gov (United States)

    Russell, Brandon J; Dierssen, Heidi M

    2015-01-01

    Mats of the pelagic macroalgae Sargassum represent a complex environment for the study of marine camouflage at the air-sea interface. Endemic organisms have convergently evolved similar colors and patterns, but quantitative assessments of camouflage strategies are lacking. Here, spectral camouflage of two crab species (Portunus sayi and Planes minutus) was assessed using hyperspectral imagery (HSI). Crabs matched Sargassum reflectance across blue and green wavelengths (400-550 nm) and diverged at longer wavelengths. Maximum discrepancy was observed in the far-red (i.e., 675 nm) where Chlorophyll a absorption occurred in Sargassum and not the crabs. In a quantum catch color model, both crabs showed effective color matching against blue/green sensitive dichromat fish, but were still discernible to tetrachromat bird predators that have visual sensitivity to far red wavelengths. The two species showed opposing trends in background matching with relation to body size. Variation in model parameters revealed that discrimination of crab and background was impacted by distance from the predator, and the ratio of cone cell types for bird predators. This is one of the first studies to detail background color matching in this unique, challenging ecosystem at the air-sea interface.

  20. Functional characterization of neuroendocrine regulation of branchial carbonic anhydrase induction in the euryhaline crab Callinectes sapidus.

    Science.gov (United States)

    Mitchell, Reed T; Henry, Raymond P

    2014-12-01

    Carbonic anhydrase (CA) plays an essential role as a provider of counterions for Na(+)/H(+) and Cl(-)/HCO3 (-) exchange in branchial ionic uptake processes in euryhaline crustaceans. CA activity and gene expression are low in crabs acclimated to full-strength seawater, with transfer to low salinity resulting in large-scale inductions of mRNA and subsequent enzyme activity in the posterior ion-regulating gills (e.g., G7). In the green crab Carcinus maenas, CA has been shown to be under inhibitory neuroendocrine control by a putative hormone in the x-organ-sinus gland complex (XOSG), located in the eyestalk. This study characterizes the neuroendocrine regulation of CA induction in the blue crab Callinectes sapidus, a commonly used experimental organism for crustacean osmoregulation. In crabs acclimated to full-strength seawater, eyestalk ligation (ESL) triggered a 1.8- and 100-fold increase in CA activity and mRNA, respectively. Re-injection with eyestalk homogenates abolished increases in CA activity and fractionally reduced CA gene expression. ESL also enhanced CA induction by 33% after 96 h in crabs transferred to 15 ppt salinity. Injection of eyestalk homogenates into intact crabs transferred from 35 to 15 ppt diminished by 43% the CA induction stimulated by low salinity. These results point to the presence of a repressor hormone in the eyestalk. Separate injections of medullary tissue (MT) and sinus gland (SG), two components of the eyestalk, reduced salinity-stimulated CA activity by 22% and 49%, suggesting that the putative repressor is localized to the SG. Crabs injected with SG extract harvested from crabs acclimated to 5 ppt showed no decrease in CA activity, demonstrating that the hormone is down-regulated at low salinity. Our results show the presence in the XOSG of an inhibitory compound that regulates salinity-stimulated CA induction. © 2014 Marine Biological Laboratory.

  1. Juvenile Justice in Milwaukee

    Science.gov (United States)

    Williams, Gary L.; Greer, Lanetta

    2010-01-01

    Historically, there have been several attempts made to address issues surrounding juvenile delinquency. The Wisconsin Legislature outlines the objectives of the juvenile justice system in the Juvenile Justice Code in s. 939.01, ?to promote a juvenile justice system capable of dealing with the problem of juvenile delinquency, a system which will…

  2. Population structure of the burrowing crab Neohelice granulata (Brachyura, Varunidae in a southwestern Atlantic salt marsh

    Directory of Open Access Journals (Sweden)

    Sabrina Angeletti

    2015-07-01

    Full Text Available Neohelice granulata inhabits estuarine and protected coastal areas in temperate regions and is the most dominant decapod crustacean in the Bahía Blanca Estuary, Argentina. The population structure was studied during a year in a SW Atlantic salt marsh located in the Bahía Blanca Estuary. Crabs were sampled monthly from August 2010 to July 2011. The maximum observed density was 30 crabs m-2 in February and 70 burrows m-2 in May. The maximum carapace width (CW was 32 and 27.5 mm in males and females respectively. Medium size crabs were between 16 and 20 mm CW. Significantly smaller sized crabs were observed at the lower intertidal regions (P < 0.05. The sex ratio was favorable for males and was significantly different from the expected 1:1 (P < 0.05. The recruitment of unsexed juveniles crabs (CW <6.5 mm was observed throughout the year and the presence of ovigerous females from October to February indicated seasonal reproduction. The average size of ovigerous females was CW = 20.8 mm and the smallest ovigerous female measured was 16 mm CW. For the first time, the population structure of the most important macro-invertebrate is analyzed in the Bahía Blanca Estuary. This study may help to make decisions in the area, where anthropic action is progressing day by day.

  3. Identification of a crab gill FXYD2 protein and regulation of crab microsomal Na,K-ATPase activity by mammalian FXYD2 peptide.

    Science.gov (United States)

    Silva, Elias C C; Masui, Douglas C; Furriel, Rosa P; McNamara, John C; Barrabin, Hector; Scofano, Helena M; Perales, Jonas; Teixeira-Ferreira, André; Leone, Francisco A; Fontes, Carlos Frederico L

    2012-11-01

    This investigation discloses the recognition of an FXYD2 protein in a microsomal Na,K-ATPase preparation from the posterior gills of the blue crab, Callinectes danae, by a mammalian (rabbit) FXYD2 peptide specific antibody (γC(33)) and MALDI-TOF-TOF mass spectrometry techniques. This is the first demonstration of an invertebrate FXYD2 protein. The addition of exogenous pig FXYD2 peptide to the crab gill microsomal fraction stimulated Na,K-ATPase activity in a dose-dependent manner. Exogenous pig FXYD2 also considerably increased enzyme affinity for K(+), ATP and NH(4)(+). K(0.5) for Na(+) was unaffected. Exogenous pig FXYD2 increased the V(max) for stimulation of gill Na,K-ATPase activity by Na(+), K(+) and ATP, by 30% to 40%. The crab gill FXYD2 is phosphorylated by PKA, suggesting a regulatory function similar to that known for the mammalian enzyme. The PKA-phosphorylated pig FXYD2 peptide stimulated the crab gill Na,K-ATPase activity by 80%, about 2-fold greater than did the non-phosphorylated peptide. Stimulation by the PKC-phosphorylated pig FXYD2 peptide was minimal. These findings confirm the presence of an FXYD2 peptide in the crab gill Na,K-ATPase and demonstrate that this peptide plays an important role in regulating enzyme activity. Copyright © 2012 Elsevier B.V. All rights reserved.

  4. Juvenile xanthogranuloma.

    Science.gov (United States)

    Singh, R; Ghazali, W

    1992-05-01

    Juvenile xanthogranuloma is a benign cutaneous growth presenting as papules or nodules. It is characterized by an intradermal collection of lipid-laden macrophages and varying degrees of fibroblastic proliferation. We have recently observed two patients with xanthogranulomas: one was found to have a papular type and the second patient had multiple nodular growths. We present these cases, which should be considered in the differential diagnosis of skin nodules.

  5. Caught in the Crab's claws

    CERN Multimedia

    2001-01-01

    'The crab', a new cryo magnet transport vehicle, starts work at CERN. Produced by the ESI group of EST division and built in Finland, it has the job of transporting LHC magnets in buildings SM18 and SMA18. If you see a huge crab scuttling around building SMA18 don't be afraid! It is the new Cryo Magnet Transport Vehicle produced by the ESI group (Engineering Support for Infrastructure, EST Division) for CERN's LHC project and built by Finnish Company ROCLA. This orange vehicle, nicknamed 'The Crab', is perhaps the strangest piece of equipment used for the construction of LHC magnets. It will start work at the end of this month. The crab will be used to transport LHC cryo-magnets and their components in the assembly and preparation building, SMA18, and test building, SM18. It has many capabilities that will allow CERN staff and contractors transport magnets between the two buildings and to locate them in the right position on the test beds. The crab in action during its first tests on 8 February. How does th...

  6. Are Crab nanoshots Schwinger sparks?

    Energy Technology Data Exchange (ETDEWEB)

    Stebbins, Albert [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States); Yoo, Hojin [Univ. of Wisconsin, Madison, WI (United States); Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States); Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Univ. of California, Berkeley, CA (United States)

    2015-05-21

    The highest brightness temperature ever observed are from "nanoshots" from the Crab pulsar which we argue could be the signature of bursts of vacuum e± pair production. If so this would be the first time the astronomical Schwinger effect has been observed. These "Schwinger sparks" would be an intermittent but extremely powerful, ~103 L, 10 PeV e± accelerator in the heart of the Crab. These nanosecond duration sparks are generated in a volume less than 1 m3 and the existence of such sparks has implications for the small scale structure of the magnetic field of young pulsars such as the Crab. As a result, this mechanism may also play a role in producing other enigmatic bright short radio transients such as fast radio bursts.

  7. Are Crab Nanoshots Schwinger Sparks?

    CERN Document Server

    Stebbins, Albert

    2015-01-01

    The highest brightness temperature ever observed are from "nanoshots" from the Crab pulsar which we argue could be the signature of bursts of vacuum $e^{\\pm}$ pair production. If so this would be the first time the astronomical Schwinger effect has been observed. These "Schwinger sparks" would be an intermittent but extremely powerful, $\\sim 10^3 L_{\\astrosun}$, 10 PeV $e^{\\pm}$ accelerator in the heart of the Crab. These nanosecond duration sparks are generated in a volume less than $1 m^3$ and the existence of such sparks has implications for the small scale structure of the magnetic field of young pulsars such as the Crab. This mechanism may also play a role in producing other enigmatic bright short radio transients such as fast radio bursts.

  8. LHC crab-cavity aspects and strategy

    Energy Technology Data Exchange (ETDEWEB)

    Calaga, R.; Tomas, R.; Zimmermann, F.

    2010-05-23

    The 3rd LHC Crab Cavity workshop (LHC-CC09) took place at CERN in October 2009. It reviewed the current status and identified a clear strategy towards a future crab-cavity implementation. Following the success of crab cavities in KEK-B and the strong potential for luminosity gain and leveling, CERN will pursue crab crossing for the LHC upgrade. We present a summary and outcome of the variousworkshop sessions which have led to the LHC crab-cavity strategy, covering topics like layout, cavity design, integration, machine protection, and a potential validation test in the SPS.

  9. Crab Hole Mosquito Blues — The Song

    Centers for Disease Control (CDC) Podcasts

    2011-04-26

    This podcast is a song about a major epizoodemic of a serious human and equine disease written and performed by the MARU Health Angels Band. Band members: K.M. Johnson, T.E. Walton (Retired); D.F. Antczak (Cornell University); W.H. Dietz (CDC); and D.H. Martin (Louisiana State University Health Science Center).  Created: 4/26/2011 by National Center for Emerging Zoonotic and Infectious Diseases (NCEZID).   Date Released: 4/26/2011.

  10. Dermatomiositis juvenil

    OpenAIRE

    Goldaracena, Pablo; Pérez, Federico

    2008-01-01

    La dermatomiositis juvenil (DMJ) es una enfermedad multi sistémica de etiología desconocida, caracterizada por una vasculitis que ocasiona una inflamación no supurativa del músculo estriado y lesiones cutáneas distintivas. La cobertura de los criterios de Bohan y Peter establece el diagnóstico: exantema patognomónico junto a debilidad muscular proximal simétrica, elevación sérica de enzimas musculares, s...

  11. Differential habitat use by demographic groups of the redfinger rubble crab Eriphia gonagra (Fabricius, 1781

    Directory of Open Access Journals (Sweden)

    LS Andrade

    Full Text Available The structurally diverse rocky shores along the northern coast of the state of São Paulo, Brazil, support a varied fauna and provide refuges for many organisms. Some of these environments allow for extensive microhabitats, among them the sand reefs formed by the polychaete Phragmatopoma lapidosa, which occupy much of this area. The beauty of the landscape attracts large numbers of tourists, who contribute to the damage to the sand reef colonies, causing an imbalance in the patterns of population distribution and of this ecosystem. We describe the structure and population biology of the redfinger rubble crab Eriphia gonagra, and investigated the differential occupation of the habitat by each demographic category of this species. Crabs were sampled monthly for two consecutive years on the rocky coast of Grande Beach, Ubatuba, São Paulo, during spring low tides. Sampling was carried out over an area of approximately 1200 m2, during two hours on the rock surface and another two hours on the sand reefs. A total of 1407 crabs were collected; 776 on the sand reef (SR and 631 on the rocky shore (RO. The majority of juvenile crabs inhabited the SR, while adult crabs were equally distributed in both microhabitats. This study showed that the SR is a natural nursery ground for the establishment of the early juvenile stages of E. gonagra, which use the reefs as a refuge and food resource. Many other organisms (mollusks, echinoderms, polychaetes etc. settle on the reefs, and these areas may be among the most important in maintaining benthic diversity in the region.

  12. Kind of Blue - Europa Blues

    DEFF Research Database (Denmark)

    Mortensen, Tore; Kirkegaard, Peter

    2009-01-01

    Bidraget reflekterer over sammenhænge mellem to værker fra det musikalske og litterære område. Det drejer sig om Miles Davis' Kind of Blue fra 1959 og Arne Dahls krimi, Europa Blues fra 2001. Den grundlæggende indfaldsvinkel er det performative, den frie, men samtidigt disciplinerede musikalske...

  13. The Sediment and Hydrographic Characteristics of Three Horseshoe Crab Nursery Beaches in Hong Kong

    Institute of Scientific and Technical Information of China (English)

    Helen M.C. Chiu; Brian Morton

    2003-01-01

    Horseshoe crab juveniles have been recorded from sand and sandy-mud nursery beaches at Pak Nai (western New Territories ), San Tau and Shui Hau (Lantau Island), Hong Kong. In order to provide a better understanding of these beaches and to identify those plausible factors which have made them preferred by spawning horseshoe crabs, environmental parameters, including temperature, salinity, pH and dissolved oxygen content of the water, and particle size distribution and organic matter content of the sediments at the three sites, were determined and compared. The hydrographic and sediment data obtained for the three study sites have revealed some common environmental features. The three nursery beaches are relatively remote, and far (in Hong Kong terms) from urbanized and densely populated areas. The beaches are generally well sheltered from strong wave action and inundated regularly by estuarine waters. Horseshoe crab adults tend to select these beaches for spawning as their protected features ensures the laid eggs are less likely to be washed out of the sand, and hatched juveniles can feed on the meiofauna and grow. Sediments of the three beaches largely comprise medium-sized sand particles and are moderately sorted, suggesting medium porosity and good water permeability. Such a sand type, with the generally high oxygen levels in incursing waters, may help create a well-oxygenated micro-environment for the normal development of horseshoe crab eggs, larvae and juveniles. Lantau Island beaches at San Tau and Shui Hau are relatively free from organic pollution, as reflected in generally high dissolved oxygen level, and low BOD5 and ammonia nitrogen values. Pak Nai is, however, more polluted.

  14. The sediment and hydrographic characteristics of three horseshoe crab nursery beaches in hong kong

    Science.gov (United States)

    Chiu, Helen M. C.; Morton, Brian

    2003-04-01

    Horseshoe crab juveniles have been recorded from sand and sandy-mud nursery beaches at Pak Nai (western New Territories), San Tau and Shui Hau (Lantau Island), Hong Kong. In order to provide a better understanding of these beaches and to identify those plausible factors which have made them preferred by spawning horseshoe crabs, environmental parameters, including temperature, salinity, pH and dissolved oxygen content of the water, and particle size distribution and organic matter content of the sediments at the three sites, were determined and compared. The hydrographic, and sediment data obtained for the three study sites have revealed some common environmental features. The three nursery beaches are relatively remote, and far (in Hong Kong terms) from urbanized and densely populated areas. The beaches are generally well sheltered from strong wave action and inundated regularly by estuarine waters. Horseshoe crab adults tend to select these beaches for spawning as their protected features ensures the laid eggs are less likely to be washed out of the sand, and hatched juveniles can feed on the meiofauna and grow. Sediments of the three beaches largely comprise medium-sized sand particles and are moderately sorted, suggesting medium porosity and good water permeability. Such a sand type, with the generally high oxygen levels in incursing waters, may help create a well-oxygenated micro-environment for the normal development of horseshoe crab eggs, larvae and juveniles. Lantau Island beaches at San Tau and Shui Hau are relatively free from organic pollution, as reflected in generally high dissolved oxygen level, and low BOD5 and ammonia nitrogen values. Pak Nai is, however, more polluted.

  15. Scaling of olfactory antennae of the terrestrial hermit crabs Coenobita rugosus and Coenobita perlatus during ontogeny

    Directory of Open Access Journals (Sweden)

    Lindsay D. Waldrop

    2014-08-01

    Full Text Available Although many lineages of terrestrial crustaceans have poor olfactory capabilities, crabs in the family Coenobitidae, including the terrestrial hermit crabs in the genus Coenobita, are able to locate food and water using olfactory antennae (antennules to capture odors from the surrounding air. Terrestrial hermit crabs begin their lives as small marine larvae and must find a suitable place to undergo metamorphosis into a juvenile form, which initiates their transition to land. Juveniles increase in size by more than an order of magnitude to reach adult size. Since odor capture is a process heavily dependent on the size and speed of the antennules and physical properties of the fluid, both the transition from water to air and the large increase in size during ontogeny could impact odor capture. In this study, we examine two species of terrestrial hermit crabs, Coenobita perlatus H. Milne-Edwards and Coenobita rugosus H. Milne-Edwards, to determine how the antennule morphometrics and kinematics of flicking change in comparison to body size during ontogeny, and how this scaling relationship could impact odor capture by using a simple model of mass transport in flow. Many features of the antennules, including the chemosensory sensilla, scaled allometrically with carapace width and increased slower than expected by isometry, resulting in relatively larger antennules on juvenile animals. Flicking speed scaled as expected with isometry. Our mass-transport model showed that allometric scaling of antennule morphometrics and kinematics leads to thinner boundary layers of attached fluid around the antennule during flicking and higher odorant capture rates as compared to antennules which scaled isometrically. There were no significant differences in morphometric or kinematic measurements between the two species.

  16. Crab shedding-system designs

    OpenAIRE

    1997-01-01

    There are as many ways to build and arrange crab shedding setups as there are people who make them. The following drawings are suggestions based on the experiencesof successful shedders. You may find changes that suit your operation better. (8pp.)

  17. Occurrence and Antimicrobial Resistance of Listeria monocytogenes Recovered from Blue Crab Meat and Blue Crab Processing Plants

    Science.gov (United States)

    Listeria monocytogenes is widely distributed in the environment. The ubiquitous nature of this bacterium can result in contamination of foods. Listeriosis is a food-borne disease caused by consumption of L. monocytogenes-contaminated food. It is a public health problem of low incidence but high mort...

  18. Effect of an escape vent in accordion-shaped traps on the catch and size of Asian paddle crabs Charybdis japonica in an artificial reef area

    Science.gov (United States)

    Zhang, Peng; Li, Chao; Li, Wentao; Zhang, Xiumei

    2016-11-01

    Accordion-shaped traps are widely used in China to catch the Asian paddle crab Charybdis japonica but traps of conventional design often catch juvenile crabs. A new type of accordion-shaped trap with an escape vent (L×W=4.3 cm×3.0 cm) was designed and a comparative study between the newly designed and conventional traps was performed in the artificial reef area of Zhuwang, Laizhou Bay, China from June to August 2012. The mean catch per unit effort (CPUE) of undersized crabs was significantly lower in the vented traps than in the conventional traps (paired t -test, n=30, Psustainable and efficient crab fishing methods using accordion-shaped traps.

  19. Blue Laser.

    Science.gov (United States)

    1985-12-01

    HOLLOW CATHODE LASER FABRICATION 13 4. EXPERIENCE WITH THE BLUE LASER 18 4.1 Operational and Processing Experience 18 4.2 Performance Testing 20 5...34 -. - . •. SECTION 3 BLUE HOLLOW CATHODE LASER FABRICATION This section presents an overview of the steps taken in creating a HCL. There is...to the laser assembly. These steps can actually be considered as the final steps in laser fabrication because some of them involve adding various

  20. AFSC/RACE/SAP/Jensen: Bitter crab disease mortality in SE Alaska Tanner crab

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — These are data from a laboratory experiment in which wild caught male Tanner crab (Chionoecetes bairdi) from Stephens Passage, SE Alaska were held to evaluate crab...

  1. Camouflage and individual variation in shore crabs (Carcinus maenas) from different habitats.

    Science.gov (United States)

    Stevens, Martin; Lown, Alice E; Wood, Louisa E

    2014-01-01

    Camouflage is widespread throughout the natural world and conceals animals from predators in a vast range of habitats. Because successful camouflage usually involves matching aspects of the background environment, species and populations should evolve appearances tuned to their local habitat, termed phenotype-environment associations. However, although this has been studied in various species, little work has objectively quantified the appearances of camouflaged animals from different habitats, or related this to factors such as ontogeny and individual variation. Here, we tested for phenotype-environment associations in the common shore crab (Carcinus maenas), a species highly variable in appearance and found in a wide range of habitats. We used field surveys and digital image analysis of the colors and patterns of crabs found in four locations around Cornwall in the UK to quantify how individuals vary with habitat (predominantly rockpool, mussel bed, and mudflat). We find that individuals from sites comprising different backgrounds show substantial differences in several aspects of color and pattern, and that this is also dependent on life stage (adult or juvenile). Furthermore, the level of individual variation is dependent on site and life stage, with juvenile crabs often more variable than adults, and individuals from more homogenous habitats less diverse. Ours is the most comprehensive study to date exploring phenotype-environment associations for camouflage and individual variation in a species, and we discuss the implications of our results in terms of the mechanisms and selection pressures that may drive this.

  2. Final focus designs for crab waist colliders

    Science.gov (United States)

    Bogomyagkov, A.; Levichev, E.; Piminov, P.

    2016-12-01

    The crab waist collision scheme promises significant luminosity gain. The successful upgrade of the DA Φ NE collider proved the principle of crab waist collision and increased luminosity 3 times. Therefore, several new projects try to implement the scheme. The paper reviews interaction region designs with the crab waist collision scheme for already existent collider DA Φ NE and SuperKEKB, presently undergoing commissioning, for the projects of SuperB in Italy, CTau in Novosibirsk and FCC-ee at CERN.

  3. Inter-annual dynamics of the Barents Sea red king crab (Paralithodes camtschaticus) stock indices in relation to environmental factors

    Science.gov (United States)

    Dvoretsky, Alexander G.; Dvoretsky, Vladimir G.

    2016-12-01

    Knowledge of relationships between environmental variables and biological processes can greatly improve fisheries assessment and management in commercially important species. We analyzed the effects of environmental factors (climatic indices and water temperature) on the stock characteristics (total population number, number of pre-recruits and number of legal males) of the red king crab (Paralithodes camtschaticus), an introduced species in the Barents Sea. Stock trends in red king crab appear to be related to decadal climate shifts. Abundances were negatively related to the North Atlantic Oscillation index (NAO) in August and positively related to water temperature in late winter-early summer. Total and commercial stock abundance were negatively correlated with the lag-1 Arctic Oscillation index (AO) in August and the lag-2 winter NAO index. The total number of P. camtschaticus was most strongly associated with water temperature in spring and summer and NAO/AO indices in April and May. Lagged NAO indices in February and August (9 or 10 yr) had a positive relationship to the commercial stock of P. camtschaticus. These findings suggest that temperature conditions of current and previous year affect natural mortality of larvae and juvenile red king crabs. Warmer temperature conditions lead to increased biomass of red king crab food items. Negative correlations between climatic indices and the red king crab stocks may be associated with predator pressure on juvenile red king crabs or higher mortality because of predator or parasite pressure and diseases. The associations between stock indices and environmental variables could help better predict recruitment patterns of P. camtschaticus.

  4. Effects of zinc on molting and body weight of the estuarine crab Neohelice granulata (Brachyura: Varunidae).

    Science.gov (United States)

    Beltrame, María Ornela; De Marco, Silvia G; Marcovecchio, Jorge E

    2010-01-01

    The semiterrestrial burrowing crab Neohelice granulata is one of the main inhabitants of the supratidal and intertidal zones of brackish salt marshes, estuaries and coastal lagoons from South America's Atlantic littoral. A large population of this species spreads out Mar Chiquita coastal lagoon (in Argentina) and its corresponding wetlands, and is considered as a key species within this system. Since high values of dissolved heavy metals (including Zn) have been recently reported within Mar Chiquita coastal lagoon, with levels unusually higher than those from other coastal systems within Argentina, it has been explored that the existence of a risk of environmental conditions endanger these populations. So, juveniles of this estuarine crab were experimentally exposed to increasing concentrations of dissolved Zn (i.e., 0, 0.5 and 1 mg Zn(2+)L(-1)) during six months, the time involved between two successive molts; in addition, both the size and weight reached after each molt were also studied in this assay. It can be concluded that zinc can be toxic to crabs only at high concentrations. Considering that levels up to 1 mg ZnL(-1) were recently reported in Mar Chiquita coastal lagoon waters, the potential occurrence of mean chronic effects on the crab population within the coastal lagoon is discussed.

  5. Territoriality and Conflict Avoidance Explain Asociality (Solitariness of the Endosymbiotic Pea Crab Tunicotheres moseri.

    Directory of Open Access Journals (Sweden)

    Louis J Ambrosio

    Full Text Available Host monopolization theory predicts symbiotic organisms inhabiting morphologically simple, relatively small and scarce hosts to live solitarily as a result of territorial behaviors. We tested this prediction with Tunicotheres moseri, an endosymbiotic crab dwelling in the atrial chamber of the morphologically simple, small, and relatively scarce ascidian Styela plicata. As predicted, natural populations of T. moseri inhabit ascidian hosts solitarily with greater frequency than expected by chance alone. Furthermore, laboratory experiments demonstrated that intruder crabs take significantly longer to colonize previously infected compared to uninfected hosts, indicating as expected, that resident crabs exhibit monopolization behaviors. While territoriality does occur, agonistic behaviors employed by T. moseri do not mirror the overt behaviors commonly reported for other territorial crustaceans. Documented double and triple cohabitations in the field coupled with laboratory observations demonstrating the almost invariable success of intruder crabs colonizing occupied hosts, suggest that territoriality is ineffective in completely explaining the solitary social habit of this species. Additional experiments showed that T. moseri juveniles and adults, when searching for ascidians use chemical cues to avoid hosts occupied by conspecifics. This conspecific avoidance behavior reported herein is a novel strategy most likely employed to preemptively resolve costly territorial conflicts. In general, this study supports predictions central to host monopolization theory, but also implies that alternative behavioral strategies (i.e., conflict avoidance may be more important than originally thought in explaining the host use pattern of symbiotic organisms.

  6. The Crab Nebula flaring activity

    Directory of Open Access Journals (Sweden)

    G. Montani

    2014-12-01

    Full Text Available The discovery made by AGILE and Fermi of a short time scale flaring activity in the gamma-ray energy emission of the Crab Nebula is a puzzling and unexpected feature, challenging particle acceleration theory. In the present work we propose the shock-induced magnetic reconnection as a viable mechanism to explain the Crab flares. We postulate that the emitting region is located at ∼1015 cm from the central pulsar, well inside the termination shock, which is exactly the emitting region size as estimated by the overall duration of the phenomenon ∼1 day. We find that this location corresponds to the radial distance at which the shock-induced magnetic reconnection process is able to accelerate the electrons up to a Lorentz factor ∼109, as required by the spectral fit of the observed Crab flare spectrum. The main merit of the present analysis is to highlight the relation between the observational constraints to the flare emission and the radius at which the reconnection can trigger the required Lorentz factor. We also discuss different scenarios that can induce the reconnection. We conclude that the existence of a plasma instability affecting the wind itself as the Weibel instability is the privileged scenario in our framework.

  7. The Crab Nebula flaring activity

    Energy Technology Data Exchange (ETDEWEB)

    Montani, G., E-mail: giovanni.montani@frascati.enea.it [ENEA – C.R, UTFUS-MAG, via Enrico Fermi 45, I-00044 Frascati (RM) (Italy); Dipartimento di Fisica, Università di Roma “Sapienza”, p.le Aldo Moro 5, I-00185 Roma (Italy); Bernardini, M.G. [INAF – Osservatorio Astronomico di Brera, via Bianchi 46, I-23807 Merate (Italy)

    2014-12-12

    The discovery made by AGILE and Fermi of a short time scale flaring activity in the gamma-ray energy emission of the Crab Nebula is a puzzling and unexpected feature, challenging particle acceleration theory. In the present work we propose the shock-induced magnetic reconnection as a viable mechanism to explain the Crab flares. We postulate that the emitting region is located at ∼10{sup 15} cm from the central pulsar, well inside the termination shock, which is exactly the emitting region size as estimated by the overall duration of the phenomenon ∼1 day. We find that this location corresponds to the radial distance at which the shock-induced magnetic reconnection process is able to accelerate the electrons up to a Lorentz factor ∼10{sup 9}, as required by the spectral fit of the observed Crab flare spectrum. The main merit of the present analysis is to highlight the relation between the observational constraints to the flare emission and the radius at which the reconnection can trigger the required Lorentz factor. We also discuss different scenarios that can induce the reconnection. We conclude that the existence of a plasma instability affecting the wind itself as the Weibel instability is the privileged scenario in our framework.

  8. Chemical Tools of Octopus maya during Crab Predation Are Also Active on Conspecifics.

    Directory of Open Access Journals (Sweden)

    Dawrin Pech-Puch

    Full Text Available Octopus maya is a major socio-economic resource from the Yucatán Peninsula in Mexico. In this study we report for the first time the chemical composition of the saliva of O. maya and its effect on natural prey, i.e. the blue crab (Callinectes sapidus, the crown conch snail (Melongena corona bispinosa, as well as conspecifics. Salivary posterior glands were collected from octopus caught by local fishers and extracted with water; this extract paralyzed and predigested crabs when it was injected into the third pereiopod. The water extract was fractionated by membrane ultrafiltration with a molecular weight cut-off of 3 kDa leading to a metabolic phase (>3 kDa and a neurotoxic fraction (<3 kDa. The neurotoxic fraction injected in the crabs caused paralysis and postural changes. Crabs recovered to their initial condition within two hours, which suggests that the effects of the neurotoxic fraction were reversible. The neurotoxic fraction was also active on O. maya conspecifics, partly paralyzing and sedating them; this suggests that octopus saliva might be used among conspecifics for defense and for reduction of competition. Bioguided separation of the neurotoxic fraction by chromatography led to a paralysis fraction and a relaxing fraction. The paralyzing activity of the saliva was exerted by amino acids, while the relaxing activity was due to the presence of serotonin. Prey-handling studies revealed that O. maya punctures the eye or arthrodial membrane when predating blue crabs and uses the radula to bore through crown conch shells; these differing strategies may help O. maya to reduce the time needed to handle its prey.

  9. Novel Geometries for the LHC Crab Cavity

    Energy Technology Data Exchange (ETDEWEB)

    Hall, B. [Lancaster Univ. (United Kingdom); Burt, G. [Lancaster Univ. (United Kingdom); Smith, J. D.A. [Lancaster Univ. (United Kingdom); Rimmer, R. [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Wang, H. [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Delayen, J. [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Calaga, R. [Brookhaven National Lab. (BNL), Upton, NY (United States)

    2009-05-01

    In 2017 the LHC is envisioned to increase its luminosity via an upgrade. This upgrade is likely to require a large crossing angle hence a crab cavity is required to align the bunches prior to collision. There are two possible schemes for crab cavity implementation, global and local. In a global crab cavity the crab cavity is far from the IP and the bunch rotates back and forward as it traverses around the accelerator in a closed orbit. For this scheme a two-cell elliptical squashed cavity at 800 MHz is preferred. To avoid any potential beam instabilities all the parasitic modes of the cavities must be damped strongly, however crab cavities have lower order and same order modes in addition to the usual higher order modes and hence a novel damping scheme must be used to provide sufficient damping of these modes. In the local scheme two crab cavities are placed at each side of the IP two start and stop rotation of the bunches. This would require crab cavities much smaller transversely than in the global scheme but the frequency cannot be increased any higher due to the long bunch length of the LHC beam. This will require a novel compact crab cavity design. A superconducting version of a two rod coaxial deflecting cavity as a suitable design is proposed in this paper.

  10. What Is Juvenile Arthritis?

    Science.gov (United States)

    ... Analgesics for Osteoarthritis (Report from AHRQ) Joint Replacement Surgery: Health Information Basics for You and Your Family NIH Pediatric Rheumatology Clinic Health Information Juvenile Arthritis Find a Clinical Trial Journal Articles Juvenile Arthritis PDF Version Size: 123 KB ...

  11. Juvenile Delinquency: An Introduction

    Science.gov (United States)

    Smith, Carolyn A.

    2008-01-01

    Juvenile Delinquency is a term which is often inaccurately used. This article clarifies definitions, looks at prevalence, and explores the relationship between juvenile delinquency and mental health. Throughout, differences between males and females are explored. (Contains 1 table.)

  12. Parenting and juvenile delinquency

    NARCIS (Netherlands)

    Hoeve, Machteld

    2008-01-01

    Juvenile delinquency is a noteworthy problem. This thesis addressed the association between parenting and juvenile delinquency by analyzing the concepts of parenting adopted in family research in relation to criminological concepts and measures of delinquent behavior. Four studies were conducted.

  13. Most Detailed Image of the Crab Nebula

    Science.gov (United States)

    2005-01-01

    This new Hubble image -- one among the largest ever produced with the Earth-orbiting observatory -- shows the most detailed view so far of the entire Crab Nebula ever made. The Crab is arguably the single most interesting object, as well as one of the most studied, in all of astronomy. The image is the largest image ever taken with Hubble's WFPC2 workhorse camera. The Crab Nebula is one of the most intricately structured and highly dynamical objects ever observed. The new Hubble image of the Crab was assembled from 24 individual exposures taken with the NASA/ESA Hubble Space Telescope and is the highest resolution image of the entire Crab Nebula ever made.

  14. 50 CFR 680.6 - Crab economic data report (EDR).

    Science.gov (United States)

    2010-10-01

    ... 50 Wildlife and Fisheries 9 2010-10-01 2010-10-01 false Crab economic data report (EDR). 680.6... General § 680.6 Crab economic data report (EDR). Persons participating in the CR crab fisheries are... complete. Use these tables to complete the EDRs described in this section: Table 1, Crab...

  15. Juvenile Arrests, 2007. Juvenile Justice Bulletin

    Science.gov (United States)

    Puzzanchera, Charles

    2009-01-01

    This Bulletin summarizes 2007 juvenile crime and arrest data reported by local law enforcement agencies across the country and cited in the FBI report, "Crime in the United States 2007." The Bulletin describes the extent and nature of juvenile crime that comes to the attention of the justice system. It serves as a baseline for comparison for…

  16. Juvenile polyposis syndrome

    NARCIS (Netherlands)

    L.A.A. Brosens; D. Langeveld; W.A. van Hattem; F.M. Giardiello; G.J.A. Offerhaus

    2011-01-01

    Juvenile polyposis syndrome is a rare autosomal dominant syndrome characterized by multiple distinct juvenile polyps in the gastrointestinal tract and an increased risk of colorectal cancer. The cumulative life-time risk of colorectal cancer is 39% and the relative risk is 34. Juvenile polyps have a

  17. Heavy metal levels in mud crabs (Scylla spp.) from East Bataan Coast.

    Science.gov (United States)

    Cruz, Chona Camille E Vince; Ramos, Gliceria; Ablan-Lagman, Ma Carmen

    2015-04-01

    Heavy metal levels (Pb and Cu) on adult mud crabs (Scylla spp.) from the East Bataan Coast were determined. Muscle tissue from each crab was processed through nitric acid digestion and analyzed using atomic absorption spectroscopy. The average concentrations in the samples were 3.37 × 10(-3) and 1.01 mg/L-both within WHO acceptable limits. These were contrasted with the levels found in sediments from catch and grow-out sites (17.9, 14.5, 37.8, and 31.3 mg/L) and were found to be significantly lower in concentration. It takes 3-8 months before adult mud crabs can be harvested from grow-out ponds, and the data suggests that the organisms, even when constantly exposed to high levels of Pb and Cu, do not bio-accumulate toxic levels of these heavy metals. Mud crabs constitute a major economic natural resource in the Philippines and in the province of Bataan. Commanding high prices due to the quality of its meat, it is also a preferred culture product due to its impressive size, rapid growth rate, and high flesh content. Mud crab culture in Bataan is primarily driven by grow-out of captured juveniles in pen or pond cultures sourced from nearby bodies of water-making them vulnerable to prolonged exposure to pollutants. The East Bataan Coast shares its waters with the polluted Manila Bay, giving rise to the concern of the quality of seafood acquired from the area.

  18. What brakes the Crab pulsar?

    Science.gov (United States)

    Čadež, A.; Zampieri, L.; Barbieri, C.; Calvani, M.; Naletto, G.; Barbieri, M.; Ponikvar, D.

    2016-03-01

    Context. Optical observations provide convincing evidence that the optical phase of the Crab pulsar follows the radio one closely. Since optical data do not depend on dispersion measure variations, they provide a robust and independent confirmation of the radio timing solution. Aims: The aim of this paper is to find a global mathematical description of Crab pulsar's phase as a function of time for the complete set of published Jodrell Bank radio ephemerides (JBE) in the period 1988-2014. Methods: We apply the mathematical techniques developed for analyzing optical observations to the analysis of JBE. We break the whole period into a series of episodes and express the phase of the pulsar in each episode as the sum of two analytical functions. The first function is the best-fitting local braking index law, and the second function represents small residuals from this law with an amplitude of only a few turns, which rapidly relaxes to the local braking index law. Results: From our analysis, we demonstrate that the power law index undergoes "instantaneous" changes at the time of observed jumps in rotational frequency (glitches). We find that the phase evolution of the Crab pulsar is dominated by a series of constant braking law episodes, with the braking index changing abruptly after each episode in the range of values between 2.1 and 2.6. Deviations from such a regular phase description behave as oscillations triggered by glitches and amount to fewer than 40 turns during the above period, in which the pulsar has made more than 2 × 1010 turns. Conclusions: Our analysis does not favor the explanation that glitches are connected to phenomena occurring in the interior of the pulsar. On the contrary, timing irregularities and changes in slow down rate seem to point to electromagnetic interaction of the pulsar with the surrounding environment.

  19. Juveniles on trial.

    Science.gov (United States)

    Quinn, Kathleen M

    2002-10-01

    This article describes common forensic evaluations requested of juvenile court mental health evaluators. There has been a legal shift toward criminalization of juvenile court, with a greater emphasis on rights, abandonment of the rehabilitative model, and greater movement of adolescents into the adult criminal court. A resulting shift has been the redefinition of juvenile court forensic evaluations toward the specificity of adult forensic work. The challenge for evaluators is to refine their knowledge of the forensic standards and bring knowledge of development, assessment, and diagnosis in juveniles and interview techniques appropriate to juveniles to improve the evaluation and forensic reports.

  20. Novel Geometries for the LHC CRAB Cavity

    CERN Document Server

    Hall, Ben

    2010-01-01

    In 2017 the LHC is envisioned to increase its luminosity via an upgrade. This upgrade is likely to require a large crossing angle hence a crab cavity is required to align the bunches prior to collision. There are two possible schemes for crab cavity implementation, global and local. In a global crab cavity the crab cavity is far from the IP and the bunch rotates back and forward as it traverses around the accelerator in a closed orbit. For this scheme a two-cell elliptical squashed cavity at 800 MHz is preferred. To avoid any potential beam instabilities all the parasitic modes of the cavities must be damped strongly, however crab cavities have lower order and same order modes in addition to the usual higher order modes and hence a novel damping scheme must be used to provide sufficient damping of these modes. In the local scheme two crab cavities are placed at each side of the IP two start and stop rotation of the bunches. This would require crab cavities much smaller transversely than in the global scheme b...

  1. Juvenile polyposis syndrome

    Institute of Scientific and Technical Information of China (English)

    Lodewijk AA Brosens; Danielle Langeveld; W Arnout van Hattem; Francis M Giardiello; G Johan A Offerhaus

    2011-01-01

    Juvenile polyposis syndrome is a rare autosomal dominant syndrome characterized by multiple distinct juvenile polyps in the gastrointestinal tract and an increased risk of colorectal cancer.The cumulative life-time risk of colorectal cancer is 39% and the relative risk is 34.Juvenile polyps have a distinctive histology characterized by an abundance of edematous lamina propria with inflammatory cells and cystically dilated glands lined by cuboidal to columnar epithelium with reactive changes.Clinically, juvenile polyposis syndrome is defined by the presence of 5 or more juvenile polyps in the colorectum,juvenile polyps throughout the gastrointestinal tract or any number of juvenile polyps and a positive family history of juvenile polyposis.In about 50%-60% of patients diagnosed with juvenile polyposis syndrome a germline mutation in the SMAD4 or BMPR1A gene is found.Both genes play a role in the BMP/TGF-beta signalling pathway.It has been suggested that cancer in juvenile polyposis may develop through the so-alled "landscaper mechanism" where an abnormal stromal environment leads to neoplastic transformation of the adjacent epithelium and in the end invasive carcinoma.Recognition of this rare disorder is important for patients and their families with regard to treatment,follow-up and screening of at risk individuals.Each clinician confronted with the diagnosis of a juvenile polyp should therefore consider the possibility of juvenile polyposis syndrome.In addition, juvenile polyposis syndrome provides a unique model to study colorectal cancer pathogenesis in general and gives insight in the molecular genetic basis of cancer. This review discusses clinical manifestations, genetics, pathogenesis and management of juvenile polyposis syndrome.

  2. Peering into the Heart of the Crab Nebula

    Science.gov (United States)

    2000-01-01

    In the year 1054 A.D., Chinese astronomers were startled by the appearance of a new star, so bright that it was visible in broad daylight for several weeks. Today, the Crab Nebula is visible at the site of the 'Guest Star.' Located about 6,500 light-years from Earth, the Crab Nebula is the remnant of a star that began its life with about 10 times the mass of our own Sun. Its life ended on July 4, 1054 when it exploded as a supernova. In this image, NASA's Hubble Space Telescope has zoomed in on the center of the Crab to reveal its structure with unprecedented detail. The Crab Nebula data were obtained by Hubble's Wide Field and Planetary Camera 2 in 1995. Images taken with five different color filters have been combined to construct this new false-color picture. Resembling an abstract painting by Jackson Pollack, the image shows ragged shards of gas that are expanding away from the explosion site at over 3 million miles per hour. The core of the star has survived the explosion as a pulsar, visible in the Hubble image as the lower of the two moderately bright stars to the upper left of center. The pulsar is a neutron star that spins on its axis 30 times a second. It heats its surroundings, creating the ghostly diffuse bluish-green glowing gas cloud in its vicinity, including a blue arc just to its right. The colorful network of filaments is the material from the outer layers of the star that was expelled during the explosion. The picture is somewhat deceptive in that the filaments appear to be close to the pulsar. In reality, the yellowish green filaments toward the bottom of the image are closer to us, and approaching at some 300 miles per second. The orange and pink filaments toward the top of the picture include material behind the pulsar, rushing away from us at similar speeds. The various colors in the picture arise from different chemical elements in the expanding gas, including hydrogen (orange), nitrogen (red), sulfur (pink), and oxygen (green). The shades

  3. What brakes the Crab pulsar?

    CERN Document Server

    Čadež, A; Barbieri, C; Calvani, M; Naletto, G; Barbieri, M; Ponikvar, D

    2015-01-01

    Optical observations provide convincing evidence that the optical phase of the Crab pulsar follows the radio one closely. Since optical data do not depend on dispersion measure variations, they provide a robust and independent confirmation of the radio timing solution. The aim of this paper is to find a global mathematical description of Crab pulsar's phase as a function of time for the complete set of published Jodrell Bank radio ephemerides (JBE) in the period 1988-2014. We apply the mathematical techniques developed for analyzing optical observations to the analysis of JBE. We break the whole period into a series of episodes and express the phase of the pulsar in each episode as the sum of two analytical functions. The first function is the best-fitting local braking index law, and the second function represents small residuals from this law with an amplitude of only a few turns, which rapidly relaxes to the local braking index law. From our analysis, we demonstrate that the power law index undergoes "inst...

  4. Chemical Tools of Octopus maya during Crab Predation Are Also Active on Conspecifics.

    Science.gov (United States)

    Pech-Puch, Dawrin; Cruz-López, Honorio; Canche-Ek, Cindy; Campos-Espinosa, Gabriela; García, Elpidio; Mascaro, Maite; Rosas, Carlos; Chávez-Velasco, Daniel; Rodríguez-Morales, Sergio

    2016-01-01

    Octopus maya is a major socio-economic resource from the Yucatán Peninsula in Mexico. In this study we report for the first time the chemical composition of the saliva of O. maya and its effect on natural prey, i.e. the blue crab (Callinectes sapidus), the crown conch snail (Melongena corona bispinosa), as well as conspecifics. Salivary posterior glands were collected from octopus caught by local fishers and extracted with water; this extract paralyzed and predigested crabs when it was injected into the third pereiopod. The water extract was fractionated by membrane ultrafiltration with a molecular weight cut-off of 3 kDa leading to a metabolic phase (>3 kDa) and a neurotoxic fraction (octopus saliva might be used among conspecifics for defense and for reduction of competition. Bioguided separation of the neurotoxic fraction by chromatography led to a paralysis fraction and a relaxing fraction. The paralyzing activity of the saliva was exerted by amino acids, while the relaxing activity was due to the presence of serotonin. Prey-handling studies revealed that O. maya punctures the eye or arthrodial membrane when predating blue crabs and uses the radula to bore through crown conch shells; these differing strategies may help O. maya to reduce the time needed to handle its prey.

  5. Ultraviolet studies of the Crab Nebula

    Science.gov (United States)

    Talavera, A.

    2017-03-01

    The Crab Nebula (Messier 1) is one of the most observed sources with the XMM-Newton space telescope of ESA. The Crab and its related pulsar are a calibration source for the on-board X-rays cameras. There are around 80 observations between 2000 and 2015. In this observations, the XMM-Newton Optical and UV Monitor (OM) has also been used. We present a preliminary study of the Crab using images obtained the OM UV filters at 291, 231 and 212 nm. Photometric data for the pulsar (PSR0531+21), created in the supernova event of AD 1054 origin of the nebula, are also presented

  6. Design of the ILC Crab Cavity System

    Energy Technology Data Exchange (ETDEWEB)

    Adolphsen, C.; Beard, C.; Bellantoni, L.; Burt, G.; Carter, R.; Chase, B.; Church, M.; Dexter, A.; Dykes, M.; Edwards, H.; Goudket, P; Jenkins, R.; Jones, R.M.; Kalinin,; Khabiboulline, T.; Ko, K.; Latina, A.; Li, Z.; Ma, L.; McIntosh, P.; Ng, C.; /SLAC /Daresbury /Fermilab /Cockcroft Inst. Accel. Sci. Tech. /CERN

    2007-08-15

    The International Linear Collider (ILC) has a 14 mrad crossing angle in order to aid extraction of spent bunches. As a result of the bunch shape at the interaction point, this crossing angle at the collision causes a large luminosity loss which can be recovered by rotating the bunches prior to collision using a crab cavity. The ILC baseline crab cavity is a 9-cell superconducting dipole cavity operating at a frequency of 3.9 GHz. In this paper the design of the ILC crab cavity and its phase control system, as selected for the RDR in February 2007 is described in fuller detail.

  7. Final focus designs for crab waist colliders

    CERN Document Server

    AUTHOR|(CDS)2084369; Levichev, Evgeny; Piminov, Pavel

    2016-01-01

    The crab waist collision scheme promises significant luminosity gain. The successful upgrade of the DA$\\Phi$NE collider proved the principle of crab waist collision and increased luminosity 3 times. Therefore, several new projects try to implement the scheme. The paper reviews interaction region designs with the crab waist collision scheme for already existent collider DA$\\Phi$NE and SuperKEKB, presently undergoing commissioning, for the projects of SuperB in Italy, CTau in Novosibirsk and FCC-ee at CERN.

  8. A large bubble around the Crab Nebula

    Science.gov (United States)

    Romani, Roger W.; Reach, William T.; Koo, Bon Chul; Heiles, Carl

    1990-01-01

    IRAS and 21 cm observations of the interstellar medium around the Crab nebula show evidence of a large bubble surrounded by a partial shell. If located at the canonical 2 kpc distance of the Crab pulsar, the shell is estimated to have a radius of about 90 pc and to contain about 50,000 solar masses of swept-up gas. The way in which interior conditions of this bubble can have important implications for observations of the Crab are described, and the fashion in which presupernova evolution of the pulsar progenitor has affected its local environment is described.

  9. Posthuman blues

    CERN Document Server

    Tonnies, Mac

    2013-01-01

    Posthuman Blues, Vol. I is first volume of the edited version of the popular weblog maintained by author Mac Tonnies from 2003 until his tragic death in 2009. Tonnies' blog was a pastiche of his original fiction, reflections on his day-to-day life, trenchant observations of current events, and thoughts on an eclectic range of material he culled from the Internet. What resulted was a remarkably broad portrait of a thoughtful man and the complex times in which he lived, rendered with intellige...

  10. Preliminary Assessment of Potential Impacts to Dungeness Crabs from Disposal of Dredged Materials from the Columbia River

    Energy Technology Data Exchange (ETDEWEB)

    Pearson, Walter H.; Miller, Martin C.; Williams, Greg D.; Kohn, Nancy P.; Skalski, John R.

    2006-02-01

    -duration disposal scenarios, the shear force and surge currents estimated from the modeling and observed previously in the field at Palos Verdes, California appear to be sufficiently high to mobilize and transport the bottom sediment and at least juvenile crab. Behavioral response to surge currents probably occurs and may reduce the occurrence and extent of movement and any associated impacts. There evidence that burial by dredged materials can effect crab survival, but confounding factors in previous experiments preclude conclusions about thresholds and extent of effects. We recommend that future studies focus on burial effects during shallow water, short duration disposal events and take into account the potential for behavioral responses to mitigate any effects.

  11. Monitoring the Crab Nebula with LOFT

    Science.gov (United States)

    Wilson-Hodge, Colleen A.

    2012-01-01

    From 2008-2010, the Crab Nebula was found to decline by 7% in the 15-50 keV band, consistently in Fermi GBM, INTEGRAL IBIS, SPI, and JEMX, RXTE PCA, and Swift BAT. From 2001-2010, the 15-50 keV flux from the Crab Nebula typically varied by about 3.5% per year. Analysis of RXTE PCA data suggests possible spectral variations correlated with the flux variations. I will present estimates of the LOFT sensitivity to these variations. Prior to 2001 and since 2010, the observed flux variations have been much smaller. Monitoring the Crab with the LOFT WFM and LAD will provide precise measurements of flux variations in the Crab Nebula if it undergoes a similarly active episode.

  12. The Pulsar in the Crab Nebula

    CERN Document Server

    Lewandowska, Natalia

    2015-01-01

    The Crab pulsar belongs to one of the most studied stellar objects in the sky. Since its accidental detection in 1968, its pulsed emission has been observed throughout most of the electromagnetic spectrum. Although currently one of more than 2000 known pulsars, its way of work has remained not understood making the Crab pulsar an object of continuous studies and interest. Referring to the pulsed emission of the Crab pulsar only at radio wavelengths, it reveals a diversity of different phenomena. They range from deviations of the predicted slowing down process of the pulsar with time (long time phenomena) to an irregularity of its single pulse emission (short time phenomena). Similar and different kinds of deviations are observed at other wavelengths. Consequently, the Crab pulsar provides a large diversity of different emission characteristics which have remained difficult to interpret with a uniform theoretical approach including all observed properties. Since a review of all currently examined properties of...

  13. Crab Orchard National Wildlife Refuge : Sign Plan

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — The Crab Orchard National Wildlife Refuge Sign Plan explains how signs are used on the Refuge to help guide and educate visitors. An inventory of current signs is...

  14. Wakefield Damping for the CLIC Crab Cavity

    Energy Technology Data Exchange (ETDEWEB)

    Ambattu, P.K.; Burt, G.; Dexter, A.C.; Carter, R.G.; /Cockcroft Inst. Accel. Sci. Tech. /Lancaster U.; Khan, V.; Jones, R.M.; /Cockcroft Inst. Accel. Sci. Tech. /Manchester U.; Dolgashev, V.; /SLAC

    2011-12-01

    A crab cavity is required in the CLIC to allow effective head-on collision of bunches at the IP. A high operating frequency is preferred as the deflection voltage required for a given rotation angle and the RF phase tolerance for a crab cavity are inversely proportional to the operating frequency. The short bunch spacing of the CLIC scheme and the high sensitivity of the crab cavity to dipole kicks demand very high damping of the inter-bunch wakes, the major contributor to the luminosity loss of colliding bunches. This paper investigates the nature of the wakefields in the CLIC crab cavity and the possibility of using various damping schemes to suppress them effectively.

  15. Crab Orchard National Wildlife Refuge : Hunting Plan

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This plan provides guidelines for the administration of hunting activity and for the development, maintenance, and enforcement of regulations and guidelines on Crab...

  16. Characterization of a Freshwater Crab Sudanonautes aubryi ...

    African Journals Online (AJOL)

    SARAH

    2014-01-31

    Jan 31, 2014 ... J. Appl. Biosci. 2014. Characterization of fresh water crab ( Sudanonautes aubryi) of ... great diversity (Dobson, 2004), their role in the ecology of freshwaters is ... Apart from fish, other groups of animals subject to exploitation ...

  17. Epizoic and ectoparasitic protozoans from crab larvae

    Digital Repository Service at National Institute of Oceanography (India)

    Santhakumari, V.

    A suctorian, Ephelota gemmipara Hertwig, infesting the zoea of the peacrab, Porcellana and an ectoparasitic flagellate Ellobiopsis chattoni Caullery infecting the zoea of the crab were observed from off Cape Comorin, the south-east coast of India...

  18. The anatomy of the king crab Hapalogaster mertensii Brandt, 1850 (Anomura: Paguroidea: Hapalogastridae): new insights into the evolutionary transformation of hermit crabs into king crabs

    NARCIS (Netherlands)

    Keiler, J.; Richter, S.; Wirkner, C.S.

    2015-01-01

    The emergence of king crabs from a hermit crab-like ancestor is one of the most curious events in decapod evolution. King crabs comprise two taxa, Lithodidae and Hapalogastridae, and while lithodids have formed the focus of various anatomical studies, the internal anatomy of hapalogastrids has never

  19. Crabs

    Digital Repository Service at National Institute of Oceanography (India)

    Chatterji, A.

    stream_size 2 stream_content_type text/plain stream_name Biodiversity_Western_Ghats_Inf_Kit_1994_3.6_1.pdf.txt stream_source_info Biodiversity_Western_Ghats_Inf_Kit_1994_3.6_1.pdf.txt Content-Encoding ISO-8859-1 Content-Type text...

  20. Feeding ecology of the freshwater crab Trichodactylus borellianus (Decapoda: Trichodactylidae in the floodplain of the Paraná River, southern South America

    Directory of Open Access Journals (Sweden)

    Verónica Williner

    2013-09-01

    Full Text Available Freshwater crabs are not commonly considered to be an important group in trophic webs, and this might be due to a lack of knowledge about their trophic roles in aquatic ecosystems. Trichodactylus borellianus is one of the most common and widely distributed freshwater crabs in the floodplains of the southern South American rivers. The main objective of the present study was to examine the trophic role of T. borellianus, in the floodplain of the Paraná River, and its relationships with the freshwater littoral community. The trophic spectrum of this species was characterized for both sexes and individuals of different sizes (adults and juveniles, throughout daily and seasonal cycles. Samples were collected from the aquatic vegetation of three shallow lakes. The diet composition and the feeding activity of T. borellianus were evaluated through the examination of the stomach contents and their degree of emptiness. This crab species consumed several plant and animal items, including amoebas, rotifers, oligochaetes, copepods, cladocerans, and insect larvae. Moreover, this species consumes filamentous and unicellular algae, diatoms, fungi, and macrophytic remains. The predatory habits varied with the season and time of day, and variations in the feeding activity of the juveniles and adults were detected and documented. The diversity of food items eaten by this crab suggests that its trophic role in the community as an omnivore and opportunistic predator provides a connection among several trophic levels from both aquatic and terrestrial communities.

  1. Color vision: retinal blues.

    Science.gov (United States)

    Johnston, Jamie; Esposti, Federico; Lagnado, Leon

    2012-08-21

    Two complementary studies have resolved the circuitry underlying green-blue color discrimination in the retina. A blue-sensitive interneuron provides the inhibitory signal required for computing green-blue color opponency.

  2. Epibiotic community of the horseshoe crab Tachypleus gigas

    Digital Repository Service at National Institute of Oceanography (India)

    Patil, J.S.; Anil, A.C.

    -epibionts) present on horseshoe crabs, according to gender, were evaluated, and the macro-epibiont population from different regions of the carapace was mapped. In general, female horseshoe crabs harbored fewer epibionts than the males. Among the diatoms, Navicula...

  3. Statement on Bills to Designate Crab Orchard Wilderness

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Statement of John Kyl on H.R. 3508 and H.R. 5893, bills to designate Crab Orchard Wilderness within Crab Orchard National Wildlife Refuge. This document includes maps.

  4. Juvenile giant fibroadenoma

    Directory of Open Access Journals (Sweden)

    Vipul Yagnik

    2011-07-01

    Full Text Available Fibroadenomas are benign solid tumor associated with aberration of normal lobular development. Juvenile giant fibroadenoma is usually single and >5 cm in size /or >500 gms in weight. Important differential diagnoses are: phyllodes tumor and juvenile gigantomastia. Simple excision is the treatment of choice.

  5. Renewing Juvenile Justice

    Science.gov (United States)

    Macallair, Daniel; Males, Mike; Enty, Dinky Manek; Vinakor, Natasha

    2011-01-01

    The Center on Juvenile and Criminal Justice (CJCJ) was commissioned by Sierra Health Foundation to critically examine California's juvenile justice system and consider the potential role of foundations in promoting systemic reform. The information gathered by CJCJ researchers for this report suggests that foundations can perform a key leadership…

  6. Philanthropist in Juvenile Reformatory

    Institute of Scientific and Technical Information of China (English)

    HAN NIU

    2007-01-01

    @@ On the afternoon of February 1, 2007, Chen Guangbiao, a noted philanthropist, found himself in the Jiangsu Provincial Juvenile Reformatory in Jurong City for a ceremony to donate two buses, 100 computers, and 100 desks and 100 chairs for the juvenile offenders to use in their study.

  7. Parenting and juvenile delinquency

    NARCIS (Netherlands)

    Hoeve, Machteld

    2008-01-01

    Juvenile delinquency is a noteworthy problem. This thesis addressed the association between parenting and juvenile delinquency by analyzing the concepts of parenting adopted in family research in relation to criminological concepts and measures of delinquent behavior. Four studies were conducted. Th

  8. Juvenile Confinement in Context

    Science.gov (United States)

    Mendel, Richard A.

    2012-01-01

    For more than a century, the predominant strategy for the treatment and punishment of serious and sometimes not-so-serious juvenile offenders in the United States has been placement into large juvenile corrections institutions, alternatively known as training schools, reformatories, or youth corrections centers. America's heavy reliance on…

  9. Parenting and juvenile delinquency

    NARCIS (Netherlands)

    Hoeve, Machteld

    2008-01-01

    Juvenile delinquency is a noteworthy problem. This thesis addressed the association between parenting and juvenile delinquency by analyzing the concepts of parenting adopted in family research in relation to criminological concepts and measures of delinquent behavior. Four studies were conducted. Th

  10. Juvenile mammary papillomatosis; Papilomatosis juvenil mamaria

    Energy Technology Data Exchange (ETDEWEB)

    Alvarez, M.; Jimenez, A. V. [Hospital Reina Sofia. Cordoba (Spain)

    2001-07-01

    Juvenile mammary papillomatosis is a benign proliferative disease of young patients, generally under 30 years of age. The most frequent clinical presentation is the existence of an elastic and mobile lymph node of the breast. Anatomopathologically, it is characterized because it presents ductal epithelial hyperplasia, sometimes with marked atypia, and there are numerous cysts having different sizes among the findings. It has been associated with an increase in the incidence of breast cancer, both in the patient herself as well as her family. We review the literature on the subject and present the mammographic and ultrasonographic findings of a 22 year old woman diagnosed of juvenile mammary papillomatosis. (Author) 12 refs.

  11. The Radio Spectral Index of the Crab Nebula

    Science.gov (United States)

    1997-11-20

    We present the results of a new, comprehensive investigation of the radio spectral index of the Crab Nebula supernova remnant. New data at 74 MHz are...thermal material in the Crab Nebula’s filaments. Apart from some possible renewed acceleration occurring in the wisps, the dominant accelerator of relativistic electrons in the Crab Nebula is the pulsar itself.

  12. Salinity and Temperature Tolerance of the Nemertean Worm Carcinonemertes errans, an Egg Predator of the Dungeness Crab.

    Science.gov (United States)

    Dunn, Paul H; Young, Craig M

    2015-04-01

    Estuaries can be harsh habitats for the marine animals that enter them, but they may also provide these species with sub-saline refuges from their parasites. The nemertean egg predator Carcinonemertes errans is known to occur less frequently and in smaller numbers on its host, the Dungeness crab Metacarcinus magister, when the hosts are found within estuaries. We examined the temperature and salinity tolerances of C. errans to determine if this observed distribution represents a true salinity refuge. We monitored the survival of juvenile and larval worms exposed to ecologically relevant salinities (5-30) and temperatures (8-20 °C) over the course of several days under laboratory conditions. Juvenile worms were unaffected by the experimental temperature levels and exhibited robustness to salinity treatments 25 and 30. However, significant mortality was seen at salinity treatments 20 and below. Larvae were less tolerant than juveniles to lowered salinity and were also somewhat more susceptible to the higher temperatures tested. Given that the Dungeness crab can tolerate forays into mesohaline (salinity 5-18) waters for several days at a time, our findings suggest that salinity gradients play an important role in creating a parasite refuge for this species within the estuaries of the Pacific Northwest.

  13. Spider Movement, UV Reflectance and Size, but Not Spider Crypsis, Affect the Response of Honeybees to Australian Crab Spiders

    Science.gov (United States)

    Llandres, Ana L.; Rodríguez-Gironés, Miguel A.

    2011-01-01

    According to the crypsis hypothesis, the ability of female crab spiders to change body colour and match the colour of flowers has been selected because flower visitors are less likely to detect spiders that match the colour of the flowers used as hunting platform. However, recent findings suggest that spider crypsis plays a minor role in predator detection and some studies even showed that pollinators can become attracted to flowers harbouring Australian crab spider when the UV contrast between spider and flower increases. Here we studied the response of Apis mellifera honeybees to the presence of white or yellow Thomisus spectabilis Australian crab spiders sitting on Bidens alba inflorescences and also the response of honeybees to crab spiders that we made easily detectable painting blue their forelimbs or abdomen. To account for the visual systems of crab spider's prey, we measured the reflectance properties of the spiders and inflorescences used for the experiments. We found that honeybees did not respond to the degree of matching between spiders and inflorescences (either chromatic or achromatic contrast): they responded similarly to white and yellow spiders, to control and painted spiders. However spider UV reflection, spider size and spider movement determined honeybee behaviour: the probability that honeybees landed on spider-harbouring inflorescences was greatest when the spiders were large and had high UV reflectance or when spiders were small and reflected little UV, and honeybees were more likely to reject inflorescences if spiders moved as the bee approached the inflorescence. Our study suggests that only the large, but not the small Australian crab spiders deceive their preys by reflecting UV light, and highlights the importance of other cues that elicited an anti-predator response in honeybees. PMID:21359183

  14. Black yeast-like fungi associated with Lethargic Crab Disease (LCD) in the mangrove-land crab, Ucides cordatus (Ocypodidae).

    NARCIS (Netherlands)

    Vicente, V.A.; Orelis-Ribeiro, R.; Najafzadeh, M.J.; Sun, J.; Guerra, R.S.; Miesch, S.; Ostrensky, A.; Meis, J.F.G.M.; Klaassen, C.H.; Hoog, G.S. de; Boeger, W.A.

    2012-01-01

    Lethargic Crab Disease (LCD) caused extensive epizootic mortality of the mangrove land crab Ucides cordatus (Brachyura: Ocypodidae) along the Brazilian coast, mainly in the Northeastern region. The disease was named after the symptoms of slow movement of infected crabs. Causative agents were suspect

  15. Rearing and growth of the Octopus Robsonella fontaniana (Cephalopoda: Octopodidae) from planktonic hatchlings to benthic juveniles.

    Science.gov (United States)

    Uriarte, Iker; Hernández, Jorge; Dörner, Jessica; Paschke, Kurt; Farías, Ana; Crovetto, Enzo; Rosas, Carlos

    2010-04-01

    Globally, octopus larviculture is one of the challenges faced in the attempt to diversify aquaculture and achieve cephalopod farming. Currently, only juveniles of Octopus vulgaris, Octopus joubini, and Enteroctopus dofleini have been obtained at an experimental level. This is the first study to look at the characteristics of planktonic and benthic Robsonella fontaniana juveniles in an effort to analyze the morphometric changes occurring during their planktonic and benthic phases and to explore the feasibility of obtaining settlement under controlled conditions. The morphometric measurements varied exponentially over time and did not show different tendencies before and after settlement. Mantle growth in relation to total length fit a logarithmic regression, whereas arm length and eye diameter increased linearly with respect to total length throughout the entire paralarval and juvenile periods. This suggests that the size of the mantle decreases with age in proportion to the total octopus length, whereas the organs more directly involved in catching prey tend to increase in direct proportion to the total length. The present study shows that R. fontaniana can be reared from hatching through the final paralarval stage on a diet of Lithodes santolla (king crab) zoeae; after settlement, the juveniles can be reared on a diet of crab such as Petrolisthes.

  16. Novel Geometries for the LHC Crab Cavity

    Energy Technology Data Exchange (ETDEWEB)

    B. Hall, G. Burt, C. Lingwood, R. Rimmer, H. Wang

    2010-05-23

    The planned luminosity upgrade to LHC is likely to necessitate a large crossing angle and a local crab crossing scheme. For this scheme crab cavities align bunches prior to collision. The scheme requires at least four such cavities, a pair on each beam line either side of the interaction point (IP). Upstream cavities initiate rotation and downstream cavities cancel rotation. Cancellation is usually done at a location where the optics has re-aligned the bunch. The beam line separation near the IP necessitates a more compact design than is possible with elliptical cavities such as those used at KEK. The reduction in size must be achieved without an increase in the operational frequency to maintain compatibility with the long bunch length of the LHC. This paper proposes a suitable superconducting variant of a four rod coaxial deflecting cavity (to be phased as a crab cavity), and presents analytical models and simulations of suitable designs.

  17. Determination of PCBs and total lipids in edible fish and crab tissue using supercritical fluid extraction

    Energy Technology Data Exchange (ETDEWEB)

    Gavlor, M.; Hale, R.; Smith, C.; Thames, J.; Mothershead, R. [Virginia Inst. of Marine Science, Gloucester Point, VA (United States). Dept. of Environmental Sciences

    1995-12-31

    An offline supercritical fluid extraction (SFE) method has been developed to determine PCB congeners and total tissue lipid content in edible fish and crab tissues collected from several river systems in Virginia. The method is rapid and safe, requiring only 40 minutes per sample and uses nonorganic solvents for total lipid extraction and only 1.5 mL isooctane for PCB extraction. The SFE approach compares favorably with soxhlet extraction, ASE and column elution. Over 800 fish and crab tissue samples were analyzed successfully, thus demonstrating the robustness of the method. Total lipid values obtained using SFE showed considerable spatial and interspecies variability ranging from 1.8% in blue crab (Callinectes sapidus) to 36.4% in striped bass (Morone saxatilis). Total PCB concentrations also varied greatly by site and species. These ranged from below the quantitation limit (1.0 {micro}1 g/kg) to 9,910 {micro}g/kg on a dry weight basis using GCELCD. Dominant PCB congeners detected were in good agreement with those reported by other researchers. Mean total PCB concentrations did not correlate well with total tissue lipid content.

  18. First laboratory insight on the behavioral rhythms of the bathyal crab Geryon longipes

    Science.gov (United States)

    Nuñez, J. D.; Sbragaglia, V.; García, J. A.; Company, J. B.; Aguzzi, J.

    2016-10-01

    The deep sea is the largest and at the same time least explored biome on Earth, but quantitative studies on the behavior of bathyal organisms are scarce because of the intrinsic difficulties related to in situ observations and maintaining animals in aquaria. In this study, we reported, for the first time, laboratory observations on locomotor rhythms and other behavioral observations (i.e. feeding, exploring and self-grooming) for the bathyal crab Geryon longipes. Crabs were collected on the middle-lower slope (720-1750 m) off the coast of Blanes (Spain). Inertial (18 h) water currents and monochromatic blue (i.e. 470 nm) light-darkness (24 h) cycles were simulated in two different experiments in flume tanks endowed with burrows. Both cycles were simulated in order to investigate activity rhythms regulation in Mediterranean deep-sea benthos. Crabs showed rhythmic locomotor activity synchronized to both water currents and light-darkness cycles. In general terms, feeding and exploring behaviors also followed the same pattern. Results presented here indicate the importance of local inertial (18 h) periodicity of water currents at the seabed as a temporal cue regulating the behavior of bathyal benthic fauna in all continental margin areas where the effects of tides is negligible.

  19. The role of kelp crabs as consumers in bull kelp forests—evidence from laboratory feeding trials and field enclosures

    Directory of Open Access Journals (Sweden)

    Katie Dobkowski

    2017-05-01

    Full Text Available The Northern kelp crab (Pugettia producta and the graceful kelp crab (Pugettia gracilis are common primary consumers in bull kelp beds near the San Juan Islands (Salish Sea, NE Pacific. In this system, urchins (often considered the most voracious herbivores exerting top-down control on kelp beds tend to remain sedentary because of the high availability of detrital macroalgae, but the extent to which kelp crabs consume kelp (and other food options is largely unknown. I conducted four types of laboratory feeding experiments to evaluate kelp crab feeding patterns: (1 feeding electivity between bull kelp (Nereocystis luetkeana and seven species of co-occurring local macroalgae; (2 feeding electivity on aged vs. fresh bull kelp; (3 feeding preference between N. luetkeana and small snails (Lacuna sp.; and (4 scaling of feeding rate with body size in P. producta and P. gracilis. In choice experiments, P. producta consumed greater mass of N. luetkeana than of other macroalgal species offered and elected to eat fresh bull kelp over aged. However, P. producta also consumed snails (Lacuna sp., indicating more generalized feeding than previously suspected. Feeding rates for P. producta exceeded the expected 3∕4 scaling rule of metabolic rates, indicating that larger P. producta may have a disproportionately large impact on bull kelp. A subtidal field experiment, designed to assess the influence of consumers on juvenile bull kelp net tissue gain, found that only fully enclosed (protected bull kelp increased in wet mass and blade length. Herbivory by kelp crabs, among other consumers, is likely to play a previously unrecognized role in mediating the growth and survival of this annual kelp species within the Salish Sea.

  20. Frequency Tuning for a DQW Crab Cavity

    CERN Document Server

    Verdú-Andrés, Silvia; Ben-Zvi, Ilan; Calaga, Rama; Capatina, Ofelia; Leuxe, Raphael; Skaritka, John; Wu, Qiong; Xiao, Binping; Zanoni, Carlo

    2016-01-01

    The nominal operating frequency for the HL-LHC crab cavities is 400.79 MHz within a bandwidth of ±60kHz. Attaining the required cavity tune implies a good understanding of all the processes that influence the cavity frequency from the moment when the cavity parts are being fabricated until the cavity is installed and under operation. Different tuning options will be available for the DQW crab cavity of LHC. This paper details the different steps in the cavity fabrication and preparation that may introduce a shift in the cavity frequency and introduces the different tuning methods foreseen to bring the cavity frequency to meet the specifications.

  1. Evolution of metabolomics profile of crab paste during fermentation.

    Science.gov (United States)

    Chen, Daian; Ye, Yangfang; Chen, Juanjuan; Yan, Xiaojun

    2016-02-01

    Crab paste is regularly consumed by people in the coastal area of China. The fermentation time plays a key role on the quality of crab paste. Here, we investigated the dynamic evolution of metabolite profile of crab paste during fermentation by combined use of NMR spectroscopy and multivariate data analysis. Our results showed that crab paste quality was significantly affected by fermentation. The quality change was manifested in the decline of lactate, betaine, taurine, trimethylamine-N-oxide, trigonelline, inosine, adenosine diphosphate, and 2-pyridinemethanol, and in the fluctuation of a range of amino acids as well as in the accumulation of glutamate, sucrose, formate, acetate, trimethylamine, and hypoxanthine. Trimethylamine production and its increased level with fermentation could be considered as a freshness index of crab paste. These results contribute to quality assessment of crab paste and confirm the metabolomics technique as a useful tool to provide important information on the crab paste quality.

  2. Modeling Crabbing Dynamics in an Electron-Ion Collider

    Energy Technology Data Exchange (ETDEWEB)

    Castilla, Alejandro [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Old Dominion Univ., Norfolk, VA (United States); Univ. de Guanajuato (DCI-UG), Leon (Mexico); Morozov, Vasiliy S. [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Satogata, Todd J. [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Old Dominion Univ., Norfolk, VA (United States); Delayen, Jean R. [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Old Dominion Univ., Norfolk, VA (United States)

    2015-09-01

    A local crabbing scheme requires π/2 (mod π) horizontal betatron phase advances from an interaction point (IP) to the crab cavities on each side of it. However, realistic phase advances generated by sets of quadrupoles, or Final Focusing Blocks (FFB), between the crab cavities located in the expanded beam regions and the IP differ slightly from π/2. To understand the effect of crabbing on the beam dynamics in this case, a simple model of the optics of the Medium Energy Electron-Ion Collider (MEIC) including local crabbing was developed using linear matrices and then studied numerically over multiple turns (1000 passes) of both electron and proton bunches. The same model was applied to both local and global crabbing schemes to determine the linear-order dynamical effects of the synchro-betatron coupling induced by crabbing.

  3. Cryopyrin-Associated Autoinflammatory Syndromes (CAPS) - Juvenile

    Science.gov (United States)

    ... Cryopyrin-Associated Autoinflammatory Syndrome (CAPS) (Juvenile) Dermatomyositis (Juvenile) Familial Mediterranean Fever (Juvenile) Fibromyalgia Giant Cell Arteritis Glucocorticoid-induced Osteoperosis ...

  4. Juvenil idiopatisk arthritis

    DEFF Research Database (Denmark)

    Herlin, Troels

    2002-01-01

    The new classification of juvenile idiopathic arthritis (JIA) is described in this review. Clinical characteristics divide JIA in to subtypes: systemic, oligoarticular (persistent and extended type), RF-positive and--negative polyarticular, enthesitis-related arthritis and psoriatic arthritis...

  5. Juvenile Rockfish Recruitment Cruise

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — In 1983, the groundfish analysis project began a series of yearly cruises designed to assess the annual abundance of juvenile rockfish along the central California...

  6. Juvenile Idiopathic Arthritis

    Science.gov (United States)

    ... Physical Therapy Regular Exercise en español Artritis idiopática juvenil It may begin with a swollen knuckle, a ... may suddenly appear and disappear, developing in one area and then another. High fevers that tend to ...

  7. Juvenile Sex Offenders.

    Science.gov (United States)

    Ryan, Eileen P; Otonichar, Joseph M

    2016-07-01

    Sexual offending by juveniles accounts for a sizable percentage of sexual offenses, especially against young children. In this article, recent research on female juvenile sex offenders (JSOs), risk factors for offending in juveniles, treatment, and the ways in which these youth may differ from general delinquents will be reviewed. Most JSOs do not go on to develop paraphilic disorders or to commit sex offenses during adulthood, and as a group, they are more similar to nonsexual offending juvenile delinquents than to adult sex offenders. Recent research has elucidated some differences between youth who commit sex offenses and general delinquents in the areas of atypical sexual interests, the use of pornography, and early sexual victimization during childhood.

  8. Juvenile Spondyloarthritis Treatment Recommendations

    OpenAIRE

    Tse, Shirley; Burgos-Vargas, Ruben; Colbert, Robert A

    2012-01-01

    No specific recommendations for the treatment of juvenile spondyloarthritis have been established. Important differences exist in how spondyloarthritis begins and progresses in children and adults, supporting the need for pediatric-specific recommendations. Recently published recommendations for the treatment of juvenile arthritis consider children with sacroiliitis in a separate group, and allow for more accelerated institution of a TNF inhibitor depending on disease activity and prognostic ...

  9. Parenting and juvenile delinquency

    OpenAIRE

    Hoeve, Machteld

    2008-01-01

    Juvenile delinquency is a noteworthy problem. This thesis addressed the association between parenting and juvenile delinquency by analyzing the concepts of parenting adopted in family research in relation to criminological concepts and measures of delinquent behavior. Four studies were conducted. The first study addressed a meta-analysis on parenting characteristics and styles in relation to delinquency. In this meta-analysis, previous manuscripts were systematically analyzed, computing mean ...

  10. A Comparative Study of Genetic Variation betwccn Chinese Mitten Crab Eriocheir Sinensis and Hepu Mitten Crab E. Hepuensis

    Institute of Scientific and Technical Information of China (English)

    LIU Guangdong; ZHANG Xiumei; GAO Tianxiang; LOU Dong

    2002-01-01

    Horizontal starch gel electrophoresis was used to investigate the biochemical genetic structure of Chinese mittencrab Eriocheir sinensis and Hepu mitten crab E. hepuensis. Sixteen putative enzyme-coding loci were examined for forty-nineChinese mitten crabs and thirty-eight Hepu mitten crabs. Nine loci, AAT-1 *, AAT-2 *, G3PDH*, GPI*, IDHP-1 *, IDHP-2 *,MDH-1 *, MDH-2 * and PGM * , are polymorphic in Chinese mitten crab, and seven, AAT-1 *, AAT-2 *, GPI *, IDHP-1 *,MDH-1 *, MDH-2 * and PGM * , are polymorphic in Hepu mitten crab. The proportion of polymorphic loci and the expectedheterozygosity are 0.562 5 and 0.080 3 for Chinese mitten crab, and 0.437 5 and 0.075 4 for Hepu mitten crab. The Nei' s ge-netic distance between two species is 0.002 4.

  11. Population structure of the red mangrove crab, Goniopsis cruentata (Decapoda: Grapsidae under different fishery impacts: Implications for resource management

    Directory of Open Access Journals (Sweden)

    Gustavo L. Hirose

    2015-06-01

    Full Text Available The red mangrove crab, Goniopsis cruentata, influences the recruitment and composition of plant species in the mangrove ecosystem and it is an important fishery resource. Nevertheless, no current management and conservation plans are available for this species for the Brazilian coast. This investigation evaluated the population structure and reproductive biology in populations of G. cruentata under contrasting fishery pressures. The sampling program was carried out in two mangroves, Vaza-Barris and Sergipe River, from January through December 2011. Crabs from both mangroves were randomly collected by a professional fisherman during daytime low tide periods, using a fishing rod baited with pieces of a locally abundant gastropod, Pugilina morio, during 20min/area (catch per unit effort. Monthly measurements of air, sediment surface layer and water temperatures were obtained with a digital thermometer and salinity with an optical refractometer. Both crab populations were compared concerning their abundance, body size, sex ratio, size at onset of sexual maturity and fecundity (FI. Abiotic factors (air, water and mud temperature; and salinity showed no significant differences between sampling localities. A total of 4 370 crabs were sampled, 2 829 from the Sergipe River and 1 541 from the Vaza-Barris River. The abundance and body size of crabs were compared between mangroves, and statistically significant differences were found. The sex ratio for both populations differed from the expected 1:1 ratio, and a significant deviation in favor of juvenile males was obtained, while adults showed a bias toward females. The estimated size at onset of sexual maturity for both sexes was similar in both populations. However, the populations differed significantly in the number and volume of eggs: a higher FI was obtained in females from the Sergipe River, while a higher egg volume was observed in females from the Vaza-Barris River mangrove. These results indicated

  12. Ocean acidification impairs crab foraging behaviour.

    Science.gov (United States)

    Dodd, Luke F; Grabowski, Jonathan H; Piehler, Michael F; Westfield, Isaac; Ries, Justin B

    2015-07-07

    Anthropogenic elevation of atmospheric CO2 is driving global-scale ocean acidification, which consequently influences calcification rates of many marine invertebrates and potentially alters their susceptibility to predation. Ocean acidification may also impair an organism's ability to process environmental and biological cues. These counteracting impacts make it challenging to predict how acidification will alter species interactions and community structure. To examine effects of acidification on consumptive and behavioural interactions between mud crabs (Panopeus herbstii) and oysters (Crassostrea virginica), oysters were reared with and without caged crabs for 71 days at three pCO2 levels. During subsequent predation trials, acidification reduced prey consumption, handling time and duration of unsuccessful predation attempt. These negative effects of ocean acidification on crab foraging behaviour more than offset any benefit to crabs resulting from a reduction in the net rate of oyster calcification. These findings reveal that efforts to evaluate how acidification will alter marine food webs should include quantifying impacts on both calcification rates and animal behaviour. © 2015 The Author(s) Published by the Royal Society. All rights reserved.

  13. Horseshoe crab behavior:Patterns and processes

    Institute of Scientific and Technical Information of China (English)

    Christopher C.Chabot; Winsor H.Watson Ⅲ

    2010-01-01

    @@ 1 Introduction The American horseshoe crab Limulus polyphemus has long served as a source of delight and inspiration to a broad cross-section of scientists - from naturalists to neuroscientists. Periodically, for the last hundred years or so, new discoveries have been made about this ancient creature that both enlighten scientists and reinforce the importance of conserving this ancient species.

  14. The tree-climbing crabs of Trinidad

    NARCIS (Netherlands)

    Hagen, von Heinrich-Otto

    1977-01-01

    An annotated list of the brachyuran (12) and anomuran (1) tree-climbing crabs of Trinidad (West Indies) is presented (see Table 1 for species names). Some of the species mentioned (e.g. Aratus pisonii, Goniopsis cruentata) are well-known treeclimbers, in others (e.g. Sesarma roberti, S. ricordi) thi

  15. HUBBLE CAPTURES DYNAMICS OF CRAB NEBULA

    Science.gov (United States)

    2002-01-01

    A new sequence of Hubble Space Telescope images of the remnant of a tremendous stellar explosion is giving astronomers a remarkable look at the dynamic relationship between the tiny Crab Pulsar and the vast nebula that it powers. This picture shows a Hubble Space Telescope image of the inner parts of the Crab. The pulsar itself is visible as the left of the pair of stars near the center of the frame. Surrounding the pulsar is a complex of sharp knots and wisp-like features. This image is one of a sequence of Hubble images taken over the course of several months. This sequence shows that the inner part of the Crab Nebula is far more dynamic than previously understood. The Crab literally 'changes it stripes' every few days as these wisps stream away from the pulsar at half the speed of light. The Hubble Space Telescope photo was taken Nov. 5, 1995 by the Wide Field and Planetary Camera 2 at a wavelength of around 550 nanometers, in the middle of the visible part of the electromagnetic spectrum. Credit: Jeff Hester and Paul Scowen (Arizona State University), and NASA

  16. Corneal laceration caused by river crab

    Directory of Open Access Journals (Sweden)

    Vinuthinee N

    2015-01-01

    Full Text Available Naidu Vinuthinee,1,2 Anuar Azreen-Redzal,1 Jaafar Juanarita,1 Embong Zunaina2 1Department of Ophthalmology, Hospital Sultanah Bahiyah, Alor Setar, 2Department of Ophthalmology, School of Medical Sciences, Universiti Sains Malaysia, Kubang Kerian, Malaysia Abstract: A 5-year-old boy presented with right eye pain associated with tearing and photophobia of 1-day duration. He gave a history of playing with a river crab when suddenly the crab clamped his fingers. He attempted to fling the crab off, but the crab flew and hit his right eye. Ocular examination revealed a right eye corneal ulcer with clumps of fibrin located beneath the corneal ulcer and 1.6 mm level of hypopyon. At presentation, the Seidel test was negative, with a deep anterior chamber. Culture from the corneal scrapping specimen grew Citrobacter diversus and Proteus vulgaris, and the boy was treated with topical gentamicin and ceftazidime eyedrops. Fibrin clumps beneath the corneal ulcer subsequently dislodged, and revealed a full-thickness corneal laceration wound with a positive Seidel test and shallow anterior chamber. The patient underwent emergency corneal toileting and suturing. Postoperatively, he was treated with oral ciprofloxacin 250 mg 12-hourly for 1 week, topical gentamicin, ceftazidime, and dexamethasone eyedrops for 4 weeks. Right eye vision improved to 6/9 and 6/6 with pinhole at the 2-week follow-up following corneal suture removal. Keywords: corneal ulcer, pediatric trauma, ocular injury

  17. Swimming of the pea crab (Pinnotheres pisum)

    NARCIS (Netherlands)

    Versteegh, C.P.C.; Muller, M.

    2014-01-01

    Aquatic organisms have to deal with different hydrodynamic regimes, depending on their size and speed during locomotion. The pea crab swims by beating the third and fourth pereiopod on opposite sides as pairs. Using particle tracking velocimetry and high-speed video recording, we quantify the kinema

  18. Power coupler for the ILC crab cavity

    Energy Technology Data Exchange (ETDEWEB)

    Burt, G.; Dexter, A.; Jenkins, R.; /Lancaster U.; Beard, C.; Goudket, P.; McIntosh, P.A.; /Daresbury; Bellantoni, Leo; /Fermilab

    2007-06-01

    The ILC crab cavity will require the design of an appropriate power coupler. The beam-loading in dipole mode cavities is considerably more variable than accelerating cavities, hence simulations have been performed to establish the required external Q. Simulations of a suitable coupler were then performed and were verified using a normal conducting prototype with variable coupler tips.

  19. The CMS Remote Analysis Builder (CRAB)

    Energy Technology Data Exchange (ETDEWEB)

    Spiga, D.; Cinquilli, M.; Servoli, L.; /INFN, Perugia /Perugia U; Lacaprara, S.; Fanzago, F.; Dorigo, A.; /INFN, Padova; Merlo, M.; Farina, F.; /INFN, Milan /Milan U; Fanfani, A.; Codispoti, G.; Bacchi, W.; /INFN, Bologna /Bologna U /CERN /INFN, CNAF /INFN, Trieste /Fermilab

    2008-01-22

    The CMS experiment will produce several Pbytes of data every year, to be distributed over many computing centers geographically distributed in different countries. Analysis of this data will be also performed in a distributed way, using grid infrastructure. CRAB (CMS Remote Analysis Builder) is a specific tool, designed and developed by the CMS collaboration, that allows a transparent access to distributed data to end physicist. Very limited knowledge of underlying technicalities are required to the user. CRAB interacts with the local user environment, the CMS Data Management services and with the Grid middleware. It is able to use WLCG, gLite and OSG middleware. CRAB has been in production and in routine use by end-users since Spring 2004. It has been extensively used in studies to prepare the Physics Technical Design Report (PTDR) and in the analysis of reconstructed event samples generated during the Computing Software and Analysis Challenge (CSA06). This involved generating thousands of jobs per day at peak rates. In this paper we discuss the current implementation of CRAB, the experience with using it in production and the plans to improve it in the immediate future.

  20. Dominance and population structure of freshwater crabs ...

    African Journals Online (AJOL)

    1997-02-06

    Feb 6, 1997 ... systems and fonm a major part of the diet of many vertebrates, little is known about their biology. ... dominant or even keystone species (Power, Tilman, Estes, .... crabs were fed ad lih with Lopis® rabbit pellets every day.

  1. Vocational Teachers' Role in Serving Juvenile Offenders.

    Science.gov (United States)

    Meers, Gary D.

    1983-01-01

    Educators need to understand the juvenile justice system to understand what juvenile offenders go through while completing their sentences. This article reviews cases and juvenile charge classifications, and presents a model for alternative sentencing options for juveniles. (JOW)

  2. Blue cures blue but be cautious

    Directory of Open Access Journals (Sweden)

    Pranav Sikka

    2011-01-01

    Full Text Available Methemoglobinemia is a disorder characterized by the presence of >1% methemoglobin (metHb in the blood. Spontaneous formation of methemoglobin is normally counteracted by protective enzyme systems, for example, nicotinamide adenine dinucleotide phosphate (NADPH methemoglobin reductase. Methemoglobinemia is treated with supplemental oxygen and methylene blue (1-2 mg/kg administered slow intravenously, which acts by providing an artificial electron acceptor for NADPH methemoglobin reductase. But known or suspected glucose-6-phosphate dehydrogenase (G6PD deficiency is a relative contraindication to the use of methylene blue because G6PD is the key enzyme in the formation of NADPH through pentose phosphate pathway and G6PD-deficient individuals generate insufficient NADPH to efficiently reduce methylene blue to leukomethylene blue, which is necessary for the activation of the NADPH-dependent methemoglobin reductase system. So, we should be careful using methylene blue in methemoglobinemia patient before G6PD levels.

  3. Trunk asymmetry in juveniles

    Directory of Open Access Journals (Sweden)

    Triantafyllopoulos Georgios

    2008-09-01

    Full Text Available Abstract Background Trunk asymmetry (TA is a common phenomenon in children, but its incidence in juveniles is not known. The present cross sectional study reports TA in normal juveniles and provides data which describe the evolution of TA from early childhood to adolescence. Materials and methods The scoliometer readings in both standing and sitting forward bending position (FBP of 3301 children, (1645 boys, and 1656 girls aged from 3 to 9 years old were studied. TA was quantified by measuring angle of trunk rotation (ATR and children were categorized as symmetric (ATR = 0°, mild asymmetric (ATR 1° – 6° and severely asymmetric (ATR ≥ 7°. The difference of TA between standing and sitting FBP as well as differences between boys and girls in frequency of TA were also calculated. The scoliometer readings were analyzed by age to reveal at which age the juvenile pattern of TA changes into the adolescent one. Results 74.2% of boys and 77% of girls were symmetric (ATR = 0° in the thoracic region in standing FBP, while 82.7% of boys and 84.1% of girls were symmetric in the thoracic region in sitting FBP. Juvenile girls are more symmetric than boys but severe TA was found almost the same between the two genders. A significant reduction in the frequency of mild TA from standing into sitting FBP, in all the examined regions in both boys and girls was found, but in severe TA this reduction is very small. Analysing scoliometer readings by age it appears that significant TA changes take place between 8–9 years of age for boys and between 6–7 and 8–9 years for girls. TA in boys is changing into the adolescent pattern at a later age than in girls. Conclusion Juveniles were found more symmetric than adolescents, who were studied previously in a different study. Furthermore, juvenile girls were found more symmetric than boys. Juvenile TA pattern seems to be in accordance with the higher incidence of juvenile idiopathic scoliosis in boys. Furthermore

  4. Juvenile Incarceration and Health.

    Science.gov (United States)

    Barnert, Elizabeth S; Perry, Raymond; Morris, Robert E

    2016-03-01

    Addressing the health status and needs of incarcerated youth represents an issue at the nexus of juvenile justice reform and health care reform. Incarcerated youth face disproportionately higher morbidity and higher mortality compared to the general adolescent population. Dental health, reproductive health, and mental health needs are particularly high, likely as a result of lower access to care, engagement in high-risk behaviors, and underlying health disparities. Violence exposure and injury also contribute to the health disparities seen in this population. Further, juvenile incarceration itself is an important determinant of health. Juvenile incarceration likely correlates with worse health and social functioning across the life course. Correctional health care facilities allow time for providers to address the unmet physical and mental health needs seen in this population. Yet substantial challenges to care delivery in detention facilities exist and quality of care in detention facilities varies widely. Community-based pediatricians can serve a vital role in ensuring continuity of care in the postdetention period and linking youth to services that can potentially prevent juvenile offending. Pediatricians who succeed in understanding and addressing the underlying social contexts of their patients' lives can have tremendous impact in improving the life trajectories of these vulnerable youth. Opportunities exist in clinical care, research, medical education, policy, and advocacy for pediatricians to lead change and improve the health status of youth involved in the juvenile justice system.

  5. Species Profiles. Life Histories and Environmental Requirements of Coastal Fishes and Invertebrates (Pacific Southwest). Brown Rock Crab, Red Rock Crab, and Yellow Crab

    Science.gov (United States)

    1989-12-01

    distinguished by a slender abdomen and Two other large Cancer species, the Dungeness crab mature females by a broad abdomen that is often hirsute (C. magister...to the scent experimental treatment . One 13th instar female crab of potential food in the water (Case 1964; Zimmer-Faust reared at 22 ’C became

  6. Extending juvenility in grasses

    Energy Technology Data Exchange (ETDEWEB)

    Kaeppler, Shawn; de Leon Gatti, Natalia; Foerster, Jillian

    2017-04-11

    The present invention relates to compositions and methods for modulating the juvenile to adult developmental growth transition in plants, such as grasses (e.g. maize). In particular, the invention provides methods for enhancing agronomic properties in plants by modulating expression of GRMZM2G362718, GRMZM2G096016, or homologs thereof. Modulation of expression of one or more additional genes which affect juvenile to adult developmental growth transition such as Glossy15 or Cg1, in conjunction with such modulation of expression is also contemplated. Nucleic acid constructs for down-regulation of GRMZM2G362718 and/or GRMZM2G096016 are also contemplated, as are transgenic plants and products produced there from, that demonstrate altered, such as extended juvenile growth, and display associated phenotypes such as enhanced yield, improved digestibility, and increased disease resistance. Plants described herein may be used, for example, as improved forage or feed crops or in biofuel production.

  7. Comparison of the population structure of the fiddler crab Uca vocator (Herbst, 1804 from three subtropical mangrove forests

    Directory of Open Access Journals (Sweden)

    Karine Delevati Colpo

    2004-03-01

    Full Text Available The population structure of U. vocator was investigated during a one-year period in three mangrove forests in southeast Brazil. The study specifically addressed comparisons on individual size , juvenile recruitment and sex-ratio. The structure of the mangrove forests, i.e. density, basal area, and diameter, and the physical properties of sediments, i.e. texture and organic matter contents, were also examined. A catch-per-unit-effort (CPUE technique was used to sample the crab populations using 15-min sampling periods by two people. Males always outnumbered females, probably due to ecological and behavioural attributes of these crabs. The median size of fiddler crabs differed among the sampled populations. The mangroves at Indaiá and Itamambuca showed higher productivity than those at Itapanhaú, where oil spills impacting the shore were reported. Marked differences were found regarding individual size , either their size at the onset of sexual maturity or their asymptotic size, suggesting that food availability may be favouring growth in the studied populations.

  8. Food and habitat choice in the spider crab Leucippa pentagona (Majoidea: Epialtidae in Bahía Bustamante, Patagonia, Argentina

    Directory of Open Access Journals (Sweden)

    Martin Varisco

    2015-03-01

    Full Text Available The aim of the present study was to analyse the feeding strategy and spatial distribution of the spider crab Leucippa pentagona in Bahía Bustamante (Patagonia, Argentina. Several microhabitat variables that could influence the spatial distribution of this crab were related to its different life stages by using redundancy analysis. Regarding its feeding preferences, we found that the sphacelariales Halopteris spp. and Sphacelaria fusca, epiphytes of the alga Gracilaria gracilis, represented over 70% of its diet. Conversely, consumption of G. gracilis was low throughout the year. These feeding preferences can be related to the higher proportion of ash-free dry mass of sphacelariales. A close association was observed between G. gracilis biomass and recruits and mature crabs; this relationship was stronger at critical periods of the crab’s life cycle such as incubation or moult. Intermolt juveniles were related to G. gracilis0 as well as to other species of macroalgae. Our results suggest that G. gracilis plays a key role in the small-scale distribution of L. pentagona in Bahía Bustamante, providing food and shelter. The consumption of G. gracilis epiphytes allows L. pentagona to maintain high foraging rates at safe living sites, minimizing the damage to G. gracilis.

  9. Laboratory trials reveal that exposure to extreme raining events prior to metamorphosis affect the post-settlement performance of an estuarine crab

    Science.gov (United States)

    Rey, Felisa; Silva Neto, Gina M.; Rosa, Rui; Queiroga, Henrique; Calado, Ricardo

    2015-03-01

    Meteorological forcing can impact planktonic communities, with extreme raining events promoting salinity decreases and triggering larval mortality in estuarine plankton. The present study evaluated how exposure to low salinities prior to metamorphosis of Carcinus maenas megalopae (last larval stage) may affect its ability to metamorphose and the post-metamorphosis performance of juvenile crabs. An extreme raining event that promoted a generalized decrease in salinity (from 25 to 10) in the whole water column of one of the main channels of a coastal lagoon was mimicked in the laboratory. Wild megalopae of C. maenas were collected and kept individually without any food at salinities of 10 or 25 (S10 or S25) until they either died or metamorphosed to the first crab instar (C1). Specimens metamorphosing in 5 days or less following their collection were labeled as early settlers (ES10 and ES25), while those taking more than 5 days were labeled as late settlers (LS10 and LS25). All newly metamorphosed crabs were kept individually until C5 at a salinity of 25 and fed ad libitum, with their intermolt periods and carapace width (CW) being recorded. Osmotic stress did not affect the survival or ability to metamorphose of C. maenas megalopae, with 89% of all larvae in both salinities being able to metamorphose. This result is supported by the ability of this larval stage to hyper-regulate. Nonetheless, an exposure of late settling megalopae to low salinities prior to metamorphosis promotes the occurrence of juvenile crabs with a smaller CW. The deleterious effects of exposing late settling megalopae to low salinities appears to be magnified during early benthic life, with C5 originating from treatment LS10 displaying a significantly smaller CW (4.87 ± 0.28 mm) and lower wet weight (WW) (28.95 ± 4.62 mg). On the other side, C5 originating from ES25 exhibited a significantly higher CW (5.90 ± 0.33 mm) and WW (50.89 ± 8.14 mg). The nutritional vulnerability experienced by

  10. DERMATOMIOSITIS JUVENIL Y EMBARAZO

    OpenAIRE

    Evans M,Gregorio; Poulsen R,Ronald; Blanco R,Romiely; Luna V,Viviana

    2002-01-01

    La dermatomiositis juvenil es un desorden inflamatorio crónico multisistémico del tejido conectivo. Tiene una incidencia de 2-3/100.000/año. Con la disminución en la mortalidad experimentada en los últimos decenios, la atención está cifrada en la morbilidad a largo plazo y en las alteraciones funcionales. Con un tratamiento agresivo los niños con dermatomiositis juvenil generalmente tienen un futuro promisorio, sin incapacidad o con incapacidad mínima. La mortalidad actualmente se estima cerc...

  11. Juvenile idiopatiske inflammatoriske myopatier

    Directory of Open Access Journals (Sweden)

    Helga Sanner

    2009-10-01

    Full Text Available Juvenile idiopathic inflammatory myopathies (JIIM is a group of rare autoimmune systemic diseases in children and adolescents, characterized by chronic skeletal muscle inflammation. Unlike in adults, dermatomyositis (JDM is by far the most common of the idiopathic inflammatory myopathies in children and adolescents. The hallmark of JDM is calcinosis, lipodystrophy and vasculitis, findings that differs the juvenile form of dermatomyosits from the adult form. JDM is still diagnosed and classified by Bohan and Peter’s criteria from 1975. There are limited data on long time outcome of this disease

  12. A 150-million-year-old crab larva and its implications for the early rise of brachyuran crabs.

    Science.gov (United States)

    Haug, Joachim T; Martin, Joel W; Haug, Carolin

    2015-03-09

    True crabs (Brachyura) are the most successful group of decapod crustaceans. This success is most likely coupled to their life history, including two specialised larval forms, zoea and megalopa. The group is comparably young, starting to diversify only about 100 million years ago (mya), with a dramatic increase in species richness beginning approximately 50 mya. Early evolution of crabs is still very incompletely known. Here, we report a fossil crab larva, 150 mya, documented with up-to-date imaging techniques. It is only the second find of any fossil crab larva, but the first complete one, the first megalopa, and the oldest one (other fossil ca. 110 mya). Despite its age, the new fossil possesses a very modern morphology, being indistinguishable from many extant crab larvae. Hence, modern morphologies must have been present significantly earlier than formerly anticipated. We briefly discuss the impact of this find on our understanding of early crab evolution.

  13. FACT. Energy spectrum of the Crab Nebula

    Energy Technology Data Exchange (ETDEWEB)

    Temme, Fabian; Einecke, Sabrina; Buss, Jens [TU Dortmund, Experimental Physics 5, Otto-Hahn-Str.4, 44221 Dortmund (Germany); Collaboration: FACT-Collaboration

    2016-07-01

    The First G-APD Cherenkov Telescope is the first Imaging Air Cherenkov Telescope which uses silicon photon detectors (G-APDs aka SiPM) as photo sensors. With more than four years of operation, FACT proved an application of SiPMs is suitable for the field of ground-based gamma-ray astronomy. Due to the stable flux at TeV energies, the Crab Nebula is handled as a ''standard candle'' in Cherenkov astronomy. The analysis of its energy spectrum and comparison with other experiments, allows to evaluate the performance of FACT. A modern analysis chain, based on data stream handling and multivariate analysis methods was developed in close cooperation with the department of computer science at the TU Dortmund. In this talk, this analysis chain and its application are presented. Further to this, results, including the energy spectrum of the Crab Nebula, measured with FACT, are shown.

  14. Pulse profile stability of the Crab pulsar

    CERN Document Server

    Jain, Chetana

    2011-01-01

    We present an X-ray timing analysis of the Crab pulsar, PSR B0531+21, using the archival RXTE data. We have investigated the stability of the Crab pulse profile, in soft (2-20 keV) and hard (30-100 keV) X-ray energies, over the last decade of RXTE operation. The analysis includes measurement of the separation between the two pulse peaks; and intensity and the widths of the two peaks. We did not find any significant time dependency in the pulse shape. The two peaks are stable in phase, intensity and widths, for the last ten years. The first pulse is relatively stronger at soft X-rays. The first pulse peak is narrower than the second peak, in both, soft- and hard X-ray energies. Both the peaks show a slow rise and a steeper fall. The ratio of the pulsed photons in the two peaks is also constant in time.

  15. Equivalent cleaning in a juvenile facultative and obligate cleaning wrasse: an insight into the evolution of cleaning in labrids?

    Science.gov (United States)

    Grutter, Alexandra S.; Feeney, William E.

    2016-09-01

    Species that exhibit ontogenetic variation in interspecific cleaning behaviours may offer insights into how interspecific cooperation evolves. We investigated the foraging ecology of the yellowtail tubelip wrasse ( Diproctacanthus xanthurus), a facultative cleaner as a juvenile and corallivore as an adult, and compared its juvenile ecology with that of juvenile blue-streak cleaner wrasse ( Labroides dimidiatus), a closely related and sympatric obligate cleaner. While juveniles of the two species differed in the amount of time they inspected clients, the number of client individuals and species that were cleaned and the proportion that posed did not differ, nor did the number of ectoparasitic isopods in their guts. In contrast, adult yellowtail tubelip wrasse had fewer isopods and more coral mucus in their guts than juveniles. These data support a hypothesized series of events in which juvenile cleaning acts as an evolutionary precursor to obligate cleaning and suggest that the yellowtail tubelip wrasse may present an intermediate between corallivory and cleaning.

  16. Multiband observations of the Crab Nebula

    Science.gov (United States)

    Krassilchtchikov, A. M.; Bykov, A. M.; Castelletti, G. M.; Dubner, G. M.; Kargaltsev, O. Yu; Pavlov, G. G.

    2017-01-01

    Results of simultaneous imaging of the Crab Nebula in the radio (JVLA), optical (HST), and X-ray (Chandra) bands are presented. The images show a variety of small-scale structures, including wisps mainly located to the north-west of the pulsar and knots forming a ring-like structure associated with the termination shock of the pulsar wind. The locations of the structures in different bands do not coincide with each other.

  17. Pulsating Radio Sources near the Crab Nebula.

    Science.gov (United States)

    Staelin, D H; Reifenstein, E C

    1968-12-27

    Two new pulsating radio sources, designated NP 0527 and NP 0532, were found near the Crab Nebula and could be coincident with it. Both sources are sporadic, and no periodicities are evident. The pulse dispersions indicate that 1.58 +/- 0.03 and 1.74 +/- 0.02 x 10(20) electrons per square centimeter lie in the direction of NP 0527 and NP 0532, respectively.

  18. THE OSMOREGULATORY ABILITY OF THREE GRAPSOID CRAB ...

    African Journals Online (AJOL)

    ... of the araPIOicl crabs Cyc1oaraJn1ll 1I1111&1atlll, Satunul CIlIMIIIiI aDd .... The experimental media used were sea-water of salinity 34%" volumetrically diluted with ... The freezing point of the haemolymph collected from the arthrodial ... marked increase in mortality at salinities below 10%0. and experiments were not ...

  19. A Large Glitch in the Crab Pulsar

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Using a new pulsar timing system at the 25-m radio telescope of Urumqi Astronomical Observatory, we have detected a large glitch in the Crab pulsar which occurred in 2000 July. The size of the gfitch is Av/v ~ 2.4 × 10-8, with a rela tive increment in frequency derivative Av/v ~ 5 × 10-3. The observing system is introduced and the observed properties of the glitch are discussed.

  20. Juvenile Battens Disease.

    Science.gov (United States)

    Gayton, Romayne

    1987-01-01

    Ten children diagnosed with juvenile Battens disease were tested over a three-year period in general intelligence, memory, listening and speech, motor skills, and general learning. Results showed that the patients followed a predetermined pattern but that the time span for development of memory, communication, and behavior problems varied greatly.…

  1. Juvenile Victimization and Delinquency.

    Science.gov (United States)

    Esbensen, Finn-Aage; Huizinga, David

    1991-01-01

    Demographic characteristics of juvenile victims of crime and a potential relationship between victimization and self-reported delinquency are examined for 877 adolescents from a large midwestern city. Lifetime victimization rates (LVRs) are higher for those involved in delinquency, and LVRs rise with age and higher levels of delinquent behavior.…

  2. Juvenile Battens Disease.

    Science.gov (United States)

    Gayton, Romayne

    1987-01-01

    Ten children diagnosed with juvenile Battens disease were tested over a three-year period in general intelligence, memory, listening and speech, motor skills, and general learning. Results showed that the patients followed a predetermined pattern but that the time span for development of memory, communication, and behavior problems varied greatly.…

  3. Juvenile idiopathic arthritis

    NARCIS (Netherlands)

    Prakken, Berent; Albani, Salvatore; Martini, Alberto

    2011-01-01

    Juvenile idiopathic arthritis is a heterogeneous group of diseases characterised by arthritis of unknown origin with onset before age of 16 years. Pivotal studies in the past 5 years have led to substantial progress in various areas, ranging from disease classification to new treatments. Gene expres

  4. The inner knot of the Crab nebula

    Science.gov (United States)

    Lyutikov, Maxim; Komissarov, Serguei S.; Porth, Oliver

    2016-02-01

    We model the inner knot of the Crab nebula as a synchrotron emission coming from the non-spherical MHD termination shock of relativistic pulsar wind. The post-shock flow is mildly relativistic; as a result the Doppler beaming has a strong impact on the shock appearance. The model can reproduce the knot location, size, elongation, brightness distribution, luminosity and polarization provided the effective magnetization of the section of the pulsar wind producing the knot is low, σ ≤ 1. In the striped wind model, this implies that the striped zone is rather wide, with the magnetic inclination angle of the Crab pulsar ≥45°; this agrees with the previous model-dependent estimate based on the gamma-ray emission of the pulsar. We conclude that the tiny knot is indeed a bright spot on the surface of a quasi-stationary magnetic relativistic shock and that this shock is a site of efficient particle acceleration. On the other hand, the deduced low magnetization of the knot plasma implies that this is an unlikely site for the Crab's gamma-ray flares, if they are related to the fast relativistic magnetic reconnection events.

  5. The Porcelain Crab Transcriptome and PCAD, the Porcelain Crab Microarray and Sequence Database

    Energy Technology Data Exchange (ETDEWEB)

    Tagmount, Abderrahmane; Wang, Mei; Lindquist, Erika; Tanaka, Yoshihiro; Teranishi, Kristen S.; Sunagawa, Shinichi; Wong, Mike; Stillman, Jonathon H.

    2010-01-27

    Background: With the emergence of a completed genome sequence of the freshwater crustacean Daphnia pulex, construction of genomic-scale sequence databases for additional crustacean sequences are important for comparative genomics and annotation. Porcelain crabs, genus Petrolisthes, have been powerful crustacean models for environmental and evolutionary physiology with respect to thermal adaptation and understanding responses of marine organisms to climate change. Here, we present a large-scale EST sequencing and cDNA microarray database project for the porcelain crab Petrolisthes cinctipes. Methodology/Principal Findings: A set of ~;;30K unique sequences (UniSeqs) representing ~;;19K clusters were generated from ~;;98K high quality ESTs from a set of tissue specific non-normalized and mixed-tissue normalized cDNA libraries from the porcelain crab Petrolisthes cinctipes. Homology for each UniSeq was assessed using BLAST, InterProScan, GO and KEGG database searches. Approximately 66percent of the UniSeqs had homology in at least one of the databases. All EST and UniSeq sequences along with annotation results and coordinated cDNA microarray datasets have been made publicly accessible at the Porcelain Crab Array Database (PCAD), a feature-enriched version of the Stanford and Longhorn Array Databases.Conclusions/Significance: The EST project presented here represents the third largest sequencing effort for any crustacean, and the largest effort for any crab species. Our assembly and clustering results suggest that our porcelain crab EST data set is equally diverse to the much larger EST set generated in the Daphnia pulex genome sequencing project, and thus will be an important resource to the Daphnia research community. Our homology results support the pancrustacea hypothesis and suggest that Malacostraca may be ancestral to Branchiopoda and Hexapoda. Our results also suggest that our cDNA microarrays cover as much of the transcriptome as can reasonably be captured in

  6. Thermal tolerance of the crab Pachygrapsus marmoratus: intraspecific differences at a physiological (CTMax) and molecular level (Hsp70).

    Science.gov (United States)

    Madeira, D; Narciso, L; Cabral, H N; Diniz, M S; Vinagre, C

    2012-11-01

    Temperature is one of the most important variables influencing organisms, especially in the intertidal zone. This work aimed to test physiological and molecular intraspecific differences in thermal tolerance of the crab Pachygrapsus marmoratus (Fabricius, 1787). The comparisons made focused on sex, size, and habitat (estuary and coast) differences. The physiological parameter was upper thermal limit, tested via the critical thermal maximum (CTMax) and the molecular parameter was total heat shock protein 70 (Hsp70 and Hsp70 plus Hsc70) production, quantified via an enzyme-linked imunosorbent assay. Results showed that CTMax values and Hsp70 production are higher in females probably due to different microhabitat use and potentially due to different hormonal regulation in males and females. Among females, non-reproducing ones showed a higher CTMax value, but no differences were found in Hsp70, even though reproducing females showed higher variability in Hsp70 amounts. As reproduction takes up a lot of energy, its allocation for other activities, including stress responses, is lower. Juveniles also showed higher CTMax and Hsp70 expression because they occur in greater shore heights and ageing leads to alterations in protein synthesis. Comparing estuarine and coastal crabs, no differences were found in CTMax but coastal crabs produce more Hsp70 than estuarine crabs because they occur in drier and hotter areas than estuarine ones, which occur in moister environments. This work shows the importance of addressing intraspecific differences in the stress response at different organizational levels. This study shows that these differences are key factors in stress research, climate research, and environmental monitoring.

  7. Non-native crab Rhithropanopeus harrisii (Gould, 1984 - a new component of the benthic communities in the Gulf of Gdańsk (southern Baltic Sea

    Directory of Open Access Journals (Sweden)

    Joanna Hegele-Drywa

    2014-01-01

    Full Text Available The aim of this study was to determine the occurrence, spatial distribution and abundance pattern of the Harris mud crab Rhithropanopeus harrisii in the Gulf of Gdańsk (southern Baltic Sea. Between 2006 and 2010, this species was found at 69 out of 129 sampling stations, at depths from 0 to 20 m. Two main aggregations of the Harris mud crab were established: (1 in Puck Bay (max. density 19 indiv. 100 m-2 and (2 in the Gdynia and Sopot area (max. density 5 indiv. 100 m-2. 920 specimens were collected during the whole sampling period: 150 juveniles, 370 females and 400 males. The minimum measured carapace width was 1.96 mm, the maximum 21.40 mm (mean 9.03 ±4.11 mm.

  8. Blue and White Pot

    Institute of Scientific and Technical Information of China (English)

    1996-01-01

    Many recent archaeological studies have proven that the earliest blue and white porcelain was produced from the kiln in Gongxian County, Henan Province in the Tang Dynasty (618-907). It was an important variety of porcelain available for export then. The early blue and white porcelain in the Yuan Dynasty appeared dark and gray. During the reign of Zhizheng, clear blue and white porcelain was produced, indicating

  9. Cellular blue naevus

    Directory of Open Access Journals (Sweden)

    Mittal R

    2001-01-01

    Full Text Available A 31-year-old man had asymptomatic, stationary, 1.5X2 cm, shiny, smooth, dark blue nodule on dorsum of right hand since 12-14 years. In addition he had developed extensive eruption of yellow to orange papulonodular lesions on extensors of limbs and buttocks since one and half months. Investigations confirmed that yellow papules were xanthomatosis and he had associated diabetes mellitus and hyperlipidaemia. Biopsy of blue nodule confirmed the clinical diagnosis of cellular blue naevus. Cellular blue naevus is rare and its association with xanthomatosis and diabetes mellitus were interesting features of above patients which is being reported for its rarity.

  10. Enhanced gamma-ray activity from the Crab nebula

    Science.gov (United States)

    Buehler, R.; Ciprini, S.

    2016-01-01

    Preliminary LAT analysis indicates enhanced gamma-ray activity from the Crab nebula. The daily-averaged gamma-ray emission (E > 100 MeV) from the direction of the Crab Nebula has surpassed 4.0 x 10^-6 ph cm^-2 s^-1 five times in the last 12 days.

  11. Brachyuran Crabs collected at Curaçao

    NARCIS (Netherlands)

    Rathbun, Mary J.

    1924-01-01

    In 1920 a report ¹) on Dr. BOEKE’S collection of crabs and shrimps from Curaçao and other Dutch West Indian Islands was published. Dr. VAN DER HORST’S collection forms an important addition to the fauna of Curaçao, especially as to the Xanthids and Majids, or spider crabs. Four new species were disc

  12. Crab biodiversity under different management schemes of mangrove ecosystems

    Directory of Open Access Journals (Sweden)

    M. Bandibas

    2016-01-01

    Full Text Available Reforestation is one of the Philippines’ government efforts to restore and rehabilitate degraded mangrove ecosystems. Although there is recovery of the ecosystem in terms of vegetation, the recovery of closely-linked faunal species in terms of community structure is still understudied. This research investigates the community structure of mangrove crabs under two different management schemes: protected mangroves and reforested mangroves. The transect-plot method was employed in each management scheme to quantify the vegetation, crab assemblages and environmental variables. Community composition of crabs and mangrove trees were compared between protected and reforested mangroves using non-metric multi-dimensional scaling and analysis of similarity in PRIMER 6. Chi-squared was used to test the variance of sex ration of the crabs. Canonical Correspondence Analysis was used to determine the relationship between crabs and environmental parameters. A total of twelve species of crabs belonging to six families were identified in protected mangroves while only four species were documented in reforested mangroves. Perisesarma indiarum and Baptozius vinosus were the most dominant species in protected and reforested mangrove, respectively.  Univariate analysis of variance of crab assemblage data revealed significant differences in crab composition and abundance between protected mangroves and from reforested mangroves (P

  13. Characteristics of cobalt removal by crab shell particles

    Energy Technology Data Exchange (ETDEWEB)

    Lee, MooYeal; Kajiuchi, Toshio [Department of International Development, Tokyi Institute of Technology, Tokyo (Korea, Republic of); Kang, Hyun Ah; Yang, Ji Won [Department of Chemical Engineering, Korea Advanced Institute of Science and Technology, Taejon (Korea, Republic of)

    1999-07-01

    The characteristics of cobalt removal by raw crab shell particles was investigated. The removal efficiency of cobalt was dependent on contact time, solution pH, crab shell dose and ionic strength. Approximately 99% of the cobalt was removed within 6 hour after contact with crab shell particles. The removal efficiency was slightly affected by initial solution pH over 5.0 and the final solution pH changed to 10 spontaneously. In addition, optimum pH range of cobalt removal was broaden by the effect of crab shell addition. Maximum uptake of cobalt was 510 mg Co/g crab shell at initial pH 5.0. The removal efficiency was affected slightly by ionic strength up to 2.0 M of NaCl. From the results of scanning electron microscopy (SEM) and energy dispersive spectrometer (EDS), the removal of cobalt by crab shell was mainly through the dissolution of CaCO{sub 3} followed by precipitation of Co(OH){sub 2} and CoCO{sub 3} and then the precipitates were adsorbed to the chitin on the surface of crab shell particles. Compared to the results with activated carbon column, the addition of crab shell to activated carbon column increased the removal efficiency dramatically.(author)

  14. Crabbed Waist Collisions in DAFNE and Super-B Design

    Energy Technology Data Exchange (ETDEWEB)

    Raimondi, P.; Alesini, D.; Biagini, M.E.; Biscari, C.; Boni, R.; Boscolo, M.; Bossi, F.; Buonomo, B.; Clozza, A.; Delle Monache, G.O.; Demma, T.; Di Pasquale, E.; Di Pirro, G.; Drago, A.; Gallo, A.; Ghigo, A.; Guiducci, S.; Ligi, C.; Marcellini, F.; Mazzitelli, Giovanni; Milardi, C.; /Frascati /Orsay, LAL /CERN /Rome III U. /Rome U. /Novosibirsk, IYF /KEK, Tsukuba /INFN, Pisa /INFN, Cosenza /SLAC /Frascati

    2011-11-02

    The new idea of increasing the luminosity of a collider with crab waist collisions and first experimental results from the DA{Phi}NE {Phi}-Factory at LNF, Frascati, using this concept are presented. Consequences for the design of future factories will be discussed. An outlook to the performance reach with crab waist collisions is given, with emphasis on future B Factories.

  15. Evolutionary diversification of coral-dwelling gall crabs (Cryptochiridae)

    NARCIS (Netherlands)

    Meij, Sancia Esmeralda Theonilla van der

    2015-01-01

    Gall crabs (Crustacea : Cryptochiridae) are small, coral-dwelling crabs that live in obligate association with their host corals (Scleractinia), on which they rely for food and shelter. They have been recorded from shallow and deeper waters (over 500 m), but the majority of the species live in reef

  16. 50 CFR Table 2 to Part 680 - Crab Species Code

    Science.gov (United States)

    2010-10-01

    ... 50 Wildlife and Fisheries 9 2010-10-01 2010-10-01 false Crab Species Code 2 Table 2 to Part 680 Wildlife and Fisheries FISHERY CONSERVATION AND MANAGEMENT, NATIONAL OCEANIC AND ATMOSPHERIC ADMINISTRATION..., Table 2 Table 2 to Part 680—Crab Species Code Species code Common name Scientific name 900...

  17. The Rhizocephalan parasite of the crab Xantho incisus (Leach)

    NARCIS (Netherlands)

    Boschma, H.

    1955-01-01

    As shown by Holthuis (1954), the correct name for the European crab commonly referred to as Xantho floridus (Montagu) is Xantho incisus (Leach). A Rhizocephalan parasite of this crab was first mentioned (without an indication of specific characters) by Gerbe (1862); afterwards specimens were recorde

  18. Land crabs as key drivers in tropical coastal forest recruitment

    Science.gov (United States)

    Lindquist, E.S.; Krauss, K.W.; Green, P.T.; O'Dowd, D. J.; Sherman, P.M.; Smith, T. J.

    2009-01-01

    Plant populations are regulated by a diverse assortment of abiotic and biotic factors that influence seed dispersal and viability, and seedling establishment and growth at the microsite. Rarely does one animal guild exert as significant an influence on different plant assemblages as land crabs. We review three tropical coastal ecosystems-mangroves, island maritime forests, and mainland coastal terrestrial forests-where land crabs directly influence forest composition by limiting tree establishment and recruitment. Land crabs differentially prey on seeds, propagules and seedlings along nutrient, chemical and physical environmental gradients. In all of these ecosystems, but especially mangroves, abiotic gradients are well studied, strong and influence plant species distributions. However, we suggest that crab predation has primacy over many of these environmental factors by acting as the first limiting factor of tropical tree recruitment to drive the potential structural and compositional organisation of coastal forests. We show that the influence of crabs varies relative to tidal gradient, shoreline distance, canopy position, time, season, tree species and fruiting periodicity. Crabs also facilitate forest growth and development through such activities as excavation of burrows, creation of soil mounds, aeration of soils, removal of leaf litter into burrows and creation of carbon-rich soil microhabitats. For all three systems, land crabs influence the distribution, density and size-class structure of tree populations. Indeed, crabs are among the major drivers of tree recruitment in tropical coastal forest ecosystems, and their conservation should be included in management plans of these forests. ?? 2009 Cambridge Philosophical Society.

  19. Small Angle Crab Compensation for LHC IR Upgrade

    CERN Document Server

    Akai, K; Dorda, U; Ohmi, K; Oide, K; Tomás, R; Zimmermann, T

    2007-01-01

    A small angle crab scheme is being considered for the LHC luminosity upgrade. In this paper we present a 400MHz superconducting cavity design and discuss the pertinent RF challenges. We also present a study on the beam-beam performance and proton-beam emittance growth in the presence of crab compensation, with RF noise sources.

  20. Relative growth in the fiddler crab Uca uruguayensis Nobili, 1901 (Brachyura, Ocypodidae from Garças River mangrove, Guaratuba Bay, southern Brazil

    Directory of Open Access Journals (Sweden)

    Salise Brandt Martins

    Full Text Available A study on the relative growth was carried out in a population of the fiddler crab Uca uruguayensis from the mangrove of Garças River, Guaratuba Bay, Paraná State, southern Brazil. The dimensions analyzed were the length of the major chela (LMC of males and width of the abdomen (AW of females, because they are related to reproductive activities of waving (males and egg incubation (females. The cheliped handedness in males was also analyzed. The LMC was measured in 480 males, the AW in 566 females, and all crabs had the carapace width (CW measured that was considered as the reference dimension for both sexes. The inflection point in the graphs between each the dimensions and CW was calculated with the aid of the software REGRANS. The CW ranged from 2.33 to 8.33 mm in males and from 1.65 to 7.79 mm in females. The relationship between CW and LMC showed an inflection point at 4.14 mm CW among males, and between CW and AW at 3.52 mm CW among females. The allometric growth was positive for both dimensions throughout the entire ontogeny of both sexes, before and after the puberty. The equations describing the relationship between CW and LMC in males were: logLMC = - 0.695960 + 1.72.logCW for juveniles and logLMC = - 1.212513 + 2.5.logCW for adults. In females, the equations were logAW = - 0.519071 + 1.02.logCW and logAW = - 0.902874 + 1.73.logCW, respectively for juveniles and adults. The population of U. uruguayensis from Guaratuba Bay is composed of the smallest crabs, and it also attains morphological sexual maturity at smallest CW. The frequency of occurrence of right and left handed males was statistically the same (1:1 as in most population of fiddler crabs.

  1. Crabs in Labs: The Shore Crab (Carcinus maenas) as Teaching Material.

    Science.gov (United States)

    Hogarth, P. J.

    1983-01-01

    The shore crab (Carcinus maenas) is an excellent subject for school study, both in the field and the laboratory. It is easily collected and maintained and can be used for a wide range of investigations. Some background details are given and possible areas of investigation suggested. (Author)

  2. 75 FR 32360 - Proposed Information Collection; Comment Request; Alaska Crab Report Forms

    Science.gov (United States)

    2010-06-08

    ... Crab Report Forms AGENCY: National Oceanic and Atmospheric Administration (NOAA), Department of.... 1801 et seq.) The FMP for Bering Sea and Aleutian Islands (BSAI) Crab includes the Crab Rationalization (CR) Program, a limited access system that allocates BSAI Management Area Crab resources...

  3. Death rate due to horseshoe crab poisoning:summarization on Thai reports

    Institute of Scientific and Technical Information of China (English)

    Beuy Joob; Viroj Wiwanitkit

    2015-01-01

    Horseshoe crab can be poisonous and intoxication due to intake of horseshoe crab is possible. Horseshoe crab intoxication can be seen in many countries with seacoasts including Thailand. Here, the authors summarized the death rate due to horseshoe crab poisoning in Thailand.

  4. Flux of crab larvae in a mangrove creek in the Gulf of Nicoya, Costa Rica

    Science.gov (United States)

    Dittel, A. I.; Epifanio, C. E.; Lizano, O.

    1991-02-01

    Transport of crab zoeae, megalopae, and early juveniles was measured in a mangrove estero (creek) in the Gulf of Nicoya on the Pacific coast of Costa Rica. In 1987, larvae were collected by quantitative pumping from a platform moored in the mouth of the estero. During each sampling period, larvae were collected every 2 h over five consecutive tidal cycles. The investigation consisted of one spring-tide sampling period and one neap-tide sampling period during each season of the year (dry season, dry-rainy transition, rainy season, and rainy-dry transition). Hourly tidal heights were available for each sampling period. A model for hindcasting tidal volume flux from the change in sea level over each half tidal cycle was developed from measurements made in the estero in 1989. This model was used to calculate tidal volume flux and consequent larval flux during each of the 1987 sampling periods. There was a net export of zoea stage I of four taxonomic groups ( Uca spp., Pinnotheres spp., Petrolistes spp., and Grapsidae) during most sampling periods, while there was a net import of zoea stage I of only two groups ( Pinnixa spp. and Xanthidae). Intermediate and late zoeal stages of all taxonomic groups were generally imported into the estero, as were megalopal and juvenile stages. Quantitative estimates of net larval transport corroborated earlier qualitative models of larval transport that had been based on observations of the vertical distribution of larvae in the water column.

  5. Feeling blue? Blue phosphors for OLEDs

    Directory of Open Access Journals (Sweden)

    Hungshin Fu

    2011-10-01

    Full Text Available Research on organic light emitting diodes (OLEDs has been revitalized, partly due to the debut of the OLED TV by SONY in 2008. While there is still plenty of room for improvement in efficiency, cost-effectiveness and longevity, it is timely to report on the advances of light emitting materials, the core of OLEDs, and their future perspectives. The focus of this account is primarily to chronicle the blue phosphors developed in our laboratory. Special attention is paid to the design strategy, synthetic novelty, and their OLED performance. The report also underscores the importance of the interplay between chemistry and photophysics en route to true-blue phosphors.

  6. Late Onset Juvenile Xanthogranuloma

    Directory of Open Access Journals (Sweden)

    Punithwavathy K

    1999-01-01

    Full Text Available A 19 year old female was seen with multiple skin coloured and hyperpigmented macules, discrete as well as grouped papules and nodules of varying sizes distributed over the face, neck, extensor and flexor aspects of both upper and lower extremities including joints. The trunk was spared. Some of the lesions showed features of spontaneous regression. Investigations confirmed the diagnosis of juvenile xanthogranuloma. Lesions regressed satisfactorily with liquid nitrogen cryotherapy.

  7. Juvenile Incarceration and Health

    OpenAIRE

    Barnert, ES; R Perry; Morris, RE

    2015-01-01

    © 2015. Addressing the health status and needs of incarcerated youth represents an issue at the nexus of juvenile justice reform and health care reform. Incarcerated youth face disproportionately higher morbidity and higher mortality compared to the general adolescent population. Dental health, reproductive health, and mental health needs are particularly high, likely as a result of lower access to care, engagement in high-risk behaviors, and underlying health disparities. Violence exposure a...

  8. Juvenile Ultracool Dwarfs

    CERN Document Server

    Rice, Emily L; Cruz, Kelle; Barman, Travis; Looper, Dagny; Malo, Lison; Mamajek, Eric E; Metchev, Stanimir; Shkolnik, Evgenya L

    2011-01-01

    Juvenile ultracool dwarfs are late spectral type objects (later than ~M6) with ages between 10 Myr and several 100 Myr. Their age-related properties lie intermediate between very low mass objects in nearby star-forming regions (ages 1-5 Myr) and field stars and brown dwarfs that are members of the disk population (ages 1-5 Gyr). Kinematic associations of nearby young stars with ages from ~10-100 Myr provide sources for juvenile ultracool dwarfs. The lowest mass confirmed members of these groups are late-M dwarfs. Several apparently young L dwarfs and a few T dwarfs are known, but they have not been kinematically associated with any groups. Normalizing the field IMF to the high mass population of these groups suggests that more low mass (mainly late-M and possibly L dwarf) members have yet to be found. The lowest mass members of these groups, along with low mass companions to known young stars, provide benchmark objects with which spectroscopic age indicators for juvenile ultracool dwarfs can be calibrated and...

  9. Blue Willow Story Plates

    Science.gov (United States)

    Fontes, Kris

    2009-01-01

    In the December 1997 issue of "SchoolArts" is a lesson titled "Blue Willow Story Plates" by Susan Striker. In this article, the author shares how she used this lesson with her middle-school students many times over the years. Here, she describes a Blue Willow plate painting project that her students made.

  10. Blue Ocean Thinking

    Science.gov (United States)

    Orem, Donna

    2016-01-01

    This article describes a concept called the "blue ocean thinking strategy," developed by W. Chan Kim and Renée Mauborgne, professors at INSEAD, an international graduate school of business in France. The "blue ocean" thinking strategy considers opportunities to create new markets for services, rather than focusing solely on…

  11. Defining the Blue economy

    CSIR Research Space (South Africa)

    Smith-Godfrey, S

    2016-01-01

    Full Text Available perspective as the relationship between land and ocean evolves in its role and importance. The “Blue Economy” as a concept finds its origin against this background. A literature review is undertaken to analyse an appropriate definition for the Blue Economy...

  12. Effects of soluble fractions of drilling fluids on development of crabs, Rhithropanopeus harrisii and Callinectes sapidus

    Energy Technology Data Exchange (ETDEWEB)

    Bookhout, C.G.; Monroe, R.J.; Forward, R.B. Jr.; Costlow, J.D. Jr.

    1984-01-01

    The mud aqueous fraction (MAF) and suspended particulate phase (SPP) of low-density lignosulfonate type mud with ferrochrome added were nontoxic to larvae during the complete larval development of Rhithropanopeus harrisii. Five percent (5000 ppm, 0.5 v/v mud in water) MAF and SPP were not toxic to Callinectes sapidus. Survival of C. sapidus larvae decreased as concentrations of MAF and SPP increased from 5% (5000 ppm, 0.5 v/v mud in water) to 50% (50,000 ppm, 5% v/v mud in water). No larvae reached the 1st crab stage in 100% (100,000 ppm, 10% v/v mud in water) MAF and SPP. Statistical analysis of the data on survival, mortality, and behavior are presented. Blue crab larval behavior is affected by exposure to MAF and SPP with the general effect being a decline in swimming speed. A significant reduction was only observed in 100% MAF but was noticed in 5, 25, 50, and 100% SPP.

  13. From blue jeans to blue genes.

    Science.gov (United States)

    Boon, Laurence M; Vikkula, Miikka

    2009-03-01

    Cutaneous venous anomalies are common. They are blue and vary in size, number, and location and account for most consultations at specialized interdisciplinary clinics for vascular anomalies. Venous lesions are clinically important because they cause pain, dysfunction, destruction of adjacent tissues, and esthetic concern. Only resection and sclerotherapy are helpful, although not always curative. Understanding etiopathogenesis could help design animal models and develop novel therapeutic approaches. John B. Mulliken, MD, envisioned a project to uncover the genetic basis of an inherited form of venous malformation in a large New England family. Recruitment of 2 young fellows resulted in a collaborative project that unraveled the searched-for gene and its mutation. This was an opening for a new era in vascular anomalies. Two blue genes' mutations were discovered, which account for most, if not all, of the inherited forms of venous anomalies, but other genes as well, for rheologically diverse lesions. Differential diagnosis and management has improved, and animal models are being made. This was achieved through the help of Dr Mulliken, who inspired 2 young investigators in blue jeans to find 2 blue genes.

  14. LHC Crab Cavity Coupler Test Boxes

    CERN Document Server

    Mitchell, James; Burt, Graeme; Calaga, Rama; Macpherson, Alick; Montesinos, Eric; Silva, Subashini; Tutte, Adam; Xiao, Binping

    2016-01-01

    The LHC double quarter wave (DQW) crab cavities have two different types of Higher Order Mode (HOM) couplers in addition to a fundamental power coupler (FPC). The FPC requires conditioning, so to achieve this we have designed a radio-frequency (RF) quarter wave resonator to provide high transmission between two opposing FPCs. For the HOM couplers we must ensure that the stop-band filter is positioned at the cavity frequency and that peak transmission occurs at the same frequencies as the strongest HOMs. We have designed two test boxes which preserve the cavity spectral response in order to test the couplers.

  15. Element Masses in the Crab Nebula

    Science.gov (United States)

    Sibley, Adam R.; Katz, Andrea M.; Satterfield, Timothy J.; Vanderveer, Steven J.; MacAlpine, Gordon M.

    2016-10-01

    Using our previously published element abundance or mass-fraction distributions in the Crab Nebula, we derived actual mass distributions and estimates for overall nebular masses of hydrogen, helium, carbon, nitrogen, oxygen and sulfur. As with the previous work, computations were carried out for photoionization models involving constant hydrogen density and also constant nuclear density. In addition, employing new flux measurements for [Ni ii] λ7378, along with combined photoionization models and analytic computations, a nickel abundance distribution was mapped and a nebular stable nickel mass estimate was derived.

  16. Identification of irradiated crab using EPR

    Energy Technology Data Exchange (ETDEWEB)

    Maghraby, A. [Radiation Dosimetry Department, National Institute for Standards (NIS), Ministry of Scientific Research, Haram, 12211- Giza, P.O. Box: 136 (Egypt)]. E-mail: maghrabism@yahoo.com

    2007-02-15

    EPR spectroscopy is a fast and powerful technique for the identification of irradiated food. Crab exoskeleton was divided into six parts: dactyl, cheliped, carapace, apron, swimming legs, and walking legs. Samples of the exoskeleton were prepared and irradiated to Cs-137 gamma radiation in the range (1.156-5.365 kGy). EPR spectra of unirradiated as well as irradiated samples were recorded and analyzed. Response to gamma radiation was plotted for each part of the exoskeleton, dactyl was found to be the most sensitive part, followed by the apron (38%), cheliped (37%), walking legs (30%), swimming legs (24%), and carapace (21%) relative to the dactyl response.

  17. Habitat Suitability Index Models: Red king crab

    Science.gov (United States)

    Jewett, Stephen C.; Onuf, Christopher P.

    1988-01-01

    A review and synthesis of existing information were used to develop a Habitat Suitability Index (HSI) model for evaluating habitat of different life stages of red king crab (Paralithodes camtschatica). A model consolidates habitat use information into a framework appropriate for field application, and is scaled to produce an index between 0.0 (unsuitable habitat) and 1.0 (optimum habitat) in Alaskan coastal waters, especially in the Gulf of Alaska and the southeastern Bering Sea. HSI models are designed to be used with Habitat Evaluation Procedures previously developed by the U.S. Fish and Wildlife Service.

  18. Luminosity and Crab Waist Collision Studies

    CERN Document Server

    Wu, Wanwei

    2015-01-01

    In high energy physics, the luminosity is one useful value to characterize the performance of a particle collider. To gain more available data, we need to maximize the luminosity in most collider experiments. With the discussions of tune shift involved the beam dynamics and a recently proposed "crabbed waist" scheme of beam-beam collisions, we present some qualitative analysis to increase the luminosity. In addition, beam-beam tune shifts and luminosities of $e^{+}e^{-}$, $pp$/$p\\bar{p}$, and $\\mu^{+}\\mu^{-}$ colliders are discussed.

  19. Genetics Home Reference: juvenile idiopathic arthritis

    Science.gov (United States)

    ... Home Health Conditions juvenile idiopathic arthritis juvenile idiopathic arthritis Printable PDF Open All Close All Enable Javascript ... view the expand/collapse boxes. Description Juvenile idiopathic arthritis refers to a group of conditions involving joint ...

  20. Genetics Home Reference: juvenile primary osteoporosis

    Science.gov (United States)

    ... Home Health Conditions juvenile primary osteoporosis juvenile primary osteoporosis Enable Javascript to view the expand/collapse boxes. ... PDF Open All Close All Description Juvenile primary osteoporosis is a skeletal disorder characterized by thinning of ...

  1. Genetics Home Reference: juvenile myoclonic epilepsy

    Science.gov (United States)

    ... Home Health Conditions juvenile myoclonic epilepsy juvenile myoclonic epilepsy Enable Javascript to view the expand/collapse boxes. ... PDF Open All Close All Description Juvenile myoclonic epilepsy is a condition characterized by recurrent seizures (epilepsy). ...

  2. Juvenile Justice Bulletin: Aftercare Services. Juvenile Justice Practices Series.

    Science.gov (United States)

    Gies, Steve V.

    This bulletin examines aftercare services that provide youth with comprehensive health, education, family, and vocational services upon their release from the juvenile justice system. Aftercare can be defined as reintegrative services that prepare out-of-home placed juveniles for reentry into the community by reestablishing the necessary…

  3. Crab death assemblages from Laguna Madre and vicinity, Texas

    Energy Technology Data Exchange (ETDEWEB)

    Plotnick, R.E.; McCarroll, S. (Univ. of Illinois, Chicago (USA)); Powell, E. (Texas A M Univ., College Station (USA))

    1990-02-01

    Crabs are a major component of modern marine ecosystems, but are only rarely described in fossil assemblages. Studies of brachyuran taphonomy have examined either the fossil end-products of the taphonomic process or the very earliest stages of decay and decomposition. The next logical step is the analysis of modern crab death assemblages; i.e., studies that examine taphonomic loss in areas where the composition of the living assemblage is known. The authors studied crab death assemblages in shallow water sediments at several localities in an near Laguna Madre, Texas. Nearly every sample examined contained some crab remains, most commonly in the form of isolated claws (dactyl and propodus). A crab fauna associated with a buried grass bed contained abundant remains of the xanthid crab Dyspanopeus texanus, including carapaces, chelipeds, and thoraxes, as well as fragments of the portunid Callinectes sapidus and the majiid Libinia dubia. Crab remains may be an overlooked portion of many preserved benthic assemblages, both in recent and modern sediments.

  4. The porcelain crab transcriptome and PCAD, the porcelain crab microarray and sequence database.

    Directory of Open Access Journals (Sweden)

    Abderrahmane Tagmount

    Full Text Available BACKGROUND: With the emergence of a completed genome sequence of the freshwater crustacean Daphnia pulex, construction of genomic-scale sequence databases for additional crustacean sequences are important for comparative genomics and annotation. Porcelain crabs, genus Petrolisthes, have been powerful crustacean models for environmental and evolutionary physiology with respect to thermal adaptation and understanding responses of marine organisms to climate change. Here, we present a large-scale EST sequencing and cDNA microarray database project for the porcelain crab Petrolisthes cinctipes. METHODOLOGY/PRINCIPAL FINDINGS: A set of approximately 30K unique sequences (UniSeqs representing approximately 19K clusters were generated from approximately 98K high quality ESTs from a set of tissue specific non-normalized and mixed-tissue normalized cDNA libraries from the porcelain crab Petrolisthes cinctipes. Homology for each UniSeq was assessed using BLAST, InterProScan, GO and KEGG database searches. Approximately 66% of the UniSeqs had homology in at least one of the databases. All EST and UniSeq sequences along with annotation results and coordinated cDNA microarray datasets have been made publicly accessible at the Porcelain Crab Array Database (PCAD, a feature-enriched version of the Stanford and Longhorn Array Databases. CONCLUSIONS/SIGNIFICANCE: The EST project presented here represents the third largest sequencing effort for any crustacean, and the largest effort for any crab species. Our assembly and clustering results suggest that our porcelain crab EST data set is equally diverse to the much larger EST set generated in the Daphnia pulex genome sequencing project, and thus will be an important resource to the Daphnia research community. Our homology results support the pancrustacea hypothesis and suggest that Malacostraca may be ancestral to Branchiopoda and Hexapoda. Our results also suggest that our cDNA microarrays cover as much of the

  5. Blue ocean strategy.

    Science.gov (United States)

    Kim, W Chan; Mauborgne, Renée

    2004-10-01

    Despite a long-term decline in the circus industry, Cirque du Soleil profitably increased revenue 22-fold over the last ten years by reinventing the circus. Rather than competing within the confines of the existing industry or trying to steal customers from rivals, Cirque developed uncontested market space that made the competition irrelevant. Cirque created what the authors call a blue ocean, a previously unknown market space. In blue oceans, demand is created rather than fought over. There is ample opportunity for growth that is both profitable and rapid. In red oceans--that is, in all the industries already existing--companies compete by grabbing for a greater share of limited demand. As the market space gets more crowded, prospects for profits and growth decline. Products turn into commodities, and increasing competition turns the water bloody. There are two ways to create blue oceans. One is to launch completely new industries, as eBay did with online auctions. But it's much more common for a blue ocean to be created from within a red ocean when a company expands the boundaries of an existing industry. In studying more than 150 blue ocean creations in over 30 industries, the authors observed that the traditional units of strategic analysis--company and industry--are of limited use in explaining how and why blue oceans are created. The most appropriate unit of analysis is the strategic move, the set of managerial actions and decisions involved in making a major market-creating business offering. Creating blue oceans builds brands. So powerful is blue ocean strategy, in fact, that a blue ocean strategic move can create brand equity that lasts for decades.

  6. Miastenia gravis juvenil Juvenile myasthenia gravis

    Directory of Open Access Journals (Sweden)

    Oscar Papazian

    2009-01-01

    Full Text Available La miastenia gravis juvenil (MGJ es un trastorno crónico auto inmune en el cual existen anticuerpos séricos que al unirse a los receptores de acetilcolin nicotínicos de la membrana muscular de la placa motora alteran la transmisión neuromuscular. El resultado es fatiga muscular precoz con progresión a la parálisis durante estados de contracción muscular iterativos (movimientos o sostenidos (posturas y más raramente parálisis permanente durante el reposo. Los músculos inervados por los nervios craneales, especialmente los extraoculares y elevadores de los párpados, tienen más tendencia a la debilidad muscular persistente que los inervados por otros pares craneales y las extremidades. Las formas clínicas de presentación son generalizadas, oculares y respiratorias. El diagnóstico se sospecha mediante la anamnesia, la fatiga anormal se comprueba mediante el examen físico y la estimulación eléctrica iterativa del nervio que inerva al músculo afectado pero no paralizado. Se corrobora mediante la administración de inhibidores de la acetilcolin esterasa (IACE que al aumentar la cantidad de acetilcolin en la hendidura sináptica, corrigen la fatiga o la debilidad muscular transitoriamente. Se hace el diagnóstico de certeza mediante la demostración sérica de anticuerpos contra los receptores de acetilcolin (ACRA. El tratamiento es a largo plazo sintomático con IACE y etiopatogénico con inmunosupresores, plasmaféresis, gamma globulina endovenosa y timectomía. El curso es crónico. La remisión espontánea o después de tratamiento sintomático o etiopatogénico ocurre entre 1-10 años respectivamente. La mortalidad es prácticamente nula aun durantes las crisis miastenias gracias a la educación de padres, pacientes y público en general sobre el tema, al desarrollo del sistema de respuesta rápida de auxilio domiciliario y las unidades de cuidados intensivos y el empleo de la ventilación asistida profiláctica, plasmaféresis y

  7. The inner knot of the Crab nebula

    CERN Document Server

    Lyutikov, Maxim; Porth, Oliver

    2015-01-01

    We model the inner knot of the Crab Nebula as a synchrotron emission coming from the non-spherical MHD termination shock of relativistic pulsar wind. The post-shock flow is mildly relativistic; as a result the Doppler-beaming has a strong impact on the shock appearance. The model can reproduce the knot location, size, elongation, brightness distribution, luminosity and polarization provided the effective magnetization of the section of the pulsar wind producing the knot is low, $\\sigma \\leq 1$. In the striped wind model, this implies that the striped zone is rather wide, with the magnetic inclination angle of the Crab pulsar $\\ge 45^\\circ$; this agrees with the previous model-dependent estimate based on the gamma-ray emission of the pulsar. We conclude that the tiny knot is indeed a bright spot on the surface of a quasi-stationary magnetic relativistic shock and that this shock is a site of efficient particle acceleration. On the other hand, the deduced low magnetization of the knot plasma implies that this i...

  8. Pulse profile stability of the Crab pulsar

    Institute of Scientific and Technical Information of China (English)

    Chetana Jain; Biswajit Paul

    2011-01-01

    We present an X-ray timing analysis of the Crab pulsar,PSR B0531+21,using archival RXTE data.We have investigated the stability of the Crab pulse profile,in soft (2-20keV) and hard (30-100keV) X-ray energies,over the last decade of RXTE operation.The analysis includes measurement of the separation between the two pulse peaks and the intensity and widths of the two peaks.We did not find any significant time dependency in the pulse shape.The two peaks have been stable in phase,intensity and width for the last ten years.The first pulse is relatively stronger at soft X-rays.The first pulse peak is narrower than the second peak in both soft and hard X-ray energies.Both the peaks show a slow rise and a steeper fall.The ratio of the pulsed photons in the two peaks is also constant in time.

  9. Le blue-jean

    OpenAIRE

    Miller, Daniel

    2012-01-01

    Le Blue-jean: pourquoi la technologie vient en dernier. La plupart des personnes pensent que la technique (ou la technologie) correspond à ce qui vient en amont du produit. Dans cet article, Daniel Miller s’intéresse plutôt à des cas dans lesquels l’ordre de la séquence est renversé et où le produit précède, ou initie, en quelque sorte, la technique. L’auteur commence par décrire les techniques d’usure artificielle des blue jeans  : une technique qui vise à copier les effets du port des blue ...

  10. Juvenile Dermatomyositis in Pregnancy

    Directory of Open Access Journals (Sweden)

    Anthony Emeka Madu

    2013-01-01

    Full Text Available Juvenile dermatomyositis has variable clinical presentations both in and outside of pregnancy. A literature review indicated that optimal maternal and fetal outcomes can be anticipated when the pregnancy is undertaken while the disease is in remission. Poorer outcomes are associated with flare-up of the disease in early pregnancy compared with exacerbation in the second or third trimester, when fetal prognosis is usually good. We present a case of JDM in pregnancy with disease exacerbation late in pregnancy and review of the relevant literature.

  11. Juvenile dermatomyositis in pregnancy.

    Science.gov (United States)

    Madu, Anthony Emeka; Omih, Edwin; Baguley, Elaine; Lindow, Stephen W

    2013-01-01

    Juvenile dermatomyositis has variable clinical presentations both in and outside of pregnancy. A literature review indicated that optimal maternal and fetal outcomes can be anticipated when the pregnancy is undertaken while the disease is in remission. Poorer outcomes are associated with flare-up of the disease in early pregnancy compared with exacerbation in the second or third trimester, when fetal prognosis is usually good. We present a case of JDM in pregnancy with disease exacerbation late in pregnancy and review of the relevant literature.

  12. Juvenile hyaline fibromatosis.

    Science.gov (United States)

    Larralde, M; Santos-Muñoz, A; Calb, I; Magariños, C

    2001-01-01

    Juvenile hyaline fibromatosis (JHF) is a rare autosomal recessive disease with onset in infancy or early childhood. It is characterized by papulonodular skin lesions, soft tissue masses, gingival hypertrophy, and flexion contractures of the large joints. The light and electron microscopic features are very distinctive. Here we report an 8-month-old boy with characteristic stiffness of the knees and elbows and pink confluent papules on the paranasal folds, and periauricular and perianal regions. He also had hard nodules all over the scalp and around the mouth, and severe gingival hypertrophy. Histologic and ultrastructural features were typical of JHF. Clinical features, pathology, and physiology are discussed.

  13. Juvenile Justice in Rural America.

    Science.gov (United States)

    Jankovic, Joanne, Ed.; And Others

    Producing a much-needed organized body of literature about rural juvenile justice, 14 papers (largely from the 1979 National Symposium on Rural Justice) are organized to identify current issues, identify forces causing changes in current systems, review programs responding to rural juvenile justice problems, and provide planning models to aid…

  14. FROM BLUE JEANS TO BLUE GENES

    OpenAIRE

    Boon, Laurence M.; Vikkula, Miikka

    2009-01-01

    Cutaneous venous anomalies are common. They are blue in color and vary in size, number and location, and account for the majority of consultations at specialized interdisciplinary clinics for vascular anomalies. Venous lesions are clinically important as they cause pain, dysfunction, destruction of adjacent tissues and esthetic concern. Only resection and sclerotherapy are helpful, although not always curative. Understanding etiopathogenesis could help design animal models and develop novel t...

  15. Blue cures blue but be cautious

    OpenAIRE

    Pranav Sikka; Bindra, V. K.; Seema Kapoor; Vivek Jain; Saxena, K.K.

    2011-01-01

    Methemoglobinemia is a disorder characterized by the presence of >1% methemoglobin (metHb) in the blood. Spontaneous formation of methemoglobin is normally counteracted by protective enzyme systems, for example, nicotinamide adenine dinucleotide phosphate (NADPH) methemoglobin reductase. Methemoglobinemia is treated with supplemental oxygen and methylene blue (1-2 mg/kg) administered slow intravenously, which acts by providing an artificial electron acceptor for NADPH methemoglobin reductase....

  16. Blue Ribbon Panel Report

    Science.gov (United States)

    An NCI Cancer Currents blog by the NCI acting director thanking the cancer community for contributing to the Cancer Moonshot Blue Ribbon Panel report, which was presented to the National Cancer Advisory Board on September 7.

  17. New York Blue

    Data.gov (United States)

    Federal Laboratory Consortium — New York Blue is used cooperatively by the Laboratory and Stony Brook University as part of the New York Center for Computation Sciences. Ranked as the 28th fastest...

  18. Methylene blue test

    Science.gov (United States)

    Methemoglobinemia - methylene blue test ... No special preparation is required for this test. ... which are genetic (problem with your genes). This test is used to tell the difference between methemoglobinemia ...

  19. Juvenile arthritis and uveitis.

    Science.gov (United States)

    Kanski, J J

    1990-01-01

    The association between juvenile arthritis and uveitis is reviewed. Some children with the HLA-B27 related spondyloarthropathies develop anterior uveitis. About 20% of patients with juvenile rheumatoid arthritis (JRA) who are negative for IgM rheumatoid factor develop a frequently bilateral, nongranulomatous chronic anterior uveitis. Risk factors for uveitis in JRA patients are: female gender, pauciarticular onset of arthritis, presence of circulating antinuclear antibodies, and the antigens HLA-DW5 and HLA-DPw2. Uveitis is rare after seven years or more have elapsed from the onset of arthritis. The visual prognosis in patients with uveitis is good in 25% and fair in 50%. The remaining 25% develop visual impairment from complicated cataract and/or secondary inflammatory glaucoma. The potential benefit of cytotoxic agents in the treatment of intractable uveitis is outweighed by the risk of serious side effects. The management of secondary inflammatory glaucoma is unsatisfactory, but the results of treatment of complicated cataracts by lensectomy-vitrectomy are good.

  20. Aggressive juvenile mandibular fibromatosis.

    Science.gov (United States)

    Ivanov, Georgi P; Atanasov, Dimitar T; Anavi, Beniamin L

    2013-01-01

    Aggressive juvenile fibromatosis of the jawbones is a rare tumor presenting as infiltrative mass with unpredictable evolution. We report herein a 17-year-old student with a 6-month history of radiologically proven resorption of a part of the mandible, lingual displacement of tooth 34 and malocclusion. Alveolar ridge resorption and three dark-brown foci in the bone were seen after the tooth was extracted. Histological study showed the tumor tissue to have a bundle-like structure; immunohistochemically it was positive for vimentin, smooth muscle actin, beta-catenin, Ki-67 (5%), and negative for desmin and cytokeratin 34bE12. The golden standard in the diagnostics of desmoid fibromatoses is the nuclear or membrane expression of beta-catenin, which is found in 90% of the cases. Differential diagnosis include mandibular fibroma, well-differentiated fibrosarcoma, fibrosing histiocytoma, and infiltration from adjacent soft-tissue tumor. Aggressive juvenile fibromatosis should be managed by radical excision. Local recurrences are not rare, but metastases do not develop. In rare cases this type of fibromatosis has been known to regress spontaneously. Aggressive fibromatosis is a diagnostic challenge, since it remains in the grey zone between benign and malignant lesions of the oral cavity.

  1. Evolutionary history of true crabs (Crustacea: Decapoda: Brachyura) and the origin of freshwater crabs.

    Science.gov (United States)

    Tsang, Ling Ming; Schubart, Christoph D; Ahyong, Shane T; Lai, Joelle C Y; Au, Eugene Y C; Chan, Tin-Yam; Ng, Peter K L; Chu, Ka Hou

    2014-05-01

    Crabs of the infra-order Brachyura are one of the most diverse groups of crustaceans with approximately 7,000 described species in 98 families, occurring in marine, freshwater, and terrestrial habitats. The relationships among the brachyuran families are poorly understood due to the high morphological complexity of the group. Here, we reconstruct the most comprehensive phylogeny of Brachyura to date using sequence data of six nuclear protein-coding genes and two mitochondrial rRNA genes from more than 140 species belonging to 58 families. The gene tree confirms that the "Podotremata," are paraphyletic. Within the monophyletic Eubrachyura, the reciprocal monophyly of the two subsections, Heterotremata and Thoracotremata, is supported. Monophyly of many superfamilies, however, is not recovered, indicating the prevalence of morphological convergence and the need for further taxonomic studies. Freshwater crabs were derived early in the evolution of Eubrachyura and are shown to have at least two independent origins. Bayesian relaxed molecular methods estimate that freshwater crabs separated from their closest marine sister taxa ~135 Ma, that is, after the break up of Pangaea (∼200 Ma) and that a Gondwanan origin of these freshwater representatives is untenable. Most extant families and superfamilies arose during the late Cretaceous and early Tertiary.

  2. Domoic acid excretion in dungeness crabs, razor clams and mussels.

    Science.gov (United States)

    Schultz, Irvin R; Skillman, Ann; Woodruff, Dana

    2008-07-01

    Domoic acid (DA) is a neurotoxic amino acid produced by several marine algal species of the Pseudo-nitzschia (PN) genus. We studied the elimination of DA from hemolymph after intravascular (IV) injection in razor clams (Siliqua patula), mussels (Mytilus edulis) and Dungeness crabs (Cancer magister). Crabs were also injected with two other organic acids, dichloroacetic acid (DCAA) and kainic acid (KA). For IV dosing, hemolymph was repetitively sampled and DA concentrations measured by HPLC-UV. Toxicokinetic analysis of DA in crabs suggested most of the injected dose remained within hemolymph compartment with little extravascular distribution. This observation is in sharp contrast to results obtained from clams and mussels which exhibited similarly large apparent volumes of distribution despite large differences in overall clearance. These findings suggest fundamentally different storage and elimination processes are occurring for DA between bivalves and crabs.

  3. Crab Orchard National Wildlife Refuge: Annual Narrative: Calender year 1997

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This annual narrative report for Crab Orchard National Wildlife Refuge summarizes refuge activities during the 1997 calendar year. The report begins with an...

  4. Narrative report : 1972 [Crab Orchard National Wildlife Refuge

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This annual narrative report for Crab Orchard National Wildlife Refuge outlines Refuge accomplishments during the 1972 calendar year. The report begins by...

  5. Crab Orchard National Wildlife Refuge [Annual narrative : January - April, 1957

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This narrative report for Crab Orchard National Wildlife Refuge outlines Refuge accomplishments from January through April of 1957. The report begins by summarizing...

  6. Narrative report : 1973 [Crab Orchard National Wildlife Refuge

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This annual narrative report for Crab Orchard National Wildlife Refuge outlines Refuge accomplishments during the 1973 fiscal year. The report begins by summarizing...

  7. Crab Orchard National Wildlife Refuge [Annual narrative : May - August, 1956

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This narrative report for Crab Orchard National Wildlife Refuge outlines Refuge accomplishments from May through August of 1956. The report begins by summarizing the...

  8. Narrative report : 1969. Crab Orchard National Wildlife Refuge.

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This annual narrative report for Crab Orchard National Wildlife Refuge outlines Refuge accomplishments during the 1969 calendar year. The report begins by...

  9. Narrative report : 1971. Crab Orchard National Wildlife Refuge.

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This annual narrative report for Crab Orchard National Wildlife Refuge outlines Refuge accomplishments during the 1971 calendar year. The report begins by...

  10. Narrative report : 1970. Crab Orchard National Wildlife Refuge.

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This annual narrative report for Crab Orchard National Wildlife Refuge outlines Refuge accomplishments during the 1970 calendar year. The report begins by...

  11. EVOLUTION OF THE CRAB NEBULA IN A LOW ENERGY SUPERNOVA

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Haifeng; Chevalier, Roger A., E-mail: hy4px@virginia.edu, E-mail: rac5x@virginia.edu [Department of Astronomy, University of Virginia, P.O. Box 400325, Charlottesville, VA 22904 (United States)

    2015-06-20

    The nature of the supernova leading to the Crab Nebula has long been controversial because of the low energy that is present in the observed nebula. One possibility is that there is significant energy in extended fast material around the Crab but searches for such material have not led to detections. An electron capture supernova model can plausibly account for the low energy and the observed abundances in the Crab. Here, we examine the evolution of the Crab pulsar wind nebula inside a freely expanding supernova and find that the observed properties are most consistent with a low energy event. Both the velocity and radius of the shell material, and the amount of gas swept up by the pulsar wind point to a low explosion energy (∼10{sup 50} erg). We do not favor a model in which circumstellar interaction powers the supernova luminosity near maximum light because the required mass would limit the freely expanding ejecta.

  12. Evolution of the Crab nebula in a low energy supernova

    CERN Document Server

    Yang, Haifeng

    2015-01-01

    The nature of the supernova leading to the Crab Nebula has long been controversial because of the low energy that is present in the observed nebula. One possibility is that there is significant energy in extended fast material around the Crab but searches for such material have not led to detections. An electron capture supernova model can plausibly account for the low energy and the observed abundances in the Crab. Here, we examine the evolution of the Crab pulsar wind nebula inside a freely expanding supernova and find that the observed properties are most consistent with a low energy event. Both the velocity and radius of the shell material, and the amount of gas swept up by the pulsar wind point to a low explosion energy ($\\sim 10^{50}$ ergs). We do not favor a model in which circumstellar interaction powers the supernova luminosity near maximum light because the required mass would limit the freely expanding ejecta.

  13. The surprising Crab pulsar and its nebula: a review.

    Science.gov (United States)

    Bühler, R; Blandford, R

    2014-06-01

    The Crab nebula and its pulsar (referred to together as 'the Crab') have historically played a central role in astrophysics. True to this legacy, several unique discoveries have been made recently. The Crab was found to emit gamma-ray pulsations up to energies of 400 GeV, beyond what was previously expected from pulsars. Strong gamma-ray flares, of durations of a few days, were discovered from within the nebula, while the source was previously expected to be stable in flux on these time scales. Here we review these intriguing and suggestive developments. In this context we give an overview of the observational properties of the Crab and our current understanding of pulsars and their nebulae.

  14. Crab Orchard National Wildlife Refuge [Annual narrative : September - December, 1949

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This narrative report for Crab Orchard National Wildlife Refuge outlines Refuge accomplishments from September through December of 1949. The report begins by...

  15. Crab Orchard National Wildlife Refuge Narrative report : November - December, 1946

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This narrative report for Crab Orchard National Wildlife Refuge outlines Refuge accomplishments from November through December of 1946. The report begins by...

  16. Crab Orchard National Wildlife Refuge [Narrative report : September - December, 1953

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This narrative report for Crab Orchard National Wildlife Refuge outlines Refuge accomplishments from September through December of 1953. The report begins by...

  17. Narrative report : 1967. Crab Orchard National Wildlife Refuge.

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This annual narrative report for Crab Orchard National Wildlife Refuge outlines Refuge accomplishments during the 1967 calendar year. The report begins by...

  18. Crab Orchard National Wildlife Refuge : Furbearer Management Plan

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — The Crab Orchard National Wildlife Refuge Furbearer Management Plan directs the management and regulation of trapping. The furbearer management program directly...

  19. Economic Assessment of the Atlantic Coast Horseshoe Crab Fishery

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — In this report, Industrial Economics, Incorporated (lEc) provides an assessment of the economic value of the Atlantic Coast horseshoe crab fishery. We accomplish...

  20. Crab Orchard National Wildlife Refuge [Annual narrative : May - August, 1950

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This narrative report for Crab Orchard National Wildlife Refuge outlines Refuge accomplishments from May through August of 1950. The report begins by summarizing the...