WorldWideScience

Sample records for mussel veliger settlement

  1. Mortality of zebra mussel, Dreissena polymorpha, veligers during downstream transport

    Science.gov (United States)

    Horvath, T.G.; Lamberti, G.A.

    1999-01-01

    1. Streams flowing from lakes which contain zebra mussels, Dreissena polymorpha, provide apparently suitable habitats for mussel colonization and downstream range expansion, yet most such streams contain few adult mussels. We postulated that mussel veligers experience high mortality during dispersal via downstream transport. They tested this hypothesis in Christiana Creek, a lake-outlet stream in south-western Michigan, U.S.A., in which adult mussel density declined exponentially with distance downstream. 2. A staining technique using neutral red was developed and tested to distinguish quickly live and dead veligers. Live and dead veligers were distinguishable after an exposure of fresh samples to 13.3 mg L-1 of neutral red for 3 h. 3. Neutral red was used to determine the proportion of live veligers in samples taken longitudinally along Christiana Creek. The proportion of live veligers (mean ?? SE) declined from 90 ?? 3% at the lake outlet to 40 ?? 8% 18 km downstream. 4. Veligers appear to be highly susceptible to damage by physical forces (e.g. shear), and therefore, mortality in turbulent streams could be an important mechanism limiting zebra mussel dispersal to downstream reaches. Predictions of zebra mussel spread and population growth should consider lake-stream linkages and high mortality in running waters.

  2. Variations in zebra mussel (Dreissena polymorpha) veliger densities throughout 1996 at Dam 52 on the lower Ohio River

    Science.gov (United States)

    Reed, Darren P.; Herod, Jeffrey J.; Sickel, James B.

    1998-01-01

    Zebra mussel veliger densities were monitored throughout 1996 at Lock and Dam 52 on the lower Ohio River near Brookport, IL. The spawning season occurred between mid June and early September with veliger densities peaking at 30,000/m3 in late June. Veliger first appeared at a water temperature of 21° C. When spawning ended in September the water temperature was 22 °C. Veligers were found throughout November when the water temperature was 10 °C. The lowest temperature at which veligers were observed was 7 ° C in March 1996. These results show that the zebra mussels in the lower Ohio River are reproducing naturally and that spawning appears to be synchronous. The presence of larvae at low temperatures in March suggests that veligers are capable of delaying settlement and overwintering in the planktonic stage.

  3. Lake Erie and Lake Michigan zebra mussel settlement monitoring and implications for chlorination treatment

    International Nuclear Information System (INIS)

    Demoss, D.; Mendelsberg, J.I.

    1992-01-01

    This paper reports on the 1991 zebra mussel veliger settlement monitoring program undertaken to record and evaluate zebra mussel veliger settlement in Lake Erie and Lake Michigan. Studies by Dr. Gerald Mackie of Canada in 1990 indicated veliger settlement may be occurring primarily during short time periods every season corresponding with warmer water temperatures. Veliger settlement monitoring was performed using a plexiglass sampler apparatus. The samplers were simple in design and consisted of a 20-inch-square plexiglass base panel with thirty-six 1 inch x 3 inch clear plexiglass microscope slides attached. The results of the monitoring program indicate the existence of preferential settlement periods for veligers correlating with sustained lake water temperatures above 70 degrees F. Veliger settlement concentrations in the south basin of Lake Michigan appear to be similar to those in western Lake Erie

  4. Quagga and zebra mussel risk via veliger transfer by overland hauled boats

    Directory of Open Access Journals (Sweden)

    Larry B. Dalton

    2013-04-01

    Full Text Available Invasive quagga and zebra mussels (Dreissena rostriformis bugensis and Dreissena polymorpha, respectively pose a great threat to USwaters. Recreational boats constitute a significant risk for spreading the organisms. Recreational boats circulate large amounts of raw waterwhen in use, and if not drained and dried correctly can transport many mussel larvae, called veligers. Veligers experience very high mortality rates; however, the number of potentially transported veligers can be a serious risk to non-infested bodies of water, especially if multiple boats are involved. The risk of veliger transport was calculated for Lake Mead and Lake Michigan using boat capacities for water circulation and specific veliger density data. Results illustrate the importance of draining, drying, and/or decontaminating recreational boats after use.

  5. Quantifying quagga mussel veliger abundance and distribution in Copper Basin Reservoir (California) using acoustic backscatter.

    Science.gov (United States)

    Anderson, Michael A; Taylor, William D

    2011-11-01

    Quagga mussels (Dreissena bugensis) have been linked to oligotrophication of lakes, alteration of aquatic food webs, and fouling of infrastructure associated with water supply and power generation, causing potentially billions of dollars in direct and indirect damages. Understanding their abundance and distribution is key in slowing their advance, assessing their potential impacts, and evaluating effectiveness of control strategies. Volume backscatter strength (Sv) measurements at 201- and 430-kHz were compared with quagga mussel veliger and zooplankton abundances determined from samples collected using a Wisconsin closing net from the Copper Basin Reservoir on the Colorado River Aqueduct. The plankton within the lower portion of the water column (>18 m depth) was strongly dominated by D-shaped quagga mussel veligers, comprising up to 95-99% of the community, and allowed direct empirical measurement of their mean backscattering cross-section. The upper 0-18 m of the water column contained a smaller relative proportion of veligers based upon net sampling. The difference in mean volume backscatter strength at these two frequencies was found to decrease with decreasing zooplankton abundance (r(2) = 0.94), allowing for correction of Sv due to the contribution of zooplankton and the determination of veliger abundance in the reservoir. Hydroacoustic measurements revealed veligers were often present at high abundances (up to 100-200 ind L(-1)) in a thin 1-2 m layer at the thermocline, with considerable patchiness in their distribution observed along a 700 m transect on the reservoir. Under suitable conditions, hydroacoustic measurements can rapidly provide detailed information on the abundance and distribution of quagga mussel veligers over large areas with high horizontal and vertical resolution. Copyright © 2011 Elsevier Ltd. All rights reserved.

  6. Toxicity of potassium chloride to veliger and byssal stage dreissenid mussels related to water quality

    Science.gov (United States)

    Moffitt, Christine M.; Stockton-Fiti, Kelly A.; Claudi, Renata

    2016-01-01

    Natural resource managers are seeking appropriate chemical eradication and control protocols for infestations of zebra mussels, Dreissena polymorpha (Pallas, 1769), and quagga mussels. D. rostiformis bugensis (Andrusov, 1897) that have limited effect on non-target species. Applications of low concentrations of potassium salt (as potash) have shown promise for use where the infestation and treatment can be contained or isolated. To further our understanding of such applications and obtain data that could support a pesticide registration, we conducted studies of the acute and chronic toxicity of potassium chloride to dreissenid mussels in four different water sources from infested and non-infested locations (ground water from northern Idaho, surface water from the Snake River, Idaho, USA, surface water from Lake Ontario, Ontario, Canada, and surface water from the Colorado River, Arizona, USA). We found short term exposure of veligers (29 d) at concentrations of 100 and 200 mg/L KCl. Rapid mortality occurred within 10 d of exposure to concentrations of 200 mg/L KCl, regardless of water source. Kaplan-Meier estimates of mean survival of byssal mussels in 100 mg/L KCl prepared in surface water from Idaho and Lake Ontario were 4.9 or 6.9 d, respectively; however, mean survival of mussels tested in the Colorado River water was > 23 d. The sodium content of the Colorado River water was nearly three times that measured in waters from the other locations, and we hypothesized sodium concentrations may affect mussel survival. To test our hypothesis, we supplemented Snake River and Lake Ontario water with NaCl to equivalent conductivity as the Colorado River, and found mussel survival increased to levels observed in tests of veliger and byssal mussels in Colorado River water. We recommend KCl disinfection and eradication protocols must be developed to carefully consider the water quality characteristics of treatment locations.

  7. Estimating survival rates of quagga mussel (Dreissena rostriformis bugensis veliger larvae under summer and autumn temperature regimes in residual water of trailered watercraft at Lake Mead, USA

    Directory of Open Access Journals (Sweden)

    Wook Jin Choi

    2013-01-01

    Full Text Available On 6 January 2007, invasive quagga mussels [Dreissena rostriformis bugensis (Andrusov, 1897] were discovered in the Boulder Basin ofLake Mead, Nevada, a popular site for recreational boating in the southwestern United States. Recreational watercraft are considered aprimary vector for overland dispersal of quagga mussel veliger larvae between water bodies. Thus, effective decontamination of veligers inresidual water carried by trailered recreation boats is critical to controlling this species’ spread. The survival rate of quagga mussel veligerswas measured during exposure to environmental temperature conditions mimicking those experienced in the residual water of traileredvessels during warm summer and cooler autumn months in the semi-arid southwestern United States. Under warm summer conditions,quagga mussel veligers survived approximately five days while under cooler autumn conditions they survived 27 days. When tested underautumn temperature conditions veliger survival times increased with increased level of larval development. The results suggested a greaterlikelihood of veliger transport in the residual water of trailered watercraft during autumn months. The results indicated that presentlyrecommended vessel quarantine times to kill all externally attached juvenile and adult dreissenid mussels prior to launching in an uninfested water body should be increased to generate 100% veliger mortality in residual water unable to be fully drained from the internal areas of watercraft.

  8. The zebra mussel: US utility implications

    International Nuclear Information System (INIS)

    McMahon, R.F.

    1990-11-01

    Dreissena polymorpha, the freshwater macrofouling zebra mussel, was introduced to Lake St. Clair, near Detroit, Michigan, in 1985. It has since spread throughout Lake Erie. Its planktonic veliger larval stage disperses on water currents and adults are transported by human and natural vectors, making it likely to spread throughout most of the United States and southern Canada except for the southwestern and southern United State, where summer water temperatures are above tolerated levels. Veligers enter raw water systems on intake currents to settle and grow to adults attached by secreted byssal threads to hard surfaces. Accumulations of adults impede flow, aggravate sedimentation and corrosion, and foul small-diameter components. Settlement occurs at flow velocities less than 1.5--2.0 m/sec. Mussels can reduce effective pipe diameters and foul intake structures, steam condensers, heat exchangers, fire protection systems, and cooling tower basins. Establishment of mussels in raw water systems should be prevented because subsequent removal is difficult and expensive. Mitigation procedures include manual removal, robotic cleaning, thermal backwashing, water jetting, application of molluscicides, and possibly line pigging and acidic chemical cleaning. Control technologies include oxidizing and non-oxidizing molluscicides, robotic cleaning, shell strainers, exposure of veligers to high voltage electrical fields, thermal backwashing and sand-filtration. The United States power industry can utilize extensive European experience with this species and domestic experience with the Asian clam in its development of effective controls for zebra mussel fouling

  9. Toxicity of a traditional molluscicide to asian clam veligers

    Science.gov (United States)

    Layhee, Megan J.; ,; Miho Yoshioka,; Bahram Farokhkish,; ,; Gross, Jackson A.; Sepulveda, Adam J.

    2014-01-01

    Aquaculture and hatchery industries are in need of effective control methods to reduce the risk of spreading aquatic invasive species, such as the Asian clam Corbicula fluminea, through aquaculture and hatchery activities. The planktonic nature of Asian clam veligers enables this life stage to enter water-based infrastructure undetected, including hatchery trucks used to stock fish. Once in hatchery trucks, veligers can disperse overland and establish in previously uninvaded habitats. As a result, there is a need to develop techniques that result in veliger mortality but do not harm fish. In September 2012, we conducted laboratory trials to determine if a molluscicide (750 mg/L potassium chloride and 25 mg/L formalin) commonly used to kill zebra mussel (Dreissena polymorpha) veligers in hatchery trucks can also effectively kill Asian clam veligers. We exposed Asian clam veligers to this molluscicide for 1, 3, and 5 h in each of two water types: deionized water and filtered lake water. We found ,20% mortality at the 1-h exposure period and 100% mortality at both the 3-h and 5-h exposure periods, regardless of water type. This laboratory study represents an important step toward reducing the spread of Asian clams by aquaculture facilities.

  10. Monitoring biofouling communities could reduce impacts to mussel aquaculture by allowing synchronisation of husbandry techniques with peaks in settlement.

    Science.gov (United States)

    Sievers, Michael; Dempster, Tim; Fitridge, Isla; Keough, Michael J

    2014-02-01

    Fouling organisms in bivalve aquaculture cause significant economic losses for the industry. Managing biofouling is typically reactive, and involves time- and labour-intensive removal techniques. Mussel spat settlement and biofouling were documented over 20 months at three mussel farms within Port Phillip Bay (PPB), Australia to determine if knowledge of settlement patterns could assist farmers in avoiding biofouling. Mussel spat settlement was largely confined to a 2-month period at one farm. Of the problematic foulers, Ectopleura crocea settlement varied in space and time at all three farms, whilst Ciona intestinalis and Pomatoceros taeniata were present predominantly at one farm and exhibited more distinct settlement periods. Within PPB, complete avoidance of biofouling is impossible. However, diligent monitoring may help farmers avoid peaks in detrimental biofouling species and allow them to implement removal strategies such as manual cleaning, and postpone grading and re-socking practices, until after these peaks.

  11. Larval settlement and metamorphosis of the mussel Mytilus coruscus in response to monospecific bacterial biofilms.

    Science.gov (United States)

    Yang, Jin-Long; Shen, Pei-Jing; Liang, Xiao; Li, Yi-Feng; Bao, Wei-Yang; Li, Jia-Le

    2013-01-01

    The effects of bacterial biofilms (BFs) on larval settlement and metamorphosis of the mussel, Mytilus coruscus, were investigated in the laboratory. Of nine different isolates, Shewanella sp.1 BF induced the highest percentage of larval settlement and metamorphosis, whereas seven other isolates had a moderate inducing activity and one isolate, Pseudoalteromonas sp. 4, had a no inducing activity. The inducing activity of individual bacterial isolates was not correlated either with their phylogenetic relationship or with the surfaces from which they were isolated. Among the eight bacterial species that demonstrated inducing activity, bacterial density was significantly correlated with the inducing activity for each strain, with the exception of Vibrio sp. 1. The Shewanella sp. 1 BF cue that was responsible for inducing larval settlement and metamorphosis was further investigated. Treatment of the BFs with formalin, antibiotics, ultraviolet irradiation, heat, and ethanol resulted in a significant decrease in their inducing activities and cell survival. BF-conditioned water (CW) did not induce larval metamorphosis, but it triggered larval settlement behavior. A synergistic effect of CW with formalin-fixed Shewanella sp. 1 BF significantly promoted larval metamorphosis. Thus, a cocktail of chemical cues derived from bacteria may be necessary to stimulate larval settlement and metamorphosis in this species.

  12. Procedures for conducting underwater searches for invasive mussels (Dreissena sp.)

    Science.gov (United States)

    Adams, Noah

    2010-01-01

    available also can kill other aquatic life. Early implementation of containment and eradication efforts requires getting reliable information to confirm the location of the infestation. One way to get this information is through the use of properly trained SCUBA divers. This document provides SCUBA divers with the necessary information to conduct underwater searchers for mussels. However, using SCUBA divers to search for mussels over a large geographic area is relatively expensive and inefficient. Early detection monitoring methods can be used to optimize the use of SCUBA divers. Early detection monitoring can be accomplished by collecting water samples or deploying artificial settlement substrates (fig. 1). Water samples are used to look for free-swimming larval mussels (called veligers). Because the veligers cannot be identified with the naked eye, the water samples are sent to a laboratory where they are examined under a microscope and/or analyzed using molecular techniques to detect veligers. To detect the presences of adult mussels, artificial substrates are deployed and periodically retrieved to determine if mussels have settled on the substrate. If veligers or adults are identified, SCUBA divers can be deployed to confirm the presence of mussels.

  13. Successful survival, growth, and reproductive potential of quagga mussels in low calcium lake water: is there uncertainty of establishment risk?

    Directory of Open Access Journals (Sweden)

    Clinton J. Davis

    2015-11-01

    Full Text Available The risk of quagga mussel (Dreissena rostriformis bugensis Andrusov 1897 establishment into water-bodies of the western US has expanded the geographic concern regarding the ecological and economic impacts this species will have in aquatic ecosystems. Thresholds based on calcium concentrations, an element critical for mussel growth and physiology, have been used as a primary predictor of quagga mussel establishment success to aid management decisions. We evaluated the invasion potential of quagga mussels in low calcium waters using laboratory experiments to compare the survival, growth and reproductive potential of adult mussels held for 90 days at low (9 and 12 ppm, moderate (15 to 32 ppm and high (72 ppm calcium water concentrations. In conjunction with adult experiments, veliger stage survival, growth and settlement were evaluated under similar low, moderate, and high calcium water treatments. Adult mussels survived, grew and showed reproductive potential in low calcium water (12 ppm. Veligers were also able to survive, grow and settle in low calcium water. Higher levels of natural seston biomass appeared to improve adult mussel life history performance in low calcium water. Survival curve analysis predicted that 99% adult mortality could occur in 15 ppm could have adults surviving more than a year. The results from these bioassays provide further evidence that quagga mussels have higher risk of establishment in low calcium lakes if habitats exist that have slightly elevated calcium. These results should help emphasize the vulnerability of water-body in the 12 to 15 ppm calcium range that could potentially be at risk of establishing sustainable quagga mussel populations. Furthermore, these results provide insights into the uncertainty of using a single parameter in assigning establishment risk given the complexity of variables in specific water-bodies that influence life history performance of introduced species.

  14. Successful survival, growth, and reproductive potential of quagga mussels in low calcium lake water: is there uncertainty of establishment risk?

    Science.gov (United States)

    Davis, Clinton J; Ruhmann, Emma K; Acharya, Kumud; Chandra, Sudeep; Jerde, Christopher L

    2015-01-01

    The risk of quagga mussel (Dreissena rostriformis bugensis Andrusov 1897) establishment into water-bodies of the western US has expanded the geographic concern regarding the ecological and economic impacts this species will have in aquatic ecosystems. Thresholds based on calcium concentrations, an element critical for mussel growth and physiology, have been used as a primary predictor of quagga mussel establishment success to aid management decisions. We evaluated the invasion potential of quagga mussels in low calcium waters using laboratory experiments to compare the survival, growth and reproductive potential of adult mussels held for 90 days at low (9 and 12 ppm), moderate (15 to 32 ppm) and high (72 ppm) calcium water concentrations. In conjunction with adult experiments, veliger stage survival, growth and settlement were evaluated under similar low, moderate, and high calcium water treatments. Adult mussels survived, grew and showed reproductive potential in low calcium water (12 ppm). Veligers were also able to survive, grow and settle in low calcium water. Higher levels of natural seston biomass appeared to improve adult mussel life history performance in low calcium water. Survival curve analysis predicted that 99% adult mortality could occur in 15 ppm could have adults surviving more than a year. The results from these bioassays provide further evidence that quagga mussels have higher risk of establishment in low calcium lakes if habitats exist that have slightly elevated calcium. These results should help emphasize the vulnerability of water-body in the 12 to 15 ppm calcium range that could potentially be at risk of establishing sustainable quagga mussel populations. Furthermore, these results provide insights into the uncertainty of using a single parameter in assigning establishment risk given the complexity of variables in specific water-bodies that influence life history performance of introduced species.

  15. Effect of pH, ethanol concentration, and temperature on detection of quagga mussel (Dreissena bugensis birefringence

    Directory of Open Access Journals (Sweden)

    Scott O’Meara

    2013-05-01

    Full Text Available In the western United States, federal, state, and local agencies have engaged in extensive efforts to detect the presence of larval dreissenid mussels (veligers in water bodies before such a presence becomes a full-scale infestation. Cross-polarized light microscopy (CPLM is commonly used to detect the veliger’s specific birefringence pattern, but the effect of sample preservation on dreissenid birefringence has not yet been determined. This study examined the effects of solution pH, ethanol concentration, and storage temperature on veliger birefringence loss. Birefringence loss was determined by examining veligers under CPLM at regular intervals over a 30 day period. Veliger birefringence loss was below five percent in all basic solutions, regardless of holding temperature or ethanol concentration. Veliger birefringence loss was also below five percent in acidic solutions that were refrigerated or contained 50–70 percent ethanol. Veligers in acidic solutions that were held at 25°C and 34°C with 0–25 percent ethanol had 7–25 percent veliger birefringence loss over a 30 day period. While ethanol addition and refrigeration are both important preservation methods, the results of this study indicate that samples collected for dreissenid veliger detection by CPLM must also be maintained at a basic pH in order to preserve veliger shell integrity and birefringence. Determining the best conditions for long-term preservation of veliger shells requires further investigation, and these results should not be assumed best for analyses other than CPLM.

  16. Settlement

    Directory of Open Access Journals (Sweden)

    John Frow

    2011-04-01

    Full Text Available The paper explores the idea of settlement in each of its three major senses: as a place of human habitation; as a fixed and stable order of habitation; and as a political consensus reconciling fractious groups. Arguing that traditional accounts of settlement depend, with a kind of pastoral nostalgia, upon a view of abstraction and social complexity as in themselves  harmful, it follows through the implications of the concept for ways of dealing with the stranger, and it uses a drawing by the nineteenth-century indigenous Australian artist Tommy McRae, done about 1890 and entitled Corroboree, or William Buckley and dancers from the Wathaurong people, to propose a counterfactual model through which a settlement with the stranger might be imagined.

  17. Cultivation of zebra mussels (Dreissena polymorpha) within their invaded range to improve water quality in reservoirs.

    Science.gov (United States)

    McLaughlan, C; Aldridge, D C

    2013-09-01

    Algal and cyanobacterial blooms in reservoirs are driven by nutrient enrichment and may present economic and conservation challenges for water managers. Current approaches such as suppression of algal growth with barley straw, ferric dosing or manipulation of fish stocks have not yielded long term successes. A possibility that has sparked growing interest is the encouragement and cultivation of natural filter feeders, such as mussels, which remove suspended matter from the water and reduce nutrient levels through biodeposition and assimilation. This review focusses on the zebra mussel (Dreissena polymorpha) as a tool for enhancement of water quality in reservoirs. Native to the Ponto-Caspian region, this species has invaded many lakes and reservoirs across North America and Western Europe, where it occurs in very high densities. While purposeful introduction of a non-native species into new sites is socially unacceptable, we investigate the possible benefits of encouraging increased abundance of zebra mussels in sites where the species is already established. We estimate that the annual nitrogen and phosphorus input into a large UK reservoir (Grafham Water) could be assimilated into zebra mussel biomass by encouraging settlement onto 3075 m and 1400 m of commercial mussel ropes, respectively. While zebra mussel cultivation has an incredible capacity to push eutrophic systems towards a clear water state, there are many risks associated with encouraging an invasive species, even within sites where it has already established. The zebra mussel is a prominent biofouler of native unionid mussels and raw water pipes, it changes the physical characteristics of the places it inhabits, in sites low in phosphorus it can be responsible for toxic cyanobacterial blooms, it alters nutrient cycling and community structure and it can have negative impacts on amenity value. Increased propagule pressure from elevated numbers of veliger larvae in the water column may increase the risk

  18. Prevention and control of zebra mussels: proactive and reactive strategies

    International Nuclear Information System (INIS)

    Claudi, R.

    1998-01-01

    Most plant people would agree that having zebra mussels in any raw water system is not desirable. System blockage, loss of heat transfer and other associated safety hazards are not pleasant to deal with. Therefore most industries strive to minimise the effect of infestation. Opinions differ as to how to do this most efficiently and economically. Some facilities are committed to preventing the settlement of veligers in their piping systems and on some of the external structures they consider critical. This is the proactive approach. Others allow settlement and only treat the system or surface after fouling has occurred. This is the reactive approach. Which is the best and most economical treatment will depend on the individual facility and sometimes on the individual system. The paper examines the different proactive and reactive strategies available to-date and how they are being used. It will also discuss some of the criteria for choosing a proactive vs. reactive approach and why the decision has to be made individually by each facility. (author)

  19. Prevention and control of zebra mussels: proactive and reactive strategies

    Energy Technology Data Exchange (ETDEWEB)

    Claudi, R. [Ontario Hydro Nuclear, Toronto, ON (Canada)

    1998-07-01

    Most plant people would agree that having zebra mussels in any raw water system is not desirable. System blockage, loss of heat transfer and other associated safety hazards are not pleasant to deal with. Therefore most industries strive to minimise the effect of infestation. Opinions differ as to how to do this most efficiently and economically. Some facilities are committed to preventing the settlement of veligers in their piping systems and on some of the externalstructures they consider critical. This is the proactive approach. Others allow settlement and only treat the system or surface after fouling has occurred. This is the reactive approach. Which is the best and most economical treatment will depend on the individual facility and sometimes on the individual system. The paper examines the different proactive and reactive strategies available to-date and how they are being used. It will also discuss some of the criteria for choosing a proactive vs. reactive approach and why the decision has to be made individually by each facility. (author)

  20. Ruinous resident: the hydroid Ectopleura crocea negatively affects suspended culture of the mussel Mytilus galloprovincialis.

    Science.gov (United States)

    Fitridge, Isla; Keough, Michael J

    2013-01-01

    Hydroids are major biofouling organisms in global aquaculture. Colonies of the hydroid Ectopleura crocea have recently established in Australian commercial mussel leases culturing Mytilus galloprovincialis. This study examined the impacts of E. crocea on mussel culture at two stages of the production cycle: spatfall and grow-out. Hydroids most commonly fouled the body, edge and dorsal regions of the mussel shell and cause a reduction in the length (4%) and weight (23%) of juvenile mussels. They also consumed mussel larvae in the field and in the laboratory. Prey numbers of many taxa, including mussel larvae, were consistent in natural hydroid diets regardless of the temporal variation in prey availability, implying some selectivity in hydroid feeding. In the laboratory, E. crocea consumed settling plantigrade mussel larvae more readily than trochophore or veliger larvae. Fouling by E. crocea is detrimental to mussel condition, and may affect the availability of wild mussel larvae in the commercial culture of M. galloprovincialis.

  1. Evaluation of several chemical disinfectants for removing zebra mussels from unionid mussels

    Science.gov (United States)

    Waller, D.L.; Fisher, S.W.

    1998-01-01

    We evaluated the safety and effectiveness of chemical treatments for killing veliger and juvenile stages of the zebra mussel Dreissena polymorpha attached to unionid mussels. Static toxicity tests were conducted on eight unionid mussel species with common aquaculture chemicals (benzalkonium chloride, formalin, hydrogen peroxide, calcium chloride, potassium chloride, and sodium chloride). The concentration and duration of each chemical treatment tested had previously been found to kill zebra mussel veligers and juveniles. Several species (e.g., Elliptio dilatata, Lampsilis cardium, and Lasmigona complanata) incurred less than 10% mortality in chloride salt treatments, while in other species (e.g., Obliquaria reflexa and Leptodea fragilis) mortality varied greatly among treatment regimes. Treatments with benzalkonium chloride, formalin, and hydrogen peroxide were less than 90% effective on juvenile stages of zebra mussels and, therefore, were ruled out after preliminary trials. Limited application of specific chemical treatments may be feasible for more tolerant species; however, effective disinfection of unionid shells will require the use of chemical treatment followed by a quarantine period to completely remove zebra mussel larvae and juveniles.

  2. Veligers of the invasive Asian clam Corbicula fluminea in the Columbia River Basin: Broadscale distribution, abundance, and ecological associations

    Science.gov (United States)

    Hassett, Whitney; Bollens, Stephen M.; Counihan, Timothy D.; Rollwagen-Bollens, Gretchen; Zimmerman, Julie; Emerson, Joshua E.

    2017-01-01

    The invasive Asian clam Corbicula fluminea was introduced to North America in the 1930s and now inhabits most regions of the conterminous United States; however, the distribution and ecology of C. fluminea in the Columbia River Basin is poorly understood. During 2013 and 2014, 5 Columbia-Snake River reservoirs were sampled monthly from May through September, along with 23 additional lakes and reservoirs sampled once each summer. Associations among C. fluminea veligers, other components of the plankton, and environmental variables were analyzed using non-metric multidimensional scaling and canonical correspondence analysis. Corbicula fluminea veligers were found in high abundances in all mainstem Columbia-Snake River reservoirs, with an annual mean abundance of 71.2 individuals per cubic meter (inds./m3). Only 3 of 23 lakes and (non-mainstem) reservoirs contained C. fluminea, with abundances considerably lower (maximum = 21.2 inds./m3) than in the mainstem reservoirs. A diatom-dominated community preceded the spawning of C. fluminea in early summer at all sites. Corbicula fluminea veligers characterized the plankton community in late summer and were associated with cyanobacteria and high water temperatures. A third community, characterized by cyanobacteria, was apparent in non-mainstem sites in July and August. Our analyses describe the relationship of C. fluminea to the plankton community and environment, which contributes to our understanding of the possible effects of C. fluminea infestations and which waterbodies in the Columbia River Basin are at risk for infestation. Understanding the effects and environmental determinants of invasive mollusks will be increasingly important in the future with the possible arrival of zebra (Dreissena polymorpha) or quagga (D. bugensis) mussels to the region.

  3. Effectiveness of EarthTec(®) for killing invasive quagga mussels (Dreissena rostriformis bugensis) and preventing their colonization in the Western United States.

    Science.gov (United States)

    Watters, Ashlie; Gerstenberger, Shawn L; Wong, Wai Hing

    2013-01-01

    Quagga mussels (Dreissena rostriformis bugensis) have created economic and ecological impacts in the western United States since their discovery in 2007. This study focuses on chemical control for preventing the spread of these mussels. The effectiveness of EarthTec(®) in killing quagga mussels (adults, juveniles, and veligers) in Lake Mead, Nevada-Arizona, was evaluated over time across six concentrations: 0, 1, 5, 10, 17, and 83 ppm. One hundred percent mortality of adult and juvenile mussels was achieved after 96 h with 17 ppm and 5 ppm (respectively), and 100% veliger mortality occurred within 30 min at 3 ppm. From December 2010 to February 2011, the effectiveness of EarthTec(®) in preventing veliger colonization was also evaluated and the results showed that 2.8 ppm was effective in preventing veliger colonization on fiberglass panels. This study indicates that EarthTec(®) has the potential to be an effective control agent against the invasive quagga mussel, and more specifically, in preventing the colonization of veligers.

  4. Prevention of zebra mussel infestation and dispersal during aquaculture operations

    Science.gov (United States)

    Waller, D.L.; Fisher, S.W.; Dabrowska, H.

    1996-01-01

    The zebra mussel Dreissena polymorpha, an exotic invasive species, poses a major threat to North American fish management programs and the aquaculture industry. Fish hatcheries may become infected with zebra mussels from a variety of sources, including the water supply, fish shipments, boats, and equipment. The hatcheries could then serve as agents for the overland dispersal of zebra mussels into stocked waters and to other fish hatcheries. We evaluated the effectiveness and safety of aquaculture chemicals for use in controlling zebra mussels in fish hatcheries and preventing dispersal of veligers during fish transport. Chemicals were evaluated for use in fish transport and as disinfectants for ponds and equipment. Standardized static toxicity tests were conducted with representative species of warmwater, coolwater, and coldwater fishes and with larval (3-d-old veligers), early juvenile (settling larvae), and adult zebra mussels. Chemical concentrations and exposure durations were based on recommended treatment levels for fish, eggs, and ponds. Recommended treatment levels were also exceeded, if necessary, to establish lethal levels for zebra mussels of different developmental stages. Our results indicate that some chemicals currently in use in hatcheries may be effective for controlling zebra mussels in various operations. Chloride salts were the safest and most effective therapeutants tested for use in fish transport. The toxicity of chloride salts to fish varied among species and with temperature; only one treatment regime (sodium chloride at 10,000 mg/L) was safe to all fish species that we tested, but it was only effective on veliger and settler stages of the zebra mussel. Effective disinfectants were benzalkonium chloride for use on equipment and rotenone for use in ponds after fish are harvested. The regulatory status of the identified chemicals is discussed as well as several nonchemical control alternatives.

  5. Zebra Mussel Research Technical Notes. Section 1 - Environmental Testing

    National Research Council Canada - National Science Library

    1998-01-01

    ...: Biology, Ecology, and Recommended Control Strategies, Larval Monitoring in a Chlorine Treatment Program to Prevent Zebra Mussel Settlement in Hydropower Facilities, Louisville District Initiates...

  6. Spatio-temporal spawning and larval dynamics of a zebra mussel (Dreissena polymorpha) population in a North Texas Reservoir: implications for invasions in the southern United States

    Science.gov (United States)

    Churchill, Christopher John

    2013-01-01

    Zebra mussels were first observed in Texas in 2009 in a reservoir (Lake Texoma) on the Texas-Oklahoma border. In 2012, an established population was found in a near-by reservoir, Ray Roberts Lake, and in June 2013, settled mussels were detected in a third north Texas reservoir, Lake Lewisville. An established population was detected in Belton Lake in September 2013. With the exception of Louisiana, these occurrences in Texas mark the current southern extent of the range of this species in the United States. Previous studies indicate that zebra mussel populations could be affected by environmental conditions, especially increased temperatures and extreme droughts, which are characteristic of surface waters of the southern and southwestern United States. Data collected during the first three years (2010–12) of a long-term monitoring program were analyzed to determine if spatio-temporal zebra mussel spawning and larval dynamics were related to physicochemical water properties in Lake Texoma. Reproductive output of the local population was significantly related to water temperature and lake elevation. Estimated mean date of first spawn in Lake Texoma was approximately 1.5 months earlier and peak veliger densities were observed two months earlier than in Lake Erie. Annual maximum veliger density declined significantly during the study period (p mussels in littoral zones. Veliger spatial distributions were associated with physicochemical stratification characteristics. Veligers were observed in the deepest oxygenated water after lake stratification, which occurred in late spring. Results of this study indicate environmental conditions can influence variability of population sizes and spatial distributions of zebra mussels along the current southern frontier of their geographic range. Although the future population size trajectory and geographic range are uncertain, increased temperatures and intermittent, extreme droughts likely will affect spatio-temporal dynamics of

  7. Zebra mussel control using acoustic energy

    International Nuclear Information System (INIS)

    Tiller, G.W.; Gaucher, T.A.; Menezes, J.K.; Dolat, S.W.

    1992-01-01

    A practical and economical device or method that reduces zebra mussel colonization without detrimental side effects is highly desirable. An ideal method is one that could be installed near, on, or in existing raw water intakes and conduits. It must have a known effect that is limited to a defined area, should have maximum effects on a targeted species, and preferably have a low life cycle cost than the current alternative methods of control and maintenance. Underwater sound could be such a desirable solution, if found to be an effective control measure for zebra mussels. Although sound most often applies specifically to acoustic energy that is audible to humans, 20 Hertz (Hz) to 20 kiloHertz (kHz), in this report we will use the terms sound and acoustic to include acoustic energy between 100 Hz and 100 MegaHertz (MHz). This research on zebra mussel biofouling is designed to effect the early developmental stages in the life cycle of Dreissena polymorpha (Pallas). Vulnerable stages in the development of D. polymorpha that might yield to site-specific acoustic deterrence measures include the free-swimming larval veliger stage, the postveliger pre-attachment demersal stage, and the immediate post-attachment stage. The proposed applications include surface treatment to prevent, reduce or eliminate colonization on underwater structures, and the stream treatment to reduce or eliminate (destroy) mussel larvae entrained in a moving volume of water

  8. Effect of zinc and benzene on respiration and excretion of mussel larvae (Perna perna (Linnaeus, 1758 (Mollusca; Bivalvia

    Directory of Open Access Journals (Sweden)

    RADLVC. Jorge

    Full Text Available The presence of pollutants in the ocean may affect different physiological parameters of animals. Oxygen consumption and ammonia excretion were evaluated in D-shaped larvae of mussels (Perna perna exposed to zinc sulphate (ZnSO4 and benzene (C6H6. When compared to the control group, both pollutants presented a significant reduction in oxygen consumption. A reduction in the ammonia excretion was also observed, both for ZnSO4 and C6H6 and also in the oxygen consumption. The results indicate that anaerobic metabolism may occur at the beginning of P. perna mussels development, as observed in veliger larvae. The O:N ratio under experimental conditions showed low values indicating that catabolism in veliger larvae was predominantly proteic.

  9. Comparative susceptibility of veliger larvae of four bivalve mollusks to a Vibrio alginolyticus strain.

    Science.gov (United States)

    Luna-González, A; Maeda-Martínez, A N; Sainz, J C; Ascencio-Valle, F

    2002-06-03

    The susceptibility of 7 d old veliger larvae of the scallops Argopecten ventricosus and Nodipecten subnodosus, the penshell Atrina maura, and the Pacific oyster Crassostrea gigas to a pathogenic strain of Vibrio alginolyticus was investigated by challenging the larvae with different bacterial concentrations in a semi-static assay. The results indicate that the larvae of the 2 scallop species are more susceptible to the V. alginolyticus strain than those of the oyster and the penshell. Signs of the disease were similar to bacillary necrosis described in previous work. Interspecies differences in susceptibility to pathogens are discussed.

  10. Mussel watch

    Science.gov (United States)

    Contamination of U.S. coastal areas may be decreasing as a result of environmental regulations that have banned or curtailed toxic chemicals, concludes a report by the National Oceanic and Atmospheric Administration. The report, “Recent Trends in Coastal Environmental Quality: Results from the Mussel Watch Project,” presents results of analyzing chemical concentrations found in mussel and oyster tissues collected every year since 1986.These mollusks are collected once a year at more than 240 sites nationwide and analyzed for over 70 polycyclic aromatic hydrocarbons, polychlorinated biphenyls, chlorinated pesticides, butyltins, and toxic trace elements such as copper, cadmium, and lead. The report states that from 1986 to 1993 there were many more decreases than increases in chemical concentrations in coastal regions. These decreasing trends were not unexpected; all of the monitored chlorinated hydrocarbons have been banned for use in the United States, and tributyltin has been banned as a biocide on recreational boats.

  11. Identification of larvae: The zebra mussel (Dreissena polymorpha), quagga mussel (Dreissena rosteriformis bugensis), and Asian clam (Corbicula fluminea)

    Science.gov (United States)

    Nichols, S. Jerrine; Black, M.G.

    1994-01-01

    There are presently four freshwater bivalves in the United States that produce larvae or veligers commonly found in the water column: two forms of Asian clams and two species of dreissenids. Portions of the geographic range of three of these bivalves, one species of Asian clam (Corbicula fluminea), zebra mussels (Dreissena polymorpha), and quagga mussels (Dreissena rosteriformis bugensis), overlap, causing problems with larval identification. To determine which characteristics can be used to separate larval forms, adult Asian clams, quaggas, and zebra mussels were brought into the laboratory and induced to spawn, and the resulting larvae were reared. Hybrids between quaggas and zebra mussels were also produced, but not reared to maturity. Characteristics allowing for the most rapid and accurate separation of larvae were hinge length, shell length/height, shell shape, shell size, and the presence or absence of a foot and velum. These characteristics were observed in laboratory-reared larvae of known parentage and field-caught larvae of unknown parentage. In most cases, larvae of the Asian clam can be readily separated from those produced by either type of dreissenid on the basis of shell size and presence of a foot. Separating the gametes and embryos of the two types of dreissenids is not possible, but after shell formation, most of the larval stages can be distinguished. Hinge length, shell length/height, and the similarity in size of the shell valves can be used to separate straight-hinged, umbonal, pediveliger, and plantigrade larvae. Quagga × zebra mussel hybrids show characteristics of both parents and are difficult to identify.

  12. Early invasion population structure of quagga mussel and associated benthic invertebrate community composition on soft sediment in a large reservoir

    Science.gov (United States)

    Wittmann, Marion E.; Chandra, Sudeep; Caires, Andrea; Denton, Marianne; Rosen, Michael R.; Wong, Wai Hing; Teitjen, Todd; Turner, Kent; Roefer, Peggy; Holdren, G. Chris

    2010-01-01

    In 2007 an invasive dreissenid mussel species, Dreissena bugensis (quagga mussel), was discovered in Lake Mead reservoir (AZ–NV). Within 2 years, adult populations have spread throughout the lake and are not only colonizing hard substrates, but also establishing in soft sediments at depths ranging from 1 to >100 m. Dreissena bugensis size class and population density distribution differs between basins; cluster analysis revealed 5 adult cohorts within Boulder Basin and Overton Arm but low densities and low cohort survival in the Las Vegas Basin. Regression analysis suggests depth and temperature are not primary controllers of D. bugensis density in Lake Mead, indicating other factors such as sediment type, food availability or other resource competition may be important. Monthly veliger tows showed at least 2 major spawning events per year, with continuous presence of veligers in the water column. Adult mussels have been found in spawn or post-spawn condition in soft sediments in shallow to deep waters (>80 m) indicating the potential for reproduction at multiple depths. Comparisons to a 1986 benthic survey suggest there have been shifts in nondreissenid macroinvertebrate composition; however, it is unclear if this is due to D. bugensis presence. Current distribution of nondreissenid macroinvertebrates is heterogeneous in all 3 basins, and their biodiversity decreased when D. bugensis density was 2500/m2 or greater.

  13. Comparative biology of zebra mussels in Europe and North America: an overview

    Science.gov (United States)

    Mackie, Gerald L.; Schloesser, Don W.

    1996-01-01

    SYNOPSIS. Since the discovery of the zebra mussel, Dreissena polymorpha, in the Great Lakes in 1988 comparisons have been made with mussel populations in Europe and the former Soviet Union. These comparisons include: Population dynamics, growth and mortality rates, ecological tolerances and requirements, dispersal rates and patterns, and ecological impacts. North American studies, mostly on the zebra mussel and a few on a second introduced species, the quagga mussel, Dreissena bugensis, have revealed some similarities and some differences. To date it appears that North American populations of zebra mussels are similar to European populations in their basic biological characteristics, population growth and mortality rates, and dispersal mechanisms and rates. Relative to European populations differences have been demonstrated for: (1) individual growth rates; (2) life spans; (3) calcium and pH tolerances and requirements; (4) potential distribution limits; and (5) population densities of veligers and adults. In addition, studies on the occurrence of the two dreissenid species in the Great Lakes are showing differences in their modes of life, depth distributions, and growth rates. As both species spread throughout North America, comparisons between species and waterbodies will enhance our ability to more effectively control these troublesome species.

  14. NMR Profiling of Metabolites in Larval and Juvenile Blue Mussels (Mytilus edulis) under Ambient and Low Salinity Conditions.

    Science.gov (United States)

    May, Melissa A; Bishop, Karl D; Rawson, Paul D

    2017-07-06

    Blue mussels ( Mytilus edulis ) are ecologically and economically important marine invertebrates whose populations are at risk from climate change-associated variation in their environment, such as decreased coastal salinity. Blue mussels are osmoconfomers and use components of the metabolome (free amino acids) to help maintain osmotic balance and cellular function during low salinity exposure. However, little is known about the capacity of blue mussels during the planktonic larval stages to regulate metabolites during osmotic stress. Metabolite studies in species such as blue mussels can help improve our understanding of the species' physiology, as well as their capacity to respond to environmental stress. We used 1D ¹H nuclear magnetic resonance (NMR) and 2D total correlation spectroscopy (TOCSY) experiments to describe baseline metabolite pools in larval (veliger and pediveliger stages) and juvenile blue mussels (gill, mantle, and adductor tissues) under ambient conditions and to quantify changes in the abundance of common osmolytes in these stages during low salinity exposure. We found evidence for stage- and tissue-specific differences in the baseline metabolic profiles of blue mussels, which reflect variation in the function and morphology of each larval stage or tissue type of juveniles. These differences impacted the utilization of osmolytes during low salinity exposure, likely stemming from innate physiological variation. This study highlights the importance of foundational metabolomic studies that include multiple tissue types and developmental stages to adequately evaluate organismal responses to stress and better place these findings in a broader physiological context.

  15. Evaluating high pH for control of dreissenid mussels

    Directory of Open Access Journals (Sweden)

    Dave Evans

    2013-04-01

    Full Text Available Two field experiments were carried out using a custom built flow-through laboratory to test the effect of elevated pH on dreissenid musselsas a potential control method. Both experiments tested the ability of dreissenid pediveligers to settle under conditions of elevated pH and thelong-term survival of adult dreissenids under the same conditions. The two experimental sites had different water quality and differentspecies of dreissenids present. The settlement of quagga mussel pediveligers at the lower Colorado River was inhibited with increasing pH.At the maximum achieved pH of 9.1, there was approximately 90% reduction compared to the maximum settlement observed in the controls.Since the settlement was almost as low in pH 8.9 as at pH 9.1, the inhibition in settlement may have been due to the presence of a precipitateformed under high pH conditions rather than the increase in background pH. No mortality of quagga mussel adults was observed in theexperimental pH levels at the lower Colorado River. At San Justo Reservoir, zebra mussel settlement decreased with increasing pH. Newsettlement was almost entirely absent at the highest pH tested (pH 9.6. The observed mortality of adult zebra mussels was low, but did tendto increase with increasing pH. We also tested the response of adult zebra mussels to short-term exposure to very high pH levels (i.e. pH 10,11, and 12. Adult mussels in poor physical condition experienced 90% mortality after 12 hours at pH 12. For unstressed adult zebra mussels,90% mortality was reached after 120 hours at pH 12. Significant mortalities were also observed both at pH 10 and pH 11. From this study,we conclude that pH elevation could be used both as a preventative treatment to eliminate settlement by dreissenid mussels and as an end ofseason treatment to eliminate adults. The high pH treatment would have to be tailored to the site water quality to prevent formation ofprecipitate during treatment and to minimize corrosive

  16. Control of zebra mussels with ultraviolet radiation

    Energy Technology Data Exchange (ETDEWEB)

    Lewis, D.P.

    1998-07-01

    This paper presents the results of research on the effects of low and medium pressure ultraviolet (UV) radiation on zebra mussel mortality carried out between 1992 and 1995. An initial 1992 study, carried out by Aquatic Sciences (ASI), showed that flow-through UV systems have the ability to kill zebra mussels and prevent them from attaching to downstream surfaces. However, this work did not include expanded testing to determine the limitations of UV radiation at higher flow rates or to further define effective working parameters. The 1994 study was carried out at the Lennox Thermal Generating Station (TGS) of Ontario Hydro in Kingston, Ontario. This study involved the testing of two open channel UV systems (medium and low pressure) in an effort to determine flow rates and volumes for which UV disinfection would be effective and practical for the prevention of zebra mussel infestation. It was recommended that medium pressure (MP) and low pressure (LP) UV systems be tested for their ability to control downstream settlement of zebra mussels, in flow-through trials.

  17. Strategies to control zebra mussel fouling at Kewaunee Nuclear Power Plant

    International Nuclear Information System (INIS)

    Schwartz, D.; Kasper, J.R.; Pisani, W.

    1992-01-01

    The zebra mussel, Dreissena polymorpha, is currently infesting the Great Lakes. First discovered in Lake St. Clair, it is now widespread in Lakes Erie and Ontario. The initial efforts relating to zebra mussel control at Wisconsin Public Service Corporation's (WPSC) Kewaunee Nuclear Power Plant (KNPP) precipitated from the Nuclear Regulatory Commission's (NRC) Generic Letter 89-13 regarding fouling of service water (SW) systems at nuclear power plants. In the summer of 1990, Stone and Webster Engineering Corporation (Stone and Webster) was contracted to perform an evaluation of known problems within the SW system. The purposes of the study were to evaluate the actual and potential magnitude of these problems, to evaluate corrective actions to resolve the problems, and to prepare recommendations which would adequately address the issues. Two of the recommendations of this study were to continue a zebra mussel monitoring program which WPSC had already implemented and to evaluate various biocide injection programs should one be required for zebra mussel control. The concern of utilities operating power stations which use waters infested with zebra mussels as their source of cooling and/or makeup water is that mussels (both adults and veligers) will enter plant water systems and foul piping and heat exchangers. This type of fouling can restrict flow through piping, process equipment, and heat exchangers. This type of fouling can restrict flow through piping, process equipment, and heat exchangers, thereby increasing head losses and reducing heat transfer capabilities. The greatest concern in that fouling of this type is within safety-related piping and equipment that are components of service water systems at nuclear power plants

  18. Aspects of growth, recruitment and conservation of the Brown Mussel Perna perna along the Tsitsikamma Coast

    Directory of Open Access Journals (Sweden)

    R. J. M Crawford

    1983-12-01

    Full Text Available Beds of brown mussels Perna perna are a dominant feature of the lower tidal range of rocky shores in the Tsitsikamma Coastal National Park. Mussels in this region attain a length of 30-40 mm by the end of their first year, and the majority probably exceed 50 mm at two years of age. Secondary settlement of plantigrades occurs from midspring through early winter, especially in summer and early autumn, and growth of adult forms is slowest prior to this settlement. Settlement occurs serially and powerful cohorts may be formed. At Nature's Valley density and biomass of mussels inside the park's boundary are significantly higher than in non-protected areas. Older age groups are also more abundant within the park.

  19. Sound Settlements

    DEFF Research Database (Denmark)

    Mortensen, Peder Duelund; Hornyanszky, Elisabeth Dalholm; Larsen, Jacob Norvig

    2013-01-01

    Præsentation af projektresultater fra Interreg forskningen Sound Settlements om udvikling af bæredygtighed i det almene boligbyggerier i København, Malmø, Helsingborg og Lund samt europæiske eksempler på best practice......Præsentation af projektresultater fra Interreg forskningen Sound Settlements om udvikling af bæredygtighed i det almene boligbyggerier i København, Malmø, Helsingborg og Lund samt europæiske eksempler på best practice...

  20. Variation in abundance of Pacific Blue Mussel (Mytilus trossulus) in the Northern Gulf of Alaska, 2006-2015

    Science.gov (United States)

    Bodkin, James L.; Coletti, Heather A.; Ballachey, Brenda E.; Monson, Daniel H.; Esler, Daniel; Dean, Thomas A.

    2018-01-01

    Alaska were affecting mussel survival and subsequently abundance. In contrast, density of primarily small mussels obtained from cores (as an index of recruitment), varied markedly by site, but did not show meaningful temporal trends. We interpret this to indicate that settlement was driven by site-specific features rather than Gulf wide factors. By extension, we hypothesize that temporal changes in mussel abundance observed was not a result of temporal variation in larval supply leading to variation in recruitment, but rather suggestive of mortality as a primary demographic factor driving mussel abundance. Our results highlight the need to better understand underlying mechanisms of change in mussels, as well as implications of that change to nearshore consumers.

  1. Evaluating high pH for control of dreissenid mussels

    OpenAIRE

    Dave Evans; Sergey E. Mastitsky; Katherine L. Prescott; Thomas H. Prescott; Renata Claudi; Anna Carolina Taraborelli

    2013-01-01

    Two field experiments were carried out using a custom built flow-through laboratory to test the effect of elevated pH on dreissenid musselsas a potential control method. Both experiments tested the ability of dreissenid pediveligers to settle under conditions of elevated pH and thelong-term survival of adult dreissenids under the same conditions. The two experimental sites had different water quality and differentspecies of dreissenids present. The settlement of quagga mussel pediveligers at ...

  2. The zebra mussel

    International Nuclear Information System (INIS)

    Bertran, A.; Esparza, J.L.; Munte, L.

    2010-01-01

    The aim of this article is, on the one hand, to provide information about the zebra mussel, its behavior, its effect on the ecosystem and the problems it poses for industry (especially in the CNA cooling systems) and, on the other hand, to review the strategies and technologies needed to control de mussel and to present the solution adopted by the power plant to combat the plague. (Author).

  3. Sound Settlements

    DEFF Research Database (Denmark)

    Mortensen, Peder Duelund; Hornyanszky, Elisabeth Dalholm; Larsen, Jacob Norvig

    2013-01-01

    Præsentation af projektresultater fra Interreg forskningen Sound Settlements om udvikling af bæredygtighed i det almene boligbyggerier i København, Malmø, Helsingborg og Lund samt europæiske eksempler på best practice...

  4. Zebra mussel monitoring

    Energy Technology Data Exchange (ETDEWEB)

    Hennagir, T.

    1994-01-01

    In less than a decade, zebra mussels have become the latest environmental scourge to plague the North American power industry. Infestations in the Great Lakes region have already reached natural disaster proportions. The invasion shows little sign of subsiding; Michigan's inland waters are the next most likely threatened area. In the southern United States, the mussles' migration has extended about 50 miles deeper than experts had originally predicted. By the year 2000, zebra mussel monitoring and control efforts will cost business and industry $5 billion, according to the federal Aquatic Nuisance Prevention and Control Act of 1990. Estimates of more than $1 million to control mussel fouling are projected for the Great Lakes area alone. While small independent hydropower stations are not as susceptible to zebra mussles as coal or nuclear facilities, there is cause for concern. Infestations can quickly foul hydropower plant components, hampering equipment operation and reducing facility efficiency. In extreme cases, leaving the mussels unchecked can result in stoplog gate flow blockage or false water level gauge readings. Advance prevention is often an effective first-line of defense against this troublesome, rapidly spreading and extremely prolific mollusk. Mussel monitoring efforts should begin a year in advance of when zebra mussels are expected to appear in a given location. Hydropower facility components that come into contact or rely exclusively on raw water are at greatest risk, as are other external components such as embayment walls, screens, trashracks and fish ladders.

  5. Human settlements

    CSIR Research Space (South Africa)

    Van Niekerk, Cornelia W

    2017-09-01

    Full Text Available risk of deaths and injuries by drowning in floods and migration- related health effects. • Increased migration, which can result in human suffering, human rights violations, conflicts and political instability. • Loss of property and livelihoods.... The vulnerability of settlements in southern Africa is impacted by various and complex socio-economic processes related to the cultural, political and institutional contexts and demographic pressure, as well as specific high-risk zones susceptible to flash floods...

  6. The use of food grade oil in the prevention of vase tunicate fouling on mussel aquaculture gear

    Directory of Open Access Journals (Sweden)

    Jiselle A. BAKKER

    2011-01-01

    Full Text Available Current mitigation strategies against invasive tunicates on mussel aquaculture gear in Prince Edward Island concentrate on labour-intensive and costly fouling removal. Instead of removal, this study focused on preventing the settlement of the vase tunicate Ciona intestinalis and other fouling organisms by applying a layer of food grade oil to gear prior to recruitment. Laboratory tests established the adherence and persistence of shortening, a food grade oil with a melting point exceeding ambient water temperatures, to rope and mussels. In situ tests showed that shortening decreased C. intestinalis weight and abundance on buoys, spat collector ropes and collector plates but not on mussel socks. Fouling by algae and other tunicates was significantly reduced on most substrates. There were no detrimental effects of shortening treatment on mussel length and abundance on mussel socks, but total mussel weight was significantly lower on shortening-treated socks. Shortening treatment did not significantly affect mussel spat settlement on spat collector ropes, but further evaluation is required. Overall, shortening application has considerable potential for reducing tunicate and other fouling, particularly on buoys.

  7. High mortality of the larvae of the common mussel at low concentrations of tributyltin

    Energy Technology Data Exchange (ETDEWEB)

    Beaumont, A.R.; Budd, M.D.

    1984-11-01

    Laboratory reared veliger larvae of the common mussel Mytilus edulis were grown for 15 days in filtered seawater containing 10 ..mu..g l/sup -1/, 1 ..mu..g l/sup -1/ and 0.1 ..mu..g l/sup -1/ tributyltin oxide, (TBTO), the biocide in recent antifouling paint formulations. No larvae survived longer than 5 days in 10 ..mu..g l/sup -1/ TBTO. Approximately half the larvae subjected to 0.1 ..mu..g/sup -1/ TBTO were dead by day 15 (approximately 15 day LC/sub 50/ = 0.1 ..sqrt..g l/sup -1/ TBTO) and most of the surviving larvae were moribund and had grown significantly more slowly than controls. It is noted that current recorded levels of TBT at several UK estuarine sites are higher than 0.1 ..mu..g l/sup -1/ and there has therefore probably been a high mortality of mussel larvae at such sites. The results are discussed in relation to the reported short-term toxicity of organotins to other marine organisms and the value of carrying out longer term tests at low levels of TBT is pointed out.

  8. Where to settle--settlement preferences of Mytilus galloprovincialis and choice of habitat at a micro spatial scale.

    Directory of Open Access Journals (Sweden)

    Christina Carl

    Full Text Available The global mussel aquaculture industry uses specialised spat catching and nursery culture ropes made of multi-filament synthetic and natural fibres to optimise settlement and retention of mussels for on-growing. However, the settlement ecology and preferences of mussels are poorly understood and only sparse information exists in a commercial context. This study quantified the settlement preferences of pediveligers and plantigrades of Mytilus galloprovincialis on increasingly complex surfaces and settlement locations at a micro spatial scale on and within ropes under commercial hatchery operating conditions using optical microscopy and X-ray micro-computed tomography (µCT. M. galloprovincialis has clear settlement preferences for more complex materials and high selectivity for settlement sites from the pediveliger through to the plantigrade stage. Pediveligers of M. galloprovincialis initially settle inside specialised culture ropes. Larger pediveligers were located close to the exterior of ropes as they increased in size over time. In contrast, smaller individuals were located deeper inside of the ropes over time. This study demonstrates that X-ray µCT is an excellent non-destructive technique for mapping settlement and attachment sites of individuals as early as one day post settlement, and quantifies the number and location of settled individuals on and within ropes as a tool to understand and optimise settlement in complex multi-dimensional materials and environments.

  9. The role of shore crabs and mussel density in mussel losses at a commercial intertidal mussel plot after seeding

    NARCIS (Netherlands)

    Capelle, Jacob J.; Scheiberlich, Gerard; Wijsman, Jeroen W.M.; Smaal, Aad C.

    2016-01-01

    Mussel losses peak after relaying seed on culture plots. The present paper is an attempt to examine the role of shore crab predation and initial mussel density on mussel losses in mussel bottom culture using an intertidal culture plot as a case study. Because of their small size and loose

  10. International mussel watch

    International Nuclear Information System (INIS)

    Farrington, J.W.; Tripp, B.W.

    1993-01-01

    Deliberate and inadvertent discharges of chemical contaminants of environmental concern to the world's coastal ocean will continue for the foreseeable future, as human population increases and human habitation intensifies in the coastal zone worldwide. The goal of the International Mussel Watch Project is to provide an assessment of the status and trends of chemical contaminants in the world's coastal waters. These data are critical for protecting both the health of people who consume seafood and the health of coastal ecosystems. The International Mussel Watch Project is a global-scale monitoring program based on the concept of a sentinel organism capable of detecting trends in concentrations of several important marine contaminants. These included chlorinated pesticides, fossil-fuel hydrocarbons, and radionuclides from the nuclear fuel cycle and nuclear weapons testing fallout. Since the 1970's, scientists of several countries have been using common bivalve organisms, such as the blue mussels and oysters, to monitor chemical contaminants in coastal waters. Bivalve mollusks are good monitors for several reasons that include their ability to bioconcentrate the chemical contaminants of interest and their sedentary nature, which makes them representative of a specific place

  11. High Pressure Inactivation of HAV within Mussels

    Science.gov (United States)

    The potential of hepatitis A virus (HAV) to be inactivated within Mediterranean mussels (Mytilus galloprovincialis) and blue mussels (Mytilus edulis) by high pressure processing was evaluated. HAV was bioaccumulated within mussels to approximately 6-log10 PFU by exposure of mussels to HAV-contamina...

  12. Deeply hidden inside introduced biogenic structures - Pacific oyster reefs reduce detrimental barnacle overgrowth on native blue mussels

    Science.gov (United States)

    Buschbaum, Christian; Cornelius, Annika; Goedknegt, M. Anouk

    2016-11-01

    In sedimentary coastal ecosystems shells of epibenthic organisms such as blue mussels (Mytilus edulis) provide the only major attachment surface for barnacle epibionts, which may cause detrimental effects on their mussel basibionts by e.g. reducing growth rate. In the European Wadden Sea, beds of native blue mussels have been invaded by Pacific oysters Crassostrea gigas, which transformed these beds into mixed reefs of oysters with mussels. In this study, we determined the spatial distribution of M. edulis and their barnacle epibionts (Semibalanus balanoides) within the reef matrix. Mean mussel density near the bottom was about twice as high compared to the mussel density near the top of an oyster reef, whereas barnacles on mussels showed a reversed pattern. Barnacle dry weight per mussel was on average 14 times higher near the top than at the bottom. This pattern was confirmed by experimentally placing clean M. edulis at the top and on the bottom of oyster reefs at two sites in the Wadden Sea (island of Texel, The Netherlands; island of Sylt, Germany). After an experimental period of five weeks (April and May 2015, the main settlement period of S. balanoides), the number of barnacles per mussel was at both sites significantly higher on mussels near the top compared to near the bottom. We conclude that the oyster reef matrix offers a refuge for M. edulis: inside reefs they are not only better protected against predators but also against detrimental barnacle overgrowth. This study shows that alien species can cause beneficial effects for native organisms and should not be generally considered as a risk for the recipient marine ecosystems.

  13. Substratum type and conspecific density as drivers of mussel patch formation

    KAUST Repository

    Bertolini, Camilla

    2017-01-19

    Biogenic reefs are an important component of aquatic ecosystems where they enhance biodiversity. These reefs are often established by dense aggregations of a single taxa and understanding the fundamental principles of biogenic reef formation is needed for their conservation and restoration. We tested whether substratum type and density affected the aggregation behaviour of two important biogenic-reef forming species, the horse mussel, Modiolus modiolus (Linnaeus, 1758), and the blue mussel, Mytilus edulis (Linnaeus, 1758). First, we tested for effects of substratum type on mussel movement and aggregation behaviour by manipulating substrata available to mussels in mesocosms (three treatments: no sediment added, sediment added, sediment and shells added). Both mussel species moved less in treatments with sediment and with both sediment and shells present than when no sediment or shells were added and the percentage of these mussels that aggregated (clumps of two or more individuals) was lower when shells were present compared to treatments without shells, however, fewer M. modiolus attached to shells than M. edulis. There was no effect of different substratum type on patch complexity of either mussel species. In addition, motivated by our interest in the restoration of M. modiolus, we also tested experimentally whether the aggregation behaviour of M. modiolus was density-dependent. M. modiolus moved a similar distance in three density treatments (100, 200 and 300 mussels m), however, their aggregation rate appeared to be greater when mussel density was higher, suggesting that the encounter rate of individuals is an important factor for aggregation. M. modiolus also formed aggregations with a higher fractal dimension in the high and medium density treatments compared to lower density, suggesting that at higher density this increased patch complexity could further facilitate increased recruitment with the enhanced habitat available for settlement. These findings add

  14. Mussel Sites - 2009 [ds658

    Data.gov (United States)

    California Natural Resource Agency — Freshwater mussels are one of the most imperiled groups of organisms on the planet (Williams et al.1993, Strayer et al.2004, Strayer 2006, R´Egnier et al.2009)....

  15. Dreissenid mussel research priorities workshop

    Science.gov (United States)

    Sytsma, Mark; Phillips, Stephen; Counihan, Timothy D.

    2015-01-01

    Currently, dreissenid mussels have yet to be detected in the northwestern part of the United States and western Canada. Infestation of one of the jurisdictions within the mussel-free Pacific Northwest would likely have significant economic, soci­etal and environmental implications for the entire region. Understanding the biology and environmental tolerances of dreissenid mussels, and effectiveness of various man­agement strategies, is key to prevention.On November 4-5, 2015, the Aquatic Bioinvasion Research and Policy Institute and the Center for Lakes and Reservoirs at Portland State University, the US Geological Survey, and the Pacific States Marine Fisheries Commission, convened a Dreissenid Mussel Research Priorities Workshop funded by the Great Northern Landscape Conservation Cooperative. The purpose of the workshop was to review dreissenid research priorities in the 2010 Quagga-Zebra Mussel Action Plan for Western U.S. Waters, reassess those priorities, incorporate new information and emerging trends, and develop priorities to strategically focus research efforts on zebra and quagga mussels in the Pacific Northwest and ensure that future research is focused on the highest priorities. It is important to note that there is some repetition among dreissenid research priority categories (e.g., prevention, detection, control, monitoring, and biology).Workshop participants with research experience in dreissenid mussel biology and management were identified by a literature review. State and federal agency managers were also invited to the workshop to ensure relevancy and practicality of the work­shop outcomes. A total of 28 experts (see sidebar) in mussel biology, ecology, and management attended the workshop.

  16. Elevated extracellular pH during early shell formation in the blue mussel Mytilus edulis

    Science.gov (United States)

    Ramesh, K.; Melzner, F.; Himmerkus, N.; Hu, M.; Bleich, M.

    2016-02-01

    Marine calcifiers are amongst the most vulnerable organisms to ocean acidification (OA). However, limited studies investigate the mechanisms underlying their hindered performance under OA stress. Working with larval stages of the blue mussel, Mytilus edulis, we use microsensors to study the pH and calcium conditions necessary for shell deposition. Using 45-48 hour, D-veliger stages, we discover alkaline conditions with respect to ambient seawater pH by 0.28 pH units and higher calcium concentrations (by 0.54mM) in the extra pallial space beneath the growing shell that likely promotes the rapid synthesis of the first shell. We further use enzyme assays in combination with immuno-stainings of sodium-potassium ATPase (NKA) and proton ATPase (VHA) to provide information on the major ion regulatory pathways that enable transport of calcium carbonate required for shell formation and pH homeostasis. We also use the juvenile stages of M. edulis to understand how extracellular pH regulation close to the shell formation site will be influenced by OA stress. This allows us to describe the pH dependency of early shell formation and to begin to develop a model of the ion regulatory network that facilitates biomineralisation in the organism. The results are discussed in the context of environmental change and consequences for mollusc developmental success.

  17. Mussel-inspired chemistry and its application

    NARCIS (Netherlands)

    Yang, J.

    2016-01-01

    Mussels can affix themselves to a variety of wet surfaces under harsh marine conditions by secreting liquid mussel foot proteins (mfps) as superglues. Inside the mussel, the superglues are fluid-like and are kept at low pH, i.e. pH 3. Upon secretion into seawater at pH 8, the superglues are cured

  18. Zebra Mussel Chemical Control Guide.

    Science.gov (United States)

    2000-01-01

    are 3 to 5 years. Zebra mussels are filter feeders, opening their shells to allow ingestion of particulates. When their sensitive chemoreceptors alert...used for oxidation of iron and manganese and to correct taste and odor problems in treated water because of its ability to produce oxidation reactions

  19. Comparing a microbial biocide and chlorine as zebra mussel control strategies in an Irish drinking water treatment plant

    Directory of Open Access Journals (Sweden)

    Sara Meehan

    2013-06-01

    Full Text Available A need exists for an environmentally friendly mussel control method to replace chlorine and other traditional control methods currentlyutilised in drinking water plants and other infested facilities. Zequanox® is a newly commercialised microbial biocide for zebra and quaggamussels comprised of killed Pseudomonas fluorescens CL145A cells. The objective of this study was to compare the efficacy of adevelopmental formulation of Zequanox (referred to as MBI 401 FDP and chlorine treatments on adult and juvenile zebra mussels byrunning a biobox trial in conjunction with chlorine treatments at an infested Irish drinking water treatment plant. Since 2009, the plantmanagement has used a residual chlorine concentration of 2 mg/L in autumn to control both adult zebra mussels and juvenile settlement intheir three concrete raw water chambers. Juvenile mussel settlement was monitored in three bioboxes as well as in three treatment chambersin the plant for three months prior to treatment. Adult mussels were seeded into the chambers and bioboxes four days before treatment. InOctober 2011, the bioboxes were treated with MBI 401 FDP at 200 mg active substance/L, while chlorine treatment took place in the waterchambers. The MBI 401 FDP treatment lasted only 8 hours while chlorine treatment lasted seven days. Juvenile numbers were reduced tozero in both the bioboxes and treated chambers within seven days. Adult mussel mortality reached 80% for both the chlorine and MBI 401FDP treatment; however, mortality was achieved faster in the chlorine treatment. These results provided important insights into zebra musselcontrol alternatives to chlorine and supported further development of the now commercial product, Zequanox.

  20. Impact of zebra and quagga mussels (Dreissena spp.) on freshwater unionids (Bivalvia: Unionidae) in the Detroit River of the Great Lakes

    Science.gov (United States)

    Schloesser, D.W.; Kovalak, W.P.; Longton, G.D.; Ohnesorg, K.L.; Smithee, R.D.

    1998-01-01

    To assess the impact of zebra and quagga mussel (Dreissena spp.) infestation on unionids, unionids (Bivalvia: Unionidae) were sampled in the Detroit River in 1982-1983, before mussels invaded the river, and in 1992 and 1994, after mussels invaded the river. Live unionids at four stations along the southeastern shore accounted for 97% (20 species) of all shells collected in 1982-1983, whereas live unionids accounted for only 10% (13 species) in 1992. A similar decline in live unionids occurred at nine stations along the northwestern shore, except the decline occurred over the three sampling periods: in 1982-83, 84% (22 species) were live; in 1992, 65% (26 species) were live; and, in 1994, only 3% (13 species) were live. The difference in time to near-total mortality of unionids along the southeastern and northwestern shores is attributed to differences in the time of invasion and abundance of zebra mussel veligers in distinct water masses emanating from Lake St. Clair located immediately upstream of the Detroit River. Although individuals of all species of all unionid subfamilies declined between 1982 and 1992/1994, members of the subfamilies Anodontinae and Lampsilinae declined more than Ambleminae. Between 1986 and 1992/1994, five Anodontinae, three Lampsilinae and 0 Ambleminae species have been extirpated from the river due to dreissenid mussel infestation. Numbers of individuals of commonly found species declined more than numbers of individuals of uncommonly found species. However, the number of uncommon species declined 47% (17 to 9) along both the southeastern and northwestern shores, whereas common species remained the same (3 species) along the southeastern shore and declined only 40% (5 to 3 species) along the northwestern shore. This study, and others, suggest that high mortality of unionids can occur between 4 and 6 yr after initial invasion by dreissenids or up to 8 yr depending on water current patterns. Infestation-induced mortality of unionids in the

  1. Simulated effects of host fish distribution on juvenile unionid mussel dispersal in a large river

    Science.gov (United States)

    Daraio, J.A.; Weber, L.J.; Zigler, S.J.; Newton, T.J.; Nestler, J.M.

    2012-01-01

    Larval mussels (Family Unionidae) are obligate parasites on fish, and after excystment from their host, as juveniles, they are transported with flow. We know relatively little about the mechanisms that affect dispersal and subsequent settlement of juvenile mussels in large rivers. We used a three-dimensional hydrodynamic model of a reach of the Upper Mississippi River with stochastic Lagrangian particle tracking to simulate juvenile dispersal. Sensitivity analyses were used to determine the importance of excystment location in two-dimensional space (lateral and longitudinal) and to assess the effects of vertical location (depth in the water column) on dispersal distances and juvenile settling distributions. In our simulations, greater than 50% of juveniles mussels settled on the river bottom within 500 m of their point of excystment, regardless of the vertical location of the fish in the water column. Dispersal distances were most variable in environments with higher velocity and high gradients in velocity, such as along channel margins, near the channel bed, or where effects of river bed morphology caused large changes in hydraulics. Dispersal distance was greater and variance was greater when juvenile excystment occurred in areas where vertical velocity (w) was positive (indicating an upward velocity) than when w was negative. Juvenile dispersal distance is likely to be more variable for mussels species whose hosts inhabit areas with steeper velocity gradients (e.g. channel margins) than a host that generally inhabits low-flow environments (e.g. impounded areas).

  2. NAAG Tobacco Settlement Payments

    Data.gov (United States)

    U.S. Department of Health & Human Services — 1999-2016. National Association of Attorneys General (NAAG). Policy—Tobacco Settlement Payments. The National Association of Attorneys General (NAAG) provides...

  3. NAAG Tobacco Settlement Payments

    Data.gov (United States)

    U.S. Department of Health & Human Services — 1999-2017. National Association of Attorneys General (NAAG). Policy—Tobacco Settlement Payments. The National Association of Attorneys General (NAAG) provides...

  4. Minnesota Power Settlement

    Science.gov (United States)

    EPA and DOJ announced a Clean Air Act settlement with Minnesota Power, an ALLETE company based in Duluth, that will cover its three coal-fired power plants and one biomass-and-coal-fired steam and electricity cogeneration plan

  5. Mussel Shell Impaction in the Esophagus

    Directory of Open Access Journals (Sweden)

    Sunmin Kim

    2013-03-01

    Full Text Available Mussels are commonly used in cooking around the world. The mussel shell breaks more easily than other shells, and the edge of the broken mussel shell is sharp. Impaction can ultimately cause erosion, perforation and fistula. Aside from these complications, the pain can be very intense. Therefore, it is essential to verify and remove the shell as soon as possible. In this report we describe the process of diagnosing and treating mussel shell impaction in the esophagus. Physicians can overlook this unusual foreign body impaction due to lack of experience. When physicians encounter a patient with severe chest pain after a meal with mussels, mussel shell impaction should be considered when diagnosing and treating the patient.

  6. Zebra mussels invade Lake Erie muds

    Science.gov (United States)

    Berkman, Paul Arthur; Haltuch, Melissa A.; Tichich, Emily; Garton, David W.; Kennedy, Gregory W.; Gannon, John E.; Mackey, Scudder D.; Fuller, Jonathan A.; Liebenthal, Dale L.

    1998-01-01

    Zebra mussels (Dreissena polymorpha) originated in western Russia but have now become widespread in Europe and North America. They are widely known for their conspicuous invasion of rocks and other hard substrates in North American and European watersheds. We have found beds of zebra mussels directly colonizing sand and mud sediments each year across hundreds of square kilometres of North America's Lake Erie. This transformation of sedimentary habitats into mussel beds represents an unforeseen change in the invasive capacity of this species.

  7. Environmental DNA mapping of Zebra Mussel populations

    Science.gov (United States)

    Amberg, Jon J.; Merkes, Christopher

    2016-01-01

    Environmental DNA (eDNA) has become a popular tool for detecting aquatic invasive species, but advancements have made it possible to potentially answer other questions like reproduction, movement, and abundance of the targeted organism. In this study we developed a Zebra Mussel (Dreissena polymorpha) eDNA protocol. We then determined if this assay could be used to help determine Zebra Mussel biomass in a lake with a well-established population of Zebra Mussels and a lake with an emerging population of mussels. Our eDNA assay detected DNA of Zebra Mussels but not DNA from more than 20 other species of fish and mussels, many commonly found in Minnesota waters. Our assay did not predict biomass. We did find that DNA from Zebra Mussels accumulated in softer substrates in both lakes, even though the mussels were predominately on the harder substrates. Therefore, we concluded that eDNA may be useful to detect the presence of Zebra Mussels in these lakes but our assay/approach could not predict biomass.

  8. Fish and mussels: importance of fish for freshwater mussel conservation

    Directory of Open Access Journals (Sweden)

    Ronaldo Sousa

    2015-12-01

    Full Text Available Co-extinctions have received trivial consideration in discussions about the global conservation crisis, even though recent studies have emphasised their importance. This situation is even more pronounced in freshwater ecosystems where this phenomenon is largely unrecognized. In this presentation we explore the role of fish for freshwater mussels’ conservation. Freshwater mussels’ need fish as a host to complete their life cycle and given this premise is expected that changes in the fish community due to species extinctions or additions may have great effects. We reviewed the published information and we found: 1 that most of the studies were published in the last few years; 2 that most of the studies were performed in North America (69%, which is probably due to the high number of endemic threatened species in this continent; 3 that most of the mussel species that are specialists in fish hosting are listed as vulnerable or endangered (55%; 4 most studies were performed in laboratory (83% and 5 that the majority of studies were focused on life cycle or on identifying suitable fish hosts of freshwater mussel species with few studies focusing on threats. Since the interaction between fish and freshwater mussels can be easily disrupted and serious threats to this interaction have arisen (e.g. loss and fragmentation of habitat, changes in river flow, climate change, introduction of invasive species, pollution a more holistic approach is needed to find the best management strategies to conserve these animals. In addition, more field studies are required and more information on African, South American and Asian species is essential. Neglect the possible fundamental role of fish in the decline or extinction of freshwater mussels may impair the success of any measure devoted to their conservation; therefore, this issue cannot be ignored.

  9. Effects of Ocean Acidification and Warming on Sperm Activity and Early Life Stages of the Mediterranean Mussel (Mytilus galloprovincialis

    Directory of Open Access Journals (Sweden)

    Mikko Vihtakari

    2013-11-01

    Full Text Available Larval stages are among those most vulnerable to ocean acidification (OA. Projected atmospheric CO2 levels for the end of this century may lead to negative impacts on communities dominated by calcifying taxa with planktonic life stages. We exposed Mediterranean mussel (Mytilus galloprovincialis sperm and early life stages to pHT levels of 8.0 (current pH and 7.6 (2100 level by manipulating pCO2 level (380 and 1000 ppm. Sperm activity was examined at ambient temperatures (16–17 °C using individual males as replicates. We also assessed the effects of temperature (ambient and ≈20 °C and pH on larval size, survival, respiration and calcification of late trochophore/early D-veliger stages using a cross-factorial design. Increased pCO2 had a negative effect on the percentage of motile sperm (mean response ratio R= 71% and sperm swimming speed (R= 74%, possibly indicating reduced fertilization capacity of sperm in low concentrations. Increased temperature had a more prominent effect on larval stages than pCO2, reducing performance (RSize = 90% and RSurvival = 70% and increasing energy demand (RRespiration = 429%. We observed no significant interactions between pCO2 and temperature. Our results suggest that increasing temperature might have a larger impact on very early larval stages of M. galloprovincialis than OA at levels predicted for the end of the century.

  10. Zebra mussel adhesion: structure of the byssal adhesive apparatus in the freshwater mussel, Dreissena polymorpha.

    Science.gov (United States)

    Farsad, Nikrooz; Sone, Eli D

    2012-03-01

    The freshwater zebra mussel (Dreissena polymorpha) owes a large part of its success as an invasive species to its ability to attach to a wide variety of substrates. As in marine mussels, this attachment is achieved by a proteinaceous byssus, a series of threads joined at a stem that connect the mussel to adhesive plaques secreted onto the substrate. Although the zebra mussel byssus is superficially similar to marine mussels, significant structural and compositional differences suggest that further investigation of the adhesion mechanisms in this freshwater species is warranted. Here we present an ultrastructural examination of the zebra mussel byssus, with emphasis on interfaces that are critical to its adhesive function. By examining the attached plaques, we show that adhesion is mediated by a uniform electron dense layer on the underside of the plaque. This layer is only 10-20 nm thick and makes direct and continuous contact with the substrate. The plaque itself is fibrous, and curiously can exhibit either a dense or porous morphology. In zebra mussels, a graded interface between the animal and the substrate mussels is achieved by interdigitation of uniform threads with the stem, in contrast to marine mussels, where the threads themselves are non-uniform. Our observations of several novel aspects of zebra mussel byssal ultrastructure may have important implications not only for preventing biofouling by the zebra mussel, but for the development of new bioadhesives as well. Copyright © 2012 Elsevier Inc. All rights reserved.

  11. Density, recruitment and growth performance of Asian green mussel (Perna viridis in Marudu Bay, Northeast Malaysian Borneo, three years after a massive mortality event

    Directory of Open Access Journals (Sweden)

    Afizah Mohd Taib

    2016-12-01

    Full Text Available Density, recruitment and growth performance of Asian green mussel (Perna viridis in a particular coastal marine environment can be affected by many factors, including environmental change, pollution, disease outbreak and massive mortality event. The present study was conducted to determine the density, recruitment and growth performance of farmed Asian green mussel in Marudu Bay, three years after a mass mortality event. The study was carried out for 12 months between April 2013 and March 2014. The length frequency data of 1,308 individuals of green mussel were analyzed using the latest version of the FAO-ICLARM Fish Stock Assessment Tools (FiSAT II. The result showed that the green mussel recruitment in Marudu Bay occurs throughout the year with two major peaks i.e. February and July which coincided with the monsoon seasons. The asymptotic length (L∞, growth coefficient (K and growth performance index (φ’ of the farmed Asian green mussel in Marudu Bay are relatively high at 113.4 mm, 1.7 year-1 and 4.34, respectively. However, despite good culture location, the settlement density of green mussel in the bay was low. We suspected that the low settlement density could be influenced by the ecological effects due to the long term suspension of the culture substrates and the physiochemical properties of the water in Marudu Bay. Nevertheless, chlorophyll-á measurement alone was not able to justify if food scarcity has resulted in high mortality of the farmed Asian green mussel in Marudu Bay.

  12. A dominance shift from the zebra mussel to the invasive quagga mussel may alter the trophic transfer of metals

    International Nuclear Information System (INIS)

    Matthews, Jonathan; Schipper, Aafke M.; Hendriks, A. Jan; Yen Le, T.T.; Vaate, Abraham bij de; Velde, Gerard van der; Leuven, Rob S.E.W.

    2015-01-01

    Bioinvasions are a major cause of biodiversity and ecosystem changes. The rapid range expansion of the invasive quagga mussel (Dreissena rostriformis bugensis) causing a dominance shift from zebra mussels (Dreissena polymorpha) to quagga mussels, may alter the risk of secondary poisoning to predators. Mussel samples were collected from various water bodies in the Netherlands, divided into size classes, and analysed for metal concentrations. Concentrations of nickel and copper in quagga mussels were significantly lower than in zebra mussels overall. In lakes, quagga mussels contained significantly higher concentrations of aluminium, iron and lead yet significantly lower concentrations of zinc66, cadmium111, copper, nickel, cobalt and molybdenum than zebra mussels. In the river water type quagga mussel soft tissues contained significantly lower concentrations of zinc66. Our results suggest that a dominance shift from zebra to quagga mussels may reduce metal exposure of predator species. - Highlights: • Invading quagga mussels often displace existing zebra mussels. • Interspecies difference in metal concentration may alter exposure of predators. • Zebra and quagga mussel soft tissue were analysed for metal concentrations. • Generally, quagga mussels contained lower concentrations of metals. • A dominance shift to quagga mussels may reduce metal exposure of predators. - A shift in dominance from zebra mussels to invading quagga mussels may reduce the transfer of metals to predator species

  13. An Inverse Almost Ideal Demand System for Mussels in Europe

    DEFF Research Database (Denmark)

    Nguyen, Thong Tien

    2012-01-01

    for farmed mussels from Spain, France, Italy, and the Netherlands are inflexible, while demand for Denmark's wild stock mussels is flexible. Dutch mussels are deemed a luxury food, while preferences for mussels from other countries appear independent of the level of total expenditure (i.e., homothetic...

  14. Spatial organisation and biomass development after relaying of mussel seed

    NARCIS (Netherlands)

    Capelle, J.J.; Wijsman, J.W.M.; Schellekens, T.; van Stralen, M.R.; Herman, P.M.J.; Smaal, A.C.

    2014-01-01

    It is not known whether and by what factors spatial heterogeneity in mussels (Mytilus edulis L.) affects mussel production in human-created mussel beds. In a field experiment, the same number of mussels was relayed on four different areas within plots of the same size, resulting in four treatments

  15. GIS-based multi-criteria site selection for zebra mussel cultivation: Addressing end-of-pipe remediation of a eutrophic coastal lagoon ecosystem.

    Science.gov (United States)

    Bagdanavičiūtė, Ingrida; Umgiesser, Georg; Vaičiūtė, Diana; Bresciani, Mariano; Kozlov, Igor; Zaiko, Anastasija

    2018-04-11

    Farming of shellfish and seaweeds is a tested tool for mitigating eutrophication consequences in coastal environments, however as many other marine economic activities it should be a subject of marine spatial planning for designating suitable sites. The present study proposes site selection framework for provisional zebra mussel farming in a eutrophic lagoon ecosystem, aimed primarily at remediation purposes. GIS-based multi-criteria approach was applied, combining data from empirical maps, numerical models and remote sensing to estimate suitability parameters. Site selection and prioritisation of suitable areas considered 15 environmental and socio-economic criteria, which contributed to 4 optimisation models (settlement, growth and survival of mussels, environmental and socio-economic) and 3 predefined scenarios representing provisional goals of mussel cultivation: spat production, biomass production and bioremediation. The relative importance of each criterion was assessed utilizing the Analytical Hierarchy Process. Site suitability index was calculated and the final result of the site selection analysis was summarized for 3 scenarios and overall suitability map. Four suitability classes (unsuitable, least, moderately and most suitable) were applied, and 3 most suitable zones for provisional zebra mussel cultivation with 12 candidate sites were selected accordingly. The integrated approach presented in this study can be adjusted for designating zebra mussel farming sites in other estuarine lagoon ecosystems, or cultivation of other mussel species for bioremediation purposes. The analytical framework and the workflow designed in this study are also adoptable for addressing other aquaculture-related spatial planning issues. Copyright © 2018 Elsevier B.V. All rights reserved.

  16. Research continues on zebra mussel control

    International Nuclear Information System (INIS)

    Anon.

    1993-01-01

    Researchers are working on many fronts to learn methods for controlling and combatting zebra mussels, a species of mussel that can attach to the inside of water intakes at hydroelectric and thermal power plants, and can reduce or block water flow. Biologists at the University of Toledo in Ohio report that compounds from the African soapberry plant called lemmatoxins are lethal to zebra mussels. In laboratory tests, researchers have determined 1 to 2 milligrams of purified lemmatoxins per liter will kill the mussels. In field tests, biologist Harold Lee flushed water through a mussel-infested pipe. He found that the berry extract killed mussels in four to eight hours, making continuous treatment of water intake pipes unnecessary, according to a report in New Scientists. The University of Toledo participated in another project, funded by the American Water Works Association Research Foundation. That project team included the cities of Toledo and Cleveland, Ohio, Finkbeiner, Pettis ampersand Strout, Ltd. consulting engineers, and researchers from Ohio's Case Western Reserve University. The team identified a chemical oxidant, sodium hypochlorite, as a cost-effective agent for controlling zebra mussels at water treatment plant intakes. Toledo has used the sodium hypochlorite and reports the chemical has cleared colonies of zebra mussels that had attached to the intake of its water treatment plant

  17. Glacial history of the European marine mussels

    NARCIS (Netherlands)

    Smietanka, B.; Burzynski, A.; Hummel, H.; Wenne, R.

    2014-01-01

    Mussels of the genus Mytilus have been used to assess the circumglacial phylogeography of the intertidal zone. These mussels are representative components of the intertidal zone and have rapidly evolving mitochondrial DNA, suitable for high resolution phylogeographic analyses. In Europe, the three

  18. Model for mapping settlements

    Science.gov (United States)

    Vatsavai, Ranga Raju; Graesser, Jordan B.; Bhaduri, Budhendra L.

    2016-07-05

    A programmable media includes a graphical processing unit in communication with a memory element. The graphical processing unit is configured to detect one or more settlement regions from a high resolution remote sensed image based on the execution of programming code. The graphical processing unit identifies one or more settlements through the execution of the programming code that executes a multi-instance learning algorithm that models portions of the high resolution remote sensed image. The identification is based on spectral bands transmitted by a satellite and on selected designations of the image patches.

  19. Settlement patterns and sustainability

    DEFF Research Database (Denmark)

    Hendriksen, Kåre

    This paper discusses settlement patterns and sustainability. Generally urbanization is recognised as an inevitable development driven by job opportunities, better service supply, education, and health services, and it is argued that this is the main driver for centralisation. Research based...... on economic and demographic studies and a large series of interviews problematize this. In Greenland the historical correlation between settlement pattern and livelihood has been decoupled, so that distributions of jobs and potential earnings to a growing extend is a consequence of political and...

  20. Collapse settlement in compacted soils

    CSIR Research Space (South Africa)

    Booth, AR

    1977-01-01

    Full Text Available Research into collapse settlement in compacted soils is described, with special reference to recent cases in Southern Africa where collapse settlement occurred in road embankments following wetting of the soil. The laboratory work described...

  1. Zebra mussels anchor byssal threads faster and tighter than quagga mussels in flow.

    Science.gov (United States)

    Peyer, Suzanne M; McCarthy, Alice J; Lee, Carol Eunmi

    2009-07-01

    While the invasive zebra mussel Dreissena polymorpha has rapidly spread throughout the Great Lakes and inland waterways, it is being displaced by the quagga mussel Dreissena bugensis in shallow water habitats. However, zebra mussels remain dominant in areas with higher water velocity. We hypothesized that the persistence of zebra over quagga mussels in habitats with higher water velocity might result from greater rate and strength of byssal thread attachment. We examined whether zebra mussels relative to quagga mussels have: (1) higher byssal thread synthesis rate, (2) lower dislodgment in flow and (3) greater mechanical force required for detachment from substrate. Specifically, we examined byssal thread synthesis rate and dislodgment of both species in response to water velocities of 0, 50, 100 and 180 cm s(-1). Byssal thread synthesis rate was significantly higher for zebra than for quagga mussels at all velocities. Dislodgment from the substrate increased for both species with increasing velocity but was significantly lower for zebra than for quagga mussels. We also tested the mechanical force to detach mussels after short (32 h) and long (two and three months) periods of attachment on hard substrate. Detachment force was significantly higher for zebra than for quagga mussels only after short-term attachment. Higher byssal thread synthesis rate in zebra mussels was a likely factor that minimized their dislodgment in flow and increased short-term attachment strength. Differences in byssal thread synthesis rate between the two species might partly account for the ability of zebra mussels to maintain dominance over quagga mussels in habitats with high velocities.

  2. A dominance shift from the zebra mussel to the invasive quagga mussel may alter the trophic transfer of metals.

    Science.gov (United States)

    Matthews, Jonathan; Schipper, Aafke M; Hendriks, A Jan; Yen Le, T T; Bij de Vaate, Abraham; van der Velde, Gerard; Leuven, Rob S E W

    2015-08-01

    Bioinvasions are a major cause of biodiversity and ecosystem changes. The rapid range expansion of the invasive quagga mussel (Dreissena rostriformis bugensis) causing a dominance shift from zebra mussels (Dreissena polymorpha) to quagga mussels, may alter the risk of secondary poisoning to predators. Mussel samples were collected from various water bodies in the Netherlands, divided into size classes, and analysed for metal concentrations. Concentrations of nickel and copper in quagga mussels were significantly lower than in zebra mussels overall. In lakes, quagga mussels contained significantly higher concentrations of aluminium, iron and lead yet significantly lower concentrations of zinc66, cadmium111, copper, nickel, cobalt and molybdenum than zebra mussels. In the river water type quagga mussel soft tissues contained significantly lower concentrations of zinc66. Our results suggest that a dominance shift from zebra to quagga mussels may reduce metal exposure of predator species. Copyright © 2015 Elsevier Ltd. All rights reserved.

  3. 15 CFR 785.17 - Settlement.

    Science.gov (United States)

    2010-01-01

    ... 15 Commerce and Foreign Trade 2 2010-01-01 2010-01-01 false Settlement. 785.17 Section 785.17... Settlement. (a) Settlements before issuance of a NOVA. When the parties have agreed to a settlement of the case prior to issuance of a NOVA, a settlement proposal consisting of a settlement agreement and order...

  4. Sanitation in informal settlements

    DEFF Research Database (Denmark)

    Unterrainer, Walter

    2015-01-01

    and to cure when having the right means. This is a humanitarian scandal. In Dharavi / Mumbai, an estimated 700.000 people live and work on less than 250 hectares in a hybrid mix of formal and informal settlement. According to an UN report, in 2006 one toilet seat existed for 1440 dwellers while...

  5. TARGET 2 and Settlement Finality

    Directory of Open Access Journals (Sweden)

    Ivan MANGATCHEV

    2011-03-01

    Full Text Available This article examines how TARGET 2 as system implements the idea of settlement finality regulated by Directive 98/26 EC of the European parliament and of the Council of 19 May 1998 on settlement finality in payment and securities settlement systems (Settlement Finality Directive and Directive 2009/44/EC of the European parliament and of the Council of 6 May 2009 amending Directive 98/26/EC on settlement finality in payment and securities settlement systems and Directive 2002/47/EC on financial collateral arrangements as regards linked systems and credit claims (Directive 2009/44/EC. As the title of the arti and finality of the settlement in this system.

  6. Environmentally Safe Control of Zebra Mussel Fouling

    Energy Technology Data Exchange (ETDEWEB)

    Daniel Molloy

    2008-02-29

    The two primary objectives of this USDOE-NETL contract were successfully achieved during the project: (1) to accelerate research on the development of the bacterium Pseudomonas fluorescens strain CL145A (Pf-CL145A) as a biocontrol agent for zebra mussels (Dreissena polymorpha) and quagga mussels (Dreissena rostriformis bugensis)--two invasive freshwater bivalve species that are infesting water pipes in power plants; and (2) to identify a private-sector company that would move forward to commercialize Pf-CL145A as a substitute for the current polluting use of biocide chemicals for control of these dreissenid mussels in power plant pipes.

  7. Naturally acidified habitat selects for ocean acidification-tolerant mussels.

    Science.gov (United States)

    Thomsen, Jörn; Stapp, Laura S; Haynert, Kristin; Schade, Hanna; Danelli, Maria; Lannig, Gisela; Wegner, K Mathias; Melzner, Frank

    2017-04-01

    Ocean acidification severely affects bivalves, especially their larval stages. Consequently, the fate of this ecologically and economically important group depends on the capacity and rate of evolutionary adaptation to altered ocean carbonate chemistry. We document successful settlement of wild mussel larvae ( Mytilus edulis ) in a periodically CO 2 -enriched habitat. The larval fitness of the population originating from the CO 2 -enriched habitat was compared to the response of a population from a nonenriched habitat in a common garden experiment. The high CO 2 -adapted population showed higher fitness under elevated P co 2 (partial pressure of CO 2 ) than the non-adapted cohort, demonstrating, for the first time, an evolutionary response of a natural mussel population to ocean acidification. To assess the rate of adaptation, we performed a selection experiment over three generations. CO 2 tolerance differed substantially between the families within the F 1 generation, and survival was drastically decreased in the highest, yet realistic, P co 2 treatment. Selection of CO 2 -tolerant F 1 animals resulted in higher calcification performance of F 2 larvae during early shell formation but did not improve overall survival. Our results thus reveal significant short-term selective responses of traits directly affected by ocean acidification and long-term adaptation potential in a key bivalve species. Because immediate response to selection did not directly translate into increased fitness, multigenerational studies need to take into consideration the multivariate nature of selection acting in natural habitats. Combinations of short-term selection with long-term adaptation in populations from CO 2 -enriched versus nonenriched natural habitats represent promising approaches for estimating adaptive potential of organisms facing global change.

  8. National Status and Trends: Mussel Watch Program

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Mussel Watch is the longest running continuous chemical contaminant monitoring program in U.S. coastal and Great Lakes waters and was created in response to concerns...

  9. National Status and Trends: Mussel Watch Project

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Mussel Watch represents the longest running continuous contaminant monitoring program in U.S. coastal and Great Lakes waters and was created in response to concerns...

  10. Native Freshwater Fish and Mussel Species Richness

    Data.gov (United States)

    U.S. Environmental Protection Agency — These data represent predicted current distributions of all native freshwater fish and freshwater mussels in the Middle-Atlantic region. The data are available for...

  11. The zebra mussel; El mejillon cebra

    Energy Technology Data Exchange (ETDEWEB)

    Bertran, A.; Esparza, J.L.; Munte, L.

    2010-07-01

    The aim of this article is, on the one hand, to provide information about the zebra mussel, its behavior, its effect on the ecosystem and the problems it poses for industry (especially in the CNA cooling systems) and, on the other hand, to review the strategies and technologies needed to control de mussel and to present the solution adopted by the power plant to combat the plague. (Author).

  12. 29 CFR 102.151 - Settlement.

    Science.gov (United States)

    2010-07-01

    ... 29 Labor 2 2010-07-01 2010-07-01 false Settlement. 102.151 Section 102.151 Labor Regulations... Expenses § 102.151 Settlement. The applicant and the General Counsel may agree on a proposed settlement of... on a proposed settlement of an award before an application has been filed, the proposed settlement...

  13. 17 CFR 10.108 - Settlements.

    Science.gov (United States)

    2010-04-01

    ... 17 Commodity and Securities Exchanges 1 2010-04-01 2010-04-01 false Settlements. 10.108 Section 10... to the Commission; Settlements § 10.108 Settlements. (a) When offers may be made. Parties may at any time during the course of the proceeding propose offers of settlement. All offers of settlement shall...

  14. 33 CFR 20.502 - Settlements.

    Science.gov (United States)

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Settlements. 20.502 Section 20... Settlements § 20.502 Settlements. (a) The parties may submit a proposed settlement to the ALJ. (b) The proposed settlement must be in the form of a proposed decision, accompanied by a motion for its entry. The...

  15. 15 CFR 719.19 - Settlement.

    Science.gov (United States)

    2010-01-01

    ... 15 Commerce and Foreign Trade 2 2010-01-01 2010-01-01 false Settlement. 719.19 Section 719.19... Settlement. (a) Settlements before issuance of a NOVA. When the parties have agreed to a settlement of the case, the Director of the Office of Export Enforcement will recommend the settlement to the Secretary...

  16. GEOGRAPHIC INFORMATION SYSTEM-BASED MODELING AND ANALYSIS FOR SITE SELECTION OF GREEN MUSSEL, Perna viridis, MARICULTURE IN LADA BAY, PANDEGLANG, BANTEN PROVINCE

    Directory of Open Access Journals (Sweden)

    I Nyoman Radiarta

    2011-06-01

    Full Text Available Green mussel is one of important species cultured in Lada Bay, Pandeglang. To provide a necessary guidance regarding green mussel mariculture development, finding suitable site is an important step. This study was conducted to identify suitable site for green mussel mariculture development using geographic information system (GIS based models. Seven important parameters were grouped into two submodels, namely environmental (water temperature, salinity, suspended solid, dissolve oxygen, and bathymetry and infrastructural (distance to settlement and pond aquaculture. A constraint data was used to exclude the area from suitability maps that cannot be allowed to develop green mussel mariculture, including area of floating net fishing activity and area near electricity station. Analyses of factors and constraints indicated that about 31% of potential area with bottom depth less than 25 m had the most suitable area. This area was shown to have an ideal condition for green mussel mariculture in this study region. This study shows that GIS model is a powerful tool for site selection decision making. The tool can be a valuable tool in solving problems in local, regional, and/or continent areas.

  17. Bacterial contamination of mussels at Mahe estuary, Malabar coast

    Digital Repository Service at National Institute of Oceanography (India)

    Gore, P.S.; Raveendran, O.; Iyer, T.S.G.; Varma, P.R.G.; Sankaranarayanan, V.N.

    Mussel samples from the mussel bed and near-by market, beach sand, sediment and water from the Mahe Estuary, Kerala, India were analysed for the bacterial quality. Indicator bacteria such as Escherichia coli and faecal streptococci were isolated...

  18. Quagga and zebra mussels: biology, impacts, and control

    Science.gov (United States)

    Nalepa, Thomas F.; Schloesser, Don W.; Nalepa, Thomas F.; Schloesser, Don W.

    2013-01-01

    Quagga and Zebra Mussels: Biology, Impacts, and Control, Second Edition provides a broad view of the zebra/quagga mussel issue, offering a historic perspective and up-to-date information on mussel research. Comprising 48 chapters, this second edition includes reviews of mussel morphology, physiology, and behavior. It details mussel distribution and spread in Europe and across North America, and examines policy and regulatory responses, management strategies, and mitigation efforts. In addition, this book provides extensive coverage of the impact of invasive mussel species on freshwater ecosystems, including effects on water clarity, phytoplankton, water quality, food web changes, and consequences to other aquatic fauna. It also reviews and offers new insights on how zebra and quagga mussels respond and adapt to varying environmental conditions. This new edition includes seven video clips that complement chapter text and, through visual documentation, provide a greater understanding of mussel behavior and distribution.

  19. Cheating the Locals: Invasive Mussels Steal and Benefit from the Cooling Effect of Indigenous Mussels.

    Directory of Open Access Journals (Sweden)

    Justin A Lathlean

    Full Text Available The indigenous South African mussel Perna perna gapes during periods of aerial exposure to maintain aerobic respiration. This behaviour has no effect on the body temperatures of isolated individuals, but when surrounded by conspecifics, beneficial cooling effects of gaping emerge. It is uncertain, however, whether the presence of the invasive mussel Mytilus galloprovincialis limits the ability of P. perna for collective thermoregulation. We investigated whether varying densities of P. perna and M. galloprovincialis influences the thermal properties of both natural and artificial mussel beds during periods of emersion. Using infrared thermography, body temperatures of P. perna within mixed artificial beds were shown to increase faster and reach higher temperatures than individuals in conspecific beds, indicating that the presence of M. galloprovincialis limits the group cooling effects of gaping. In contrast, body temperatures of M. galloprovincialis within mixed artificial mussel beds increased slower and exhibited lower temperatures than for individuals in beds comprised entirely of M. galloprovincialis. Interestingly, differences in bed temperatures and heating rates were largely dependent on the size of mussels, with beds comprised of larger individuals experiencing less thermal stress irrespective of species composition. The small-scale patterns of thermal stress detected within manipulated beds were not observed within naturally occurring mixed mussel beds. We propose that small-scale differences in topography, size-structure, mussel bed size and the presence of organisms encrusting the mussel shells mask the effects of gaping behaviour within natural mussel beds. Nevertheless, the results from our manipulative experiment indicate that the invasive species M. galloprovincialis steals thermal properties as well as resources from the indigenous mussel P. perna. This may have significant implications for predicting how the co-existence of

  20. Bibliography of Dreissena polymorpha (zebra mussels) and Dreissena rostriformis Bugensis (QUAGGA mussels): 1989 to 2011

    Science.gov (United States)

    Schloesser, Don W.; Schmuckal, Christine

    2012-01-01

    Dreissenid mussels invaded and colonized waters of the Laurentian Great Lakes during the late 1980s. Their colonization and resulting impact have been characterized as one of the most important ecological changes in freshwater systems in North America. The need for information on dreissenid mussels has grown during the past 2 decades, which has prompted the compilation of this bibliography. Two previous bibliographies of dreissenid mussels indicate average publication rates were 6 publications/year between 1771 and 1964 (1,180 in 194 y) and 30 publications/year between 1964 and 1993 (885 in 30 y). In the current bibliography, the average rate of publication doubled during the past 23 y (1989 to 2011) to 66 publications/year based on a total of 1,502 publications. These rates may be biased by increased numbers of researchers and journals over time but, at a minimum, these rates indicate continued interest and concern by humans about the impact of dreissenid mussels on water availability and the expanding range of dreissenids throughout the world. The current bibliography has a 94% efficiency rate for subject and 100% efficiency for title search criteria when compared with references in published studies of dreissenid mussels in 2011. In addition to publications, we included 206 student theses and 225 chapters in 26 books including 6 books devoted solely to dreissenid mussels. A vast majority of student theses were about dreissenid mussels in North America, especially in the Laurentian Great Lakes. The 6 books devoted to dreissenid mussels contained a variety of chapters that described biology, impact, control, and ecology of dreissenid mussels in both Europe (published in 1992 and 2010) and North America (1993, 1994, 1997, and 2000). In addition, there is a 7th book devoted solely to dreissenid mussels that is near completion.

  1. The Settlement Utopia

    DEFF Research Database (Denmark)

    Villadsen, Kaspar

    2016-01-01

    terms. This article explores the trajectory of the comparatively under-researched Danish offspring of the movement. It demonstrates the tempering and compromise that occurred when utopian ideals of ‘brotherly love’, ‘God’s Kingdom’, and ‘radical social change’ were realized in concrete social...... arrangements. Contradictions and ambiguities arose when utopian ideas were confronted with what could be done. The Settlement became a highly ambiguous space, a ‘heterotopia’. The roots of the contradictions cannot simply be identified in the external pressure of legal requirements and funding criteria...

  2. Trust Mines: Legal Documents and Settlements

    Science.gov (United States)

    Legal Documents and Settlements related to the Northern Abandoned Uranium Mines Region including the Phase 1 Settlement Agreement and Environmental Response Trust Agreement, Phase 2 Settlement Agreement Removal Site Evaluation (RSE) Trust Agreement.

  3. 76 FR 42625 - International Settlements Policy Reform

    Science.gov (United States)

    2011-07-19

    ...] International Settlements Policy Reform AGENCY: Federal Communications Commission. ACTION: Notice of proposed rulemaking. SUMMARY: The Federal Communications Commission proposes to remove the International Settlements... proposes to remove the International Settlements Policy (ISP) from all U.S. international routes except...

  4. Subsistence and recreational mussel ( Perna perna ) collecting in ...

    African Journals Online (AJOL)

    Natal. The former collect 200–2501 of mussels annually from about 110 km of rocky shore and the latter 12–501 from 3 km of rocky shore. Recreational collectors are subject to a daily bag limit of 50 mussels and so select larger mussels than ...

  5. Length- and weight-dependent clearance rates of juvenile mussels (

    NARCIS (Netherlands)

    Jacobs, P.; Troost, K.; Riegman, R.; van der Meer, J.

    2015-01-01

    Filtration capacity and feeding behaviour has been intensely studied for adult mussels (Mytilus edulis), but less information is available for juvenile mussels (1.5–25 mm, <1 year), especially in natural sea water. The recent introduction of mussel seed collectors in the Netherlands prompted the

  6. Zebra Mussels Pose a Threat to Virginia's Waters

    OpenAIRE

    Helfrich, Louis A. (Louis Anthony), 1942-; Weigmann, Diana L.; Speenburgh, Renee M.; Neves, Richard J.; Kitchel, Lisie; Bruenderman, Sue A., 1962-

    2005-01-01

    Provides an brief introduction to the invasion of the zebra mussel into American waters, explains the economic consequences they pose, and discusses if Virginia will inherit the problem, what the public can do to help, the general lifecycle of the zebra mussel and if they can be controlled, and who is working on the zebra mussel problem.

  7. Aggregation and attachment responses of blue mussels, Mytilus edulis—impact of substrate composition, time scale and source of mussel seed

    DEFF Research Database (Denmark)

    Christensen, Helle Torp; Dolmer, Per; Hansen, Benni Winding

    2015-01-01

    to an optimization of the production. The effect of substrate composition and timing of formation of a mussel bed in relation to aggregation and attachment of mussels were investigated with mussel seeds obtained from two different sources: mussel seed dredged from a natural mussel bed and mussel seed collected from......Survival after transplantation of mussel seeds is crucial for the production output of blue mussels (Mytilus edulis L.) in bottom cultures. Hence, an understanding of the interactions between bed formation, habitat structure and performance of mussel seed of different origins can contribute...... showed that complex substrate indeed had a stabilizing effect on the mussel structure resulting in less aggregation and increased attachment strength. The 3D matrix forming a mussel bed was achieved faster on complex substrate, and led to reduced mortality of transplanted mussels. Despite significantly...

  8. Requirements for Space Settlement Design

    Science.gov (United States)

    Gale, Anita E.; Edwards, Richard P.

    2004-02-01

    When large space settlements are finally built, inevitably the customers who pay for them will start the process by specifying requirements with a Request for Proposal (RFP). Although we are decades away from seeing the first of these documents, some of their contents can be anticipated now, and provide insight into the variety of elements that must be researched and developed before space settlements can happen. Space Settlement Design Competitions for High School students present design challenges in the form of RFPs, which predict basic requirements for space settlement attributes in the future, including structural features, infrastructure, living conveniences, computers, business areas, and safety. These requirements are generically summarized, and unique requirements are noted for specific space settlement locations and applications.

  9. Review of techniques to prevent introduction of zebra mussels (Dreissena polymorpha) during native mussel (Unionoidea) conservation activities

    Science.gov (United States)

    Cope, W.G.; Newton, T.J.; Gatenby, C.M.

    2003-01-01

    Because of the declines in diversity and abundance of native freshwater mussels (superfamily Unionoidea), and the potential decimation of populations of native mussels resulting from the rapid spread of the exotic zebra mussel Dreissena polymorpha, management options to eliminate or reduce the threat of the zebra mussel are needed. Relocating native mussels to refugia (artificial and natural) has been proposed to mitigate the threat of zebra mussels to native species. Relocation of native mussels to refugia such as fish hatchery facilities or natural habitats within their historic range. Which are unlikely to be infested by zebra mussels, necessitates that protocols be developed to prevent the inadvertent introduction of zebra mussels. Several recent studies have developed Such protocols, and have assessed their effectiveness on the health and survival of native mussels during subsequent relocation to various refugia. The purpose of this project is to synthesize and evaluate the current protocols and to develop a set of procedures that resource managers and researchers should consider before conducting conservation activities in zebra mussel infested waters. We found that the existing protocols have many common points of concern, such as facility modification and suitability, zebra mussel risk assessment and management procedures, and health and disease management procedures. These conservation protocols may have broad applicability to other situations and locations. A summary and evaluation of the information in these main areas, along with recommended guidelines, are presented in this article.

  10. EPRI's zebra mussel monitoring and control guidelines

    International Nuclear Information System (INIS)

    Mussalli, Y.G.; Armor, A.; Edwards, R.; Mattice, J.; Miller, M.; Nott, B.; Tsou, J.L.

    1992-01-01

    The Electric Power Research Institute (EPRI) Zebra Mussel Monitoring and Control Guidelines is a comprehensive compilation of US and European practices. The zebra mussel has infested all the Great Lakes and is positioned to spread to the adjoining river basins. The impact of the zebra mussel on power plants is as a biofouler clogging water systems and heat exchangers. The EPRI guidelines discuss the distribution of the zebra mussel in the US, identification of the zebra mussel, potential threats to power plants, and methods to initiate the monitoring and control program. Both preventive and corrective measures are presented. Preventive measures include various monitoring methods to initiate control techniques. The control techniques include both chemical and nonchemical together with combining techniques. Corrective methods include operational considerations, chemical cleaning, and mechanical/physical cleaning. It may also be possible to incorporate design changes, such as open to closed-loop backfit, backflushing, or pretreatment for closed systems. Table 1 shows a matrix of the monitoring methods. Table 2 presents a control matrix related to nuclear, fossil, and hydro raw water systems. Table 3 is a summary of the applicability of treatments to the various raw water systems. Appendixes are included that contain specifications to aid utilities in implementing several of the control technologies

  11. Changing perspectives on pearly mussels, North America's most imperiled animals

    Science.gov (United States)

    Strayer, David L.; Downing, John A.; Haag, Wendell R.; King, Timothy L.; Layzer, James B.; Newton, Teresa J.; Nichols, S. Jerrine

    2004-01-01

    Pearly mussels (Unionacea) are widespread, abundant, and important in freshwater ecosystems around the world. Catastrophic declines in pearly mussel populations in North America and other parts of the world have led to a flurry of research on mussel biology, ecology, and conservation. Recent research on mussel feeding, life history, spatial patterning, and declines has augmented, modified, or overturned long-held ideas about the ecology of these animals. Pearly mussel research has begun to benefit from and contribute to current ideas about suspension feeding, life-history theory, metapopulations, flow refuges, spatial patterning and its effects, and management of endangered species. At the same time, significant gaps in understanding and apparent paradoxes in pearly mussel ecology have been exposed. To conserve remaining mussel populations, scientists and managers must simultaneously and aggressively pursue both rigorous research and conservation actions.

  12. Zebra mussels enter the compost pile

    Energy Technology Data Exchange (ETDEWEB)

    1992-08-01

    Zebra mussels, introduced accidentally into the Great Lakes, are overpopulating at phenomenal rates, especially in Lake Erie, where they damage oyster beds, foster excessive algae growth and cling to boats. They also clog the intake pipes of city water systems and power generating plants. The expense of cleaning intake screens is considerable, since they have to be physically removed and cleaned. Then the mussels must be disposed of, costing some power plants as much as $50,000 a year to landfill, says Wayne Koser of the Michigan Department of Natural Resources.

  13. Scope of problem assessed at IVO. The zebra mussel`s campaign of world conquest

    Energy Technology Data Exchange (ETDEWEB)

    Silvonen, J; Oesch, P [ed.

    1998-07-01

    The migrating shell - or `zebra mussel` as it is called on account of its black and white stripes - was originally a fresh-water mussel, but has since also adapted to brackish waters. As a result of human activity the species has spread quickly and widely from its native habitat. Operators of power plants and water treatment plants in particular have not been very happy about this. During its larval stage the zebra mussel can enter the cooling water systems; fasten itself to the pipes and - in the worst case - clog the system. The Environmental Protection Division of IVO has been assessing the spread of the zebra mussel and the resulting problems with the aid of reference literature and the assistance of Finnish researchers

  14. Fortified settlement Veletin

    Directory of Open Access Journals (Sweden)

    Jovanović Vojislav S.

    2003-01-01

    Full Text Available Remnants of the fortified settlement Veletin are located on a hill of the same name (map marking 969 near the small town Janjevo, in the vicinity of the Monastery Gračanica in Kosovo, in a region rich in metal ore (pic. 1-3. Veletin is mentioned for the first time as a landmark in King Milutin’s charter for the Monastery Gračanica issued in 1321. Namely, the boundary of villages donated to the monastery ran "from Oštri vrh on Veletjen between Sušica and between Gušterica". Villages of Sušica and Gušterica still exist under the same names. The mentioned Veletin refers to the hill with a fortified settlement or fortress at the top. In the past the hill and the fortress were for a long time a characteristic part of the historical landscape. Thanks to its favourable geostrategic position, vicinity of important roads and above all to the nearness of rich silver mines, the hill of Veletin was settled and fortified in pre-historic time, then in antiquity and in the middle ages. It is supposed that the Roman town Ulpiana (Justiniana Secunda, near the Monastery Gračanica, developed because of the vicinity of silver mines and that as a municipium became a center of administration of Janjevo - Novo Brdo metals in the II c. Mining reached its peak in this area only in the first half of the XV c., during the reign of Serbian despots. When this part of Serbia fell under Turkish rule in 1455, mining began to decline. In 1488, during the reign of Sultan Bajazet II, special regulations were made for the organization of work in Janjevo silver mines, which testify about their importance. It is hard to form an opinion about the appearance of Veletin at the time the Gračanica Charter was issued. Mining was growing at that time and it is possible that there was a fortress with a small crew to protect Janjevo and other nearby mining settlements. Veletin is explicitly mentioned as a fortress only in three cartographic sources of a later date. The first was

  15. 7 CFR 1427.21 - Settlement.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 10 2010-01-01 2010-01-01 false Settlement. 1427.21 Section 1427.21 Agriculture... § 1427.21 Settlement. (a) The settlement of cotton loans will be made by CCC on the basis of the quality... maximum storage credit rates as determined and announced by CCC. (b) For purposes of settlements for...

  16. 39 CFR 962.26 - Settlement.

    Science.gov (United States)

    2010-07-01

    ... 39 Postal Service 1 2010-07-01 2010-07-01 false Settlement. 962.26 Section 962.26 Postal Service... CIVIL REMEDIES ACT § 962.26 Settlement. (a) Either party may make offers of settlement or proposals of... settlement terms to the Attorney General, as appropriate. [59 FR 51860, Oct. 13, 1994] ...

  17. 49 CFR 1016.306 - Settlement.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 8 2010-10-01 2010-10-01 false Settlement. 1016.306 Section 1016.306... Settlement. The applicant and agency counsel may agree on a proposed settlement of the award before final action on the application, either in connection with a settlement of the underlying proceeding, or after...

  18. 49 CFR 826.35 - Settlement.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 7 2010-10-01 2010-10-01 false Settlement. 826.35 Section 826.35 Transportation... Settlement. The applicant and agency counsel may agree on a proposed settlement of the award before final action on the application, either in connection with a settlement of the underlying proceeding, or after...

  19. 17 CFR 148.25 - Settlement.

    Science.gov (United States)

    2010-04-01

    ... 17 Commodity and Securities Exchanges 1 2010-04-01 2010-04-01 false Settlement. 148.25 Section 148... Considering Applications § 148.25 Settlement. The applicant may propose settlement of the award to the Commission before final action on the application, either in connection with a settlement of the adjudicatory...

  20. 49 CFR 511.26 - Settlement.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 6 2010-10-01 2010-10-01 false Settlement. 511.26 Section 511.26 Transportation...; Summary Judgment; Settlement § 511.26 Settlement. (a) Applicability. This section applies only to cases of..., 89 Stat. 911 (15 U.S.C. section 2007(3)). Settlement in other cases may be made only in accordance...

  1. 31 CFR 501.710 - Settlement.

    Science.gov (United States)

    2010-07-01

    ... 31 Money and Finance: Treasury 3 2010-07-01 2010-07-01 false Settlement. 501.710 Section 501.710... the Enemy Act (TWEA) Penalties § 501.710 Settlement. (a) Availability. Either the Director or any..., propose an offer of settlement. The amount accepted in settlement may be less than the civil penalty that...

  2. 47 CFR 1.1525 - Settlement.

    Science.gov (United States)

    2010-10-01

    ... 47 Telecommunication 1 2010-10-01 2010-10-01 false Settlement. 1.1525 Section 1.1525... Settlement. The applicant and Bureau counsel may agree on a proposed settlement of the award before final action on the application, either in connection with a settlement of the underlying proceeding, or after...

  3. 7 CFR 1.198 - Settlement.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 1 2010-01-01 2010-01-01 false Settlement. 1.198 Section 1.198 Agriculture Office of....198 Settlement. The applicant and agency counsel may agree on a proposed settlement of the award before final action on the application, either in connection with a settlement of the underlying...

  4. 24 CFR 14.320 - Settlement.

    Science.gov (United States)

    2010-04-01

    ... 24 Housing and Urban Development 1 2010-04-01 2010-04-01 false Settlement. 14.320 Section 14.320... Applications § 14.320 Settlement. The applicant and agency counsel may agree on a proposed settlement of the award before final action on the application, either in connection with a settlement of the underlying...

  5. 10 CFR 851.41 - Settlement.

    Science.gov (United States)

    2010-01-01

    ... 10 Energy 4 2010-01-01 2010-01-01 false Settlement. 851.41 Section 851.41 Energy DEPARTMENT OF ENERGY WORKER SAFETY AND HEALTH PROGRAM Enforcement Process § 851.41 Settlement. (a) DOE encourages settlement of a proceeding under this subpart at any time if the settlement is consistent with this part. The...

  6. 29 CFR 2200.100 - Settlement.

    Science.gov (United States)

    2010-07-01

    ... 29 Labor 9 2010-07-01 2010-07-01 false Settlement. 2200.100 Section 2200.100 Labor Regulations... Miscellaneous Provisions § 2200.100 Settlement. (a) Policy. Settlement is permitted and encouraged by the... parties include any particular language in a settlement agreement, but does require that the agreement...

  7. 14 CFR 15.109 - Settlements.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Settlements. 15.109 Section 15.109... Act of 1958 § 15.109 Settlements. (a) A publisher may not settle a claim with another party, for which... publisher submits a copy of the proposed settlement, and a statement justifying the settlement, to the Chief...

  8. 16 CFR 1025.26 - Settlements.

    Science.gov (United States)

    2010-01-01

    ... 16 Commercial Practices 2 2010-01-01 2010-01-01 false Settlements. 1025.26 Section 1025.26... PROCEEDINGS Prehearing Procedures, Motions, Interlocutory Appeals, Summary Judgments, Settlements § 1025.26 Settlements. (a) Availability. Any party shall have the opportunity to submit an offer of settlement to the...

  9. 10 CFR 12.305 - Settlement.

    Science.gov (United States)

    2010-01-01

    ... 10 Energy 1 2010-01-01 2010-01-01 false Settlement. 12.305 Section 12.305 Energy NUCLEAR... Considering Applications § 12.305 Settlement. The applicant and the NRC counsel may agree on a proposed settlement of the award before final action on the application, either in connection with a settlement of the...

  10. 10 CFR 590.309 - Settlements.

    Science.gov (United States)

    2010-01-01

    ... 10 Energy 4 2010-01-01 2010-01-01 false Settlements. 590.309 Section 590.309 Energy DEPARTMENT OF... RESPECT TO THE IMPORT AND EXPORT OF NATURAL GAS Procedures § 590.309 Settlements. The parties may conduct settlement negotiations. If settlement negotiations are conducted during a conference, at the request of one...

  11. 7 CFR 1434.19 - Settlement.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 10 2010-01-01 2010-01-01 false Settlement. 1434.19 Section 1434.19 Agriculture... FOR HONEY § 1434.19 Settlement. The value of the settlement of loans shall be made by CCC on the... commodity: (1) If the value of the collateral at settlement is less than the amount due, the producer shall...

  12. 17 CFR 171.12 - Settlement.

    Science.gov (United States)

    2010-04-01

    ... 17 Commodity and Securities Exchanges 1 2010-04-01 2010-04-01 false Settlement. 171.12 Section 171... RESPONSIBILITY ACTIONS General Provisions § 171.12 Settlement. At any time before the Commission has reached a... settlement agreement. If, in its view, the settlement is consistent with the public interest, the Commission...

  13. 12 CFR 747.612 - Settlement.

    Science.gov (United States)

    2010-01-01

    ... 12 Banks and Banking 6 2010-01-01 2010-01-01 false Settlement. 747.612 Section 747.612 Banks and... Board Adjudications § 747.612 Settlement. The applicant and counsel for NCUA may agree on a proposed settlement of the award before final action on the application, either in connection with a settlement of the...

  14. 29 CFR 18.9 - Consent order or settlement; settlement judge procedure.

    Science.gov (United States)

    2010-07-01

    ... has sole discretion to decide whether to appoint a settlement judge, except that a settlement judge... assigned to hear and decide the case. (ii) The settlement judge shall not be appointed to hear and decide... 29 Labor 1 2010-07-01 2010-07-01 true Consent order or settlement; settlement judge procedure. 18...

  15. Settlement of uranium mill tailings

    International Nuclear Information System (INIS)

    Chen, P.K.; Guros, F.B.; Keshian, B.

    1988-01-01

    Two test embankments were constructed on top of an old tailings deposit near Ambrosia Lake, New Mexico to determine settlement characteristics of hydraulically- deposited uranium mill tailings. Before construction of the embankments, properties of in-situ tailings and foundation soils were determined using data from boreholes, piezocone soundings, and laboratory tests. These properties were used to estimate post-construction settlement of a planned disposal embankment to be constructed on the tailings. However, excessive uncertainty existed in the following: field settlement rates of saturated and unsaturated tailings, degree of preconsolidation of the upper 15 feet of tailings, and the ability of an underlying silty sand foundation layer to facilitate drainage. Thus, assurance could not be provided that differential settlements of the radon barrier and erosion protection layers would be within allowable limits should the planned disposal embankment be constructed in a single-stage

  16. Learning to live with zebra mussels

    International Nuclear Information System (INIS)

    Anon.

    1993-01-01

    Fingernail-sized mollusks from Europe pose a threat to Clean Coal Technology demonstration projects. This article describes the mussels life cycle and behavior, fouling of utility water systems, and effective methods of control, including chemical treatment, thermal treatment, mechanical treatment, and coatings

  17. Immune Response in Mussels To Environmental Pollution.

    Science.gov (United States)

    Pryor, Stephen C.; Facher, Evan

    1997-01-01

    Describes the use of mussels in measuring the extent of chemical contamination and its variation in different coastal regions. Presents an experiment to introduce students to immune response and the effects of environmental pollution on marine organisms. Contains 14 references. (JRH)

  18. Freshwater mussel response to bedform movement: experimental stream studies

    Science.gov (United States)

    Kozarek, J. L.; MacGregor, K. R.; Hornbach, D.; Hove, M.

    2017-12-01

    Freshwater mussels are intrinsically linked to near-bed sediment dynamics, but it remains unclear how mussels respond to changing sediment loads across spatial and temporal scales. The interactions between mussels and sediment transport are complex and often involve feedback loops. Mussels are filter feeders removing suspended particles from the water column and the physical presence of mussels can have significant impacts on the structure of riverbed habitat. We investigated the feedbacks between mussels, flow, and migrating bedforms during flood experiments in the St. Anthony Falls Laboratory Outdoor StreamLab (OSL) at the University of Minnesota. The OSL is a field-scale sand-bed meandering stream channel with independent control over sediment feed (recirculated) and water flow (diverted from the Mississippi River). Mussel location, orientation to flow, and protrusion from sediment was surveyed immediately before, after, and one and two days after each flood event. Flow fields, bed shear stress, bedform migration, and bar topography were measured during each flooding event with and without mussels present (density = 4/m2 and 8/m2) to quantify the influence of mussels on channel morphology and bedform migration. Mobile bedforms (up to 14 cm high) were present for all flood events with quasi-equilibrium, aggrading, and degrading bed conditions. Mussels moved little horizontally during all flood events, but were shown to move quickly to deeper water after the flood receded. However, mussels moved vertically, burrowing or being buried under mobile bedforms, during each flood event. The research presented here will focus on feedbacks between three mussel species with different shell sculptures, flow conditions, and migrating bedforms during flooding events. These results reveal how freshwater mussels respond to and affect flow and sediment transport during flood events that are difficult to observe in the field.

  19. Crustacean fauna of a mussel cultivated raft system in the Black Sea

    Directory of Open Access Journals (Sweden)

    Murat Sezgin

    2013-06-01

    Full Text Available The aim of the current study was to make a faunistic analysis of the crustaceans associated with cultivated mussels grown on ropes. Mussel samples from 30 cm ropes were collected from rope-grown mussel beds by hand. The crustacean fauna associated with mussel population were quantified. The density of crustacean fauna associated with mussels was significantly greater within rope-grown mussel assemblages than on other biotopes around.

  20. Comparative study of predatory responses in blue mussels (Mytilus edulis L.) produced in suspended long line cultures or collected from natural bottom mussel beds

    DEFF Research Database (Denmark)

    Christensen, Helle Torp; Dolmer, Per; Petersen, Jens Kjerulf

    2011-01-01

    Blue mussels (Mytilus edulis L.) are a valuable resource for commercial shellfish production and may also have uses as a tool in habitat improvement, because mussel beds can increase habitat diversity and complexity. A prerequisite for both commercial mussel production and habitat improvement...... originated from suspended cultures had a higher length increment and lower mortality when compared to bottom mussels. It is concluded that suspended mussels potentially are an alternative resource to bottom culture and can be used in habitat improvement of mussel beds, but that the use of suspended mussels...

  1. Mussels (Mytilus sp.) as an indicator of lead pollution

    International Nuclear Information System (INIS)

    Chow, T.J.; Snyder, H.G.; Snyder, C.B.

    1976-01-01

    The lead contents of two species of mussels (Mytilus californianus and M. edulis) collected along the Pacific coast from Piedras Blancas, California to Punta Bnada, Baja California were determined by isotope dilution method. The whole soft parts of the mussels, on a dry weight basis, contained from 0.27 to 42 ppm of lead which can be related to their local habitats. The gill tissues of the mussels showed the highest lead concentration

  2. Will the Displacement of Zebra Mussels by Quagga Mussels Increase Water Clarity in Shallow Lakes during Summer? Results from a Mesocosm Experiment

    OpenAIRE

    Mei, Xueying; Zhang, Xiufeng; Kassam, Sinan-Saleh; Rudstam, Lars G.

    2016-01-01

    Zebra mussels (Dreissena polymorpha) are known to increase water clarity and affect ecosystem processes in invaded lakes. During the last decade, the conspecific quagga mussels (D. rostriformis bugensis) have displaced zebra mussels in many ecosystems including shallow lakes such as Oneida Lake, New York. In this study, an eight-week mesocosm experiment was conducted to test the hypothesis that the displacement of zebra mussels by quagga mussels leads to further decreases in phytoplankton and...

  3. Preliminary characterization of digestive enzymes in freshwater mussels

    Science.gov (United States)

    Sauey, Blake W.; Amberg, Jon J.; Cooper, Scott T.; Grunwald, Sandra K.; Newton, Teresa J.; Haro, Roger J.

    2015-01-01

    Resource managers lack an effective chemical tool to control the invasive zebra mussel Dreissena polymorpha. Zebra mussels clog water intakes for hydroelectric companies, harm unionid mussel species, and are believed to be a reservoir of avian botulism. Little is known about the digestive physiology of zebra mussels and unionid mussels. The enzymatic profile of the digestive glands of zebra mussels and native threeridge (Amblema plicata) and plain pocketbook mussels (Lampsilis cardium) are characterized using a commercial enzyme kit, api ZYM, and validated the kit with reagent-grade enzymes. A linear correlation was shown for only one of nineteen enzymes, tested between the api ZYM kit and a specific enzyme kit. Thus, the api ZYM kit should only be used to make general comparisons of enzyme presence and to observe trends in enzyme activities. Enzymatic trends were seen in the unionid mussel species, but not in zebra mussels sampled 32 days apart from the same location. Enzymatic classes, based on substrate, showed different trends, with proteolytic and phospholytic enzymes having the most change in relative enzyme activity.

  4. Forecasting the expansion of zebra mussels in the United States.

    Science.gov (United States)

    Bossenbroek, Jonathan M; Johnson, Ladd E; Peters, Brett; Lodge, David M

    2007-06-01

    Because zebra mussels spread rapidly throughout the eastern United States in the late 1980s and early 1990s, their spread to the western United States has been expected. Overland dispersal into inland lakes and reservoirs, however, has occurred at a much slower rate than earlier spread via connected, navigable waterways. We forecasted the potential western spread of zebra mussels by predicting the overland movement of recreational boaters with a production-constrained gravity model. We also predicted the potential abundance of zebra mussels in two western reservoirs by comparing their water chemistry characteristics with those of water bodies with known abundances of zebra mussels. Most boats coming from waters infested with zebra mussels were taken to areas that already had zebra mussels, but a small proportion of such boats did travel west of the 100th meridian. If zebra mussels do establish in western U.S. water bodies, we predict that population densities could achieve similar levels to those in the Midwestern United States, where zebra mussels have caused considerable economic and ecological impacts. Our analyses suggest that the dispersal of zebra mussels to the western United States is an event of low probability but potentially high impact on native biodiversity and human infrastructure. Combining these results with economic analyses could help determine appropriate investment levels in prevention and control strategies.

  5. Factors Affecting Zebra Mussel Kill by the Bacterium Pseudomonas fluorescens

    Energy Technology Data Exchange (ETDEWEB)

    Daniel P. Molloy

    2004-02-24

    The specific purpose of this research project was to identify factors that affect zebra mussel kill by the bacterium Pseudomonas fluorescens. Test results obtained during this three-year project identified the following key variables as affecting mussel kill: treatment concentration, treatment duration, mussel siphoning activity, dissolved oxygen concentration, water temperature, and naturally suspended particle load. Using this latter information, the project culminated in a series of pipe tests which achieved high mussel kill inside power plants under once-through conditions using service water in artificial pipes.

  6. Behavioral Responses of Concholepas concholepas (Bruguière, 1789) Larvae to Natural and Artificial Settlement Cues and Microbial Films.

    Science.gov (United States)

    Rodriguez, S R; Riquelme, C; Campos, E O; Chavez, P; Brandan, E; Inestrosa, N C

    1995-12-01

    The behavioral responses of veliger larvae of the gastropod Concholepas concholepas were studied in the presence of different natural and artificial settlement cues and microbial films. Early pre-competent larvae stopped swimming, sank (due to ciliary arrests, retraction of the velum into the shell, or both), and remained inactive on the substratum when exposed to conspecific mucus and hemolymph. In both cases the effect was time-dependent and the number of larvae showing these behaviors decreased over time. Larvae exposed to NH4Cl (ammonium ion) showed a similar time- and dose-dependent response. A positive and time-dependent response was also observed when larvae were exposed to different extracellular matrix (ECM) components (i.e., collagen, gelatin, and fibronectin) and sulfated polysaccharides (i.e., carrageenan, heparin, and chondroitin sulfate). In this case the larvae remained attached to the substratum. However, the effect of sulfated polysaccharides on C. concholepas larval behavior was faster than that observed with other ECM molecules. We also studied the responses of premetamorphic C. concholepas larvae exposed to different microbial films. In chemotaxis experiments with different films, with glass as the substratum, larvae showed a significant preference for multispecific and diatoms films. When shells of C. concholepas were used as the substratum, the preference for multispecific films was clear and significant. Likewise, larvae showed velar contractions in the presence of all the films tested. Larvae exposed to multispecific films and to the microalga Prasinocladus marinus showed an increased ciliar movement. The finding that mucus and hemolymph of conspecific adults and ECM molecules (mainly sulfated polysaccharides) induce the cessation of swimming of C. concholepas larvae suggests a possible role for cell-surface receptors in mediating the larval response of marine organisms. Likewise, the positive chemotaxis responses of C. concholepas larvae to

  7. The Initial Nine Space Settlements

    Science.gov (United States)

    Gale, Anita E.; Edwards, Richard P.

    2003-01-01

    The co-authors describe a chronology of space infrastructure development illustrating how each element of infrastructure enables development of subsequent more ambitious infrastructure. This is likened to the ``Southern California freeway phenomenon'', wherein a new freeway built in a remote area promotes establishment of gas stations, restaurants, hotels, housing, and eventually entire new communities. The chronology includes new launch vehicles, inter-orbit vehicles, multiple LEO space stations, lunar mining, on-orbit manufacturing, tourist destinations, and supporting technologies required to make it all happen. The space settlements encompassed by the chronology are in Earth orbit (L5 and L4), on the lunar surface, in Mars orbit, on the Martian surface, and in the asteroid belt. Each space settlement is justified with a business rationale for construction. This paper is based on materials developed for Space Settlement Design Competitions that enable high school students to experience the technical and management challenges of working on an industry proposal team.

  8. Ocean acidification impacts mussel control on biomineralisation.

    Science.gov (United States)

    Fitzer, Susan C; Phoenix, Vernon R; Cusack, Maggie; Kamenos, Nicholas A

    2014-08-28

    Ocean acidification is altering the oceanic carbonate saturation state and threatening the survival of marine calcifying organisms. Production of their calcium carbonate exoskeletons is dependent not only on the environmental seawater carbonate chemistry but also the ability to produce biominerals through proteins. We present shell growth and structural responses by the economically important marine calcifier Mytilus edulis to ocean acidification scenarios (380, 550, 750, 1000 µatm pCO2). After six months of incubation at 750 µatm pCO2, reduced carbonic anhydrase protein activity and shell growth occurs in M. edulis. Beyond that, at 1000 µatm pCO2, biomineralisation continued but with compensated metabolism of proteins and increased calcite growth. Mussel growth occurs at a cost to the structural integrity of the shell due to structural disorientation of calcite crystals. This loss of structural integrity could impact mussel shell strength and reduce protection from predators and changing environments.

  9. Obtainment of calcium carbonate from mussels shell

    International Nuclear Information System (INIS)

    Hamester, M.R.R.; Becker, D.

    2010-01-01

    The mussels and oyster shell are discarded at environment, and this accumulation is causing negative consequences to ecosystem. Calcium carbonate is main constituent of the shell chemical composition. Aiming to reduce environmental aggression and generate income to shellfish producer, there was the possibility of using these shells as an alternative to commercial calcium carbonate. For this physics, chemicals and thermal properties were evaluated, using X-ray fluorescence, thermogravimetric analysis, size distribution, abrasiveness and scanning electronic microscopy. The results indicate that mussels shells have an initial degradation temperature higher than commercial calcium carbonate e same lost weight behavior and 95% of shell chemical composition is calcium carbonate. The sample size distribution was influenced by grinding condition and time as well as its abrasiveness. (author)

  10. Monitoring informal settlements using SAR polarimetry

    CSIR Research Space (South Africa)

    Kleynhans, W

    2012-10-01

    Full Text Available for settlement mapping and detection has remained largely unexplored in Southern Africa. The objective of this study is to investigate the possible role that SAR polarimetry could play in the monitoring of informal settlements....

  11. Prediction of embankment settlement over soft soils.

    Science.gov (United States)

    2009-06-01

    The objective of this project was to review and verify the current design procedures used by TxDOT : to estimate the total and rate of consolidation settlement in embankments constructed on soft soils. Methods : to improve the settlement predictions ...

  12. 17 CFR 201.240 - Settlement.

    Science.gov (United States)

    2010-04-01

    ... 17 Commodity and Securities Exchanges 2 2010-04-01 2010-04-01 false Settlement. 201.240 Section... of Practice Initiation of Proceedings and Prehearing Rules § 201.240 Settlement. (a) Availability... party to a proceeding already instituted, may, at any time, propose in writing an offer of settlement...

  13. 28 CFR 24.304 - Settlement.

    Science.gov (United States)

    2010-07-01

    ... 28 Judicial Administration 1 2010-07-01 2010-07-01 false Settlement. 24.304 Section 24.304... DEPARTMENT OF JUSTICE ADMINISTRATIVE PROCEEDINGS Procedures for Considering Applications § 24.304 Settlement. A prevailing party and Department counsel may agree on a proposed settlement of an award before...

  14. 29 CFR 101.7 - Settlements.

    Science.gov (United States)

    2010-07-01

    ... 29 Labor 2 2010-07-01 2010-07-01 false Settlements. 101.7 Section 101.7 Labor Regulations Relating... Section 10 (a) to (i) of the Act and Telegraph Merger Act Cases § 101.7 Settlements. Before any complaint... for the submission and consideration of facts, argument, offers of settlement, or proposals of...

  15. 15 CFR 18.19 - Settlement.

    Science.gov (United States)

    2010-01-01

    ... 15 Commerce and Foreign Trade 1 2010-01-01 2010-01-01 false Settlement. 18.19 Section 18.19... Procedures for Considering Applications § 18.19 Settlement. The applicant and agency counsel may agree on a proposed settlement of the award before final action on the application, either in connection with a...

  16. 49 CFR 6.29 - Settlement.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 1 2010-10-01 2010-10-01 false Settlement. 6.29 Section 6.29 Transportation... PROCEEDINGS Procedures for Considering Applications § 6.29 Settlement. The applicant and agency counsel may agree on a proposed settlement of the award before final action on the application, either in connection...

  17. 7 CFR 1.345 - Settlement.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 1 2010-01-01 2010-01-01 false Settlement. 1.345 Section 1.345 Agriculture Office of... Under the Program Fraud Civil Remedies Act of 1986 § 1.345 Settlement. (a) A respondent may make offers of compromise of settlement at any time. (b) The reviewing official has the exclusive authority to...

  18. 22 CFR 134.25 - Settlement.

    Science.gov (United States)

    2010-04-01

    ... 22 Foreign Relations 1 2010-04-01 2010-04-01 false Settlement. 134.25 Section 134.25 Foreign... Considering Applications § 134.25 Settlement. The applicant and the Department of State may agree on a proposed settlement of the award before final action on the application, either in connection with a...

  19. 17 CFR 201.54 - Settlement.

    Science.gov (United States)

    2010-04-01

    ... 17 Commodity and Securities Exchanges 2 2010-04-01 2010-04-01 false Settlement. 201.54 Section 201... Regulations Pertaining to the Equal Access to Justice Act § 201.54 Settlement. The applicant and counsel for the Office or Division of the Commission may agree on a proposed settlement of the award before final...

  20. 40 CFR 17.24 - Settlement.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 1 2010-07-01 2010-07-01 false Settlement. 17.24 Section 17.24... JUSTICE ACT IN EPA ADMINISTRATIVE PROCEEDINGS Procedures for Considering Applications § 17.24 Settlement. A prevailing party and EPA counsel may agree on a proposed settlement of an award before final...

  1. 14 CFR 14.25 - Settlement.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Settlement. 14.25 Section 14.25 Aeronautics... IMPLEMENTING THE EQUAL ACCESS TO JUSTICE ACT OF 1980 Procedures for Considering Applications § 14.25 Settlement. The applicant and agency counsel may agree on a proposed settlement of the award before final action...

  2. 29 CFR 2704.305 - Settlement.

    Science.gov (United States)

    2010-07-01

    ... 29 Labor 9 2010-07-01 2010-07-01 false Settlement. 2704.305 Section 2704.305 Labor Regulations... Settlement. In the event that counsel for the Secretary and an applicant agree to settle an EAJA claim after... of the settlement and request dismissal of the application. [63 FR 63177, Nov. 12, 1998] ...

  3. 24 CFR 1720.180 - Settlements.

    Science.gov (United States)

    2010-04-01

    ... 24 Housing and Urban Development 5 2010-04-01 2010-04-01 false Settlements. 1720.180 Section 1720... Proceedings General Provisions § 1720.180 Settlements. Parties may propose in writing, at any time during the course of a proceeding, offers of settlement which shall be submitted to the Secretary. If determined to...

  4. 37 CFR 11.26 - Settlement.

    Science.gov (United States)

    2010-07-01

    ... 37 Patents, Trademarks, and Copyrights 1 2010-07-01 2010-07-01 false Settlement. 11.26 Section 11... Disciplinary Proceedings; Jurisdiction, Sanctions, Investigations, and Proceedings § 11.26 Settlement. Before or after a complaint under § 11.34 is filed, a settlement conference may occur between the OED...

  5. 39 CFR 960.17 - Settlement.

    Science.gov (United States)

    2010-07-01

    ... 39 Postal Service 1 2010-07-01 2010-07-01 false Settlement. 960.17 Section 960.17 Postal Service... ACT IN POSTAL SERVICE PROCEEDINGS Procedures for Considering Applications § 960.17 Settlement. The applicant and the Postal Service may agree on a proposed settlement of the award before final action on the...

  6. 32 CFR 536.55 - Structured settlements.

    Science.gov (United States)

    2010-07-01

    ... 32 National Defense 3 2010-07-01 2010-07-01 true Structured settlements. 536.55 Section 536.55... AGAINST THE UNITED STATES Investigation and Processing of Claims § 536.55 Structured settlements. (a) The... of this part, structured settlements cannot be required but are encouraged in situations listed above...

  7. 39 CFR 958.23 - Settlement.

    Science.gov (United States)

    2010-07-01

    ... 39 Postal Service 1 2010-07-01 2010-07-01 false Settlement. 958.23 Section 958.23 Postal Service..., CLEAN-UP COSTS AND DAMAGES FOR VIOLATION OF HAZARDOUS MATERIAL REGULATIONS § 958.23 Settlement. Either party may make offers of settlement or proposals of adjustment at any time. The Determining Official has...

  8. 7 CFR 1782.20 - Debt Settlement.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 12 2010-01-01 2010-01-01 false Debt Settlement. 1782.20 Section 1782.20 Agriculture... (CONTINUED) SERVICING OF WATER AND WASTE PROGRAMS § 1782.20 Debt Settlement. Pursuant to 7 U.S.C. 1981, this section prescribes policies for debt settlement of Water and Waste Disposal loans; Watershed loans and...

  9. 5 CFR 2430.10 - Settlement.

    Science.gov (United States)

    2010-01-01

    ... 5 Administrative Personnel 3 2010-01-01 2010-01-01 false Settlement. 2430.10 Section 2430.10... FEDERAL LABOR RELATIONS AUTHORITY AWARDS OF ATTORNEY FEES AND OTHER EXPENSES § 2430.10 Settlement. The applicant and the General Counsel may agree on a proposed settlement of the award before final action on the...

  10. 19 CFR 212.24 - Settlement.

    Science.gov (United States)

    2010-04-01

    ... 19 Customs Duties 3 2010-04-01 2010-04-01 false Settlement. 212.24 Section 212.24 Customs Duties... IMPLEMENTATION OF THE EQUAL ACCESS TO JUSTICE ACT Procedures for Considering Applications § 212.24 Settlement. The applicant and the Commission may agree on a proposed settlement of the award before final action...

  11. 15 CFR 904.213 - Settlements.

    Science.gov (United States)

    2010-01-01

    ... 15 Commerce and Foreign Trade 3 2010-01-01 2010-01-01 false Settlements. 904.213 Section 904.213 Commerce and Foreign Trade Regulations Relating to Commerce and Foreign Trade (Continued) NATIONAL OCEANIC... and Appeal Procedures General § 904.213 Settlements. If settlement is reached before the Judge has...

  12. 12 CFR 1705.24 - Settlement.

    Science.gov (United States)

    2010-01-01

    ... 12 Banks and Banking 7 2010-01-01 2010-01-01 false Settlement. 1705.24 Section 1705.24 Banks and... Consideration of the Application for Award § 1705.24 Settlement. The applicant and agency counsel may agree on a proposed settlement of an award before the final decision on the application for award is made, either in...

  13. 7 CFR 1951.213 - Debt settlement.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 14 2010-01-01 2009-01-01 true Debt settlement. 1951.213 Section 1951.213 Agriculture... and Grants § 1951.213 Debt settlement. Subpart C of part 1956 of this chapter prescribes policies and procedures for debt settlement actions for loans covered under this subpart when it is determined that a debt...

  14. 24 CFR 28.45 - Settlements.

    Science.gov (United States)

    2010-04-01

    ... 24 Housing and Urban Development 1 2010-04-01 2010-04-01 false Settlements. 28.45 Section 28.45... IMPLEMENTATION OF THE PROGRAM FRAUD CIVIL REMEDIES ACT OF 1986 § 28.45 Settlements. (a) HUD and the respondent may enter into a settlement agreement at any time prior to the issuing of a notice of final...

  15. 10 CFR 1023.324 - Settlement.

    Science.gov (United States)

    2010-01-01

    ... 10 Energy 4 2010-01-01 2010-01-01 false Settlement. 1023.324 Section 1023.324 Energy DEPARTMENT OF... Justice Act Procedures for Considering Applications § 1023.324 Settlement. The applicant and agency counsel may agree on a proposed settlement of the award before final action on the application, either in...

  16. 24 CFR 3800.60 - Settlements.

    Science.gov (United States)

    2010-04-01

    ... 24 Housing and Urban Development 5 2010-04-01 2010-04-01 false Settlements. 3800.60 Section 3800... DEVELOPMENT INVESTIGATIONS IN CONSUMER REGULATORY PROGRAMS § 3800.60 Settlements. (a) At any time during an investigation, the Department and the parties subject to an investigation may conduct settlement negotiations...

  17. 14 CFR 1262.305 - Settlement.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 5 2010-01-01 2010-01-01 false Settlement. 1262.305 Section 1262.305... PROCEEDINGS Procedures for Considering Applications § 1262.305 Settlement. The applicant and agency counsel may agree on a proposed settlement of the award before final action on the application, either in...

  18. 15 CFR 990.25 - Settlement.

    Science.gov (United States)

    2010-01-01

    ... 15 Commerce and Foreign Trade 3 2010-01-01 2010-01-01 false Settlement. 990.25 Section 990.25... DAMAGE ASSESSMENTS Authorities § 990.25 Settlement. Trustees may settle claims for natural resource damages under this part at any time, provided that the settlement is adequate in the judgment of the...

  19. 15 CFR 280.219 - Settlement.

    Science.gov (United States)

    2010-01-01

    ... 15 Commerce and Foreign Trade 1 2010-01-01 2010-01-01 false Settlement. 280.219 Section 280.219... Enforcement § 280.219 Settlement. (a) Cases may be settled before service of a charging letter. In cases in which settlement is reached before service of a charging letter, a proposed charging letter will be...

  20. 45 CFR 13.24 - Settlements.

    Science.gov (United States)

    2010-10-01

    ... 45 Public Welfare 1 2010-10-01 2010-10-01 false Settlements. 13.24 Section 13.24 Public Welfare... ACT IN AGENCY PROCEEDINGS Procedures for Considering Applications § 13.24 Settlements. The applicant and the agency's litigating party may agree on a proposed settlement of the award at any time prior to...

  1. 17 CFR 9.7 - Settlement.

    Science.gov (United States)

    2010-04-01

    ... 17 Commodity and Securities Exchanges 1 2010-04-01 2010-04-01 false Settlement. 9.7 Section 9.7... DISCIPLINARY, ACCESS DENIAL OR OTHER ADVERSE ACTIONS General Provisions § 9.7 Settlement. At any time before... accordance with § 9.20, the parties may file a stipulation for dismissal based on a settlement agreement...

  2. 29 CFR 2204.306 - Settlement.

    Science.gov (United States)

    2010-07-01

    ... 29 Labor 9 2010-07-01 2010-07-01 false Settlement. 2204.306 Section 2204.306 Labor Regulations... Procedures for Considering Applications § 2204.306 Settlement. The applicant and the Secretary may agree on a proposed settlement of the award before final action on the application, either in connection with a...

  3. 13 CFR 134.217 - Settlement.

    Science.gov (United States)

    2010-01-01

    ... 13 Business Credit and Assistance 1 2010-01-01 2010-01-01 false Settlement. 134.217 Section 134... BEFORE THE OFFICE OF HEARINGS AND APPEALS Rules of Practice for Most Cases § 134.217 Settlement. At any... have settled the case, and may file with such motion a copy of the settlement agreement. If the Judge...

  4. 5 CFR 2610.306 - Settlement.

    Science.gov (United States)

    2010-01-01

    ... 5 Administrative Personnel 3 2010-01-01 2010-01-01 false Settlement. 2610.306 Section 2610.306... ACCESS TO JUSTICE ACT Procedures for Considering Applications § 2610.306 Settlement. The applicant and agency counsel may agree on a proposed settlement of the award before final action on the application...

  5. 29 CFR 16.303 - Settlement.

    Science.gov (United States)

    2010-07-01

    ... 29 Labor 1 2010-07-01 2010-07-01 true Settlement. 16.303 Section 16.303 Labor Office of the Secretary of Labor EQUAL ACCESS TO JUSTICE ACT Procedures for Considering Applications § 16.303 Settlement. The applicant and agency counsel may agree on a proposed settlement of the award before final action...

  6. 15 CFR 766.18 - Settlement.

    Science.gov (United States)

    2010-01-01

    ... 15 Commerce and Foreign Trade 2 2010-01-01 2010-01-01 false Settlement. 766.18 Section 766.18... PROCEEDINGS § 766.18 Settlement. (a) Cases may be settled before service of a charging letter. In cases in which settlement is reached before service of a charging letter, a proposed charging letter will be...

  7. 12 CFR 625.20 - Settlement.

    Science.gov (United States)

    2010-01-01

    ... 12 Banks and Banking 6 2010-01-01 2010-01-01 false Settlement. 625.20 Section 625.20 Banks and... UNDER THE EQUAL ACCESS TO JUSTICE ACT Procedures for Considering Applications § 625.20 Settlement. A prevailing party and the FCA through its counsel may agree on a proposed settlement of an award at any time...

  8. 7 CFR 1951.894 - Debt settlement.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 14 2010-01-01 2009-01-01 true Debt settlement. 1951.894 Section 1951.894 Agriculture... REGULATIONS (CONTINUED) SERVICING AND COLLECTIONS Rural Development Loan Servicing § 1951.894 Debt settlement. Debt settlement of all claims will be handled in accordance with the Federal Claims Collection...

  9. Settlement during vibratory sheet piling

    NARCIS (Netherlands)

    Meijers, P.

    2007-01-01

    During vibratory sheet piling quite often the soil near the sheet pile wall will settle. In many cases this is not a problem. For situations with houses, pipelines, roads or railroads at relative short distance these settlements may not be acceptable. The purpose of the research described in this

  10. The Density of Sustainable Settlements

    DEFF Research Database (Denmark)

    Lauring, Michael; Silva, Victor; Jensen, Ole B.

    2010-01-01

    This paper is the initial result of a cross-disciplinary attempt to encircle an answer to the question of optimal densities of sustainable settlements. Urban density is an important component in the framework of sustainable development and influences not only the character and design of cities...

  11. Antifouling Activity towards Mussel by Small-Molecule Compounds from a Strain of Vibrio alginolyticus Bacterium Associated with Sea Anemone Haliplanella sp.

    Science.gov (United States)

    Wang, Xiang; Huang, Yanqiu; Sheng, Yanqing; Su, Pei; Qiu, Yan; Ke, Caihuan; Feng, Danqing

    2017-03-28

    Mussels are major fouling organisms causing serious technical and economic problems. In this study, antifouling activity towards mussel was found in three compounds isolated from a marine bacterium associated with the sea anemone Haliplanella sp. This bacterial strain, called PE2, was identified as Vibrio alginolyticus using morphology, biochemical tests, and phylogenetic analysis based on sequences of 16S rRNA and four housekeeping genes ( rpoD, gyrB, rctB, and toxR ). Three small-molecule compounds (indole, 3-formylindole, and cyclo (Pro-Leu)) were purified from the ethyl acetate extract of V. alginolyticus PE2 using column chromatography techniques. They all significantly inhibited byssal thread production of the green mussel Perna viridis , with EC 50 values of 24.45 μg/ml for indole, 50.07 μg/ml for 3-formylindole, and 49.24 μg/ml for cyclo (Pro-Leu). Previous research on the antifouling activity of metabolites from marine bacteria towards mussels is scarce. Indole, 3-formylindole and cyclo (Pro-Leu) also exhibited antifouling activity against settlement of the barnacle Balanus albicostatus (EC 50 values of 8.84, 0.43, and 11.35 μg/ml, respectively) and the marine bacterium Pseudomonas sp. (EC 50 values of 42.68, 69.68, and 39.05 μg/ml, respectively). These results suggested that the three compounds are potentially useful for environmentally friendly mussel control and/or the development of new antifouling additives that are effective against several biofoulers.

  12. Prey selection of a captive Oystercatcher Haematopus ostralegus hammering Mussels Mytilus edulis from the ventral side

    NARCIS (Netherlands)

    Ens, Bruno J.; Alting, D

    1996-01-01

    We studied prey choice of a captive Oystercatcher:hat hammered Mussels from the ventral side. The results replicate previous findings that ventral hammerers select Mussels of intermediate size, select against thick-shelled Mussels, abandon an increasing proportion of Mussels with increasing size and

  13. Increased Relative Calcification, Shell Dissolution and Maintained Larval Growth in Mussel (Mytilus edulis) Larvae Exposed to Acidified Under-Saturated Seawater

    Science.gov (United States)

    Ventura, A.; Dupont, S. T.; Schulz, S.

    2016-02-01

    Ocean acidification (OA) is known to affect bivalve early life-stages. It is often assumed that aragonite saturation state (Ωa) is the main driver of the biological response. However saturation state of different CaCO3 forms is not the main driver of most physiological processes and pH/pCO2 are playing an overarching role (e.g. acid-base regulation). The aim of our study was to investigate the effects of a wide range of seawater pH on different physiological parameters (e. g. calcification; growth) of blue mussel (Mytilus edulis) developing larvae in order to identify a physiological tipping point beyond which they are no longer capable of carrying out those functions necessary to their survival and recruitment into the adult population. Our results confirmed that increasing seawater acidity and decreasing saturation state increases larval mortality rate and the percentage of abnormally developing larvae. No larvae reared at pHT ≈ 7.1 were able to reach the D-shell veliger stage and their development appeared to be arrested at the trochophore stage. However - despite morphological shell abnormalities - larvae were capable of reaching the D-shell stage when reared at pHT ≈ 7.35 and normally D-shaped larvae were observed in all the remaining treatments (pH ≈ 7.6, 7.85 and 8.1) including in under-saturated seawater with Ωa as low as 0.75 ± 0.03 (mean ± SE). Growth rate of these larvae was not affected by lower pHT despite potential increased energy costs associated with compensatory calcification in response to increased shell dissolution. Overall, our results suggest a shift in energy allocation toward growth in larvae exposed to ocean acidification.

  14. Sealed-Bid Auction of Dutch Mussels : Statistical Analysis

    NARCIS (Netherlands)

    Kleijnen, J.P.C.; van Schaik, F.D.J.

    2007-01-01

    This article presents an econometric analysis of the many data on the sealed-bid auction that sells mussels in Yerseke town, the Netherlands. The goals of this analy- sis are obtaining insight into the important factors that determine the price of these mussels, and quantifying the performance of an

  15. Ingestion rates and grazing impact of the brackwater mussel ...

    African Journals Online (AJOL)

    Bivalves feed on a combination of phytoplankton and zooplankton and have the potential to impact considerably the planktonic biomass, especially when they occur in high densities, such as in oyster and mussel beds. The brackwater mussel Brachidontes virgiliae is numerically dominant during wet phases within Africa's ...

  16. Sealed-bid auction of Netherlands mussels: statistical analysis

    NARCIS (Netherlands)

    Kleijnen, J.P.C.; van Schaik, F.D.J.

    2011-01-01

    This article presents an econometric analysis of the many data on the sealed-bid auction that sells mussels in Yerseke town, the Netherlands. The goals of this analysis are obtaining insight into the important factors that determine the price of these mussels, and quantifying the performance of an

  17. Large-Scale Spatial Dynamics of Intertidal Mussel (

    NARCIS (Netherlands)

    Folmer, E.O.; Drent, J.; Troost, K.; Büttger, H.; Dankers, N.; Jansen, J.; van Stralen, M.; Millat, G.; Herlyn, M.; Philippart, C.J.M.

    2014-01-01

    Intertidal blue mussel beds are important for the functioning and community composition of coastal ecosystems. Modeling spatial dynamics of intertidal mussel beds is complicated because suitable habitat is spatially heterogeneously distributed and recruitment and loss are hard to predict. To get

  18. Processes limiting mussel bed restoration in the Wadden-Sea

    NARCIS (Netherlands)

    de Paoli, Helene; van de Koppel, Johan; van der Zee, Els; Kangeri, Arno; van Belzen, Jim; Holthuijsen, Sander; van den Berg, Aniek; Herman, Peter; Olff, Han; van der Heide, Tjisse

    This paper reports on experimental restoration of mussel beds in the Wadden Sea and the processes that might limit successful restoration of this foundation species (i.e. substrate, predation, hydrodynamics). The importance of substrate, predation, hydrodynamic conditions and location on mussel

  19. Fluctuating and Directional Asymmetry of the Blue Mussel (

    NARCIS (Netherlands)

    Lajus, D.; Katolikova, M.; Strelkov, P.; Hummel, H.

    2015-01-01

    In this work we examined morphological variation at different levels to study performance and population structuring of the blue mussel Mytilus edulis. Our objectives were: (i) to develop an integrated technique for analyzing morphological variation in blue mussels and, based on this technique; (ii)

  20. Progress Toward Sustainable Mussel Aquaculture in Mar Piccolo, Italy

    Directory of Open Access Journals (Sweden)

    Carmela Caroppo

    2012-09-01

    Full Text Available Mar Piccolo of Taranto is an estuarine basin heavily exploited for commercial mussel (Mytilus galloprovincialis L. farming. The historical renown of the Taranto mussels has suffered over the last decade following policy decisions to expand the mussel farms and to relocate a portion of the urban sewage to an outfall outside of Mar Piccolo. The resulting decline in mussel quality and the quandary of how to restore stability to Taranto mussel production became the focal issue for our application of the systems approach framework (SAF. We simulated the ecological, economic, and social interactions that affect mussel production. Stakeholders and mussel farmers contributed by participating in meetings during the entire exercise. Our simulation analysis provided them with a means for understanding the effects of policy scenarios on the system. We present three aspects from our initial results that demonstrate the value of the SAF, as: (1 an operational model to monitor and better research the status of the ecosystem, (2 a management tool to evaluate sustainable mussel farming strategies, and (3 an opportunity for improved communication with and engagement of stakeholders, policy, and the public. The application has also raised important questions about how the food chain is controlled, what could be changed to stabilize the ecosystem to a higher level of productivity, and what role the public and policy could play in promoting sustainable development.

  1. Invasion of the Zebra Mussels: A Mock Trial Activity

    Science.gov (United States)

    Beck, Judy A.; Czerniak, Charlene M.

    2005-01-01

    In this activity, students learn about the important topic of invasive species, specifically Zebra Mussels. Students role-play different characters in a real-life situation: the trial of the Zebra Mussel for unlawful disruption of the Great Lakes ecosystem. Students will also learn about jurisprudential inquiry by examining the trial process. This…

  2. IMPACT OF WATER PH ON ZEBRA MUSSEL MORTALITY

    International Nuclear Information System (INIS)

    Molloy, Daniel P.

    2002-01-01

    The experiments conducted this past quarter have suggested that the bacterium Pseudomonas fluorescens strain CL0145A is effective at killing zebra mussels throughout the entire range of pH values tested (7.2 to 8.6). Highest mortality was achieved at pH values characteristic of preferred zebra mussel waterbodies, i.e., hard waters with a range of 7.8 to 8.6. In all water types tested, however, ranging from very soft to very hard, considerable mussel kill was achieved (83 to 99% mean mortality), suggesting that regardless of the pH or hardness of the treated water, significant mussel kill can be achieved upon treatment with P. fluorescens strain CL0145A. These results further support the concept that this bacterium has significant potential for use as a zebra mussel control agent in power plant pipes receiving waters with a wide range of physical and chemical characteristics

  3. Mussel dredging: Impact on epifauna in Limfjorden, Denmark

    DEFF Research Database (Denmark)

    Dolmer, Per

    2002-01-01

    Species composition and population density of epibenthos are described in two areas in Limfjorden, Denmark. Both areas covered both a mussel fishing ground and an area that has been permanently closed for mussel dredging since 1988. Furthermore, mussels were dredged in a part of the mussel fishing...... grounds in both areas four months before the investigations. The rest of the fishing grounds had not been exploited for at least four years. This study describes the short-term impact (4 mo) and long-term impact (>4 y) of mussel dredging using the permanently closed areas as controls. The data were...... analyzed by multivariate statistics. In both short-term study areas significant effects of dredging were observed. A number of taxa (sponges, echinoderms, anthozoans, molluscs, crustaceans, and ascidians) had a reduced density or were not observed in fished areas four months after the fishing was ended...

  4. IMPACT OF WATER PH ON ZEBRA MUSSEL MORTALITY

    Energy Technology Data Exchange (ETDEWEB)

    Daniel P. Molloy

    2002-10-15

    The experiments conducted this past quarter have suggested that the bacterium Pseudomonas fluorescens strain CL0145A is effective at killing zebra mussels throughout the entire range of pH values tested (7.2 to 8.6). Highest mortality was achieved at pH values characteristic of preferred zebra mussel waterbodies, i.e., hard waters with a range of 7.8 to 8.6. In all water types tested, however, ranging from very soft to very hard, considerable mussel kill was achieved (83 to 99% mean mortality), suggesting that regardless of the pH or hardness of the treated water, significant mussel kill can be achieved upon treatment with P. fluorescens strain CL0145A. These results further support the concept that this bacterium has significant potential for use as a zebra mussel control agent in power plant pipes receiving waters with a wide range of physical and chemical characteristics.

  5. Water Loss in Small Settlements

    OpenAIRE

    Mindaugas Rimeika; Anželika Jurkienė

    2014-01-01

    The main performance indicators of a water supply system include the quality and safety of water, continuous work, relevant pressure and small water loss. The majority of foreign and local projects on reducing water loss have been carried out in the water supply systems of metropolitans; however, the specificity of small settlements differs from that of big cities. Differences can be observed not only in the development of infrastructure and technical indicators but also in the features of wa...

  6. The exhalant jet of mussels Mytilus edulis

    DEFF Research Database (Denmark)

    Riisgard, Hans Ulrik; Jørgensen, Bo Hoffmann; Lundgreen, Kim

    2011-01-01

    shell lengths. Here, we present results of a detailed study of fully open mussels Mytilus edulis in terms of filtration rate, exhalant siphon aperture area, jet velocity, gill area and body dry weight, all as a function of shell length (mean +/- SD) over the range 16.0 +/- 0.4 to 82.6 +/- 2.9 mm...... detailed 2-component velocity distributions near the exhalant siphon in 5 planes parallel to the axis of the jet and the major axis of the oval aperture, and hence estimates of momentum and kinetic energy flows in addition to mean velocity. Data obtained on particles inside the exhalant jet of filtered...

  7. Copper and copper-nickel alloys as zebra mussel antifoulants

    Energy Technology Data Exchange (ETDEWEB)

    Dormon, J.M.; Cottrell, C.M.; Allen, D.G.; Ackerman, J.D.; Spelt, J.K. [Univ. of Toronto, Ontario (Canada)

    1996-04-01

    Copper has been used in the marine environment for decades as cladding on ships and pipes to prevent biofouling by marine mussels (Mytilus edulis L.). This motivated the present investigation into the possibility of using copper to prevent biofouling in freshwater by both zebra mussels and quagga mussels (Dreissena polymorpha and D. bugensis collectively referred to as zebra mussels). Copper and copper alloy sheet proved to be highly effective in preventing biofouling by zebra mussels over a three-year period. Further studies were conducted with copper and copper-nickel mesh (lattice of expanded metal) and screen (woven wire with a smaller hole size), which reduced the amount of copper used. Copper screen was also found to be strongly biofouling-resistant with respect to zebra mussels, while copper mesh reduced zebra mussel biofouling in comparison to controls, but did not prevent it entirely. Preliminary investigations into the mechanism of copper antifouling, using galvanic couples, indicated that the release of copper ions from the surface of the exposed metal into the surrounding water is directly or indirectly responsible for the biofouling resistance of copper.

  8. Dreissenid mussels from the Great Lakes contain elevated thiaminase activity

    Science.gov (United States)

    Tillitt, D.E.; Riley, S.C.; Evans, A.N.; Nichols, S.J.; Zajicek, J.L.; Rinchard, J.; Richter, C.A.; Krueger, C.C.

    2009-01-01

    We examined thiaminase activity in dreissenid mussels collected at different depths and seasons, and from various locations in Lakes Michigan, Ontario, and Huron. Here we present evidence that two dreissenid mussel species (Dreissena bugensis and D. polymorpha) contain thiaminase activity that is 5-100 fold greater than observed in Great Lakes fishes. Thiaminase activity in zebra mussels ranged from 10,600 to 47,900??pmol g- 1??min- 1 and activities in quagga mussels ranged from 19,500 to 223,800??pmol g- 1??min- 1. Activity in the mussels was greatest in spring, less in summer, and least in fall. Additionally, we observed greater thiaminase activity in dreissenid mussels collected at shallow depths compared to mussels collected at deeper depths. Dreissenids constitute a significant and previously unknown pool of thiaminase in the Great Lakes food web compared to other known sources of this thiamine (vitamin B1)-degrading enzyme. Thiaminase in forage fish of the Great Lakes has been causally linked to thiamine deficiency in salmonines. We currently do not know whether linkages exist between thiaminase activities observed in dreissenids and the thiaminase activities in higher trophic levels of the Great Lakes food web. However, the extreme thiaminase activities observed in dreissenids from the Great Lakes may represent a serious unanticipated negative effect of these exotic species on Great Lakes ecosystems.

  9. Evaluation of relocation of unionid mussels into artificial ponds

    Science.gov (United States)

    Newton, T.J.; Monroe, E.M.; Kenyon, R.; Gutreuter, S.; Welke, K.I.; Thiel, P.A.

    2001-01-01

    Relocation of unionid mussels into refuges (e.g., hatchery ponds) has been suggested as a management tool to protect these animals from the threat of zebra mussel (Dreissena polymorpha) invasion. To evaluate the efficacy of relocation, we experimentally relocated 768 mussels, representing 5 species (Leptodea fragilis, Obliquaria reflexa, Fusconaia flava, Amblema plicata, and Quadrula quadrula) into an earthen pond at a National Fish Hatchery or back into the river. In both locations, mussels were placed into 1 of 4 treatments (mesh bags, corrals, and buried or suspended substrate-filled trays). Mussels were examined annually for survival, growth (shell length and wet mass), and physiological condition (glycogen concentration in foot and mantle and tissue condition index) for 36 mo in the pond or 40 mo in the river. We observed significant differences in mortality rates between locations (mortality was 4 times greater in the pond than in the river), among treatments (lowest mortality in the suspended trays), and among species (lower mortality in the amblemines than lamp-silines). Overall survival in both locations averaged 80% the 1st year; survival in the pond decreased dramatically after that. Although length and weight varied between locations and over time, these changes were small, suggesting that their utility as short-term measures of well being in long-lived unionids is questionable. Mussels relocated to the pond were in poor physiological condition relative to those in the river, but the magnitude of these differences was small compared to the inherent variability in physiological condition of reference mussels. These data suggest that relocation of unionids into artificial ponds is a high-risk conservation strategy; alternatives such as introduction of infected host fish, identification of mussel beds at greatest risk from zebra mussels, and a critical, large-scale assessment of the factors contributing to their decline should be explored.

  10. Trace Metals in Mussels from the N.W. Mediterranean

    International Nuclear Information System (INIS)

    Fowler, S.W.; Oregioni, B.

    1976-01-01

    A coastal survey in the northwestern Mediterranean region was initiated to measure existing levels of selected trace metals in mussels. For most metals the highest values were found in samples from port cities and areas in the vicinity of river discharge. Marked seasonal variation for many metals was evident; an overall increase in metal concentration in mussels from most stations during March 1974 was attributed to high precipitation and attendant run-off rather than to local pollution. Data comparison indicates that average metal levels in northwestern Mediterranean mussels do not differ markedly from those measured in similar species from different localities throughout the world. (author)

  11. Public Policy and Environment : The Golden Mussel Case

    Directory of Open Access Journals (Sweden)

    Luíz Ricardo Santana de Araújo Júnior

    2016-12-01

    Full Text Available The papper carries out an analysis of the National Task Force Control of Golden Mussel and Emergency Action Plan, which are considered environmental policies. The bibliographical research, using primary and secondary sources, make a conceptual approach to bioinvasion the Golden Mussel. Then it perfomes analysis of the general characteristics of the National Task Force and the Emergency Plan, pointing to inconsistencies that were found, either in the planning or implementation of policy, as a basis for an analysis of the environmental policy effectiveness. Finally, they analyse possible ways to avoid the appearance of inconsistencies that were found in the case of Golden Mussel.

  12. IMPACT OF WATER TEMPERATURE ON ZEBRA MUSSEL MORTALITY

    Energy Technology Data Exchange (ETDEWEB)

    Daniel P. Molloy

    2002-08-07

    These tests conducted this past quarter have indicated that the bacterium Pseudomonas fluorescens strain CL0145A is effective at killing zebra mussels at water temperatures ranging from 7 to 23 C. Percent kill will likely be somewhat lower at very low temperatures, e.g., 7 C, but even at such low temperatures high mussel kill can still be achieved (>70% kill). This is significant because the development of a zebra mussel control method that is efficacious in such a wide range of temperatures broadens its usefulness as a potential commercial product.

  13. Mussel as biomonitor of environmental contamination

    International Nuclear Information System (INIS)

    Souza, Vivianne L.B.; Nascimento, Rizia Keila do; Melo, Jessica V. de

    2013-01-01

    The presence of agricultural input, domestic and industrial discharges, can result in a contaminant impact in aquatic ecosystems and in elevated concentrations of trace metals that may exert direct toxic effects and maybe accumulated in organisms consumed by man. The objective of the present study was to investigate some metal concentrations in Mytilidae falcate collected from Channel of Santa Cruz, Brazil. There are some industries located along the Channel of Santa Cruz that manufacture aluminum, paper and cellulose, pesticides, and caustic soda. Mussels collected at this area were carefully opened, dried and 0.5g of samples were heating with a mixture of acids; the final solution was filtered and made up to 50 mL. Metals concentrations were measured at aICP-MS (FINNIGAN) and AAS (VARIAN). The results demonstrated that there is more Fe and Mn in the mussels than any other studied metals (Fe >Mn >Cd >Pb >Cu >Th >U).The results for Fe and Mn concentrations are similar to those reported in the literature for invertebrates and fishes collected in regions contaminated by domestic and industrial sewage. Lead and Cd values, on the other hand, are beyond the limiting values for human consumption. Only the levels of copper are within to the Brazilian legislation. Uranium concentration was lower than results showed in literature. (author)

  14. Production of hydroxyapatite from waste mussel shells

    Energy Technology Data Exchange (ETDEWEB)

    Jones, Mark I; Barakat, Haneen; Patterson, Darrell Alec, E-mail: mark.jones@auckland.ac.nz [Department Chemical and Materials Engineering, University of Auckland, New Zealand Private Bag 92019, Auckland Mail Centre, Auckland, 1142 (New Zealand)

    2011-10-29

    This work describes the formation of Hydroxyaptite, Ca{sub 10}(PO{sub 4}){sub 6}(OH){sub 2}, from waste mussel shells from the New Zealand aquaculture industry. The raw shells are first calcined to produce lime (CaO) and then reacted in a purpose built reactor to form the Hydroxyapatite (HA) in a low temperature batch process. The calcination was studied in terms of the effects of temperature, heating rate, holding time, nitrogen flow rate and particle size. The crystals formed in the batch reactor were characterized by X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM), Energy Dispersive Spectroscopy (EDS) and X-Ray Photoelectron Spectroscopy (XPS). Optimised conditions in the calcination stage resulted in powder with around 95% conversion to lime. The as-produced HA showed poor crystallinity and the presence of impurities, although both of these features were improved by a suitable post heat treatment process. The post treated material showed good crystallinity and was comparable to commercially produced material. Preliminary biocompatibility experiments showed that the HA stimulated cell growth and promoted mineralization. The production of HA from mussel shells in a room temperature, ambient pressure process is not only a sustainable use of waste material, but also from an industrial point of view the process has considerable potential for reducing costs associated with both starting materials and energy.

  15. Mussel as biomonitor of environmental contamination

    Energy Technology Data Exchange (ETDEWEB)

    Souza, Vivianne L.B.; Nascimento, Rizia Keila do, E-mail: vlsouza@cnen.gov.br, E-mail: riziakelia@hotmail.com [Centro Regional de Ciencias Nucleares do Nordeste (CRCN-NE/CNEN-PE), Recife, PE (Brazil); Melo, Jessica V. de, E-mail: jessica_clorofila@hotmail [Universidade Federal de Pernambuco (UFPE), Recife, PE (Brazil)

    2013-07-01

    The presence of agricultural input, domestic and industrial discharges, can result in a contaminant impact in aquatic ecosystems and in elevated concentrations of trace metals that may exert direct toxic effects and maybe accumulated in organisms consumed by man. The objective of the present study was to investigate some metal concentrations in Mytilidae falcate collected from Channel of Santa Cruz, Brazil. There are some industries located along the Channel of Santa Cruz that manufacture aluminum, paper and cellulose, pesticides, and caustic soda. Mussels collected at this area were carefully opened, dried and 0.5g of samples were heating with a mixture of acids; the final solution was filtered and made up to 50 mL. Metals concentrations were measured at aICP-MS (FINNIGAN) and AAS (VARIAN). The results demonstrated that there is more Fe and Mn in the mussels than any other studied metals (Fe >Mn >Cd >Pb >Cu >Th >U).The results for Fe and Mn concentrations are similar to those reported in the literature for invertebrates and fishes collected in regions contaminated by domestic and industrial sewage. Lead and Cd values, on the other hand, are beyond the limiting values for human consumption. Only the levels of copper are within to the Brazilian legislation. Uranium concentration was lower than results showed in literature. (author)

  16. Settlement characteristics of major infrastructures in Shanghai

    Directory of Open Access Journals (Sweden)

    X. Jiao

    2015-11-01

    Full Text Available Critical infrastructures in Shanghai have undergone uneven settlement since their operation, which plays an important role in affecting the security of Shanghai. This paper, taking rail transportation as example, investigates settlement characteristics and influencing factors of this linear engineering, based on long-term settlement monitoring data. Results show that rail settlement is related to geological conditions, regional ground subsidence, surrounding construction activities and structural differences in the rail systems. In order to effectively decrease the impact of regional ground subsidence, a monitoring and early-warning mechanism for critical infrastructure is established by the administrative department and engineering operators, including monitoring network construction, settlement monitoring, information sharing, settlement warning, and so on.

  17. Marine pollution risk in a coastal city: use of an eco-genotoxic tool as a stress indicator in mussels from the Eastern Aegean Sea.

    Science.gov (United States)

    Kacar, Asli; Pazi, Idil; Gonul, Tolga; Kucuksezgin, Filiz

    2016-08-01

    Coastal areas, such as bays, estuaries, and harbors, are heavily polluted since these areas are the settlements to which toxic chemicals from industrial and domestic wastes are discharged. The genetic damage was evaluated using bioindicator mussel Mytilus galloprovincialis caused by toxic chemicals (metals and polycyclic aromatic hydrocarbons) in İzmir and Çandarlı Bays (the Eastern Aegean Sea) through comet assay. Three sampling sites from the two bays were selected and the study was conducted during the spring and autumn periods. The highest levels of DNA damage expressed as %Tail-DNA were observed in İzmir Bay (34.60 % Tail-DNA) in the spring. Analysis of the correlation between PAHs and metals in mussels and %T-DNA in the hemolymph and gill cells showed a statistically significant positive correlation between %T-DNA and ∑PAH, chromium (p llution level of the İzmir and Çandarlı Bays by using the DNA damage to the mussel, which can identify the effects of environmental pollutants at the cellular levels. These results confirm that comet assay can be used to determine the temporal and spatial differences of DNA damage, and as a suitable tool for the measurement of genotoxicity in regions with low pollutant concentrations.

  18. The influence of atmospheric cold fronts on larval supply and settlement of intertidal invertebrates: Case studies in the Cabo Frio coastal upwelling system (SE Brazil)

    Science.gov (United States)

    de Azevedo Mazzuco, Ana Carolina; Christofoletti, Ronaldo Adriano; Coutinho, Ricardo; Ciotti, Áurea Maria

    2018-07-01

    Atmospheric fronts such as cold fronts are dynamic mesoscale systems with potential effects on the ecology of marine communities. In this study, larval dynamics in subtropical rocky shore communities were evaluated under the influence of atmospheric frontal systems. The hypothesis is that these systems may promote favorable conditions for larval supply and settlement regardless of taxa or site, and that supply and settlement vary in association with fluctuations of meteorological and oceanographic conditions driven by the fronts. This study was carried out in the Southeastern Brazil littoral region under the influence of coastal upwelling events (Cabo Frio) and subject to weekly atmospheric frontal systems, cold polar fronts. The spatial and temporal variability of larvae and settlers of barnacles and mussels were assessed by collecting daily samples at three sites before, during and after atmospheric cold fronts, and the atmospheric and pelagic conditions were monitored. Contrasts among rates, events and sites were tested using discriminant function analysis, analyses of variance and correlation analysis. Atmospheric frontal systems were considered to influence the sites when wind direction changed to SW-S-SE and persisted for at least a day, and waves from SW-SW-SE increased in height. The results corroborate the hypothesis that cold fronts are important regulators of larval dynamics and intertidal communities on rocky shores of the studied area. Both larval supply and settlement were highly correlated with fluctuations in wind speed and direction. Higher settlement rates of barnacles occurred one-day prior, or on the onset of cold fronts. Mussels species tended to settle during all conditions, but on average, settlement rates were higher during the cold fronts. Some temporal trends were site specific and variability was detected among taxa and larval stages. Our findings suggest that mesoscale oceanographic/atmospheric systems are particularly relevant on the

  19. 26 CFR 301.6224(c)-3 - Consistent settlements.

    Science.gov (United States)

    2010-04-01

    ... 26 Internal Revenue 18 2010-04-01 2010-04-01 false Consistent settlements. 301.6224(c)-3 Section... settlements. (a) In general. If the Internal Revenue Service enters into a settlement agreement with any..., settlement terms consistent with those contained in the settlement agreement entered into. (b) Requirements...

  20. Development of a molecular diagnostic system to discriminate Dreissena polymorpha (zebra mussel) and Dreissena bugensis (quagga mussel)

    Science.gov (United States)

    Hoy, M.S.; Kelly, K.; Rodriguez, R.J.

    2010-01-01

    A 3-primer PCR system was developed to discriminate invasive zebra (Dreissena polymorpha) and quagga (Dreissena bugensis) mussel. The system is based on: 1) universal primers that amplifies a region of the nuclear 28s rDNA gene from both species and 2) a species-specific primer complementary to either zebra or quagga mussel. The species-specific primers bind to sequences between the binding sites for the universal primers resulting in the amplification of two products from the target species and one product from the nontarget species. Therefore, nontarget products are positive amplification controls. The 3-primer system accurately discriminated zebra and quagga mussels from seven geographically distinct populations.

  1. Area-intensive bottom culture production of blue mussels, Mytilus edulis (L.)

    DEFF Research Database (Denmark)

    Christensen, Helle Torp

    column have the potential to become an alternative seed source for mussel production in bottom cultures. When compared to mussels collected from natural benthic mussel beds, suspended mussels had an active predator response by developing a significantly stronger attach-ment to the substrate and having...... a more pronounced aggregation behaviour. Bottom mussels exhibited a passive strategy by developing a thicker shell and larger relative size of the posterior adductor muscle. When comparing the performance of suspended and bottom seed mussels on complex and smooth sub-strate, respectively, originally...

  2. Will the Displacement of Zebra Mussels by Quagga Mussels Increase Water Clarity in Shallow Lakes during Summer? Results from a Mesocosm Experiment.

    Directory of Open Access Journals (Sweden)

    Xueying Mei

    Full Text Available Zebra mussels (Dreissena polymorpha are known to increase water clarity and affect ecosystem processes in invaded lakes. During the last decade, the conspecific quagga mussels (D. rostriformis bugensis have displaced zebra mussels in many ecosystems including shallow lakes such as Oneida Lake, New York. In this study, an eight-week mesocosm experiment was conducted to test the hypothesis that the displacement of zebra mussels by quagga mussels leads to further decreases in phytoplankton and increases in water clarity resulting in increases in benthic algae. We found that the presence of zebra mussels alone (ZM, quagga mussels alone (QM, or an equal number of both species (ZQ reduced total phosphorus (TP and phytoplankton Chl a. Total suspended solids (TSS was reduced in ZM and ZQ treatments. Light intensity at the sediment surface was higher in all three mussel treatments than in the no-mussel controls but there was no difference among the mussel treatments. There was no increase in benthic algae biomass in the mussel treatments compared with the no-mussel controls. Importantly, there was no significant difference in nutrient (TP, soluble reactive phosphorus and NO3- levels, TSS, phytoplankton Chl a, benthic algal Chl a, or light intensity on the sediment surface between ZM, QM and ZQ treatments. These results confirm the strong effect of both mussel species on water clarity and indicate that the displacement of zebra mussel by an equivalent biomass of quagga mussel is not likely to lead to further increases in water clarity, at least for the limnological conditions, including summer temperature, tested in this experiment.

  3. Will the Displacement of Zebra Mussels by Quagga Mussels Increase Water Clarity in Shallow Lakes during Summer? Results from a Mesocosm Experiment.

    Science.gov (United States)

    Mei, Xueying; Zhang, Xiufeng; Kassam, Sinan-Saleh; Rudstam, Lars G

    2016-01-01

    Zebra mussels (Dreissena polymorpha) are known to increase water clarity and affect ecosystem processes in invaded lakes. During the last decade, the conspecific quagga mussels (D. rostriformis bugensis) have displaced zebra mussels in many ecosystems including shallow lakes such as Oneida Lake, New York. In this study, an eight-week mesocosm experiment was conducted to test the hypothesis that the displacement of zebra mussels by quagga mussels leads to further decreases in phytoplankton and increases in water clarity resulting in increases in benthic algae. We found that the presence of zebra mussels alone (ZM), quagga mussels alone (QM), or an equal number of both species (ZQ) reduced total phosphorus (TP) and phytoplankton Chl a. Total suspended solids (TSS) was reduced in ZM and ZQ treatments. Light intensity at the sediment surface was higher in all three mussel treatments than in the no-mussel controls but there was no difference among the mussel treatments. There was no increase in benthic algae biomass in the mussel treatments compared with the no-mussel controls. Importantly, there was no significant difference in nutrient (TP, soluble reactive phosphorus and NO3-) levels, TSS, phytoplankton Chl a, benthic algal Chl a, or light intensity on the sediment surface between ZM, QM and ZQ treatments. These results confirm the strong effect of both mussel species on water clarity and indicate that the displacement of zebra mussel by an equivalent biomass of quagga mussel is not likely to lead to further increases in water clarity, at least for the limnological conditions, including summer temperature, tested in this experiment.

  4. Threatened and Endangered Freshwater Fish and Mussel Species Richness

    Data.gov (United States)

    U.S. Environmental Protection Agency — These data represent predicted current distributions of all US listed Threatened and Endangered freshwater fish and freshwater mussels in the Middle-Atlantic region....

  5. Mussels as bioindicators of diclofenac contamination in coastal environments.

    Science.gov (United States)

    Cunha, S C; Pena, A; Fernandes, J O

    2017-06-01

    Diclofenac a nonsteroidal anti-inflammatory drug (NSAID) has been confirmed as an emerging contaminant in the aquatic environment. Toxicology studies have revealed that harmful effects may emerge from diclofenac presence not only for human health, but also for marine organisms, which implies its monitoring. To overcome the demanding challenges of diclofenac quantification in biotic aquatic species, a novel method for the determination of diclofenac in mussels (Mytilus galloprovincialis and Mytilus edulis) and macroalgae (Laminaria digitata) using high performance liquid chromatography coupled to tandem mass spectrometry was developed and validated according to the EC Decision 2002/657/EC. Additionally, a study was done about diclofenac contamination in mussels collected from 8 sites along the 1115 miles of coastline in Portugal in 2015. The results suggested that levels in mussels are closely related to the environmental contamination. Therefore, mussels can be a potential bioindicator of diclofenac contamination in the coastal environment. Copyright © 2017 Elsevier Ltd. All rights reserved.

  6. USGS Zebra Mussel Monitoring Program for north Texas

    Science.gov (United States)

    Churchill, Christopher J.; Baldys, Stanley

    2012-01-01

    The U.S. Geological Survey (USGS) Zebra Mussel Monitoring Program for north Texas provides early detection and monitoring of zebra mussels (Dreissena polymorpha) by using a holistic suite of detection methods. The program is designed to assess zebra mussel occurrence, distribution, and densities in north Texas waters by using four approaches: (1) SCUBA diving, (2) water-sample collection with plankton tow nets (followed by laboratory analyses), (3) artificial substrates, and (4) water-quality sampling. Data collected during this type of monitoring can assist rapid response efforts and can be used to quantify the economic and ecological effects of zebra mussels in the north Texas area. Monitoring under this program began in April 2010. The presence of large zebra mussel populations often causes undesirable economic and ecological effects, including damage to water-processing infrastructure and hydroelectric powerplants (with an estimated 10-year cost of $3.1 billion), displacement of native mussels, increases in concentrations of certain species of cyanobacteria, and increases in concentrations of geosmin (an organic compound that results in taste and odor issues in water). Since no large-scale, environmentally safe eradication method has been developed for zebra mussels, it is difficult to remove established populations. Broad physicochemical adaptability, prolific reproductive capacity, and rapid dispersal methods have enabled zebra mussels, within a period of about 20 years, to establish populations under differing environmental conditions across much of the eastern part of the United States. In Texas, the presence of zebra mussels was first confirmed in April 2009 in Lake Texoma in the Red River Basin along the Texas-Oklahoma border. They were most likely introduced into Lake Texoma through overland transport from an infested water body. Since then, the presence of zebra mussels has been reported in both the Red River and Washita River arms of Lake Texoma, in

  7. Evolutionary process of deep-sea bathymodiolus mussels.

    Science.gov (United States)

    Miyazaki, Jun-Ichi; de Oliveira Martins, Leonardo; Fujita, Yuko; Matsumoto, Hiroto; Fujiwara, Yoshihiro

    2010-04-27

    Since the discovery of deep-sea chemosynthesis-based communities, much work has been done to clarify their organismal and environmental aspects. However, major topics remain to be resolved, including when and how organisms invade and adapt to deep-sea environments; whether strategies for invasion and adaptation are shared by different taxa or unique to each taxon; how organisms extend their distribution and diversity; and how they become isolated to speciate in continuous waters. Deep-sea mussels are one of the dominant organisms in chemosynthesis-based communities, thus investigations of their origin and evolution contribute to resolving questions about life in those communities. We investigated worldwide phylogenetic relationships of deep-sea Bathymodiolus mussels and their mytilid relatives by analyzing nucleotide sequences of the mitochondrial cytochrome c oxidase subunit I (COI) and NADH dehydrogenase subunit 4 (ND4) genes. Phylogenetic analysis of the concatenated sequence data showed that mussels of the subfamily Bathymodiolinae from vents and seeps were divided into four groups, and that mussels of the subfamily Modiolinae from sunken wood and whale carcasses assumed the outgroup position and shallow-water modioline mussels were positioned more distantly to the bathymodioline mussels. We provisionally hypothesized the evolutionary history of Bathymodilolus mussels by estimating evolutionary time under a relaxed molecular clock model. Diversification of bathymodioline mussels was initiated in the early Miocene, and subsequently diversification of the groups occurred in the early to middle Miocene. The phylogenetic relationships support the "Evolutionary stepping stone hypothesis," in which mytilid ancestors exploited sunken wood and whale carcasses in their progressive adaptation to deep-sea environments. This hypothesis is also supported by the evolutionary transition of symbiosis in that nutritional adaptation to the deep sea proceeded from extracellular

  8. Reseeding of mussels on denuded rocky shores: preliminary studies ...

    African Journals Online (AJOL)

    A method is developed to establish clumps of mussels Perna perna in denuded areas on high-energy rocky shores on the south-east coast of South Africa. A total of 20 small (20–30 mm total length) mussels is placed under a 30 cm half-section of perforated PVC drainage pipe bolted to the rock surface. The pipe is left in ...

  9. Evolutionary process of deep-sea bathymodiolus mussels.

    Directory of Open Access Journals (Sweden)

    Jun-Ichi Miyazaki

    Full Text Available BACKGROUND: Since the discovery of deep-sea chemosynthesis-based communities, much work has been done to clarify their organismal and environmental aspects. However, major topics remain to be resolved, including when and how organisms invade and adapt to deep-sea environments; whether strategies for invasion and adaptation are shared by different taxa or unique to each taxon; how organisms extend their distribution and diversity; and how they become isolated to speciate in continuous waters. Deep-sea mussels are one of the dominant organisms in chemosynthesis-based communities, thus investigations of their origin and evolution contribute to resolving questions about life in those communities. METHODOLOGY/PRINCIPAL FINDING: We investigated worldwide phylogenetic relationships of deep-sea Bathymodiolus mussels and their mytilid relatives by analyzing nucleotide sequences of the mitochondrial cytochrome c oxidase subunit I (COI and NADH dehydrogenase subunit 4 (ND4 genes. Phylogenetic analysis of the concatenated sequence data showed that mussels of the subfamily Bathymodiolinae from vents and seeps were divided into four groups, and that mussels of the subfamily Modiolinae from sunken wood and whale carcasses assumed the outgroup position and shallow-water modioline mussels were positioned more distantly to the bathymodioline mussels. We provisionally hypothesized the evolutionary history of Bathymodilolus mussels by estimating evolutionary time under a relaxed molecular clock model. Diversification of bathymodioline mussels was initiated in the early Miocene, and subsequently diversification of the groups occurred in the early to middle Miocene. CONCLUSIONS/SIGNIFICANCE: The phylogenetic relationships support the "Evolutionary stepping stone hypothesis," in which mytilid ancestors exploited sunken wood and whale carcasses in their progressive adaptation to deep-sea environments. This hypothesis is also supported by the evolutionary transition of

  10. Implicit price of mussel characteristics in the auction market

    DEFF Research Database (Denmark)

    Nguyen, Thong Tien

    2012-01-01

    This study explores desired and undesired characteristics of mussels in wholesale market by applying hedonic price analysis. Transaction data in auction market in Yerseke, the Netherlands, was used to estimate linear and semi-log price models. Meat content and size count, which are measured...... of raw mussels are significant discounting factors on the price. The study also investigates the impact of farming locations and seasons on the price and the price trend during the period of 2002–2009....

  11. Hydrocarbon uptake and loss by the mussel Mytilus edulis

    Energy Technology Data Exchange (ETDEWEB)

    Fossato, V U; Canzonier, W J

    1976-01-01

    The dynamics of accumulation and elimination of hydrocarbons by the blue mussel Mytilus edulis were studied in a continuous-flow system. Mussels were exposed for as long as 41 days to 200 to 400 ..mu..g/l of diesel fuel adsorbed on kaolin particles. Hydrocarbons were accumulated in the tissues in excess of 1000 times the exposure levels. Upon termination of dosing, the mussels exhibited a rather rapid loss of hydrocarbons for the first 15 to 20 days (biological half-life = 2.7 to 3.5 days). Subsequently, however, elimination was reduced to a minimum and a considerable fraction of the hydrocarbons could be recovered from the tissues after as long as 32 days of depuration. The mussels exhibited definite signs of physiological stress due to chronic exposure to diesel fuel, although recovery was rapid upon termination of dosing. It is concluded that mussels could be utilized as a test organism for monitoring long-term hydrocarbon pollution in marine waters. The implications for the mussel culture industry are discussed.

  12. Influence of Thermal Preparation Method on Mineral Composition of Mussels

    Directory of Open Access Journals (Sweden)

    Gheorghe Valentin GORAN

    2018-02-01

    Full Text Available This study focuses on evaluation of the effects of 3 different thermal preparation methods (boiling, roasting, microwaving on mineral concentrations of mussels from Bucharest market. The mineral content in raw and cooked mussel samples was evaluated by ICP-OES and relative humidity of raw and cooked mussels by thermogravimetry. Se level in microwaved samples was significantly decreased compared to raw and the other 2 cooked mussel samples. Zn concentration in raw samples was not significantly different compared to those in roasted samples. Fe level was insignificantly different between boiled and roasted samples and significantly lowers in microwaved samples. Ni, Pb, and Se levels were significantly higher in boiled samples, and Cd levels were insignificantly different reported to cooking method. The percentage of water loss during roasting was lower than the other 2 thermal preparation methods. Potassium concentrations in cooked mussels were higher compared to raw ones. Mineral concentrations were highest in roasted samples and heavy metal concentrations in boiled mussels.

  13. When and how? Freshwater mussel recolonization in Lake Orta

    Directory of Open Access Journals (Sweden)

    Nicoletta Riccardi

    2016-04-01

    Full Text Available Thanks to a video posted on a social network, live mussels of Unio elongatulus, have been recorded from Lake Orta (Italy over one century after the last (and only report. With its long and well documented history of pollution, Lake Orta offers the opportunity to document the post-extirpation recovery of freshwater unionid mussels. This case evidences that recovery/recolonization is possible despite a high devastation in the past, and permits to evaluate how fast recolonization may occur, in which way, and in what conditions.  The answer to the 'how fast' was sought by estimating the age of the larger and seemingly older individuals of the population. To address the 'in which way' we compared the haplotypes of Lake Orta specimens of Unio elongatulus (the only species present with those of surrounding populations. We concluded that, since Lake Orta lacks a direct connection with the putative source populations, colonizing mussels were almost certainly transported by fish carrying glochidia that were used for lake restocking after liming. Data from the long-term monitoring of water chemistry and sediments have allowed defining what conditions proved to be suitable for survival making possible the start of mussels recovery. But not only water and sediment quality matters for mussels recovery, which was delayed by nearly ten years after the reappearance of fish. This delay reflects the need of the whole trophic chain to be reestablished to allow the survival of the suitable and healthy host-fish populations necessary for mussels reproduction.

  14. Livelihoods of squatter settlements : analysis from tenure perspective

    NARCIS (Netherlands)

    Shrestha, Ashokkumar; Nepali, Purna; Panday, U.S.; Shrestha, Reshma

    2017-01-01

    Squatter settlements are inevitable in most of the urban areas. Livelihood situation of squatter settlements seem poor, vulnerable and miserable. Living condition in these settlements suffered from overcrowding, inadequate accommodation, limited access to clean water and sanitation, lack of proper

  15. Occurence of the Quagga Mussel Dreissena bugensis and the Zebra Mussel Dreissena polymorha in the Upper Mississippi River System

    Science.gov (United States)

    This manuscript reports on a range expansion of the invasive quagga mussel in the Great Rivers of the Upper Missippi River Basin. This research will be of interest to great river ecologists and to invasive species specialists.

  16. Zebra Mussel Research Technical Notes. Impacts of Zebra Mussel Infestations on Water Quality. Section 1 - Environmental Testing

    National Research Council Canada - National Science Library

    Ashby, Steven

    1998-01-01

    ..., and sediment quality. The purpose of this technical note describes potential changes in water quality as a result of zebra mussel infestations in aquatic systems, based on a review of the literature...

  17. Efficacy of Pseudomonas fluorescens strain CL145A spray dried powder for controlling zebra mussels adhering to native unionid mussels within field enclosures

    Science.gov (United States)

    Luoma, James A.; Weber, Kerry L.; Severson, Todd J.; Mayer, Denise A.

    2015-01-01

    The efficacy of a commercially prepared spray dried powder (SDP) formulation of Pseudomonas fluorescens (strain CL145A) was evaluated for removing zebra mussels (Dreissena polymorpha) adhering to a population of unionid mussels in Lake Darling (Alexandria, Minnesota). Two groups of unionid mussels were used in the study. Unionid mussels were collected near the test area, weighed, photographed, individually tagged, and randomly allocated to one of nine test enclosures in equal proportions and then divided into two groups. The first group of unionid mussels (Group 1, n = 5 per test enclosure) were indiscriminately selected from each test enclosure and used to estimate the number of zebra mussels adhering to unionid mussels prior to exposure. The second group of unionid mussels (Group 2, n = 22 per test enclosure) were used to evaluate the efficacy of SDP for removal of adhering zebra mussels. Both Group 1 and Group 2 mussels were used to evaluate the effects of SDP exposure on unionid mussel survival.

  18. NATURE-RURAL SETTLEMENT INTERACTIONS

    Directory of Open Access Journals (Sweden)

    Zehra Eminağaoğlu

    2006-04-01

    Full Text Available Conservation and management of natural environments are generally brought up upon adverse developments against nature in the humannature interactions. Although individual actions are often considered to be more immediate innatıre-related issuesi ecologic problems tend to spread in time and lead to reginol or even global problems. For this reason, it stands imperative that economic, ecologic and aesthetic values of the environment we live in be protected and used sustainably. Being the scene of nature and the environment landscape signifies the whole with living and nonliving entities where we live in. Dameged and destroyed landscape scenes particularly in urban areas necessitaites the reconsideration of human-nature relations and nature-frendly life style. This study investigates the rural settlements that show harmony with nature and reflects qualities of natural environments on the dwellings. Particularly, with the examples of drawing and pictures it examines the associatiation of rural settlements with nature as well as the use of the green as an occasional or spacial element.

  19. 7 CFR 1427.172 - Settlement.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 10 2010-01-01 2010-01-01 false Settlement. 1427.172 Section 1427.172 Agriculture Regulations of the Department of Agriculture (Continued) COMMODITY CREDIT CORPORATION, DEPARTMENT OF AGRICULTURE LOANS, PURCHASES, AND OTHER OPERATIONS COTTON Recourse Seed Cotton Loans § 1427.172 Settlement. (a...

  20. 5 CFR 838.135 - Settlements.

    Science.gov (United States)

    2010-01-01

    ... 5 Administrative Personnel 2 2010-01-01 2010-01-01 false Settlements. 838.135 Section 838.135 Administrative Personnel OFFICE OF PERSONNEL MANAGEMENT (CONTINUED) CIVIL SERVICE REGULATIONS (CONTINUED) COURT... § 838.135 Settlements. (a) OPM must comply with the terms of a properly filed court order acceptable for...

  1. 42 CFR 402.17 - Settlement.

    Science.gov (United States)

    2010-10-01

    ... 42 Public Health 2 2010-10-01 2010-10-01 false Settlement. 402.17 Section 402.17 Public Health CENTERS FOR MEDICARE & MEDICAID SERVICES, DEPARTMENT OF HEALTH AND HUMAN SERVICES GENERAL PROVISIONS CIVIL MONEY PENALTIES, ASSESSMENTS, AND EXCLUSIONS General Provisions § 402.17 Settlement. CMS or OIG has...

  2. 45 CFR 150.413 - Settlement.

    Science.gov (United States)

    2010-10-01

    ... 45 Public Welfare 1 2010-10-01 2010-10-01 false Settlement. 150.413 Section 150.413 Public Welfare DEPARTMENT OF HEALTH AND HUMAN SERVICES REQUIREMENTS RELATING TO HEALTH CARE ACCESS CMS ENFORCEMENT IN GROUP AND INDIVIDUAL INSURANCE MARKETS Administrative Hearings § 150.413 Settlement. CMS has exclusive...

  3. 42 CFR 1003.126 - Settlement.

    Science.gov (United States)

    2010-10-01

    ... 42 Public Health 5 2010-10-01 2010-10-01 false Settlement. 1003.126 Section 1003.126 Public Health OFFICE OF INSPECTOR GENERAL-HEALTH CARE, DEPARTMENT OF HEALTH AND HUMAN SERVICES OIG AUTHORITIES CIVIL MONEY PENALTIES, ASSESSMENTS AND EXCLUSIONS § 1003.126 Settlement. The Inspector General has exclusive...

  4. 20 CFR 498.126 - Settlement.

    Science.gov (United States)

    2010-04-01

    ... 20 Employees' Benefits 2 2010-04-01 2010-04-01 false Settlement. 498.126 Section 498.126 Employees' Benefits SOCIAL SECURITY ADMINISTRATION CIVIL MONETARY PENALTIES, ASSESSMENTS AND RECOMMENDED EXCLUSIONS § 498.126 Settlement. The Inspector General has exclusive authority to settle any issues or case...

  5. 5 CFR 838.1018 - Settlements.

    Science.gov (United States)

    2010-01-01

    ... 5 Administrative Personnel 2 2010-01-01 2010-01-01 false Settlements. 838.1018 Section 838.1018 Administrative Personnel OFFICE OF PERSONNEL MANAGEMENT (CONTINUED) CIVIL SERVICE REGULATIONS (CONTINUED) COURT... Settlements. The former spouse may request that an amount be withheld from the retirement benefits that is...

  6. Internalization, Clearing and Settlement, and Liquidity

    NARCIS (Netherlands)

    Degryse, H.A.; van Achter, M.; Wuyts, G.

    2012-01-01

    Abstract: We study the relation between liquidity in financial markets and post-trading fees (i.e. clearing and settlement fees). The clearing and settlement agent (CSD) faces different marginal costs for different types of transactions. Costs are lower for an internalized transaction, i.e. when

  7. Improving settlement type classification of aerial images

    CSIR Research Space (South Africa)

    Mdakane, L

    2014-10-01

    Full Text Available , an automated method can be used to help identify human settlements in a fixed, repeatable and timely manner. The main contribution of this work is to improve generalisation on settlement type classification of aerial imagery. Images acquired at different dates...

  8. Assessment of blue mussel Mytilus edulis fisheries and waterbird shellfish-predator management in the Danish Wadden Sea

    DEFF Research Database (Denmark)

    Laursen, Karsten; Kristensen, Per Sand; Clausen, Preben

    2010-01-01

    biomass and mussel bed areas in zones closed to fishery, (ii) decrease in eiders Somateria mollissima numbers and increase or stable numbers for oystercatcher Haematopus ostralegus and herring gull Larus argentatus and (iii) that energy estimations based on ecological food requirements for the mussel-eating......We assessed the blue mussel Mytilus edulis fishery management scheme introduced in 1994 in the Danish Wadden Sea that regulate fishing vessels, fishery quota, set-aside for mussel-eating birds and established zones closed to mussel fishery. The results showed (i) a reduction in the blue mussel......, it is recommended to revise the present blue mussel management scheme in the Danish Wadden Sea, to continue and improve mussel stock and bird surveys, and to consider novel studies of the mussel-eating birds’ energetics for improved set-aside estimates and future assessments....

  9. Aggregations of brittle stars can perform similar ecological roles as mussel reefs

    KAUST Repository

    Geraldi, NR; Bertolini, C; Emmerson, MC; Roberts, D; Sigwart, JD; O’ Connor, NE

    2016-01-01

    considered. We quantified the abundance of sessile horse mussels Modiolus modiolus and aggregating brittle stars Ophiothrix fragilis and tested for correlations between the density of mussels (live and dead) and brittle stars each with (1) abundance, biomass

  10. A Survey of Freshwater Mussels in the West Pearl River, Mississippi and Louisiana, 1995

    National Research Council Canada - National Science Library

    Miller, Andrew

    1997-01-01

    .... The nonindigenous zebra mussel, Dreissena polymorpha, introduced into the Great Lakes in the late 1980s, and the threatened mussel, Potamilus inflatus, listed as endangered, were not found although...

  11. Settlement-Size Scaling among Prehistoric Hunter-Gatherer Settlement Systems in the New World.

    Directory of Open Access Journals (Sweden)

    W Randall Haas

    Full Text Available Settlement size predicts extreme variation in the rates and magnitudes of many social and ecological processes in human societies. Yet, the factors that drive human settlement-size variation remain poorly understood. Size variation among economically integrated settlements tends to be heavy tailed such that the smallest settlements are extremely common and the largest settlements extremely large and rare. The upper tail of this size distribution is often formalized mathematically as a power-law function. Explanations for this scaling structure in human settlement systems tend to emphasize complex socioeconomic processes including agriculture, manufacturing, and warfare-behaviors that tend to differentially nucleate and disperse populations hierarchically among settlements. But, the degree to which heavy-tailed settlement-size variation requires such complex behaviors remains unclear. By examining the settlement patterns of eight prehistoric New World hunter-gatherer settlement systems spanning three distinct environmental contexts, this analysis explores the degree to which heavy-tailed settlement-size scaling depends on the aforementioned socioeconomic complexities. Surprisingly, the analysis finds that power-law models offer plausible and parsimonious statistical descriptions of prehistoric hunter-gatherer settlement-size variation. This finding reveals that incipient forms of hierarchical settlement structure may have preceded socioeconomic complexity in human societies and points to a need for additional research to explicate how mobile foragers came to exhibit settlement patterns that are more commonly associated with hierarchical organization. We propose that hunter-gatherer mobility with preferential attachment to previously occupied locations may account for the observed structure in site-size variation.

  12. Commuting in the settlement system of Serbia

    Directory of Open Access Journals (Sweden)

    Lukić Vesna

    2011-01-01

    Full Text Available Territorial organization of settlement system is the framework for internal migration flows. The purpose of this paper is to consider the relation between commuting and the settlement structure. Commuting patterns and characteristics of commuters in Serbia are relatively unknown and insufficiently researched, and as such, can not be adequately used in creation of development strategies and public policies which would include commuters' issues. It has been emphasized the importance of research of commuting ties between different settlements and also pointed out in which way commuting flows could be researched and analyzed by using existing sources, due to better understanding of connections between migrations and settlements. Commuting patterns of workers in Serbia and interrelations between the scope and the structure of commuting flows, as well as the type and population size of settlements in Serbia have been examined. Apart from territorial dimension of commuting phenomenon, socio-economic component of commuting population has also been considered. The use of costumised tabulations from 2002 Census have enabled us to examine all types of commuting and emphasise dominant directions of commuting flows of economically active population according to gender, level of education and sector of economic activity, within the settlement hierarchy. Workers have been classified into seven groups according to place of residence and place of work. The findings reveal there is a clear connection between the hierarchy structure and commuting patterns in Serbia. Further, we find some evidence that only 9,5% of workers - commuters have been working in the settlement of the same population size and type such as their residing settlement. Commuting flows within Serbia’s settlement system point out to certain variations when looking at individual categories of population, but it can be concluded that there is general trend of commuting "upwards" within the

  13. The existence of microplastic in Asian green mussels

    Science.gov (United States)

    Khoironi, A.; Anggoro, S.; Sudarno

    2018-03-01

    Due to resistance of polymer as basic properties of plastic, several studies have been conducted to understand the fate of plastic debris in the marine environment. Degradation is the most important process to control distribution of plastic debris a long the marine environment until the existence of plastic in the food chain. The physical and chemical changes of plastic because of degradation process will lead to the release of polluted substances which eventually more toxic for the environment. Furthermore, when plastic degraded become a microplastic will lead to easy ingested by biotic such as mussell which commonly consumed by humans. The aim of this research was to investigate the concentration of microplastic adsorbed and ingested by mussels considering characteristic of sea water. About 30 samples have been collected from 3 different locations that is brackish water (31 ppb), high salinity (36 ppb) and low salinity (33 ppb) for measuring a number of microplastic in mussels on three different salinity. The result of microstructure analysis by microscope showed that mussel evaluated from the marine environment contaminated by microplastic with average size of 211.163 μm. In high salinity sea water, microplastic found in mussel was greater than low salinity and brackish water. The SEM/EDX analysis showed the presence of SIO2 0.14 % (w/w), Na2O 24.27 %(w/w) and Al2O3 0.27 % (w/w) in the microplastic obtained in the mussel indicating the components which are mostly found in the plastic industries. The amount of microplastic in mussell could be used as pollution indicator in the marine environmental by plastic waste.

  14. Decontamination strategies in contaminated settlement

    International Nuclear Information System (INIS)

    Hubert, P.; Jouve, A.; Tallec, V. Le

    1996-01-01

    Six years after the Chernobyl accident, decontamination actions had been completed in many places, the contamination could be considered as fixed, especially on urban surfaces and the social situation was felt to be stabilized. Under those conditions the efficiency of the 'classical' decontamination techniques was under question, it was worthwhile to look at new specific techniques. Besides it was necessary to discuss the interest of new decontamination actions in settlements. The European Union (EU) sponsored a project ECP 4 in order to look at the opportunities for further dose reduction actions in the contaminated territories of the three republics affected by the accident. The objective was to provide a local decision maker, faced with many alternatives for decontamination, with all the elements for determining what to do according to the various objectives he might pursue. The main results are presented here. (author)

  15. Pervasive hydrologic effects on freshwater mussels and riparian trees in southeastern floodplain ecosystems

    Science.gov (United States)

    Andrew L. Rypel; Wendell R. Haag; Robert H. Findlay

    2009-01-01

    We present long-term growth trends for 13 freshwater mussel species from two unregulated rivers and one regulated river in the southeastern U.S. Coastal Plain. We also collected baldcypress (Taxodium distichum (L.) Rich.) tree cores adjacent to mussel collection sites in one river and directly compared tree and mussel chronologies in this river. To extend our analysis...

  16. Assimilation and depuration of microcystin–LR by the zebra mussel, Dreissena polymorpha

    NARCIS (Netherlands)

    Pires, L.M.D.; Karlsson, K.M.; Meriluoto, J.A.O.; Kardinaal, E.A.; Visser, P.M.; Siewertsen, K.; Van Donk, E.; Ibelings, B.W.

    2004-01-01

    Zebra mussels (Dreissena polymorpha) are an important component of the foodweb of shallow lakes in the Netherlands, amongst others in Lake IJsselmeer, an international important wetland. Large numbers of ducks feed on these mussels in autumn and winter. The mussels are filter feeders and are exposed

  17. Evaluation of the Danish mussel fishery: suggestions for an ecosystem management approach

    DEFF Research Database (Denmark)

    Dolmer, Per; Frandsen, Rikke

    2002-01-01

    fishery are suggested. The suggested modifications include: a fishery practice where the mussel beds are thinned out when the mussels have attained good quality, and a transplantation practice of mussels from areas with a high mortality to areas with a high growth rate. Both practices intensify...

  18. Modeling mussel bed influence on fine sediment dynamics on a Wadden Sea intertidal flat

    NARCIS (Netherlands)

    van Leeuwen, Bas; Augustijn, Dionysius C.M.; van Wesenbeeck, Bregje K.; Hulscher, Suzanne J.M.H.; de Vries, Mindert

    2008-01-01

    Mussel beds are coherent colonies of mussels and are widespread in the Dutch Wadden Sea and the Eastern Scheldt estuary. Mussel beds are known to be an important factor in biogeomorphological processes, primarily because of the influence on fine sediment dynamics. Ongoing research to explore the use

  19. The process of negotiating settlements at FERC

    International Nuclear Information System (INIS)

    Littlechild, Stephen

    2012-01-01

    Interstate gas pipelines and their customers presently settle about 90% of the rate cases set for hearing before the Federal Energy Regulatory Commission (FERC). The conventional regulatory litigation process is now only an occasional means of dispute resolution. This paper explains the settlement process, illustrating with the 12 section 4 rate cases brought by pipelines from 2008 and 2009. The paper also discusses and illustrates why parties prefer settlement to litigation, what difference it makes, which cases tend to settle, what might account for the increasing frequency of settlements over time, the recent phenomenon of pre-filing settlements and the recent settlement of section 5 cases brought by FERC. In contrast to many other regulatory jurisdictions, FERC Trial Staff play an active role in facilitating negotiation and settlement. They make an initial analysis 3 months after a pipeline files for a tariff rate increase. Thereafter, the regulatory aim is to bring the parties into agreement, not to determine an outcome and impose it upon them. This is a different role for the regulatory body than was previously apparent. - Highlights: ► About 90% of FERC rate cases are settled, not litigated. ► FERC Trial Staff play an active role in facilitating negotiation and settlement. ► Conventional regulation is now only an occasional means of dispute resolution. ► The paper also discusses which cases settle and what difference it makes.

  20. Biological challenges of true space settlement

    Science.gov (United States)

    Mankins, John C.; Mankins, Willa M.; Walter, Helen

    2018-05-01

    "Space Settlements" - i.e., permanent human communities beyond Earth's biosphere - have been discussed within the space advocacy community since the 1970s. Now, with the end of the International Space Station (ISS) program fast approaching (planned for 2024-2025) and the advent of low cost Earth-to-orbit (ETO) transportation in the near future, the concept is coming once more into mainstream. Considerable attention has been focused on various issues associated with the engineering and human health considerations of space settlement such as artificial gravity and radiation shielding. However, relatively little attention has been given to the biological implications of a self-sufficient space settlement. Three fundamental questions are explored in this paper: (1) what are the biological "foundations" of truly self-sufficient space settlements in the foreseeable future, (2) what is the minimum scale for such self-sustaining human settlements, and (3) what are the integrated biologically-driven system requirements for such settlements? The paper examines briefly the implications of the answers to these questions in relevant potential settings (including free space, the Moon and Mars). Finally, this paper suggests relevant directions for future research and development in order for such space settlements to become viable in the future.

  1. Do invasive mussels restrict offshore phosphorus transport in Lake Huron?

    Science.gov (United States)

    Cha, Yoonkyung; Stow, Craig A; Nalepa, Thomas F; Reckhow, Kenneth H

    2011-09-01

    Dreissenid mussels were first documented in the Laurentian Great Lakes in the late 1980s. Zebra mussels (Dreissena polymorpha) spread quickly into shallow, hard-substrate areas; quagga mussels (Dreissena rostriformis bugensis) spread more slowly and are currently colonizing deep, offshore areas. These mussels occur at high densities, filter large water volumes while feeding on suspended materials, and deposit particulate waste on the lake bottom. This filtering activity has been hypothesized to sequester tributary phosphorus in nearshore regions reducing offshore primary productivity. We used a mass balance model to estimate the phosphorus sedimentation rate in Saginaw Bay, a shallow embayment of Lake Huron, before and after the mussel invasion. Our results indicate that the proportion of tributary phosphorus retained in Saginaw Bay increased from approximately 46-70% when dreissenids appeared, reducing phosphorus export to the main body of Lake Huron. The combined effects of increased phosphorus retention and decreased phosphorus loading have caused an approximate 60% decrease in phosphorus export from Saginaw Bay to Lake Huron. Our results support the hypothesis that the ongoing decline of preyfish and secondary producers including diporeia (Diporeia spp.) in Lake Huron is a bottom-up phenomenon associated with decreased phosphorus availability in the offshore to support primary production.

  2. 210Po activity concentrations in mussels at Aegean Turkish Coast

    International Nuclear Information System (INIS)

    Sekkin, F.; Tanbay, A.; Vener, V.

    2000-01-01

    In Turkey mussels (Mytilus galloprovincialis) are consumed in relatively large quantities. Therefore, analyses of mussel samples from different sampling sites in Aegean Sea were performed in order to evaluate the ingestion of 210 Po and 210 Pb by the Turkey population. Polonium analyses were performed with a complete dissolution of the sample in mineral acids. Polonium isotopes were plated onto a copper discs in 0.5 M HCl solution in the presence of ascorbic acid using a technique modified from Flynn (1968). The alpha activity measurements of polonium isotopes plated on copper discs were performed with ZnS(Ag) detector. The highest concentrations was found in Karaburun mussels as 254 Bq.kg -1 and the lowest one was at Inciralti as 18 Bq.kg -1 . Based on these 210 Po activity concentrations, annual dose equivalent rates delivered to biological tissues in mussels would vary widely, from 136 to 10 mSv.y -1 . It is concluded that in mussels living in the Aegean Sea a wide range of internal radiation dose exists and it is essentially sustained by 210 Po food-chain transfer. (author)

  3. Magnetic resonance imaging of live freshwater mussels (Unionidae)

    Science.gov (United States)

    Michael, Holliman F.; Davis, Denise; Bogan, Arthur E.; Kwak, Thomas J.; Cope, W. Gregory; Levine, Jay F.

    2008-01-01

    We examined the soft tissues of live freshwater mussels, Eastern elliptio Elliptio complanata, via magnetic resonance imaging (MRI), acquiring data with a widely available human whole-body MRI system. Anatomical features depicted in the profile images included the foot, stomach, intestine, anterior and posterior adductor muscles, and pericardial cavity. Noteworthy observations on soft tissue morphology included a concentration of lipids at the most posterior aspect of the foot, the presence of hemolymph-filled fissures in the posterior adductor muscle, the presence of a relatively large hemolymph-filled sinus adjacent to the posterior adductor muscle (at the ventral-anterior aspect), and segmentation of the intestine (a diagnostic description not reported previously in Unionidae). Relatively little is known about the basic biology and ecological physiology of freshwater mussels. Traditional approaches for studying anatomy and tissue processes, and for measuring sub-lethal physiological stress, are destructive or invasive. Our study, the first to evaluate freshwater mussel soft tissues by MRI, clarifies the body plan of unionid mussels and demonstrates the efficacy of this technology for in vivoevaluation of the structure, function, and integrity of mussel soft tissues.

  4. 48 CFR 49.109-5 - Partial settlements.

    Science.gov (United States)

    2010-10-01

    ... 48 Federal Acquisition Regulations System 1 2010-10-01 2010-10-01 false Partial settlements. 49... MANAGEMENT TERMINATION OF CONTRACTS General Principles 49.109-5 Partial settlements. The TCO should attempt... settlements covering particular items of the prime contractor's settlement proposal. However, when a TCO...

  5. Mussels as a tool for mitigation of nutrients in the marine environment

    DEFF Research Database (Denmark)

    Petersen, Jens Kjerulf; Hasler, Berit; Timmermann, Karen

    2014-01-01

    Long-line mussel farming has been proposed as a mitigation tool for removal of excess nutrients in eutrophic coastal waters. A full-scale mussel farm optimized for cost efficient nutrient removal was established in the eutrophic Skive Fjord, Denmark where biological and economic parameters related...... to establishment, maintenance and harvest revealed that mussel production optimized for mitigation can be carried out at a lower cost compared to mussel production for (human) consumption. The costs for nutrient removal was 14.8€kg−1N making mitigation mussel production a cost-efficient measure compared...

  6. Epibiosis Reduction on Productivity in a Mussel Culture of Perna perna (Linné, 1758

    Directory of Open Access Journals (Sweden)

    Rafael Metri

    2002-09-01

    Full Text Available Cultivated mussels (Perna perna were studied to test for the effects of cleaning on their growth. These effects were examined by experimentally cleaning mussels and by changing mussel density. Treatment was performed twice, at two and four months after immerging the ropes. Two months after the first treatment and three months after the second treatment, mussels were harvested and measured (weight, length, width and thickness. Analysis of variance showed that none of the treatments resulted in increased growth of the mussels, nor did increased density result in decreased growth when compared with the control. It was concluded that it was not necessary to clean the shells to increase harvest.

  7. Epibiosis Reduction on Productivity in a Mussel Culture of Perna perna (Linné, 1758

    Directory of Open Access Journals (Sweden)

    Metri Rafael

    2002-01-01

    Full Text Available Cultivated mussels (Perna perna were studied to test for the effects of cleaning on their growth. These effects were examined by experimentally cleaning mussels and by changing mussel density. Treatment was performed twice, at two and four months after immerging the ropes. Two months after the first treatment and three months after the second treatment, mussels were harvested and measured (weight, length, width and thickness. Analysis of variance showed that none of the treatments resulted in increased growth of the mussels, nor did increased density result in decreased growth when compared with the control. It was concluded that it was not necessary to clean the shells to increase harvest.

  8. Are Predators Limiting Zebra Mussel Colonization of Unionid Mussels in Great Lake Coastal Wetlands?

    Science.gov (United States)

    de Szalay, F. A.; Bowers, R.

    2005-05-01

    Although many native mollusc populations have been eliminated in the Laurentian Great Lakes by the exotic zebra mussel, recent surveys have found abundant unionid (Bivalvia: Unionidae) populations in some coastal wetlands. Unionid burrowing in soft sediments and predation by fish have been shown to reduce numbers of attached zebra mussels, and we tested these factors in a Lake Erie coastal wetland. In 2002, we held live unionids (Leptodea fragilis, Quadrula quadrula) and Pyganodon grandis shells in exclosures with wire mesh bottoms that were buried to sediment depths of either 5, 10, or 20 cm. After 2 months, numbers of attached dreissenids on unionids were significantly higher inside all exclosure treatments than outside exclosures. This indicated that either unionid burrowing was prevented in all sediment depth treatments or molluscivores were excluded by exclosures. In 2004, we measured dreissenid colonization on Q. quadrula and PVC plates in bottomless exclosures with different mesh sizes. After 6 months, dreissenid numbers on PVC plates and on Q. quadrula in 2.5 cm X 2.5 cm and 5 cm X 10 cm mesh exclosures were significantly higher than in open exclosures. These data suggest that molluscivores are important in limiting dreissenids in Great Lake coastal wetlands.

  9. Mussel dynamics model: A hydroinformatics tool for analyzing the effects of different stressors on the dynamics of freshwater mussel communities

    Science.gov (United States)

    Morales, Y.; Weber, L.J.; Mynett, A.E.; Newton, T.J.

    2006-01-01

    A model for simulating freshwater mussel population dynamics is presented. The model is a hydroinformatics tool that integrates principles from ecology, river hydraulics, fluid mechanics and sediment transport, and applies the individual-based modelling approach for simulating population dynamics. The general model layout, data requirements, and steps of the simulation process are discussed. As an illustration, simulation results from an application in a 10 km reach of the Upper Mississippi River are presented. The model was used to investigate the spatial distribution of mussels and the effects of food competition in native unionid mussel communities, and communities infested by Dreissena polymorpha, the zebra mussel. Simulation results were found to be realistic and coincided with data obtained from the literature. These results indicate that the model can be a useful tool for assessing the potential effects of different stressors on long-term population dynamics, and consequently, may improve the current understanding of cause and effect relationships in freshwater mussel communities. ?? 2006 Elsevier B.V. All rights reserved.

  10. Measurement of Narora reactor building relative settlement

    International Nuclear Information System (INIS)

    Deo, P.M.; Pande, K.C.; Patwardhan, H.S.

    1977-01-01

    The civil construction of the reactor building of Narora Atomic Power Project has a special problem. The stability of the structure is liable to settlement as this location falls in seismic zone. To obviate the possibility of large scale unequal settlements, the reactor building is founded on a 4 meter thick rigid raft concreted in three layers, at a depth of 13 meters below ground. Stainless steel tanks will be embedded at 17 locations to measure relative settlements. The relative elevation difference will be detected by electrical probes when the water level in any one of the tanks touches the tip of the probes. The design envisages a maximum permissible unequal settlements of about 10 mm. over a period of 20 years. (K.B.)

  11. Optimization of thermal processing of canned mussels.

    Science.gov (United States)

    Ansorena, M R; Salvadori, V O

    2011-10-01

    The design and optimization of thermal processing of solid-liquid food mixtures, such as canned mussels, requires the knowledge of the thermal history at the slowest heating point. In general, this point does not coincide with the geometrical center of the can, and the results show that it is located along the axial axis at a height that depends on the brine content. In this study, a mathematical model for the prediction of the temperature at this point was developed using the discrete transfer function approach. Transfer function coefficients were experimentally obtained, and prediction equations fitted to consider other can dimensions and sampling interval. This model was coupled with an optimization routine in order to search for different retort temperature profiles to maximize a quality index. Both constant retort temperature (CRT) and variable retort temperature (VRT; discrete step-wise and exponential) were considered. In the CRT process, the optimal retort temperature was always between 134 °C and 137 °C, and high values of thiamine retention were achieved. A significant improvement in surface quality index was obtained for optimal VRT profiles compared to optimal CRT. The optimization procedure shown in this study produces results that justify its utilization in the industry.

  12. Mussel glue protein has an open conformation.

    Science.gov (United States)

    Williams, T; Marumo, K; Waite, J H; Henkens, R W

    1989-03-01

    Both native glue protein from marine mussels and a synthetic nonhydroxylated analog were analyzed by far-uv CD under a variety of conditions. Analysis of the CD spectra using various models strongly suggest a primarily random coil structure for both forms of the protein, a fact also supported by the absence of spectral change for the glue protein upon dilution into 6 M guanidine hydrochloride. The nonhydroxylated analog, which consists of 20 repeats of the peptide sequence Ala-Lys-Pro-Ser-Tyr-Pro-Pro-Thr-Tyr-Lys, was further characterized by enzyme modification using mushroom tyrosinase. Enzymatic hydroxylation of tyrosines was found to be best fit by a model containing two rate constants, 5.6 (+/- 0.6) X 10(-3) and 7.2 (+/- 0.3) X 10(-2) min-1. At equilibrium, HPLC analysis of digests showed nearly 100% conversion of Tyr-9 and only 15 to 35% conversion of Tyr-5. The Chou and Fasman rules for predicting structure were applied to the repeat sequence listed above. The rules predict the absence of alpha helix and beta pleated sheets in the structure of this peptide. On the other hand, beta turns are predicted to be present with Tyr-5 being in the region of highest probability. These data suggest that the protein in solution has only a small amount of secondary structure.

  13. Mussel remains from prehistoric salt works, clarke county, Alabama

    Science.gov (United States)

    McGregor, S.W.; Dumas, A.A.

    2010-01-01

    Archaeological research at salt springs in Clarke County, AL (Tombigbee River drainage), documented bivalve mollusk exploitation by late prehistoric American Indians. A total of 582 valves representing 19 species of freshwater mussels (Unionidae) and an estuarine clam (Mactridae) from the Lower Salt Works Site (ca. A.D. 900-1550) and 41 valve fragments representing 6 mussel species from the Stimpson Site (ca. A.D. 1200-1550) were documented. The Lower Salt Works fauna was dominated numerically by Fusconaia ebena and Quadrula asperata, the dominant species reported during recent local surveys. The mussel species represented are known from medium to large streams in sand and gravel habitats and include four federally protected species and other species of conservation concern in Alabama. Results offer comparative data for other archaeological and ecological studies in the region.

  14. IMPACT OF OXYGEN CONCENTRATION ON ZEBRA MUSSEL MORTALITY

    Energy Technology Data Exchange (ETDEWEB)

    Daniel P. Molloy

    2003-01-27

    These tests have indicated that the bacterium Pseudomonas fluorescens strain CL0145A is effective at killing zebra mussels in environments having dissolved oxygen (DO) concentrations ranging from very low to very high. The results suggest that the highest mussel kill can be achieved in moderately to highly aerated environments, while kill may be 0-20% lower under conditions of very low oxygen. For example, under highly oxygenated conditions 97% kill was achieved while conditions having low DO produced 79% mussel kill. Service water measured in a local power plant indicated that DO concentrations were in the range of 8-9 ppm (e.g., highly aerated) within their pipes. Therefore, we will not expect to see decreases in the efficacy of CL0145A treatments due to oxygen levels within such power plant pipes.

  15. IMPACT OF FIVE TREATMENT FACTORS ON MUSSEL MORTALITY

    Energy Technology Data Exchange (ETDEWEB)

    Daniel P. Molloy

    2003-12-08

    Under this USDOE-NETL contract, the bacterium Pseudomonas fluorescens is being developed as a biocontrol agent for zebra mussels. The specific purpose of the contract is to identify factors that affect mussel kill. Test results reported herein indicate that mussel kill should not be affected by: (1) air bubbles being carried by currents through power plant pipes; (2) pipe orientation (e.g., vertical or horizontal); (3) whether the bacterial cell concentration during a treatment is constant or slightly varying; (4) whether a treatment is between 3 hr and 12 hr in duration, given that the total quantity of bacteria being applied to the pipe is a constant; and (5) whether the water temperature is between 13 C and 23 C.

  16. IMPACT OF OXYGEN CONCENTRATION ON ZEBRA MUSSEL MORTALITY

    International Nuclear Information System (INIS)

    Molloy, Daniel P.

    2003-01-01

    These tests have indicated that the bacterium Pseudomonas fluorescens strain CL0145A is effective at killing zebra mussels in environments having dissolved oxygen (DO) concentrations ranging from very low to very high. The results suggest that the highest mussel kill can be achieved in moderately to highly aerated environments, while kill may be 0-20% lower under conditions of very low oxygen. For example, under highly oxygenated conditions 97% kill was achieved while conditions having low DO produced 79% mussel kill. Service water measured in a local power plant indicated that DO concentrations were in the range of 8-9 ppm (e.g., highly aerated) within their pipes. Therefore, we will not expect to see decreases in the efficacy of CL0145A treatments due to oxygen levels within such power plant pipes

  17. Do cues matter? Highly inductive settlement cues don't ensure high post-settlement survival in sea urchin aquaculture.

    Directory of Open Access Journals (Sweden)

    Benjamin Mos

    Full Text Available Increasing settlement and post-settlement survival during the critical transition from planktonic larvae to benthic juveniles will increase efficiency for sea urchin aquaculture. This study investigated the effects of temperature and settlement cues on the settlement and post-settlement survival of the sea urchin Tripneustes gratilla during this phase. The current commercial methodology, which utilises natural biofilm settlement plates, was tested and resulted in low settlement (90% than a natural biofilm (∼25%. The addition of macroalgae-conditioned seawater to natural biofilm significantly increased settlement rates (>85%. Mixed consortia and single strains of bacteria isolated from macroalgae, biofilms and adult conspecifics all induced significant settlement, but at significantly lower rates than macroalgae. No evidence was found that higher rates of settlement to bacteria on macroalgae were generated by a cofactor from the macroalgae. Age of bacterial cultures, culturing bacteria on solid and liquid media and concentration of nutrients in cultures had little effect on settlement rates. Finally, macroalgae-conditioned seawater combined with natural biofilm settlement plates induced significantly higher settlement than to the biofilm plates alone in a commercial scale trial. However, high post-settlement mortality resulted in equivalent survival between treatments after 25 days. This study highlights that settlement studies should extend to post-settlement survival, which remains poor for T. gratilla and is a significant obstacle to increasing efficiency for aquaculture.

  18. Seasonal variations of arsenic in mussels Mytilus galloprovincialis

    Science.gov (United States)

    Klarić, Sanja; Pavičić-Hamer, Dijana; Lucu, Čedomil

    2004-10-01

    Total arsenic concentration in the edible part of mussels Mytilus galloprovincialis was evaluated seasonally in the coastal area of Rijeka Bay (North Adriatic Sea, Croatia). Sampling stations were located close to the City of Bakar with no industrial facilities (site 1), in the vicinity of the oil refinery and oil thermoelectric power plant (Urinj, site 2), and 4 miles away from the Plomin coal thermoelectric power plant (Brseč village, site 3). Additionally, the concentration of arsenic in the tail muscle of the lobster Nephrops norvegicus, collected in Rijeka Bay, was studied. During winter at sites 2 and 3, the total arsenic in the edible part of the mussels was 16.4 mg As/kg FW (FW=fresh weight) and 4.38 mg As/kg FW, respectively, and increased during springtime at site 2 (6.5 mg As/kg FW) compared to the rest of the year, when individual total arsenic concentration at all sites ranged from 1.7 to 3.7 mg As/kg FW. In the winter (sites 2 and 3) and springtime (site 2) there was no correlation between the length of the mussel shell and the arsenic concentration in the edible part of the mussels. In the other seasons, at sites 1, 2 and 3, there was a correlation between arsenic in the edible part of mussels and shell length in most cases (correlation coefficients r varied from 0.64 to 0.85; P edible part of the mussels shows linearity with a high regression coefficient (r =0.914; P edible part during winter. In addition, a linear relationship was found between body length and arsenic concentration in the tail muscle (mean 17.11±4.48 mg As/kg FW) of the Norway lobster.

  19. Differential metabolic responses in three life stages of mussels Mytilus galloprovincialis exposed to cadmium.

    Science.gov (United States)

    Wu, Huifeng; Xu, Lanlan; Yu, Deliang; Ji, Chenglong

    2017-01-01

    Cadmium (Cd) is one of the most important metal contaminants in the Bohai Sea. In this work, NMR-based metabolomics was used to investigate the toxicological effects of Cd at an environmentally relevant concentration (50 µg L -1 ) in three different life stages (D-shape larval, juvenile and adult) of mussels Mytilus galloprovincialis. Results indicated that the D-shape larval mussel was the most sensitive life stage to Cd. The significantly different metabolic profiles meant that Cd induced differential toxicological effects in three life stages of mussels. Basically, Cd caused osmotic stress in all the three life stages via different metabolic pathways. Cd exposure reduced the anaerobiosis in D-shape larval mussels and disturbed lipid metabolism in juvenile mussels, respectively. Compared with the D-shape larval and juvenile mussels, the adult mussels reduced energy consumption to deal with Cd stress.

  20. Review of toxic episodes and management strategies in the Danish mussel production

    DEFF Research Database (Denmark)

    Jørgensen, Kevin; Andersen, Per; Thorbjørnsen, Bjarne Ring

    Denmark has in many years been one of the world’s main producers of blue mussels caught from natural banks. The Danish mussel aquaculture sector is now growing. The Danish production areas have been regarded as “low risk” areas with respect to toxic algae and occurrence of marine biotoxins....... The change to more production of cultured mussel results in higher risk for occurrence of marine biotoxins because of the closer interaction between toxic algae and mussels. Results showing the difference between content of marine biotoxins in bottom mussel and cultured mussel from the same production areas...... cell toxicity of potential toxic algae in combination with algae cell number and mussel toxicity for opening or closing of production areas....

  1. Accumulation of a low pathogenic avian influenza virus in zebra mussels (Dreissena polymorpha).

    Science.gov (United States)

    Stumpf, Petra; Failing, Klaus; Papp, Tibor; Nazir, Jawad; Böhm, Reinhard; Marschang, Rachel E

    2010-12-01

    In order to investigate the potential role of mussels as a vector of influenza A viruses, we exposed zebra mussels (Dreissena polymorpha) to natural lake water containing a low pathogenic H5N1 avian influenza virus. Mussels were kept in water containing virus for 48 hr, then transferred into fresh water for another 14 days. Virus detection in mussels and water samples was performed by quantitative real-time reverse transcriptase-PCR (qRRT-PCR) and egg culture methods. Virus uptake was detected in all of the mussel groups that were exposed to virus. Even after 14 days in fresh water, virus could still be detected in shellfish material by both qRRT-PCR and egg culture methods. The present study demonstrates that zebra mussels are capable of accumulating influenza A viruses from the surrounding water and that these viruses remain in the mussels over an extended period of time.

  2. Dispersed and decentralised settlement system

    Directory of Open Access Journals (Sweden)

    Andrej Černe

    2004-01-01

    Full Text Available In the process of reintegration of the urban system new settlements are emerging on theurban rim, transitional zones are reurbanised, derelict areas within the cities are being developedand degraded urban areas of derelict industrial complexes are being renaturalised. Inthe periphery combined research and production parks are being set up, in the open landscapeintegrated business, trade and recreational centres are springing up. Decentralisationand recentralisation of focal points of development accompany the contemporary processesof reurbanisation and suburbanisation – they are simultaneous and move in two-direction i.e. to and from the city. We understand them as manifestation of a dynamic balance amongcontradiction existing between the centre and the rim. Deindustrialisation and relocation ofproduction and distribution from the centres of gravity to the periphery generate extensivedegraded urban areas within cities and between the city and suburbs. The periphery is beingurbanised with the creation of new, dispersed and nonhierachical poles of development, andthe city and inner city is undergoing reurbanization. The general environmental conditionsin the city and in the countryside are being equalised, the potentials of development arebeing sought in the comparative advantages of local conditions: be it attractive urban districts,be it suburban entities or countryside areas.

  3. Processing of chopped mussel meat in retort pouch

    Directory of Open Access Journals (Sweden)

    Giustino TRIBUZI

    2015-01-01

    Full Text Available Abstract Chopped mussel meat packaged in retort pouches was processed in a laboratory-scale water immersion retort, adapted for processing under overpressure conditions. Retort temperature effects on product yield and on cook value were evaluated by setting the F0 at 7 min. The effects of different pre-treatments (salting and marination on the characteristics of mussels were evaluated after processing at retort temperature of 118 °C and during a whole year of storage at 25 °C. The salted samples showed better yield during storage, while no differences were found for the other physicochemical parameters.

  4. Payment for ecosystem services - paying mussel producers for nitrogen mitigation

    DEFF Research Database (Denmark)

    Hasler, Berit; Petersen, Jens Kjerulf; Zandersen, Marianne

    2015-01-01

    to the marine environment, and the costs of implementing these abatement measures for nutrient load reductions are increasing at the margin. The nutrient uptake by the mussels can be regarded an ecosystem service, that might be utilized, but which need motivation and incentives for the mussel producers...... as a transferable development right where farmers buy the right to continue current fertilizer practices by paying for N retention in another location (here in the water bodies). It is also possible to learn from the GHG policy where it is possible to pay for abatement elsewhere, where it’s more cost...

  5. Development of a molecular diagnostic system to discriminate Dreissena polymorpha (zebra mussel) and Dreissena bugensis (quagga mussel).

    Science.gov (United States)

    Hoy, Marshal S; Kelly, Kevin; Rodriguez, Rusty J

    2010-01-01

    A 3-primer PCR system was developed to discriminate invasive zebra (Dreissena polymorpha) and quagga (Dreissena bugensis) mussel. The system is based on: 1) universal primers that amplifies a region of the nuclear 28s rDNA gene from both species and 2) a species-specific primer complementary to either zebra or quagga mussel. The species-specific primers bind to sequences between the binding sites for the universal primers resulting in the amplification of two products from the target species and one product from the nontarget species. Therefore, nontarget products are positive amplification controls. The 3-primer system accurately discriminated zebra and quagga mussels from seven geographically distinct populations. Published 2009. This article is a US Government work and is the public domain in the USA.

  6. The morphological / settlement pattern classification of South African settlements based on a settlement catchment approach, to inform facility allocation or service delivery

    CSIR Research Space (South Africa)

    Sogoni, Zukisa

    2016-07-01

    Full Text Available , it is of the utmost importance that a critical evaluation of settlement structure and patterns is undertaken to directly inform the manner in which social services are delivered in different settlement types....

  7. Studies on the variations in the settlement of macrofoulants in Kalpakkam coastal waters, east coast of India

    International Nuclear Information System (INIS)

    Sahu, Gouri; Prasad, M.V.R.; Satpathy, K.K.; Biswas, S.; Selvanaygam, M.

    2008-01-01

    Biofouling studies in the coastal waters of Kalpakkam were carried out with an aim to delineate the present seasonal succession and fouling potential of macrofoulants, the dominant species and their breeding period. Three series (weekly, monthly and cumulative at 30 d interval observations) of teak wood panels were exposed to coastal waters from a jetty. A marked variation was observed in the colonization of the biofoulers on the weekly panels during the present study. The highest and lowest numbers of organisms observed were 136 and 1 per sq. cm respectively. Dominance of barnacles (12.4 - 99 %) on weekly panels was found throughout the study period. A climax community of green mussels (Perna viridis) was observed in the cumulative observations. Biofouling biomass of weekly panels varied between 1 and 11 g. (100 cm) -2 , however, a steep increase in biomass was observed in 28 d (77 g. (100 cm) -2 ), 56 d (97 g. (100 cm) -2 ), 112 d (185 g. (100 cm) -2 ) and 150 d (648 g. (100 cm) -2 ) old panels. In the present study, the biomass values found to be significantly higher than those of the earlier reported values (33 and 52 g. (100 cm) -2 in 43 d and 128 d exposure respectively). Interestingly, a visible shift in the peak settlement period of green mussels (Perna viridis) was observed in the present investigation, as compared to the earlier study. (author)

  8. Transport corridors and settlements in a region. Linking settlements to public transport

    Directory of Open Access Journals (Sweden)

    Mojca Šašek Divjak

    2004-01-01

    Full Text Available The focus of the article is conditioning settlement to public transport on the regional and urban level. Similar to occurrences in Western Europe even in Slovenia strong settlement pressures and issues tied to development of suburbanisation are emerging in wider hinterlands of larger cities. In regional centres, where strong transport flows with frequent congestion happen, public transport should be the backbone of the transport system. It is important for consolidation of larger gravitation areas, especially conurbations. We can nevertheless establish that parallel to increasing use of private cars, the use of public transport is decreasing. Thus the present condition demands improvements of transport systems and suitable settlement density in conjunction with development of public transport. This can be achieved only by synergetic linking of public transport development and physical planning in a sustainable settlement system. In the Ljubljana functional region we specifically dealt with links between settlement and the regional public transport system, above all the proposed regional light-railway and tram system in the strict urban area. The decentralised denser settlement model is presented. Based on the study concerning settlement development in the railway corridors we proposed potential possibilities for denser settlement in the immediate areas of suburban railway stations in the northern part of the region, from Črnuče to Kamnik.

  9. Deja vu? A second mytilid mussel, Semimytilus algosus , invades ...

    African Journals Online (AJOL)

    A second marine mussel is shown to have invaded South Africa's west coast. Molecular techniques, based on intraspecific gene sequence divergences, prove its identity as Semimytilus algosus, a member of the family Mytilidae, native to Chile. The identity of an older introduced population found in Namibia is also ...

  10. Regulation of the branchial ciliary activity in the mussel

    NARCIS (Netherlands)

    Dral, A.D.G.

    1977-01-01

    In mussels the movement of the cilia on the gill are basically autonomous and influenced by environmental factors. The branchial nerve has an inhibitory as well as a stimulating effect on the activity of the lateral cilia. The reactions of these cilia to changing temperature and chlorinity in

  11. Biochemical population genetics of the black mussel Choromytilus ...

    African Journals Online (AJOL)

    Gene products of nine loci were examined by horizontal starch-gel electrophoresis in five samples of black mussels, Choromytilus meridionalis, from the south-western Cape coast. Allelic frequency variation for four polymorphic proteins suggests no racial differences between west and south coast populations.

  12. Spatial and temporal variability in recruitment of intertidal mussels ...

    African Journals Online (AJOL)

    Intensity of intertidal mussel recruitment was compared across a range of different spatial and temporal scales around the coast of southern Africa between June 1995 and October 1996. Comparison of the east and west coasts revealed significantly higher recruit densities on the west coast, corresponding to larger adult ...

  13. Effects of salinity on the survival of the Brackwater mussel ...

    African Journals Online (AJOL)

    During drought periods, the razor clam Solen cylindraceus is the dominant bivalve in the St Lucia estuarine system, although restricted to its South Lake region. However, with the recent onset of a wet phase, the mussel Brachidontes virgiliae has become widespread and overwhelmingly dominant throughout the system.

  14. Differential cold-shock resistance among acclimated European mussel populations

    NARCIS (Netherlands)

    Jansen, J.M.; Wendelaar Bonga, S.E.; Hummel, H.

    2007-01-01

    To study differential cold-shock resistance of marine mussel populations (Mytilus spp.) from different climatic regions in Europe, we sampled 12 populations, ranging from 43 to 58°N. Minimum critical temperatures for aerobic metabolism (CTmin) were determined before and after 3 months of common

  15. Effects of turbidity, sediment, and polyacrylamide on native freshwater mussels

    Science.gov (United States)

    Buczek, Sean B.; Cope, W. Gregory; McLaughlin, Richard A.; Kwak, Thomas J.

    2018-01-01

    Turbidity is a ubiquitous pollutant adversely affecting water quality and aquatic life in waterways globally. Anionic polyacrylamide (PAM) is widely used as an effective chemical flocculent to reduce suspended sediment (SS) and turbidity. However, no information exists on the toxicity of PAM‐flocculated sediments to imperiled, but ecologically important, freshwater mussels (Unionidae). Thus, we conducted acute (96 h) and chronic (24 day) laboratory tests with juvenile fatmucket (Lampsilis siliquoidea) and three exposure conditions (nonflocculated settled sediment, SS, and PAM‐flocculated settled sediment) over a range of turbidity levels (50, 250, 1,250, and 3,500 nephelometric turbidity units). Survival and sublethal endpoints of protein oxidation, adenosine triphosphate (ATP) production, and protein concentration were used as measures of toxicity. We found no effect of turbidity levels or exposure condition on mussel survival in acute or chronic tests. However, we found significant reductions in protein concentration, ATP production, and oxidized proteins in mussels acutely exposed to the SS condition, which required water movement to maintain sediment in suspension, indicating responses that are symptoms of physiological stress. Our results suggest anionic PAM applied to reduce SS may minimize adverse effects of short‐term turbidity exposure on juvenile freshwater mussels without eliciting additional lethal or sublethal toxicity.

  16. The Quagga mussel invades the Lake Superior basin - journal article

    Science.gov (United States)

    Prior studies recognized the presence of a single dreissenid species in Lake Superior--the zebra mussel Dreissena polymorpha. However, taxonomic keys based on traditional shell morphology are not always able to differentiate dreissenid species with confidence. We thus employed ge...

  17. Subsistence and recreational mussel (Perna perna) collecting in ...

    African Journals Online (AJOL)

    tional collectors are subject to a daily bag limit of 50 mussels and so select ... in subsistence collecting at Kosi Bay is required, but the limited access policy should ... in India (P. viridis and P. indica), Indonesia (P. viridis) and ...... by women in Palau, Micronesia. ... Inshore marine resources and associated opportunities for.

  18. A hierarchical classification of freshwater mussel diversity in North America

    Science.gov (United States)

    Wendell R. Haag

    2010-01-01

    Aim North America harbours the most diverse freshwater mussel fauna on Earth. This fauna has high endemism at the continental scale and within individual river systems. Previous faunal classifications for North America were based on intuitive, subjective assessments of species distributions, primarily the occurrence of endemic species, and do not portray continent-wide...

  19. Intercalibration of mussel Mytilus edulis clearance rate measurements

    NARCIS (Netherlands)

    Kjerulf Petersen, J.; Bougrier, S.; Smaal, A.C.; Garen, P.; Robert, S.; Larsen, J.E.N.; Brummelhuis, E.B.M.

    2004-01-01

    Clearance rate (CR) was measured in blue mussels Mytilus edulis L. from Aiguillon Bay and the Oosterschelde using 3 different methods: the flow-through method, the bio-deposition method and the indirect or clearance method. CR differed significantly as a function of the method used and of the origin

  20. 78 FR 5481 - Quagga Mussel Strategic Planning Meeting

    Science.gov (United States)

    2013-01-25

    ... DEPARTMENT OF THE INTERIOR Fish and Wildlife Service [FWS-HQ-FHC-2013-N008; 94140-1341-0000-N5] Quagga Mussel Strategic Planning Meeting AGENCY: Fish and Wildlife Service, Interior. ACTION: Notice of meeting. SUMMARY: This notice announces a meeting to gather information for planning an FY13 strategy to...

  1. Zebra mussels mitigation at Ontario Hydro's hydroelectric generating facilities

    International Nuclear Information System (INIS)

    Dorneanu, A.M.

    1992-01-01

    The Great Lakes and their connecting channels have recently been invaded by a tiny freshwater mollusc that has already cost Ontario Hydro millions of dollars. Dreissena polymorpha, commonly known as the zebra mussel, entered the great lakes in ballast water carried by a ship from Europe in 1985. These mussels threaten to reduce or totally block the flow of water in auxiliary systems of any generating station, water treatment plant or municipal water facility that uses raw lake water and to cause accelerated corrosion of the metallic substrate to which they attach themselves. To satisfy the immediate need for control, chlorination was identified as the most effective interim measure to prevent the biofouling of the raw water systems. Detection and monitoring of mussels and the installation, operation, environmental constraints, benefits and deficiencies of the chemical treatment system are presented. Long term objectives for control of the mussels are to develop alternatives to chlorination (ozone, hydrogen peroxide, protective coatings, thermal shock, mechanical filtration, etc.) for application at existing facilities and for incorporation into the design of new facilities and rehabilitation programs. 3 refs., 5 figs

  2. Review on methods of golden mussel control in pires

    Directory of Open Access Journals (Sweden)

    Edemir Luiz Kowalski

    2008-07-01

    Full Text Available At the beginning of the 90’s, they were detected in Rio da Prata in Argentina the first samples of the exotic specie named limnoperna fortunei, from Asia, maybe introduced through ballast water of ships came from Asia. In Brazil the first samples were detected in Lagoa dos Patos in Rio Grande do Sul in the 90’s, possibly by the same reason. A second axis was verified in Campo Grande in Mato Grosso do Sul derived probably from Argentina because of the navigation through the Paraguay river going down to Lagoa de Itaipú causing its contamination. The invader specie has the capacity of fouling pipings where the contaminated water circulates, causing considerable financial damage to the infected industries. In Brazil the indrustries located in Rio Grande do Sul as well as hydroelectric plants as Itaipu, they manage these problems stopping the equipments for their maintenance and cleaning more times than the habitual. The United States of America and Canada already have the same kind of problem with the similar specie found here in Brazil. The target of this work is to introduce a review about the main methods to control the golden mussel mollusk without using any kind of chemical products, based on The USA and Canada’s experiences, where there are similar problems but with the specie zebra mussel. Key-words: Non Chemicals Methods, Golden Mussel, Zebra Mussel

  3. Mussel beds are biological power stations on intertidal flats

    Science.gov (United States)

    Engel, Friederike G.; Alegria, Javier; Andriana, Rosyta; Donadi, Serena; Gusmao, Joao B.; van Leeuwe, Maria A.; Matthiessen, Birte; Eriksson, Britas Klemens

    2017-05-01

    Intertidal flats are highly productive areas that support large numbers of invertebrates, fish, and birds. Benthic diatoms are essential for the function of tidal flats. They fuel the benthic food web by forming a thin photosynthesizing compartment in the top-layer of the sediment that stretches over the vast sediment flats during low tide. However, the abundance and function of the diatom film is not homogenously distributed. Recently, we have realized the importance of bivalve reefs for structuring intertidal ecosystems; by creating structures on the intertidal flats they provide habitat, reduce hydrodynamic stress and modify the surrounding sediment conditions, which promote the abundance of associated organisms. Accordingly, field studies show that high chlorophyll a concentration in the sediment co-vary with the presence of mussel beds. Here we present conclusive evidence by a manipulative experiment that mussels increase the local biomass of benthic microalgae; and relate this to increasing biomass of microalgae as well as productivity of the biofilm across a nearby mussel bed. Our results show that the ecosystem engineering properties of mussel beds transform them into hot spots for primary production on tidal flats, highlighting the importance of biological control of sedimentary systems.

  4. The effects of natural biofilms on the reattachment of young adult zebra mussels to artificial substrata.

    Science.gov (United States)

    Kavouras, Jerry H; Maki, James S

    2003-08-01

    This laboratory study examined the effects of natural biofilms on the reattachment of young adult zebra mussels, Dreissena polymorpha, in Petri dishes. Natural biofilms were developed in glass and polystyrene Petri dishes using water samples collected at various times of the year. Biofilms were developed over 1, 3, 8, and 14 d. Controls were clean glass and polystyrene Petri dishes. Zebra mussels collected from the field (Zebra mussels reattached to the dish surface or the shells of other mussels in the dish, or remained unattached. The data indicate that reattachment to clean glass was greater than to clean polystyrene (p Zebra mussels in control and filmed glass dishes reattached in higher percentages to the dish surface compared to the shells of other mussels (p mussel of reattachment between the dish surface and the shells of other mussels in most control polystyrene dishes (p > 0.05, ANOVA), whereas in filmed polystyrene the percentage of reattachment to the dish surface was greater than to the shells of other mussels (p zebra mussels.

  5. Zebra mussel filtration and its potential uses in industrial water treatment.

    Science.gov (United States)

    Elliott, Paul; Aldridge, David C; Moggridge, Geoff D

    2008-03-01

    The zebra mussel (Dreissena polymorpha) is a notorious freshwater biofouling pest, and populations of the species can alter aquatic environments through their substantial filtration capabilities. Despite the ecological importance of zebra mussel filtration, many predictions of their large-scale effects on ecosystems rely on extrapolations from filtration rates obtained in static laboratory experiments, not accounting for natural mussel densities, boundary layer effects, flow rates or elevated algal concentrations. This study used large-scale industrial flume trials to investigate the influence of these factors on zebra mussel filtration and proposes some novel industrial applications of these findings. The flume trials revealed some of the highest zebra mussel clearance rates found to date, up to 574+/-20mlh(-1)g(-1) of wet tissue mass. Under low algal concentrations, chlorophyll a removal by zebra mussels was not proportional to mussel density, indicating that field rates of zebra mussel grazing may be much lower than previous studies have predicted. Increasing ambient velocities up to 100mls(-1) ( approximately 4cms(-1)) led to increased clearance rates by zebra mussels, possibly due to the replenishment of locally depleted resources, but higher velocities of 300mls(-1) (12cms(-1)) did not lead to further significant increases in clearance rate. When additional algal cultures were dosed into the flumes, chlorophyll a removal increased approximately logarithmically with zebra mussel density and there were no differences in the clearance of three different species of alga: Ankyra judayi, Pandorina morum and Cyclotella meneghinia. Some novel industrial uses of these zebra mussel filtration studies are proposed, such as: (1) helping to inform models that predict the large-scale grazing effects of the mussels, (2) allowing estimates of zebra mussel densities in industrial pipelines, and (3) constructing large-scale biofilters for use in water clarification.

  6. Comparison of accumulation of micropollutants between igenous and transplanted zebra mussels (Dreissena polymorpha).

    Science.gov (United States)

    Bervoets, Lieven; Voets, Judith; Chu, Shaogang; Covaci, Adrian; Schepens, Paul; Blust, Ronny

    2004-08-01

    Zebra mussels (Dreissena polymorpha) were exposed at 12 canals and lakes situated in Flanders (Belgium), in cages for six weeks during the summer of 2002. Accumulation of polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs), hexachlorobenzene, and trace metals were measured in the transplanted mussels and levels compared to levels in indigenous mussels. Additionally, zebra mussels were exposed at a small lake in the vicinity of Antwerp (Belgium), and accumulation of contaminants was followed for an extended period from December 2001 to April 2002. Analysis of the pollutants in the indigenous mussels showed that the selected sites displayed a wide range of pollution from near to background to very high levels of metals and/or organic contaminants when compared to the literature. For organic contaminants and for most metals, comparison of levels between caged and resident mussels revealed no significant differences. Only for cadmium and nickel, significant differences were observed, with levels being either higher (cadmium) or lower (nickel) in caged mussels. For organic contaminants, significant correlations between levels in caged and resident mussels were found with r2 values up to 0.98. For some metals, no or poor correlations were found. At most sites, concentrations of those metals were of the same order of magnitude and comparable to levels in mussels from unpolluted sites. This might explain the absence of significant correlations. When mussels were exposed for an extended period, the concentration of some pollutants increased, whereas others decreased with time. Only in the case of certain metals did levels differ significantly because of the slow depuration of metals already present in the transplanted mussels. This is an additional indication that measured concentrations in transplanted mussels indeed reflected the local situation. With this study, we were able to prove the applicability of transplanted mussels as a biomonitoring tool

  7. Microplastics in mussels along the coastal waters of China

    International Nuclear Information System (INIS)

    Li, Jiana; Qu, Xiaoyun; Su, Lei; Zhang, Weiwei; Yang, Dongqi; Kolandhasamy, Prabhu; Li, Daoji; Shi, Huahong

    2016-01-01

    Microplastic has been confirmed as an emerging pollutant in marine environments. One of the primary environmental risks of microplastics is their bioavailability for aquatic organisms. Bivalves are of particular interest because their extensive filter-feeding activity exposes them directly to microplastics present in the water column. In the present study, we investigated microplastic pollution in mussels (Mytilus edulis) from 22 sites along 12,400 mile coastlines of China in 2015. The number of total microplastics varied from 0.9 to 4.6 items/g and from 1.5 to 7.6 items/individual. M. edulis contained more microplastics (2.7 items/g) in wild groups than that (1.6 items/g) in farmed groups. The abundance of microplastics was 3.3 items/g in mussels from the areas with intensive human activities and significantly higher than that (1.6 items/g) with less human activities. The most common microplastics were fibers, followed by fragments. The proportion of microplastics less than 250 μm in size arranged from 17% to 79% of the total microplastics. Diatom was distinguished from microplastics in mussels for the first time using Scanning Electron Microscope. Our results suggested that the numbers of microplastic kept within a relatively narrow range in mussels and were closely related to the contamination of the environments. We proposed that mussels could be used as a potential bioindicator of microplastic pollution of the coastal environment. - Highlights: • Microplastics varied from 0.9 to 4.6 items/g in Mytilus edulis. • M. edulis contained more microplastics in wild groups than farmed groups. • The most common microplastics were fibers. • Diatom was distinguished from microplastics in mussels. • Mussels could be used as a potential bioindicator of microplastic. - Microplastics varied from 0.9 to 4.6 items/g in wild and farmed Mytilus edulis from 22 sites along the coastal waters of China.

  8. Settlement Prediction of Footings Using VS

    Directory of Open Access Journals (Sweden)

    Hyung Ik CHO

    2017-10-01

    Full Text Available The shear wave velocity (VS is a key parameter for estimating the deformation characteristics of soil. In order to predict the settlement of shallow footings in granular soil, the VS and the concept of Schmertmann’s framework were adopted. The VS was utilized to represent soil stiffness instead of cone tip resistance (qc because the VS can be directly related to the small-strain shear modulus. By combining the VS measured in the field and the modulus reduction curve measured in the laboratory, the deformation characteristics of soil can be reliably estimated. Vertical stress increments were determined using two different profiles of the strain influence factor (Iz proposed in Schmertmann’s method and that calculated from the theory of elasticity. The corresponding modulus variation was determined by considering the stress level and strain at each depth. This state-dependent stress-strain relationship was utilized to calculate the settlement of footings based on the theory of elasticity. To verify the developed method, geotechnical centrifuge tests were carried out. The VS profiles were measured before each loading test, and the load-settlement curves were obtained during the tests. Comparisons between the measured and estimated load-settlement curves showed that the developed method adequately predicts the settlement of footings, especially for over-consolidated ground conditions.

  9. Microplastics in mussels along the coastal waters of China.

    Science.gov (United States)

    Li, Jiana; Qu, Xiaoyun; Su, Lei; Zhang, Weiwei; Yang, Dongqi; Kolandhasamy, Prabhu; Li, Daoji; Shi, Huahong

    2016-07-01

    Microplastic has been confirmed as an emerging pollutant in marine environments. One of the primary environmental risks of microplastics is their bioavailability for aquatic organisms. Bivalves are of particular interest because their extensive filter-feeding activity exposes them directly to microplastics present in the water column. In the present study, we investigated microplastic pollution in mussels (Mytilus edulis) from 22 sites along 12,400 mile coastlines of China in 2015. The number of total microplastics varied from 0.9 to 4.6 items/g and from 1.5 to 7.6 items/individual. M. edulis contained more microplastics (2.7 items/g) in wild groups than that (1.6 items/g) in farmed groups. The abundance of microplastics was 3.3 items/g in mussels from the areas with intensive human activities and significantly higher than that (1.6 items/g) with less human activities. The most common microplastics were fibers, followed by fragments. The proportion of microplastics less than 250 μm in size arranged from 17% to 79% of the total microplastics. Diatom was distinguished from microplastics in mussels for the first time using Scanning Electron Microscope. Our results suggested that the numbers of microplastic kept within a relatively narrow range in mussels and were closely related to the contamination of the environments. We proposed that mussels could be used as a potential bioindicator of microplastic pollution of the coastal environment. Copyright © 2016 Elsevier Ltd. All rights reserved.

  10. New environmentally friendly MSPD solid support based on golden mussel shell: characterization and application for extraction of organic contaminants from mussel tissue.

    Science.gov (United States)

    Rombaldi, Caroline; de Oliveira Arias, Jean Lucas; Hertzog, Gabriel Ianzer; Caldas, Sergiane Souza; Vieira, João P; Primel, Ednei Gilberto

    2015-06-01

    The use of golden mussel shells as a solid support in vortex-assisted matrix solid-phase dispersion (MSPD) was evaluated for the first time for extraction of residues of 11 pesticides and nine pharmaceutical and personal care products from mussel tissue samples. After they had been washed, dried, and milled, the mussel shells were characterized by scanning electron microscopy, energy-dispersive X-ray spectroscopy, infrared spectroscopy, and Brunauer-Emmett-Teller analysis. The MSPD procedure with analysis by liquid chromatography-tandem mass spectrometry allowed the determination of target analytes at trace concentrations (nanograms per gram), with mean recoveries ranging from 61 to 107 % and relative standard deviations lower than 18 %. The optimized method consisted of dispersion of 0.5 g of mussel tissue, 0.5 g of NaSO4, and 0.5 g of golden mussel shell for 5 min, and subsequent extraction with 5 mL of ethyl acetate. The matrix effect was evaluated, and a low effect was found for all compounds. The results showed that mussel shell is an effective material and a less expensive material than materials that have traditionally been used, i.e., it may be used in the MSPD dispersion step during the extraction of pesticides and pharmaceutical and personal care products from golden mussel tissues. Graphical Abstract Vortex-assited matrix solid-phase dispersion for extraction of 11 pesticides and 9 PPCPs care products from mussel tissue samples.

  11. Planning urban settlements for quality of life

    DEFF Research Database (Denmark)

    Boje Groth, N.; Hansen, K.E.; Björnberg, U.

    Notatet er et indlæg på den Europæiske Økonomiske Kommissions (ECE) konference om by- og regionforskning, tema II: "Research on the Quality of Life in Urban Settlements, Warszawa, maj 1976. I notatet opstilles en begrebsramme for livskvalitetsbegrebet, og man diskuterer hvorledes livskvalitetsana......Notatet er et indlæg på den Europæiske Økonomiske Kommissions (ECE) konference om by- og regionforskning, tema II: "Research on the Quality of Life in Urban Settlements, Warszawa, maj 1976. I notatet opstilles en begrebsramme for livskvalitetsbegrebet, og man diskuterer hvorledes...

  12. Development of a toxicity model for paralytic shellfish toxins in mussel: uptake and release of toxins in Green Bay mussel

    International Nuclear Information System (INIS)

    Tabbada, Rhett Simon DC.; Ranada, Ma. Llorina O.; De Leon, Aileen L.; Bulos, Adelina M.; Sta, Maria; Efren, J.; De Vera, Azucena; Balagtas, Angelina; Sombrito, Elvira Z.

    2009-01-01

    In view of the expressed need to study shellfish toxicity and elucidate the kinetics of saxitoxin in green mussels Perna viridis), uptake/depuration rates of saxitoxin were studied in Juag Lagoon, Sorsogon and Sorsogon Bay. Both areas experience recurring blooms of Pyrodinium bahamanse var compressum (PbC) making them excellent study sites. Two sampling stations were selected, to which, mussels were introduced. Algal cell density and mussel toxicity were measured by receptor binding assay (RBA) and high performance liquid chromatography (HPLC) from May to December 2007. During this period, two bloom events occurred, wherein, a decrease in cell density by two orders of magnitude (30,000 to 600 cells·1 +1 ) caused an order of magnitude decrease in toxicity (600 to 30 μg STX eq./100 g shellfish meat). A time lag between peaks of cell density and the corresponding toxicity was revealed. Vegetative cells were present throughout the sampling period, and a uniform horizontal and vertical distribution of cells was observed between the stations. Cell densities were significantly correlated with both RBA and HPLC estimates of STX content in mussels (Pearson r values of 0.7486 and 0.4325 for RBA and HPLC, respectively). In Sorsogon Bay, six sampling stations were also chosen, from which, water and mussels were being collected. Preliminary data showed that the cellular toxin content was primarily STX, making up to 90-100% of total toxin quantified. The average toxicity was estimated at 52.81fmol/cell. The effect of physiological factors to overall shellfish toxicity, though not directly characterized, may be deduced from these studies. (author)

  13. Bioaccumulation of pathogenic bacteria and amoeba by zebra mussels and their presence in watercourses.

    Science.gov (United States)

    Mosteo, R; Goñi, P; Miguel, N; Abadías, J; Valero, P; Ormad, M P

    2016-01-01

    Dreissena polymorpha (the zebra mussel) has been invading freshwater bodies in Europe since the beginning of the nineteenth century. Filter-feeding organisms can accumulate and concentrate both chemical and biological contaminants in their tissues. Therefore, zebra mussels are recognized as indicators of freshwater quality. In this work, the capacity of the zebra mussel to accumulate human pathogenic bacteria and protozoa has been evaluated and the sanitary risk associated with their presence in surface water has also been assessed. The results show a good correlation between the pathogenic bacteria concentration in zebra mussels and in watercourses. Zebra mussels could therefore be used as an indicator of biological contamination. The bacteria (Escherichia coli, Enterococcus spp., Pseudomonas spp., and Salmonella spp.) and parasites (Cryptosporidium oocysts and free-living amoebae) detected in these mussels reflect a potential sanitary risk in water.

  14. The production of relaid blue mussels ( Mytilus edulis L.) in a Danish fjord

    DEFF Research Database (Denmark)

    Kristensen, Per Sand; Lassen, H.

    1997-01-01

    Mussels (Mytilus edulis L.) smaller than the commercial size caught in Limfjorden, as in other areas, are typically discarded. However, during the period 1990 to 1993 these small mussels were returned, after sorting to mussel beds for later harvest; a process defined as ''relay''. This paper...... presents data from two commercial culture beds and from two smaller experimental beds established to study growth and mortality of these small mussel discards. The data were analysed by a yield- per-recruit model to calculate yields from such relays. This model was also used to predict the optimal time...... of harvest. The parameters utilized in the model were: (1) initial mortality due to harvesting, unshipping and sorting; (2) growth and mortality between relay and harvest; and, (3) the drained wet weight of a mussel of a given shell length. The initial mortality was estimated from observations of mussels...

  15. Temperature- and Turbidity-Dependent Competitive Interactions Between Invasive Freshwater Mussels.

    Science.gov (United States)

    Huang, Qihua; Wang, Hao; Ricciardi, Anthony; Lewis, Mark A

    2016-03-01

    We develop a staged-structured population model that describes the competitive dynamics of two functionally similar, congeneric invasive species: zebra mussels and quagga mussels. The model assumes that the population survival rates are functions of temperature and turbidity, and that the two species compete for food. The stability analysis of the model yields conditions on net reproductive rates and intrinsic growth rates that lead to competitive exclusion. The model predicts quagga mussel dominance leading to potential exclusion of zebra mussels at mean water temperatures below [Formula: see text] and over a broad range of turbidities, and a much narrower set of conditions that favor zebra mussel dominance and potential exclusion of quagga mussels at temperatures above [Formula: see text] and turbidities below 35 NTU. We then construct a two-patch dispersal model to examine how the dispersal rates and the environmental factors affect competitive exclusion and coexistence.

  16. An economic assessment of patent settlements in the pharmaceutical industry.

    Science.gov (United States)

    Dickey, Bret; Orszag, Jonathan; Tyson, Laura

    2010-01-01

    This article demonstrates that in recent years, patent settlements between branded and generic manufacturers involving "reverse payments" from branded manufacturers to generic manufacturers have received close antitrust scrutiny, driven by concerns that such settlements harm consumers by delaying the entry of lower-priced generic drugs. The authors note that such settlements will be a focus of the Obama Administration's antitrust enforcement policy, yet there is a growing consensus among the courts that such settlements are anticompetitive only under narrow sets of circumstances. In this article, the authors present an analytical framework for evaluating the competitive effects of patent settlements, including those involving reverse payments, and demonstrate that these settlements can benefit consumers. Thus, the authors conclude that while continued scrutiny of such settlements is important, broad brush treatments are inappropriate and only a more individualized evaluation can correctly determine the competitive effects of a particular settlement agreement.

  17. The Settlements Growth in Mijen District, Suburb of Semarang

    Science.gov (United States)

    Pigawati, B.; Yuliastuti, N.; Mardiansjah, F. H.

    2018-02-01

    Semarang is one of metropolitan cities in Indonesia. As common in metropolitan cities, Semarang has problems regarding the availability of urban space, especially for settlements. This is related to the increase of population in Semarang. The selection of settlements should consider the suitability of space usage. This study aimed to analyze the growth of Semarang settlements in 2006-2015, distribution patterns, characteristics, directions and factors affecting growth. The location of the research is Mijen District located in Suburb of Semarang. This research used a quantitative descriptive spatial approach by using remote sensing technique and Geographic Information System (GIS). The results showed that some of the growth sites of settlements in Mijen District, the suburb of Semarang are located in areas which not suitable for settlements. There are several types of settlement patterns in Mijen District. Accessibility is the major factor driving the growth of settlements. An integrated development policy is needed to maintain a sustainable balance of urban settlement development.

  18. 48 CFR 49.108-3 - Settlement procedure.

    Science.gov (United States)

    2010-10-01

    ... MANAGEMENT TERMINATION OF CONTRACTS General Principles 49.108-3 Settlement procedure. (a) Contractors shall settle with subcontractors in general conformity with the policies and principles relating to settlement...

  19. Optically and biologically active mussel protein-coated double-walled carbon nanotubes.

    Science.gov (United States)

    Jung, Yong Chae; Muramatsu, Hiroyuki; Fujisawa, Kazunori; Kim, Jin Hee; Hayashi, Takuya; Kim, Yoong Ahm; Endo, Morinobu; Terrones, Mauricio; Dresselhaus, Mildred S

    2011-12-02

    A method of dispersing strongly bundled double-walled carbon nanotubes (DWNTs) via a homogeneous coating of mussel protein in an aqueous solution is presented. Optical activity, mechanical strength, as well as electrical conductivity coming from the nanotubes and the versatile biological activity from the mussel protein make mussel-coated DWNTs promising as a multifunctional scaffold and for anti-fouling materials. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. IMPACT OF SIPHONING ACTIVITY AND NATURALLY SUSPENDED PARTICLE LOAD ON MUSSEL KILL by PSEUDOMONAS FLUORESCENS

    International Nuclear Information System (INIS)

    Daniel Molloy

    2003-01-01

    Under this USDOE-NETL contract, the bacterium Pseudomonas fluorescens is being developed as a biocontrol agent for zebra mussels. The specific purpose of the contract is to identify biotic and abiotic factors that affect mussel kill. Ingestion of these bacteria by zebra mussels is required to achieve kill, and tests evaluating factors that relate to mussel feeding are contained in this report. Specifically the impact of the following two factors were investigated: (1) Mussel siphoning behavior--In nature, zebra mussels typically have their two shells spread apart and their inhalant siphon tube extended from between their shells for taking food particles into their mantle cavities (Fig. 1). Our tests indicated that there is a direct correlation between mussel siphoning activity and mussel mortality achieved by a bacterial treatment. Therefore, to encourage mussel feeding on bacteria, future pipe treatments within power plants should be carried out using procedures which minimize disturbance to mussel siphoning. 2. Naturally suspended particle loads--Since bacterial cells are lethal only if ingested by mussels, waters containing very high levels of naturally suspended particles might reduce the mortality that can be achieved by a bacterial treatment. If true, this inhibition might occur as a result of particle exclusion, i.e., there could be reduced ingestion of bacterial cells since they represent a reduced percentage of all particles ingested. Our tests indicated that a range of particle concentrations that might naturally exist in a turbid river did not inhibit mussel kill by the bacterial cells, but that an artificially high load of natural particles was capable of causing a reduction in kill. To be conservative, therefore, future pipe treatments should be timed to occur when intake waters have relatively low quantities of naturally suspended particulate matter

  1. Sea otters homogenize mussel beds and reduce habitat provisioning in a rocky intertidal ecosystem.

    Directory of Open Access Journals (Sweden)

    Gerald G Singh

    Full Text Available Sea otters (Enhydra lutris are keystone predators that consume a variety of benthic invertebrates, including the intertidal mussel, Mytilus californianus. By virtue of their competitive dominance, large size, and longevity, M. californianus are ecosystem engineers that form structurally complex beds that provide habitat for diverse invertebrate communities. We investigated whether otters affect mussel bed characteristics (i.e. mussel length distributions, mussel bed depth, and biomass and associated community structure (i.e. biomass, alpha and beta diversity by comparing four regions that varied in their histories of sea otter occupancy on the west coast of British Columbia and northern Washington. Mussel bed depth and average mussel lengths were 1.5 times lower in regions occupied by otters for >20 years than those occupied for <5 yrs. Diversity of mussel bed associated communities did not differ between regions; however, the total biomass of species associated with mussel beds was more than three-times higher where sea otters were absent. We examined alternative explanations for differences in mussel bed community structure, including among-region variation in oceanographic conditions and abundance of the predatory sea star Pisaster ochraceus. We cannot discount multiple drivers shaping mussel beds, but our findings indicate the sea otters are an important one. We conclude that, similar to their effects on subtidal benthic invertebrates, sea otters reduce the size distributions of intertidal mussels and, thereby, habitat available to support associated communities. Our study indicates that by reducing populations of habitat-providing intertidal mussels, sea otters may have substantial indirect effects on associated communities.

  2. Local monitoring program for invasion of zebra mussel (Dreissena polymorpha) in the Dam lake Zhrebchevo, Bulgaria

    OpenAIRE

    Stoyanova, Stefka; Nikolov, Galin; Velichkova, Katya; Atanasoff, Alexander; Mumun, Sevdegul

    2015-01-01

    Zebra mussels (Dreissena polymorpha) are bivalve mollusks approximately 1 to 5 cm long that live in freshwater lakes. They have invaded many Bulgarian freshwater ecosystems in recent decades. Because of their ability to settle on almost any substrate, zebra mussels cause severe damage to closed water systems, RAS and intensive fish farming systems. In order to assess the status of the mussel population in the lake in the area of the Forest group fish farm, the distribution, extent of coloniza...

  3. Sympatric Dreissena species in the Meuse River : towards a dominance shift from zebra to quagga mussels

    OpenAIRE

    Marescaux, Jonathan; Boets, Pieter; Lorquet, Julien; Sablon, Rose; Van Doninck, Karine; Beisel, Jean-Nicolas

    2015-01-01

    The rapid spread of the quagga mussel, Dreissena rostriformis, in Western Europe is of particular concern since the species is known to have serious ecological and economic impacts, similar to those of the well-established zebra mussel, Dreissena polymorpha. This study aimed (1) to provide an update on the quagga mussel distribution in several Belgian inland waterways, and (2) to check if a shift in dominance between Dreissena species is occurring. Using density measurements and artificial su...

  4. Quagga mussels Dreissena rostriformis burgensis (Andrusov, 1897) in the Main River (Germany)

    OpenAIRE

    Velde, G. van der; Platvoet, D.

    2007-01-01

    The first record of the quagga mussel Dreissena rostriformis bugensis (Andrusov, 1897) in Germany is described. This species has expanded its distribution area in Europe at a slower rate than the zebra mussel Dreissena polymorpha (Pallas, 1771). Recent records from the Danube in Romania and from an enclosed Rhine-Meuse estuary in The Netherlands, suggest that the Main-Danube canal and River Rhine have functioned as the dispersal pathway of the quagga mussel to The Netherlands. The record of t...

  5. Estimation of mussel population response to hydrologic alteration in a southeastern U.S. stream

    Science.gov (United States)

    Peterson, J.T.; Wisniewski, J.M.; Shea, C.P.; Rhett, Jackson C.

    2011-01-01

    The southeastern United States has experienced severe, recurrent drought, rapid human population growth, and increasing agricultural irrigation during recent decades, resulting in greater demand for the water resources. During the same time period, freshwater mussels (Unioniformes) in the region have experienced substantial population declines. Consequently, there is growing interest in determining how mussel population declines are related to activities associated with water resource development. Determining the causes of mussel population declines requires, in part, an understanding of the factors influencing mussel population dynamics. We developed Pradel reverse-time, tag-recapture models to estimate survival, recruitment, and population growth rates for three federally endangered mussel species in the Apalachicola- Chattahoochee-Flint River Basin, Georgia. The models were parameterized using mussel tag-recapture data collected over five consecutive years from Sawhatchee Creek, located in southwestern Georgia. Model estimates indicated that mussel survival was strongly and negatively related to high flows during the summer, whereas recruitment was strongly and positively related to flows during the spring and summer. Using these models, we simulated mussel population dynamics under historic (1940-1969) and current (1980-2008) flow regimes and under increasing levels of water use to evaluate the relative effectiveness of alternative minimum flow regulations. The simulations indicated that the probability of simulated mussel population extinction was at least 8 times greater under current hydrologic regimes. In addition, simulations of mussel extinction under varying levels of water use indicated that the relative risk of extinction increased with increased water use across a range of minimum flow regulations. The simulation results also indicated that our estimates of the effects of water use on mussel extinction were influenced by the assumptions about the

  6. Predation on exotic zebra mussels by native fishes: Effects on predator and prey

    Science.gov (United States)

    Magoulick, D.D.; Lewis, L.C.

    2002-01-01

    1. Exotic zebra mussels, Dreissena polymorpha, occur in southern U.S. waterways in high densities, but little is known about the interaction between native fish predators and zebra mussels. Previous studies have suggested that exotic zebra mussels are low profitability prey items and native vertebrate predators are unlikely to reduce zebra mussel densities. We tested these hypotheses by observing prey use of fishes, determining energy content of primary prey species of fishes, and conducting predator exclusion experiments in Lake Dardanelle, Arkansas. 2. Zebra mussels were the primary prey eaten by 52.9% of blue catfish, Ictalurus furcatus; 48.2% of freshwater drum, Aplodinotus grunniens; and 100% of adult redear sunfish, Lepomis microlophus. Blue catfish showed distinct seasonal prey shifts, feeding on zebra mussels in summer and shad, Dorosoma spp., during winter. Energy content (joules g-1) of blue catfish prey (threadfin shad, Dorosoma petenense; gizzard shad, D. cepedianum; zebra mussels; and asiatic clams, Corbicula fluminea) showed a significant species by season interaction, but shad were always significantly greater in energy content than bivalves examined as either ash-free dry mass or whole organism dry mass. Fish predators significantly reduced densities of large zebra mussels (>5 mm length) colonising clay tiles in the summers of 1997 and 1998, but predation effects on small zebra mussels (???5 mm length) were less clear. 3. Freshwater drum and redear sunfish process bivalve prey by crushing shells and obtain low amounts of higher-energy food (only the flesh), whereas blue catfish lack a shell-crushing apparatus and ingest large amounts of low-energy food per unit time (bivalves with their shells). Blue catfish appeared to select the abundant zebra mussel over the more energetically rich shad during summer, then shifted to shad during winter when shad experienced temperature-dependent stress and mortality. Native fish predators can suppress adult zebra

  7. Hydraulic modeling of mussel habitat at a bridge-replacement site, Allegheny River, Pennsylvania, USA

    Science.gov (United States)

    Fulton, John W.; Wagner, Chad R.; Rogers, Megan E.; Zimmerman, Gregory F.

    2010-01-01

    The Allegheny River in Pennsylvania supports a large and diverse freshwater-mussel community, including two federally listed endangered species, Pleurobema clava(Clubshell) and Epioblasma torulosa rangiana (Northern Riffleshell). It is recognized that river hydraulics and morphology play important roles in mussel distribution. To assess the hydraulic influences of bridge replacement on mussel habitat, metrics such as depth, velocity, and their derivatives (shear stress, Froude number) were collected or computed.

  8. IMPACT OF SIPHONING ACTIVITY AND NATURALLY SUSPENDED PARTICLE LOAD ON MUSSEL KILL by PSEUDOMONAS FLUORESCENS

    Energy Technology Data Exchange (ETDEWEB)

    Daniel Molloy

    2003-08-04

    Under this USDOE-NETL contract, the bacterium Pseudomonas fluorescens is being developed as a biocontrol agent for zebra mussels. The specific purpose of the contract is to identify biotic and abiotic factors that affect mussel kill. Ingestion of these bacteria by zebra mussels is required to achieve kill, and tests evaluating factors that relate to mussel feeding are contained in this report. Specifically the impact of the following two factors were investigated: (1) Mussel siphoning behavior--In nature, zebra mussels typically have their two shells spread apart and their inhalant siphon tube extended from between their shells for taking food particles into their mantle cavities (Fig. 1). Our tests indicated that there is a direct correlation between mussel siphoning activity and mussel mortality achieved by a bacterial treatment. Therefore, to encourage mussel feeding on bacteria, future pipe treatments within power plants should be carried out using procedures which minimize disturbance to mussel siphoning. 2. Naturally suspended particle loads--Since bacterial cells are lethal only if ingested by mussels, waters containing very high levels of naturally suspended particles might reduce the mortality that can be achieved by a bacterial treatment. If true, this inhibition might occur as a result of particle exclusion, i.e., there could be reduced ingestion of bacterial cells since they represent a reduced percentage of all particles ingested. Our tests indicated that a range of particle concentrations that might naturally exist in a turbid river did not inhibit mussel kill by the bacterial cells, but that an artificially high load of natural particles was capable of causing a reduction in kill. To be conservative, therefore, future pipe treatments should be timed to occur when intake waters have relatively low quantities of naturally suspended particulate matter.

  9. Predation and physical environment structure the density and population size structure of zebra mussels

    OpenAIRE

    Naddafi, Rahmat; Pettersson, Kurt; Eklöv, Peter

    2010-01-01

    The zebra mussel (Dreissena polymorpha) provides one example of successful invaders in novel environments. However, little attention has been devoted to exploring the factors regulating zebra mussel density and population size structure at the local scale. We tested effects of physicochemical factors and fish predation on the density of zebra mussels at several sites and between years in a natural lake. Water depth and roach (Rutilus rutilus) density were the most important variables affectin...

  10. Development of a Common Nordic Balance Settlement

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2006-02-15

    NordREG finds it essential for the customers that a common integrated end-user electricity market is developed and that all end-users are able to take part in the Nordic market. A common Nordic balance settlement is one important part of such a change. However, attention has to be paid to the comments that a badly designed common system is worse than well-designed national systems. It is thus important that the change to a common balance settlement is so thoroughly investigated that the common system gives a basis for a well-functioning market. An important basis for such a change is an agreed vision for the process: The present different systems for balance settlement shall by the year 2010 be replaced by a common Nordic balance settlement. This means that: It will be possible for a supplier to sell to the whole Nordic market from one legal entity and using only one system for customer management and reporting. The common Nordic balance settlement will be designed in such a way that it contributes to a well functioning market. This means for example that it will be attractive even for small suppliers and some end-users to be balance responsible parties. It is feasible that the first phase is focused on those present differences that are most decisive for fulfilment of the vision. NordREG recommends that the following issues shall be discussed and agreed in co-operation between NordREG, Nordel and relevant stakeholders in the first phase: The definition shall include how the common Nordic balance settlement shall interact with the balance control and the balance regulation of the interconnected power system and the balance settlement between countries performed by the TSOs. The definition should include the cost-base for common Nordic balance settlement in relation to other system responsibility costs. The core activities of system responsibility have also been analyzed by NordREG. It is important to find a balance between inter alia the need for simplicity and the

  11. Development of a Common Nordic Balance Settlement

    International Nuclear Information System (INIS)

    2006-02-01

    NordREG finds it essential for the customers that a common integrated end-user electricity market is developed and that all end-users are able to take part in the Nordic market. A common Nordic balance settlement is one important part of such a change. However, attention has to be paid to the comments that a badly designed common system is worse than well-designed national systems. It is thus important that the change to a common balance settlement is so thoroughly investigated that the common system gives a basis for a well-functioning market. An important basis for such a change is an agreed vision for the process: The present different systems for balance settlement shall by the year 2010 be replaced by a common Nordic balance settlement. This means that: It will be possible for a supplier to sell to the whole Nordic market from one legal entity and using only one system for customer management and reporting. The common Nordic balance settlement will be designed in such a way that it contributes to a well functioning market. This means for example that it will be attractive even for small suppliers and some end-users to be balance responsible parties. It is feasible that the first phase is focused on those present differences that are most decisive for fulfilment of the vision. NordREG recommends that the following issues shall be discussed and agreed in co-operation between NordREG, Nordel and relevant stakeholders in the first phase: The definition shall include how the common Nordic balance settlement shall interact with the balance control and the balance regulation of the interconnected power system and the balance settlement between countries performed by the TSOs. The definition should include the cost-base for common Nordic balance settlement in relation to other system responsibility costs. The core activities of system responsibility have also been analyzed by NordREG. It is important to find a balance between inter alia the need for simplicity and the

  12. The urban features of informal settlements in Jakarta, Indonesia

    Directory of Open Access Journals (Sweden)

    Waleed Alzamil

    2017-12-01

    Full Text Available This data article contains the urban features of three informal settlements in Jakarta: A. Kampung Bandan; B. Kampung Luar Batang; And C. Kampung Muara Baru. The data describes the urban features of physical structures, infrastructures, and public services. These data include maps showing locations of these settlements, photography of urban status, and examples of urban fabric. The data are obtained from the statistical records and field surveys of three settlements cases. Keywords: Informal settlements, Physical, Features, Urban, Kampung, Jakarta, Indonesia

  13. DNA adduct measurements in zebra mussels, Dreissena polymorpha, Pallas

    International Nuclear Information System (INIS)

    Le Goff, J.; Gallois, J.; Pelhuet, L.; Devier, M.H.; Budzinski, H.; Pottier, D.; Andre, V.; Cachot, J.

    2006-01-01

    The purpose of this study was to examine PAH accumulation and bulky DNA adduct formation in the digestive gland of zebra mussels exposed in their habitat or in controlled laboratory conditions to complex mixture of PAH. DNA adducts were measured using a 32 P-postlabelling protocol with nuclease P1 enrichment adapted from Reddy and Randerath [Reddy, M.V., Randerath, K., 1986. Nuclease P1-mediated enhancement of sensitivity of 32 P-postlabelling test for structurally diverse DNA adducts. Carcinogenesis 7, 1543-1551]. Specimens collected in the upper part of the Seine estuary were shown to accumulate higher levels of PAH (up to 1.6 μg g -1 dry weight) in comparison to individuals from the reference site (0.053 μg g -1 dry weight). The former exhibited elevated levels of DNA adducts (up to 4.0/10 8 nucleotides) and higher diversity of individual adducts with five distinct spots being specifically detected in individuals originating from the Seine estuary. Zebra mussels exposed for 5 days to 0.01% (v/v) of organic extract of sediment from the Seine estuary were shown to accumulate high amounts of PAH (up to 138 μg g -1 dry weight) but exhibited relatively low levels of DNA adducts. Exposure to benzo[a]pyrene led to a dose-dependent accumulation of B[a]P (up to 7063 μg g -1 dry weight) and a clear induction of DNA adduct formation in the digestive gland of mussels (up to 1.13/10 8 nucleotides). Comparisons with other bivalves exposed to the same model PAH, revealed similar levels of adducts and comparable adduct profiles with a main adduct spot and a second faint one. This study clearly demonstrated that zebra mussels are able to biotransform B[a]P and probably other PAH into reactive metabolites with DNA-binding activity. This work also demonstrated the applicability of the nuclease P1 enhanced 32 P-postlabelling method for bulky adduct detection in the digestive gland of zebra mussels. DNA adduct measurement in zebra mussels could be a suitable biomarker to monitor

  14. DNA adduct measurements in zebra mussels, Dreissena polymorpha, Pallas

    Energy Technology Data Exchange (ETDEWEB)

    Le Goff, J. [GRECAN, UPRES EA-1772, University of Caen, Caen (France); Gallois, J. [Laboratory F. Duncombe, Conseil General du Calvados, Caen (France); Pelhuet, L. [LPTC, UMR-5472 CNRS, University Bordeaux I, Bordeaux (France); Devier, M.H. [LPTC, UMR-5472 CNRS, University Bordeaux I, Bordeaux (France); Budzinski, H. [LPTC, UMR-5472 CNRS, University Bordeaux I, Bordeaux (France); Pottier, D. [GRECAN, UPRES EA-1772, University of Caen, Caen (France); Andre, V. [GRECAN, UPRES EA-1772, University of Caen, Caen (France); Cachot, J. [LEMA, UPRES EA-3222, IFRMP 23, University of Le Havre, 25 rue Philippe Lebon, B.P. 540, 76058 Le Havre Cedex (France)]. E-mail: jerome.cachot@univ-lehavre.fr

    2006-08-12

    The purpose of this study was to examine PAH accumulation and bulky DNA adduct formation in the digestive gland of zebra mussels exposed in their habitat or in controlled laboratory conditions to complex mixture of PAH. DNA adducts were measured using a {sup 32}P-postlabelling protocol with nuclease P1 enrichment adapted from Reddy and Randerath [Reddy, M.V., Randerath, K., 1986. Nuclease P1-mediated enhancement of sensitivity of {sup 32}P-postlabelling test for structurally diverse DNA adducts. Carcinogenesis 7, 1543-1551]. Specimens collected in the upper part of the Seine estuary were shown to accumulate higher levels of PAH (up to 1.6 {mu}g g{sup -1} dry weight) in comparison to individuals from the reference site (0.053 {mu}g g{sup -1} dry weight). The former exhibited elevated levels of DNA adducts (up to 4.0/10{sup 8} nucleotides) and higher diversity of individual adducts with five distinct spots being specifically detected in individuals originating from the Seine estuary. Zebra mussels exposed for 5 days to 0.01% (v/v) of organic extract of sediment from the Seine estuary were shown to accumulate high amounts of PAH (up to 138 {mu}g g{sup -1} dry weight) but exhibited relatively low levels of DNA adducts. Exposure to benzo[a]pyrene led to a dose-dependent accumulation of B[a]P (up to 7063 {mu}g g{sup -1} dry weight) and a clear induction of DNA adduct formation in the digestive gland of mussels (up to 1.13/10{sup 8} nucleotides). Comparisons with other bivalves exposed to the same model PAH, revealed similar levels of adducts and comparable adduct profiles with a main adduct spot and a second faint one. This study clearly demonstrated that zebra mussels are able to biotransform B[a]P and probably other PAH into reactive metabolites with DNA-binding activity. This work also demonstrated the applicability of the nuclease P1 enhanced {sup 32}P-postlabelling method for bulky adduct detection in the digestive gland of zebra mussels. DNA adduct measurement in

  15. Canning process that diminishes paralytic shellfish poison in naturally contaminated mussels (Mytilus galloprovincialis).

    Science.gov (United States)

    Vieites, J M; Botana, L M; Vieytes, M R; Leira, F J

    1999-05-01

    Changes in toxin profile and total toxicity levels of paralytic shellfish poison (PSP)-containing mussels were monitored during the standard canning process of pickled mussels and mussels in brine using mouse bioassays and high-performance liquid chromatography. Detoxification percentages for canned mussel meat exceeded 50% of initial toxicity. Total toxicity reduction did not fully correspond to toxin destruction, which was due to the loss of PSP to cooking water and packing media of the canned product. Significant differences in detoxification percentages were due to changes in toxin profile during heat treatment in packing media. Toxin conversion phenomena should be determined to validate detoxification procedures in the canning industry.

  16. Evaluation of caged freshwater mussels as an alternative method for environmental effects monitoring (EEM) studies

    International Nuclear Information System (INIS)

    Martel, Pierre; Kovacs, Tibor; Voss, Ron; Megraw, Stan

    2003-01-01

    Results from caged mussel experiments agreed with benthic invertebrate surveys, but not with trends observed for fish. - On three occasions between 1998 and 2000, freshwater mussels were collected by divers in Lake Memphremagog during the spring and transplanted to various locations in the St-Francois River (Quebec, Canada). Mussel growth was monitored by comparing total weight and length at the beginning and end of the exposure period. In 1998, mussels were caged for 60 days at 10 stations, including locations receiving treated effluents from three pulp and paper mills. Overall, there was an apparent trend of increased mussel growth from upstream to downstream along the river. However, mussels caged downstream from the effluent discharge of a bleached kraft pulp and paper mill grew more slowly than those caged immediately upstream in the river. In 1999 and 2000, we further investigated the situation in the vicinity of this bleached kraft mill. The measurements again indicated that growth of mussels in the effluent plume from this mill was reduced in comparison to sites upstream. Overall, in terms of growth, the caged mussels responded both positively and negatively to different environmental conditions. Compared with other monitoring approaches used at these sites during the same period, the caged mussel experiment results were consistent with the trends observed with the benthic invertebrate survey but not with the trends observed for fish

  17. Allometric relationships of 210Po and 210Pb in mussels and their application to environmental monitoring

    International Nuclear Information System (INIS)

    Carvalho, Fernando P.; Oliveira, Joao M.; Alberto, Georgeta; Vives i Batlle, J.

    2010-01-01

    Mussels from the Portuguese coast collected during several seasons of the year have shown 210 Po and 210 Pb body burdens (Bq mussel -1 ) that increased with mussels' body size but displayed significant decrease in radionuclide concentrations (Bq kg -1 ). For example, the increase of mussel size from 2.5 cm to 5.0 cm maximum shell length corresponded in average to a 50% decrease of 210 Po activity concentration in soft tissues from 1065 Bq kg -1 (dw) to 540 Bq kg -1 (dw). A similar reduction in concentration was observed for 210 Pb. The physiological condition of mussels, relating to fat and glycogen storage, had an effect on radionuclide concentrations, although the total body burden of radionuclide in mussels remained nearly constant throughout the year. These factors may play an important role in data interpretation for environmental monitoring programmes. Besides the mussel size and condition index, due to the inter-individual variation even inside narrow mussel size classes, the sample size, i.e., the number of specimens in one mussel sample is another key factor to be considered when obtaining environmentally representative radionuclide concentrations.

  18. Evaluation of freshwater mussel relocation as a conservation and management strategy

    Science.gov (United States)

    Cope, W. Gregory; Waller, Diane L.

    1995-01-01

    The relocation of unionacean mussels is commonly used as a conservation and management tool in large rivers and streams. Relocation has been used to recolonize areas where mussel populations have been eliminated by prior pollution events, to remove mussels from construction zones and to re-establish populations of endangered species. More recently, relocation has been used to protect native freshwater mussels from colonization by the exotic zebra mussel Dreissena polymorpha. We conducted a literature review of mussel relocations and evaluated their relative success as a conservation and management strategy. We found that 43% of all relocations were conducted because of construction projects that were forced to comply with the Endangered Species Act 1973 and that only 16% were monitored for five or more consecutive years. Most (43%) relocation projects were conducted from July to September, presumably a period when reproductive stress is relatively low for most species and the metabolic rate is sufficient for reburrowing in the substrate. The mortality of relocated mussels was unreported in 27% of projects; reported mortality varied widely among projects and species and was difficult to assess. The mean mortality of relocated mussels was 49% based on an average recovery rate of 43%. There is little guidance on the methods for relocation or for monitoring the subsequent long-term status of relocated mussels. Based on this evaluation, research is needed to develop criteria for selecting a suitable relocation site and to establish appropriate methods and guidelines for conducting relocation projects.

  19. Mitigation of unionid mortality caused by zebra mussel infestation: cleaning of unionids

    Science.gov (United States)

    Schloesser, Don W.

    1996-01-01

    Exotic zebra mussels Dreissena polymorpha have infested and caused mortality of native unionids in the Great Lakes since 1986; no other such parasitism of native unionids occurs in North America. Survival of unionids threatened by zebra mussel infestation was tested by suspending uncleaned and cleaned unionids in nearshore waters of western Lake Erie. Survival was determined, and newly settled zebra mussels were removed from clean unionids at eight intervals that ranged from 21 d to 77 d between 5 July 1990 and 3 July 1991. After 1 year, survival rates of uncleaned and cleaned unionids were 0% and 42%, respectively. Of the 10 species examined, only indivduals from 3 species (Amblema plicata plicata, Fusconaia flava, and Quadrula quadrula) survived 1 year. These species have relatively thick shells, which may have contributed to their survival. Removal of newly settled zebra mussels may be important to unionid survival because 98% of the zebra mussels removed after the initial cleaning were small mussels (zebra mussels cause mortality of unionids, but the removal of zebra mussels from unionids is the only method known that successfully reduces unionid mortality in waters colonized by zebra mussels.

  20. California mussels (Mytilus californianus) as sentinels for marine contamination with Sarcocystis neurona.

    Science.gov (United States)

    Michaels, Lauren; Rejmanek, Daniel; Aguilar, Beatriz; Conrad, Patricia; Shapiro, Karen

    2016-05-01

    Sarcocystis neurona is a terrestrial parasite that can cause fatal encephalitis in the endangered Southern sea otter (Enhydra lutris nereis). To date, neither risk factors associated with marine contamination nor the route of S. neurona infection to marine mammals has been described. This study evaluated coastal S. neurona contamination using California mussels (Mytilus californianus) as sentinels for pathogen pollution. A field investigation was designed to test the hypotheses that (1) mussels can serve as sentinels for S. neurona contamination, and (2) S. neurona contamination in mussels would be highest during the rainy season and in mussels collected near freshwater. Initial validation of molecular assays through sporocyst spiking experiments revealed the ITS-1500 assay to be most sensitive for detection of S. neurona, consistently yielding parasite amplification at concentrations ⩾5 sporocysts/1 mL mussel haemolymph. Assays were then applied on 959 wild-caught mussels, with detection of S. neurona confirmed using sequence analysis in three mussels. Validated molecular assays for S. neurona detection in mussels provide a novel toolset for investigating marine contamination with this parasite, while confirmation of S. neurona in wild mussels suggests that uptake by invertebrates may serve as a route of transmission to susceptible marine animals.

  1. Water and sediment temperatures at mussel beds in the upper Mississippi River basin

    Science.gov (United States)

    Newton, Teresa J.; Sauer, Jennifer; Karns, Byron

    2013-01-01

    Native freshwater mussels are in global decline and urgently need protection and conservation. Declines in the abundance and diversity of North American mussels have been attributed to human activities that cause pollution, waterquality degradation, and habitat destruction. Recent studies suggest that effects of climate change may also endanger native mussel assemblages, as many mussel species are living close to their upper thermal tolerances. Adult and juvenile mussels spend a large fraction of their lives burrowed into sediments of rivers and lakes. Our objective was to measure surface water and sediment temperatures at known mussel beds in the Upper Mississippi (UMR) and St. Croix (SCR) rivers to estimate the potential for sediments to serve as thermal refugia. Across four mussel beds in the UMR and SCR, surface waters were generally warmer than sediments in summer, and were cooler than sediments in winter. This suggests that sediments may act as a thermal buffer for mussels in these large rivers. Although the magnitude of this effect was usually cause mortality in laboratory studies. These data suggest that elevated water temperatures resulting from global warming, thermal discharges, water extraction, and/or droughts have the potential to adversely affect native mussel assemblages.

  2. Flexibility of Physiological Traits Underlying Inter-Individual Growth Differences in Intertidal and Subtidal Mussels Mytilusgalloprovincialis.

    Directory of Open Access Journals (Sweden)

    María José Fernández-Reiriz

    Full Text Available Mussel seed (Mytilusgalloprovincialis gathered from the intertidal and subtidal environments of a Galician embayment (NW, Spain were maintained in the laboratory during five months to select fast (F and slow (S growing mussels. The physiological basis underlying inter-individual growth variations were compared for F and S mussels from both origins. Fast growing seemed to be a consequence of greater energy intake (20% higher clearance and ingestion rate and higher food absorption rate coupled with low metabolic costs. The enhanced energy absorption (around 65% higher resulted in 3 times higher Scope for Growth in F mussels (20.5±4.9 J h(-1 than S individuals (7.3±1.1 J h(-1. The higher clearance rate of F mussels appears to be linked with larger gill filtration surface compared to S mussels. Intertidal mussels showed higher food acquisition and absorption per mg of organic weight (i.e. mass-specific standardization than subtidal mussels under the optimal feeding conditions of the laboratory. However, the enhanced feeding and digestive rates were not enough to compensate for the initial differences in tissue weight between mussels of similar shell length collected from the intertidal and subtidal environments. At the end of the experiment, subtidal individuals had higher gill efficiency, which probably lead to higher total feeding and absorption rates relative to intertidal individuals.

  3. Farmers risk perception and risk management strategies in an emerging mussel aquaculture industry in Denmark

    DEFF Research Database (Denmark)

    Ahsan, Dewan; Roth, Eva

    2010-01-01

    The aim of this exploratory study is to provide empirical insight into how the mussel farmers perceive and manage risks. The results show that future price and demand of mussel are the high ranked perceived risk. Bad weather, oxygen depletion, harmful algal blooms, E-coli, change in governmental...... regulation and public view towards mussel culture are also considered important risk factors in mussel farming. On the other hand, produced at lowest possible cost, cooperative marketing, good relation with government, prioritize liquidity, adopt new technology and experience sharing are perceived most...

  4. The Effect of Zebra Mussels on Algal Community Structure in an Impounded River System

    Science.gov (United States)

    Trumble, A. F.; Luttenton, M.

    2005-05-01

    The zebra mussel, Dreissena polymorpha, invaded the Great Lakes Region in the mid 1980's, and subsequently colonized inland lakes and coastal river systems through secondary invasions. The Muskegon River below Croton Dam was colonized by zebra mussels in 2000 following their introduction into Croton impoundment in the late 1990's. No zebra mussels were found below Croton Dam in 1999 but had increased to 25,000 m-2 by 2001. We examined the affect of zebra mussels on epilithic periphyton communities by comparing plots that were and were not colonized by zebra mussels. Chlorophyll a increased in both treatments over time but was significantly higher in control plots than in zebra mussel plots. The concentration of chlorophyll a in the control plots increased from 14 µgcm-2 to 26 µgcm-2 and the concentration in the zebra mussel plots started at 12 µgcm-2, peaked at 19 µgcm-2, and then decreased to 15 µgcm-2 over a 6 week period. In a related experiment using artificial streams, chlorophyll a increased with increasing zebra mussel density, but differences were not significant. The different trends observed between the two experiments may be explained in part by arthropod invertebrates associated with zebra mussel populations.

  5. Evaluation of zebra mussels (Dreissena polymorpha) as biomonitors of mercury contamination in aquatic ecosystems.

    Science.gov (United States)

    Blackwell, Bradley D; Driscoll, Charles T; Spada, Michael E; Todorova, Svetoslava G; Montesdeoca, Mario R

    2013-03-01

    Zebra mussels have invaded many lakes in the United States and could be a useful tool for monitoring responses of aquatic biota to changes in mercury loading. The goal of the present study was to evaluate zebra mussels for use as a biomonitor of mercury contamination by comparing zebra mussel mercury concentrations between a lake with only indirect atmospheric mercury contamination (Otisco Lake, NY, USA) and a lake that was directly contaminated by mercury discharges (Onondaga Lake, NY, USA). Zebra mussels were sampled in both the spring and fall of 2004 and 2005. Total mercury (THg) concentrations in zebra mussels were approximately seven times greater in Onondaga Lake than in Otisco Lake, and water column mercury concentrations differed by an order of magnitude between the two lakes. Seasonal differences resulted in significantly higher zebra mussel THg concentrations during the fall for both lakes. There was also significant variation among different sampling sites in Onondaga Lake. Mussel methylmercury concentrations averaged 53% of THg concentrations but were highly variable. Strong relationships between water column THg and zebra mussel THg suggest that zebra mussels are a good indicator of aquatic mercury concentrations and could be used as an effective biomonitor of mercury contamination in aquatic ecosystems. Copyright © 2013 SETAC.

  6. 7 CFR 1940.406 - Real estate settlement procedures.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 13 2010-01-01 2009-01-01 true Real estate settlement procedures. 1940.406 Section... AGRICULTURE (CONTINUED) PROGRAM REGULATIONS (CONTINUED) GENERAL Truth in Lending-Real Estate Settlement Procedures § 1940.406 Real estate settlement procedures. (a) General. This section provides the instructions...

  7. Infrastructure Provision and Classification of Rural Settlements in ...

    African Journals Online (AJOL)

    This study classifies the selected rural settlements on the basis of available infrastructure .To achieve this aim, 22 rural settlements were randomly selected. The cluster analysis was applied on the data in order to group the rural settlements on the basis of their infrastructure profiles. Thus the hierarchical method of cluster ...

  8. 6 CFR 13.46 - Compromise or settlement.

    Science.gov (United States)

    2010-01-01

    ... 6 Domestic Security 1 2010-01-01 2010-01-01 false Compromise or settlement. 13.46 Section 13.46 Domestic Security DEPARTMENT OF HOMELAND SECURITY, OFFICE OF THE SECRETARY PROGRAM FRAUD CIVIL REMEDIES § 13.46 Compromise or settlement. (a) Parties may Make offers of compromise or settlement at any time...

  9. 48 CFR 49.110 - Settlement negotiation memorandum.

    Science.gov (United States)

    2010-10-01

    ... 48 Federal Acquisition Regulations System 1 2010-10-01 2010-10-01 false Settlement negotiation... CONTRACT MANAGEMENT TERMINATION OF CONTRACTS General Principles 49.110 Settlement negotiation memorandum. (a) The TCO shall, at the conclusion of negotiations, prepare a settlement negotiation memorandum...

  10. 24 CFR 3500.9 - Reproduction of settlement statements.

    Science.gov (United States)

    2010-04-01

    ... 24 Housing and Urban Development 5 2010-04-01 2010-04-01 false Reproduction of settlement... HOUSING AND URBAN DEVELOPMENT REAL ESTATE SETTLEMENT PROCEDURES ACT § 3500.9 Reproduction of settlement... in sections F and H, respectively. (3) Reproduction of the HUD-1 must conform to the terminology...

  11. Settlement and juvenile habitat of the European spiny lobster Palinurus elephas (Crustacea: Decapoda: Palinuridae in the western Mediterranean Sea

    Directory of Open Access Journals (Sweden)

    David Díaz

    2001-12-01

    Full Text Available Settlement characteristics, like timing, depth, microhabitat and density of European spiny lobster Palinurus elephas are described for the very first time. Regular SCUBA-diving surveys were conducted from July 1998 to January 2000 on rocky bottoms of three different geologic origins to assess substratum-dependent differences in recruitment density. Settlement of pueruli took place in June-July, a few weeks after sea surface temperature started to rise. The highest density of juveniles was found at 10-15 m depth. Most spiny lobsters settled in limestone rocks, into empty holes of the date mussel Lithophaga lithophaga, which provided daytime refuge. As they grew, individuals were increasingly found in larger holes and crevices of the rock surface. Sizes were estimated from photographs taken at night when the animals were actively foraging. The smallest observed individuals measured 7.5-8 mm carapace length (CL, but they reached 15-18 mm CL at the end of October. The consequences of our results for the management of the spiny lobster populations in the northwestern Mediterranean are summarily discussed.

  12. Researching Entrepreneurship in Low-income Settlements

    DEFF Research Database (Denmark)

    Gough, Katherine V.; Langevang, Thilde; Namatovu, Rebecca

    2014-01-01

    of entrepreneurship conducted in a low-income settlement, which combined participatory quantitative and qualitative approaches, highlighting the strengths and challenges of using participatory methods. The paper demonstrates how drawing on a range of participatory methods can contribute to creating more engaging...

  13. Clearing and settlement of exchange traded derivatives

    OpenAIRE

    John McPartland

    2009-01-01

    Derivatives are a class of financial instruments that derive their value from some underlying commodity, security, index, or other asset. Futures and options are common forms of derivatives. This article explains how clearing and settlement systems for exchange traded derivatives work.

  14. Directional layouts in central lowland Maya settlement

    DEFF Research Database (Denmark)

    Bevan, Andrew; Jobbová, Eva; Helmke, Christophe

    2013-01-01

    This paper suggests the existence of non-random, directional patterns in the location of housemounds across the Late Classic Maya settlement landscape at Baking Pot, Belize, and then explores the wider implications of this patterning in the central Maya lowlands. It introduces an anisotropic method...

  15. Between archaeology and anthropology: imagining Neolithic settlements

    Czech Academy of Sciences Publication Activity Database

    Květina, Petr; Hrnčíř, V.

    2013-01-01

    Roč. 51, č. 2 (2013), s. 323-347 ISSN 0323-1119. [Theory and method in the prehistoric archaeology of Central Europe. Mikulov, 24.10.2012-26.10.2012] R&D Projects: GA MK(CZ) DF12P01OVV032 Keywords : Neolithic longhouse * ethnographic analogy * settlement patterns Subject RIV: AC - Archeology, Anthropology, Ethnology

  16. 17 CFR 8.16 - Settlement offers.

    Science.gov (United States)

    2010-04-01

    ... Section 8.16 Commodity and Securities Exchanges COMMODITY FUTURES TRADING COMMISSION EXCHANGE PROCEDURES FOR DISCIPLINARY, SUMMARY, AND MEMBERSHIP DENIAL ACTIONS Disciplinary Procedure § 8.16 Settlement... the disciplinary committee at any time after the investigation report is completed. The disciplinary...

  17. Modelling of settlement induced building damage

    NARCIS (Netherlands)

    Giardina, G.

    2013-01-01

    This thesis focuses on the modelling of settlement induced damage to masonry buildings. In densely populated areas, the need for new space is nowadays producing a rapid increment of underground excavations. Due to the construction of new metro lines, tunnelling activity in urban areas is growing.

  18. Trade-off between increased survival and reduced growth for blue mussels living on Pacific oyster reefs

    DEFF Research Database (Denmark)

    Eschweiler, Nina; Christensen, Helle Torp

    2011-01-01

    Pacific oysters Crassostrea gigas (Thunberg 1793) have been introduced into the Wadden Sea (North Sea, Germany) in the mid of the 1980s and have invaded native blue mussel Mytilus edulis (L.) beds. The latter turned into oyster reefs where mussels seem to be relegated to the bottom in between...... the much larger oysters. By combining field and laboratory experiments, we reveal how mussels react to cohabitation with the invasive oysters. Mussels subjected to direct contact with crabs Carcinus maenas migrate from top to bottom positions between oysters in both field and laboratory experiments within...... 22days. Shell growth was significantly reduced for mussels placed on the bottom compared to mussels at the top of an oyster reef. Condition index was lower for mussels on the bottom of the reef irrespective of whether placed between dead or living oysters. We conclude that mussels experience a trade...

  19. On the dynamics of the stocks of blue mussels ( Mytilus edulis L.) in the Danish Wadden Sea

    DEFF Research Database (Denmark)

    Munch-Petersen, Sten; Kristensen, Per Sand

    2001-01-01

    As biological basis for the monitoring programme for the commercially exploited stock(s) of mussels (Mytilus edulis L.) in the Danish Wadden Sea, samples of mussels have been collected regularly since 1986, both from sub-tidal and inter- tidal mussel beds. These samples are the basis for the esti...... with figures from other investigations. These analyses have been the basis for annual assessments of the mussel stocks, which again are used in the current management of mussel fishery in the Danish Wadden Sea.......As biological basis for the monitoring programme for the commercially exploited stock(s) of mussels (Mytilus edulis L.) in the Danish Wadden Sea, samples of mussels have been collected regularly since 1986, both from sub-tidal and inter- tidal mussel beds. These samples are the basis...

  20. Habitat engineering by the invasive zebra mussel Dreissena polymorpha (Pallas) in a boreal coastal lagoon: impact on biodiversity

    Science.gov (United States)

    Zaiko, Anastasija; Daunys, Darius; Olenin, Sergej

    2009-03-01

    Habitat engineering role of the invasive zebra mussel Dreissena polymorpha (Pallas) was studied in the Curonian lagoon, a shallow water body in the SE Baltic. Impacts of live zebra mussel clumps and its shell deposits on benthic biodiversity were differentiated and referred to unmodified (bare) sediments. Zebra mussel bed was distinguished from other habitat types by higher benthic invertebrate biomass, abundance, and species richness. The impact of live mussels on biodiversity was more pronounced than the effect of shell deposits. The structure of macrofaunal community in the habitats with >103 g/m2 of shell deposits devoid of live mussels was similar to that found within the zebra mussel bed. There was a continuous shift in species composition and abundance along the gradient ‘bare sediments—shell deposits—zebra mussel bed’. The engineering impact of zebra mussel on the benthic community became apparent both in individual patches and landscape-level analyses.

  1. THE CULTURE OF SETTLEMENT AREAS IN SLOVENIA

    Directory of Open Access Journals (Sweden)

    Urša Suhadolnik Vovko

    2013-01-01

    Full Text Available To study and grasp the contemporary rural areas in Slovenia, the students of the Faculty of Architecture carried out a public opinion survey on the subject of the culture of settlement areas, with a particular reference to the visual image of the experiential space of the settlements. Today, human needs and living values are an integral part of all documents, as they represent the starting-point of designing new concepts of living. Personal quality of living is explained by Mandič [1999] through the use of Allard's classification of human needs; however, Mercer's Quality of Living ranking is often used to measure the quality of the living environmentThe paper represents the results of the study, which included two target groups: The experts in spatial management and planning employed at municipal administrative offices; and the senior years’ students at the Faculty of Architecture of the University of Ljubljana. The study represented here addressed the values of the living environment. The study was triggered by the 'colourfulness' that knows no limits in Slovenia. Putting the everyday indignation over the variety of all possible shades aside, it has become evident that the tiny elements that are also destroying the image of our settlements are all too often neglected: billboards, log cabins complementing garages and decorative elements, stalls during celebrations and fairs, fountains, monuments, mix of exotic plants, the Snow White and the Seven Dwarfs etc. The study included a survey to obtain a more objective approach to the studying of the quality from the viewpoints of the changing living culture and the use of communal external space in Slovenian settlements. The key question that resonated in most of other questions was: What would improve the quality of life in the settlement?

  2. Biokinetics of 237Np in mussels and shrimp

    International Nuclear Information System (INIS)

    Guary, J.C.; Fowler, S.W.

    1977-01-01

    Neptunium-237 kinetics were studied in marine shrimp and mussels using a thick source alpha counting technique. Bioaccumulation of 237 Np from water was relatively slow in both species, reaching whole body concentration factors of only 15 to 20 after three months. Surface adsorption was implicated in the initial uptake. Both uptake and loss of the radioisotope were not significantly affected by temperature; this may be a reflection of the physical nature of the uptake. By virtue of the large amounts of accumulated 237 Np associated with the exoskeleton of shrimp, molting will play an important role in the biogeochemical cycling of this transuranic in the marine environment. Rapid growth of organisms like mussels acts to reduce the 237 Np concentration in tissues during a period of decontamination

  3. Quagga and Zebra Mussel Eradication and Control Tactics

    OpenAIRE

    Culver, Carolynn; Lahr, Heather; Johnson, Leigh; Cassell, Jodi

    2013-01-01

    Aquatic invasive species (AIS)continue to threaten coastal and marine habitats in California. The goal of this project is to conduct research and develop outreach materials that help agencies, groups and individuals prevent, eradication and control AIS. Current objectives include: 1) investigate recruitment dynamics of quagga mussels in southern California to provide baseline informaiton on infestations in various locations, inform monitoring efforts and to identify factors influencing the su...

  4. Mechanical design of mussel byssus: material yield enhances attachment strength

    Science.gov (United States)

    Bell; Gosline

    1996-01-01

    The competitive dominance of mussels in the wave-swept rocky intertidal zone is in part due to their ability to maintain a secure attachment. Mussels are tethered to the substratum by a byssus composed of numerous extracellular, collagenous threads secreted by the foot. Each byssal thread has three serially arranged parts: a corrugated proximal region, a smooth distal region and an adhesive plaque. This study examines the material and structural properties of the byssal threads of three mussel species: Mytilus californianus, M. trossulus, and M. galloprovincialis. Tensile tests in general reveal similar material properties among species: the proximal region has a lower initial modulus, a lower ultimate stress and a higher ultimate strain than the distal region. The distal region also yields at a stress well below its ultimate value. In whole thread tests, the proximal region and adhesive plaque are common sites of structural failure and are closely matched in strength, while the distal region appears to be excessively strong. We propose that the high strength of the distal region is the byproduct of a material designed to yield and extend before structural failure occurs. Experimental and theoretical evidence is presented suggesting that thread yield and extensibility provide two important mechanisms for increasing the overall attachment strength of the mussel: (1) the reorientation of threads towards the direction of applied load, and (2) the 'recruitment' of more threads into tension and the consequent distribution of applied load over a larger cross-sectional area, thereby reducing the stress on each thread. This distal region yield behavior is most striking for M. californianus and may be a key to its success in extreme wave-swept environments.

  5. METHODOLOGY RELATED TO ESTIMATION OF INVESTMENT APPEAL OF RURAL SETTLEMENTS

    Directory of Open Access Journals (Sweden)

    A. S. Voshev

    2010-03-01

    Full Text Available Conditions for production activity vary considerably from region to region, from area to area, from settlement to settlement. In this connection, investors are challenged to choose an optimum site for a new enterprise. To make the decision, investors follow such references as: investment potential and risk level; their interrelation determines investment appeal of a country, region, area, city or rural settlement. At present Russia faces a problem of «black boxes» represented by a lot of rural settlements. No effective and suitable techniques of quantitative estimation of investment potential, rural settlement risks and systems to make the given information accessible for potential investors exist until now.

  6. The use of waste mussel shells for the adsorption of dyes and heavy metals

    Science.gov (United States)

    Papadimitriou, Chrysi A.; Krey, Grigorios; Stamatis, Nikolaos; Kallaniotis, Argyris

    2016-04-01

    Mussel culture is very important sector of the Greek agricultural economy. The majority of mussel culture activities take place in the area of Central Macedonia, Greece, 60% of total mussel production in Greece producing almost 12 tons of waste mussels shells on a daily basis. Currently there is no legislation concerning the disposal of mussel shells. In the present study the waste shells were used for the removal of dyes and heavy metals from aqueous solutions while powdered mussel shells were added in activated sludge processes for the removal of hexavalent chromium. Mussel shells were cleaned, dried and then crushed in order to form a powder. Powdered mussels shells were used in standard adsorption experiments for the removal of methylene blue and methyl red as well as for the removal of Cr (VI), Cd and Cu. Moreover the powdered mussel shells were added in laboratory scale activated sludge reactors treating synthetic wastewater with hexavalent chromium, in order investigate the effects in activated sludge processes and their potential attribution to the removal of hexavalent chromium. Adsorption experiments indicated almost 100% color removal, while adsorption was directly proportional to the amount of powdered mussel shells added in each case. The isotherms calculated for the case of methylene blue indicated similar adsorption capacity and properties to those of the commercially available activated carbon SAE 2, Norit. High removal efficiencies were observed for the metals, especially in the case of chromium and copper. The addition of powdered mussel shells in the activated sludge processes enhanced the removal of chromium and phosphorus, while enabled the formation of heavier activated sludge flocs and thus enhanced the settling properties of the activated sludge.

  7. Stoichiometric constraints do not limit successful invaders: zebra mussels in Swedish lakes.

    Science.gov (United States)

    Naddafi, Rahmat; Eklöv, Peter; Pettersson, Kurt

    2009-01-01

    Elemental imbalances of carbon (C): nitrogen (N): phosphorus (P) ratios in food resources can constrain the growth of grazers owning to tight coupling between growth rate, RNA allocation and biomass P content in animals. Testing for stoichiometric constraints among invasive species is a novel challenge in invasion ecology to unravel how a successful invader tackles ecological barriers in novel ecosystems. We examined the C:P and N:P ratios and the condition factor of a successful invader in lakes, the zebra mussel (Dreissena polymorpha), collected from two Swedish lakes. Concurrently, we analyzed the elemental composition of the food (seston) and tissue of the mussels in which nutrient composition of food and mussels varied over time. Zebra mussel condition factor was weakly related to the their own tissue N:P and C:P ratios, although the relation with the later ratio was not significant. Smaller mussels had relatively lower tissue N:P ratio and higher condition factor. There was no difference in C:P and N:P ratios between seston and mussels' tissues. Our results indicated that the variation in nutrient stoichiometry of zebra mussels can be explained by food quality and quantity. Our study suggests that fitness of invasive zebra mussels is not constrained by nutrient stoichiometry which is likely to be important for their proliferation in novel ecosystems. The lack of imbalance in C:P and N:P ratios between seston and mussels along with high tissue C:P ratio of the mussel allow them to tolerate potential P limitation and maintain high growth rate. Moreover, zebra mussels are able to change their tissue C:P and N:P ratios in response to the variation in elemental composition of their food. This can also help them to bypass potential nutrient stoichiometric constraints. Our finding is an important step towards understanding the mechanisms contributing to the success of exotic species from stoichiometric principles.

  8. Stoichiometric constraints do not limit successful invaders: zebra mussels in Swedish lakes.

    Directory of Open Access Journals (Sweden)

    Rahmat Naddafi

    Full Text Available Elemental imbalances of carbon (C: nitrogen (N: phosphorus (P ratios in food resources can constrain the growth of grazers owning to tight coupling between growth rate, RNA allocation and biomass P content in animals. Testing for stoichiometric constraints among invasive species is a novel challenge in invasion ecology to unravel how a successful invader tackles ecological barriers in novel ecosystems.We examined the C:P and N:P ratios and the condition factor of a successful invader in lakes, the zebra mussel (Dreissena polymorpha, collected from two Swedish lakes. Concurrently, we analyzed the elemental composition of the food (seston and tissue of the mussels in which nutrient composition of food and mussels varied over time. Zebra mussel condition factor was weakly related to the their own tissue N:P and C:P ratios, although the relation with the later ratio was not significant. Smaller mussels had relatively lower tissue N:P ratio and higher condition factor. There was no difference in C:P and N:P ratios between seston and mussels' tissues. Our results indicated that the variation in nutrient stoichiometry of zebra mussels can be explained by food quality and quantity.Our study suggests that fitness of invasive zebra mussels is not constrained by nutrient stoichiometry which is likely to be important for their proliferation in novel ecosystems. The lack of imbalance in C:P and N:P ratios between seston and mussels along with high tissue C:P ratio of the mussel allow them to tolerate potential P limitation and maintain high growth rate. Moreover, zebra mussels are able to change their tissue C:P and N:P ratios in response to the variation in elemental composition of their food. This can also help them to bypass potential nutrient stoichiometric constraints. Our finding is an important step towards understanding the mechanisms contributing to the success of exotic species from stoichiometric principles.

  9. Biomarker responses of mussels exposed to earthquake disturbances

    Science.gov (United States)

    Chandurvelan, Rathishri; Marsden, Islay D.; Glover, Chris N.; Gaw, Sally

    2016-12-01

    The green-lipped mussel, Perna canaliculus is recognised as a bioindicator of coastal contamination in New Zealand (NZ). Mussels (shell length 60-80 mm) were collected from three intertidal areas of Canterbury in the South Island of NZ prior to extreme earthquake disturbances on 22nd February 2011, and 9 months later in October 2011. Trace elements, including arsenic (As), cadmium (Cd), copper (Cu), lead (Pb), nickel (Ni), and zinc (Zn), were measured in the gills, digestive gland, foot and mantle. Metal levels in tissues were site specific, and mostly unaffected by earthquake disturbances. Physiological biomarkers were negatively affected by earthquake disturbances and mussels from the Port of Lyttelton had higher negative scope for growth post-earthquake. Metallothionein-like protein in the digestive gland correlated with metal content of tissues, as did catalase activity in the gill and lipid peroxidation values for the digestive gland. This research demonstrates that physiological and other biomarkers are effective at detecting the effects of multiple stressors following seismic disturbances.

  10. Pollutants bioavailability and toxicological risk from microplastics to marine mussels

    International Nuclear Information System (INIS)

    Avio, Carlo Giacomo; Gorbi, Stefania; Milan, Massimo; Benedetti, Maura; Fattorini, Daniele; D'Errico, Giuseppe; Pauletto, Marianna; Bargelloni, Luca; Regoli, Francesco

    2015-01-01

    Microplastics represent a growing environmental concern for the oceans due to their potential of adsorbing chemical pollutants, thus representing a still unexplored source of exposure for aquatic organisms. In this study polyethylene (PE) and polystyrene (PS) microplastics were shown to adsorb pyrene with a time and dose-dependent relationship. Results also indicated a marked capability of contaminated microplastics to transfer this model PAH to exposed mussels Mytilus galloprovincialis; tissue localization of microplastics occurred in haemolymph, gills and especially digestive tissues where a marked accumulation of pyrene was also observed. Cellular effects included alterations of immunological responses, lysosomal compartment, peroxisomal proliferation, antioxidant system, neurotoxic effects, onset of genotoxicity; changes in gene expression profile was also demonstrated through a new DNA microarray platform. The study provided the evidence that microplastics adsorb PAHs, emphasizing an elevated bioavailability of these chemicals after the ingestion, and the toxicological implications due to responsiveness of several molecular and cellular pathways to microplastics. - Highlights: • Polyethylene and polystyrene microplastics efficiently adsorbed pyrene. • Pyrene adsorbed on microplastics was readily bioavailable for mussels. • Microplastics affected several molecular and cellular pathways. • Potential toxicological risk can arise from virgin and contaminated microplastics. - Pyrene adsorbed on microplastics is accumulated in tissues of marine mussels. Transcriptional and cellular responses highlight the potential risk of virgin and contaminated polymers

  11. Mercury in mussels of Bellingham Bay, Washington, (USA)

    Energy Technology Data Exchange (ETDEWEB)

    Roesijadi, G.; Drum, A.S.; Bridge, J.R.

    1978-11-01

    Laboratory experiments demonstrated the existence of metallothionein-like, low molecular weight, mercury-binding proteins in the marine mussel Mytilus edulis. Relatively large quantities of mercury were associated with such proteins in gills and digestive gland, the organs of interest in the present study. /sup 14/C-incorporation indicated induction of the protein in gills, but not in digestive gland. Mercury in digestive gland may have bound to existing metal-binding proteins. Short-term incorporation of mercury occurred primarily in gills. The induction of mercury-binding proteins in gills may have facilitated detoxification of mercury at the site of uptake. Mercury in mussels of Bellingham Bay were shown to have decreased from 1970 to 1978, the collection date for the present study. Mercury levels were low but approximately three times higher than those from uncontaminated areas. Mercury associated with the mercury-binding protein of gills and digestive glands of Bellingham Bay mussels were low and reflected the concentrations measured in the whole tissues. However, the highest concentration of mercury was associated with the low molecular pool components, the identity of which is not presently known.

  12. Pseudodiarrhoea in zebra mussels Dreissena polymorpha (Pallas) exposed to microcystins.

    Science.gov (United States)

    Juhel, Guillaume; Davenport, John; O'Halloran, John; Culloty, Sarah; Ramsay, Ruth; James, Kevin; Furey, Ambrose; Allis, Orla

    2006-03-01

    Microcystins are produced by bloom-forming cyanobacteria and pose significant health and ecological problems. In this study we show that zebra mussels respond differently to different strains of Microcystis aeruginosa, and that a highly toxic strain causes zebra mussels to produce large quantities of mucous pseudofaeces, 'pseudodiarrhoea', that are periodically expelled hydraulically through the pedal gape by shell valve adductions rather than by the normal ciliary tracts. Analysis of the pseudofaecal ejecta showed that the proportion of Microcystis aeruginosa relative to Asterionella formosa was high in the pseudofaeces and even higher in the 'pseudodiarrhoea' when a mixed diet was given to the mussels. This confirms that very toxic Microcystis aeruginosa were preferentially being rejected by comparison with the non-toxic diatom in the pseudofaeces and even more so in the 'pseudodiarrhoea'. Such selective rejection was not observed with low or non-toxic strains and would therefore tend to enhance the presence of toxic Microcystis aeruginosa in mixed Microcystis aeruginosa cyanobacterial blooms, as well as transferring toxins from the water column to the benthos. The observed acute irritant response to the toxin represents the first demonstration of an adverse sublethal effect of microcystins on invertebrate ecophysiology. Our results also suggest that it could be a specific response to microcystin-LF, a little studied toxin variant.

  13. The morphological /settlement pattern classification of South African settlements based on a settlement catchment approach, to inform facility allocation and service delivery

    CSIR Research Space (South Africa)

    Sogoni, Z

    2016-07-01

    Full Text Available / settlement pattern classification of South African settlements based on a settlement catchment approach, to inform facility allocation and service delivery Zukisa Sogoni Planning Africa Conference 2016 4 July 2Project Focus and Background • CSIR... services. • Purpose is to support application & planning for new investment & prevent “unsustainable” investments / White elephants. 3Outputs • National set of service delivery catchments • Profile information per individual catchment • Ranking...

  14. Impact of the blue mussel Mytilus edulis on the microbial food web in the western Wadden Sea, The Netherlands.

    NARCIS (Netherlands)

    Jacobs, P.; Riegman, R.; van der Meer, J.

    2015-01-01

    To study the impact of juvenile blue mussels Mytilus edulis on the microbial food web in the Dutch Wadden Sea, natural sea water was first exposed to mussel filtration. Subsequently, filtered plankton communities were used in a dilution experiment to establish mussel-induced changes in bacterial,

  15. Impact of the blue mussel Mytilus edulis on the microbial food web in the western Wadden Sea, the Netherlands

    NARCIS (Netherlands)

    Jacobs, P.; Riegman, R.; Meer, van der J.

    2015-01-01

    To study the impact of juvenile blue mussels Mytilus edulis on the microbial food web in the Dutch Wadden Sea, natural sea water was first exposed to mussel filtration. Subsequently, filtered plankton communities were used in a dilution experiment to establish mussel-induced changes in bacterial,

  16. Interactions between the introduced Pacific oyster Crassostrea gigas and the indigenous blue mussel Mytilus edulis. Local-scale food competition

    NARCIS (Netherlands)

    Hans, I.W.

    2004-01-01

    The aim of this study was to determine if food competition between mussels and oysters occurs, and how mussel and oyster growth is affected by this interaction. This was done by relating mussel growth to oyster density relating oyster growth to oyster biomass and perform a field control, by

  17. Dredging of blue mussels ( Mytilus edulis L.) in a Danish sound: stock sizes and fishery-effects on mussel population dynamic

    DEFF Research Database (Denmark)

    Dolmer, Per; Kristensen, Per Sand; Hoffmann, Erik

    1999-01-01

    In April 1993, 1994 and 1995 the abundance of blue mussels, Mytilus edulis L., was estimated in Limfjorden, Denmark. The stocks were assessed by using a down-scaled model of a commercial mussel dredge which efficiency was analysed by comparing its samples with others collected by diver. The mean...... dredge efficiency was 17%. The fishing area in Limfjorden (700 km(2)) is divided into 22 fishery zones and mussel stock size was calculated for each zone. From April 1993 to April 1994 the total stock size declined from 771 000 to 616 000 t. In the same period, the exploitation rate in the fishery was 14...

  18. Predation of the zebra mussel (Dreissena polymorpha) by freshwater drum in western Lake Erie

    Science.gov (United States)

    French, John R. P.; Bur, Michael T.; Nalepa, Thomas F.; Schloesser, Donald W.

    1992-01-01

    Environmental and economic problems associated with the colonization of zebra mussels (Dreissena polymorpha) in western Lake Erie created a need to investigate control mechanisms. Predation by fishes is one potential means of control, but predation on zebra mussels by native fishes in Lake Erie is unknown. The freshwater drum (Aplodinotus grunniens) is the most likely fish predator since it is the only fish with pharyngeal teeth capable of crushing mollusk shells. In 1990, freshwater drum were collected in western Lake Erie from 9 sites near rocky reefs and 13 sites with silt or sand bottoms, and gut contents were examined. Predation on zebra mussels increased as drum size increased. Small drum (200-249 mm in length) fed mainly on dipterans, amphipods, and small fish; small zebra mussels (375 mm in length) fed almost exclusively on zebra mussels (seasons and locations combined). The smallest drum capable of crushing zebra mussel shells was 265 mm. Since freshwater drum over 375 mm feed heavily on zebra mussels, they may become a possible biological control mechanism for mussels in portions of North America.

  19. Modelling the effects of diving ducks on zebra mussels Dreissena polymorpha in lakes

    NARCIS (Netherlands)

    Nes, van E.H.; Noordhuis, R.; Lammens, E.H.R.R.; Portielje, R.; Reeze, B.; Peeters, E.T.H.M.

    2008-01-01

    An individual-based model describing the growth of zebra mussels (Dreissena polymorpha) is presented. The model is spatially explicit and predicts length¿frequency distributions of zebra mussels. The parameters and model inputs with the strongest effect on the model outcomes were identified using a

  20. Freshwater mussel assemblage structure in a regulated river in the Lower Mississippi river Alluvial Basin, USA

    Science.gov (United States)

    Wendell R. Haag; Melvin L. Warren

    2007-01-01

    1. This paper documents a diverse, reproducing freshwater mussel community (20 species) in Lower Lake } an impounded, regulated portion of the Little Tallahatchie River below Sardis Dam in Panola Co., Mississippi, USA. 2. Despite being regulated and impounded, the lake has a heterogeneous array of habitats that differ markedly in mussel community attributes...

  1. Current Distributional Information on Freshwater Mussels (family Unionidae) in Mississippi National Forests

    Science.gov (United States)

    Wendell R. Haag; Melvin L. Warren

    1995-01-01

    Little is known about the distribution of freshwater mussels in Mississippi national forests. Review of the scant available information revealed that the national forests harbor a diverse mussel fauna of possibly 46 or more species (including confirmed, probable, and potential occurrences). Occurrence of 33 species is confirmed. Because of the geographic, physiographic...

  2. Baseline levels of benzo(a)pyrene in southern California mussels

    Energy Technology Data Exchange (ETDEWEB)

    Dunn, B P [Univ. of British Columbia, Vancouver; Young, D R

    1976-12-01

    Marine mussels accumulate the carcinogen benzo(a)-pyrene from contaminated environments. Baseline studies in California indicate that levels of the carcinogen in mussels are at or near zero, except in areas of human activity. This finding runs counter to previous suggestions that benzo(a)pyrene is widely distributed in marine organisms.

  3. Recovery and recruitment of the brown mussel, Perna perna (L.), in ...

    African Journals Online (AJOL)

    The brown mussel Perna perna, has been an important food resource for indigenous inhabitants of the Transkei coast for centuries. The impoverished state of mussel stocks in this region and major differences in lowshore community structure between exploited and protected areas, have been ascribed to the ...

  4. Reducing the Effects of Maintenance Dredging on Freshwater Mussels in the Alabama River, Alabama

    National Research Council Canada - National Science Library

    Miller, Andrew

    2000-01-01

    In September 1998, detailed studies of freshwater mussels (Family: Unionidae) were conducted at four mussel beds in the Alabama River, located at River Miles (RM) 20.2-20.4,30.1-30.4, 121.8-122.6, and 124.4-124.9...

  5. Reducing the Effects of Maintenance Dredging on Freshwater Mussels in the Alabama River, Alabama

    National Research Council Canada - National Science Library

    Miller, Andrew

    2000-01-01

    In September 1998, detailed studies of freshwater mussels (Family: Unionidae) were conducted at four mussel beds in the Alabama River, located at River Miles (RM) 20.2-20.4, 30.1-30.4,121.8-122.6, and 124.4-124.9...

  6. The invasive Asian green mussel Perna viridis in South Africa: all ...

    African Journals Online (AJOL)

    The Asian green mussel Perna viridis is an invasive Indo-Pacific species recently reported from South African harbours. To verify the invasion, a phylogenetic (and morphological) analysis of green-shelled mussels (n = 39), found in six South African harbours, was conducted using the mitochondrial cytochrome c oxidase ...

  7. An analysis of mussel bed habitats in the Dutch Wadden Sea

    NARCIS (Netherlands)

    Brinkman, A.G.; Dankers, N.M.J.A.; Stralen, van M.

    2002-01-01

    A habitat suitability analysis for littoral mussel beds in the Dutch Wadden Sea was carried out. The analysis was based on the presence of mussel beds in the years 1960-1970, and a number of environmental characteristics: wave action, flow velocity, median grain size, emersion times and distance to

  8. Seasonal variability in nutrient regeneration by mussel Mytilus edulis rope culture in oligotrophic systems

    NARCIS (Netherlands)

    Jansen, H.M.; Strand, O.; Strohmeier, T.; Krogness, C.; Verdegem, M.C.J.; Smaal, A.C.

    2011-01-01

    Blue mussel Mytilus edulis cultures contribute to nutrient cycling in coastal ecosystems. Mussel populations filter particulate nutrients from the water column and inorganic nutrients are regenerated by excretion of metabolic wastes and decomposition of (pseudo-)faeces. The objective of this study

  9. Integrated coastal monitoring of a gas processing plant using native and caged mussels

    Energy Technology Data Exchange (ETDEWEB)

    Brooks, Steven, E-mail: sbr@niva.no [Norwegian Institute for Water Research (NIVA), Gaustadalleen 21, NO-0349 Oslo (Norway); Harman, Christopher [Norwegian Institute for Water Research (NIVA), Gaustadalleen 21, NO-0349 Oslo (Norway); Soto, Manu; Cancio, Ibon [CBET Res Grp, R and D Centre for Experimental Marine Biology and Biotechnology (PIE), Univ Basque Country, Areatza Z/G, Plentzia-Bizkaia, E-48620 Basque Country (Spain); Glette, Tormod [Det Norske Veritas (DNV), Veritasveien 1, 1363 Hovik (Norway); Marigomez, Ionan [CBET Res Grp, R and D Centre for Experimental Marine Biology and Biotechnology (PIE), Univ Basque Country, Areatza Z/G, Plentzia-Bizkaia, E-48620 Basque Country (Spain)

    2012-06-01

    The biological effects of a coastal process water (PW) discharge on native and caged mussels (Mytilus edulis) were assessed. Chemical analyses of mussel tissues and semi permeable membrane devices, along with a suite of biomarkers of different levels of biological complexity were measured. These were lysosomal membrane stability in haemocytes and digestive cells; micronuclei formation in haemocytes; changes in cell-type composition in the digestive gland epithelium; integrity of digestive gland tissue; peroxisome proliferation; and oxidative stress. Additionally the Integrative Biological Response (IBR/n) index was calculated. This integrative biomarker approach distinguished mussels, both native and caged, exhibiting different stress conditions not identified from the contaminant exposure. Mussels exhibiting higher stress responses were found with increased proximity to the PW discharge outlet. However, the biological effects reported could not be entirely attributed to the PW discharge based on the chemicals measured, but were likely due to either other chemicals in the discharge that were not measured, the general impact of the processing plant and or other activities in the local vicinity. - Highlights: Black-Right-Pointing-Pointer Good agreement between biomarkers for the different mussel groups. Black-Right-Pointing-Pointer IBR/n was able to differentiate between exposed and reference mussels. Black-Right-Pointing-Pointer Mussels closest to the PW outlet were in poorest health. Black-Right-Pointing-Pointer Chemical concentrations were low or undetected in all SPMD and mussel samples. Black-Right-Pointing-Pointer Biomarker responses could not be entirely attributed to the PW discharge.

  10. Area-intensive bottom culture of blue mussels Mytilus edulis in a micro-tidal estuary

    DEFF Research Database (Denmark)

    Dolmer, Per; Christensen, Helle Torp; Hansen, Benni Winding

    2012-01-01

    Dredge fishery for blue mussels Mytilus edulis (L.) impacts the benthic ecosystem, and substitution by area-intensive bottom culture production may reduce adverse effects on the ecosystem. Two different field studies in 2007 and 2009 tested the productivity of bottom culture of blue mussels, and ...

  11. Mussels and sediment as monitoring tools for contaminants: which to use when?

    Science.gov (United States)

    For decades, sediments and mussels have been used to assess the ecological and human health risks associated with concentrations of bioavailable organic and metal contaminants in a variety of coastal-wide and localized monitoring programs. Mussels (Mytilus edulis) bioaccumulate o...

  12. Detection of Cryptosporidium oocysts in green mussels (Perna viridis) from shell-fish markets of Thailand.

    Science.gov (United States)

    Srisuphanunt, M; Wiwanitkit, Viroj; Saksirisampant, W; Karanis, P

    2009-09-01

    Mussels filter large volumes of water and can concentrate pathogenic organisms, which may act as potential vehicles of transmission to the consumer. A survey study was carried out to investigate the presence of Cryptosporidium protozoan parasites in green mussels (Perna viridis), the smussles pecies most destined for consumption in Thailand. In total, 56 samples were examined from Bangkok (n = 24) and Samut Prakan (n = 32) a wholesale shell-fish markets located at the mouth of the Chao Phraya River. The market for green mussels was closed to the mussel culture placed along the coastal line and this localization may have significant economical impact if the mussels' cultures are found contaminated. Cryptosporidium spp. oocysts were detected by the immunofluorescence antibody method (IFA) in 12.5% of the samples examined. The detection of Cryptosporidium oocysts in green mussels' population of Samut Prakan was higher (15.6%) than in Bangkok market (8.3%). These differences in positive samples from the two locations may be caused by physical, ecological and anthropogenic conditions. This could relay to different contamination levels of marine water by Cryptosporidium oocysts and consequently to contamination of harvested shellfish populations. The results demonstrate that the Cryptosporidium spp. oocysts were found indigenous in mussels from the coastal line of Thailand, indicating that mussels may act as a reservoir of Cryptosporidium foodborne infections for humans.

  13. Quagga mussels Dreissena rostriformis burgensis (Andrusov, 1897) in the Main River (Germany)

    NARCIS (Netherlands)

    Velde, G. van der; Platvoet, D.

    2007-01-01

    The first record of the quagga mussel Dreissena rostriformis bugensis (Andrusov, 1897) in Germany is described. This species has expanded its distribution area in Europe at a slower rate than the zebra mussel Dreissena polymorpha (Pallas, 1771). Recent records from the Danube in Romania and from an

  14. Data on the changes of the mussels' metabolic profile under different cold storage conditions

    DEFF Research Database (Denmark)

    Aru, Violetta; Pisano, Maria Barbara; Savorani, Francesco

    2016-01-01

    galloprovincialis. This data article provides information on the average distribution of the microbial loads in mussels' specimens and on the acquisition, processing, and multivariate analysis of the 1H NMR spectra from the hydrosoluble phase of stored mussels. This data article is referred to the research article...

  15. Biofouling leads to reduced shell growth and flesh weight in the cultured mussel Mytilus galloprovincialis.

    Science.gov (United States)

    Sievers, Michael; Fitridge, Isla; Dempster, Tim; Keough, Michael J

    2013-01-01

    Competitive interactions between cultured mussels and fouling organisms may result in growth and weight reductions in mussels, and compromised aquaculture productivity. Mussel ropes were inoculated with Ciona intestinalis, Ectopleura crocea or Styela clava, and growth parameters of fouled and unfouled Mytilus galloprovincialis were compared after two months. Small mussels (≈ 50 mm) fouled by C. intestinalis and E. crocea were 4.0 and 3.2% shorter in shell length and had 21 and 13% reduced flesh weight, respectively, compared to the controls. Large mussels (≈ 68 mm) fouled by S. clava, C. intestinalis and E. crocea were 4.4, 3.9 and 2.1% shorter than control mussels, respectively, but flesh weights were not significantly reduced. A series of competitive feeding experiments indicated that S. clava and C. intestinalis did not reduce mussels' food consumption, but that E. crocea, through interference competition, did. Fouling by these species at the densities used here reduced mussel growth and flesh weight, likely resulting in economic losses for the industry, and requires consideration when developing biofouling mitigation strategies.

  16. Effects of elevated water temperature on physiological responses in adult freshwater mussels

    Science.gov (United States)

    Ganser, Alissa M.; Newton, Teresa J.; Haro, Roger J.

    2015-01-01

    Freshwater mussels (order Unionoida) face multiple environmental stressors, which pose serious conservation challenges to this diverse assemblage of aquatic invertebrates. Of these stressors, elevated water temperature from global climate change and other anthropogenic sources may be the most ubiquitous and could be placing many mussel populations dangerously close to their thermal maxima.

  17. The impact of the adult blue mussel (Mytilus edulis) population on settling of conspecific larvae

    DEFF Research Database (Denmark)

    Dolmer, Per; Stenalt, Ea

    2010-01-01

    The choice of a mussel bed as a settling locality by conspecific mussel larvae is a trade-off between reduced fitness due to an increased risk of larval predation and post-settling food competition with the filtering adults and the benefit from a reduced post-settling mortality. This reduced post...

  18. Host fishes and infection strategies of freshwater mussels in large Mobile Basin streams, USA

    Science.gov (United States)

    Wendell R. Haag; Melvin L. Warren

    2003-01-01

    We investigated host fishes, timing and modes of glochidial release, and host-attraction strategies for 7 species of freshwater mussels from the Buttahatchee and Sipsey rivers (Mobile Basin), Alabama and Mississippi, USA. We determined hosts as fish species that produced juvenile mussels from laboratory-induced glochidial infections. We established the following...

  19. Effects of suspended sediments on food uptake for zebra mussels in Lake Markermeer, The Netherlands

    NARCIS (Netherlands)

    Penning, W.E.; Pozzato, L.; Vijverberg, T.; Noordhuis, R.; bij de Vaate, A.; Van Donk, E.; Dionisio Pires, L.M.

    2013-01-01

    Until 1992, zebra mussels (Dreissena polymorpha) were an important food source for diving ducks in Lake Markermeer (The Netherlands). After 1993, the mussel biomass sharply declined, and the current population is in poor condition (maximum shell length <15 mm) compared to populations from adjacent

  20. ANALYSIS OF MATERIALS IN AN EXPERIMENTAL TESTING PIPE SYSTEM FOR AN INHIBITOR OF MUSSEL KILL

    Energy Technology Data Exchange (ETDEWEB)

    Daniel P. Molloy

    2003-06-04

    A comprehensive series of 16 laboratory experiments demonstrated that the presence of vinyl tubing within a recirculating pipe system was responsible for lowering zebra mussel kill following treatment with the bacterium Pseudomonas fluorescens. All vinyl tubing was replaced in all testing units with silicone tubing, and high mussel kill (>95%) was then obtained.

  1. ZEBRA MUSSEL COLONIZATION OF RUSTY CRAYFISH IN GREEN BAY, LAKE MICHIGAN

    Science.gov (United States)

    In August, 1995 six rusty crayfish colonized with zebra mussels were captured in small-meshed fyke-nets sets set apart as of a fish sampling effort at Peter's Marsh and Long-Tail Point Wetland in lower Green Bay. Mussels colonized virtually all areas of the crayfish bodies, but ...

  2. Newspaper Coverage of Zebra Mussels in North America : A Case of "Afghanistanism"?

    OpenAIRE

    Roush, Donny; Fortner, Rosanne

    1996-01-01

    Few environmental issues have arisen so abruptly, spread so rapidly, and been so clearly linked to human activity as has the introduction of nonindigenous zebra mussels to the surface freshwater of North America. This research examines communication patterns in information about zebra mussels as an example of how the mass media deal with threats to the environment.

  3. Madrid principles of Nagorno-Karabakh settlement

    Directory of Open Access Journals (Sweden)

    K K Babayan

    2014-12-01

    Full Text Available As part of this work presents the analysis of the basic document and the legal framework of the peace settlement of the Nagorno-Karabakh conflict on the modern stage - «Madrid or Basic principles», presented to the sides of the negotiations at the OSCE ministerial conference in the Spanish capital Madrid in November 2007. The both side’s statements, international mediators and institutes form a legal background of the vector and the framework of the negotiation process. There are the fundamental differences and contradictions in the approaches of the sides of the negotiations to the «Basic principles» of the settlement in this article. The work contains a comparison of the various items and elements of the Madrid document both in relation to each other, and to the principles of international law.

  4. Spatial Analyses of Harappan Urban Settlements

    Directory of Open Access Journals (Sweden)

    Hirofumi Teramura

    2006-12-01

    Full Text Available The Harappan Civilization occupies a unique place among the early civilizations of the world with its well planned urban settlements, advanced handicraft and technology, religious and trade activities. Using a Geographical Information Systems (GIS, this study presents spatial analyses that locate urban settlements on a digital elevation model (DEM according to the three phases of early, mature and late. Understanding the relationship between the spatial distribution of Harappan sites and the change in some factors, such as topographic features, river passages or sea level changes, will lead to an understanding of the dynamism of this civilization. It will also afford a glimpse of the factors behind the formation, development, and decline of the Harappan Civilization.

  5. Research on the Starokuybyshevskoye Fortified Settlement

    Directory of Open Access Journals (Sweden)

    Gubaydullin Ayrat M.

    2012-06-01

    Full Text Available The Starokuybyshevskoye (Old-Kuybyshev fortified settlement is situated on the bank of the Bezdna river, 200 m to the northeast of Bolgar city. The site is being considerably eroded by the waters of the river and the Kuibyshev water reservoir. Currently it is situated on an island, under threat of complete destruction. In this regard, in 1946, 1987 and 1996, conservation and rescue excavations were conducted on the site. The detailed results of the 1996 studies are offered in the article. The ruins of an above-ground dwelling with an oven and three household pits were excavated. The ceramic assemblage of these structures has obvious features of the pre-Mongol Bulgar culture. In general, the findings make it possible to conclude that the settlement had existed only in the 11th through to the 13th century and that its collapse was associated with the Mongol invasion.

  6. Modern settlements in special needs education

    DEFF Research Database (Denmark)

    Ratner, Helene Gad

    2016-01-01

    . Settlements of this controversy govern whether the pupil or the educational institution becomes the main point of intervention. In Denmark, the particularities of settlements can be identified by juxtaposing the introduction of intelligence testing in the 1930s with the contemporary policy agenda of inclusion....... With intelligence testing, special needs education was to service children whose needs were seen as part of their human nature. Inclusion, in turn, assumes special needs to be stigmatizing cultural labels that need to be abandoned by changing school cultures. Drawing on actor-network theory we can approach......In the history of special needs education, the distinction between human nature and its social environment has been a controversial matter. The controversy regards whether special needs are primarily caused by the child's psycho-medical body or by cultural concepts of normality and deviance...

  7. COMPENSATORY INTEREST SETTLEMENT AND CREDIT BANKING MORATORIUM

    OpenAIRE

    Avelino Sánchez, Esteban Marino

    2014-01-01

    First is explained the reasons for this article, it mentions the specific legal rules that support the settlement of interest on the credit operations of companies in the financial system with end users, and then presents the average interest rates of some operations credit. Then we present the formula for calculating interest, and illustrates its application with examples 1 and 2 (the simplest). The following is, in examples 3 and 4, the calculation of interest with imputation of partial pay...

  8. Assessment of metal element concentrations in mussel (M. Galloprovincialis) in Eastern Black Sea, Turkey

    Energy Technology Data Exchange (ETDEWEB)

    Cevik, U. [Karadeniz Technical University, Department of Physics, 61080 Trabzon (Turkey)], E-mail: berrenazli@yahoo.com; Damla, N.; Kobya, A.I. [Karadeniz Technical University, Department of Physics, 61080 Trabzon (Turkey); Bulut, V.N. [Giresun University, Department of Chemistry, 28049 Giresun (Turkey); Duran, C. [Karadeniz Technical University, Department of Chemistry, 61080 Trabzon (Turkey); Dalgic, G. [Rize University, Faculty of Fisheries, 53100 Rize (Turkey); Bozaci, R. [Karadeniz Technical University, Department of Physics, 61080 Trabzon (Turkey)

    2008-12-30

    The main goal of this work is to determine the effects of pollution of copper, lead and zinc mines on the Eastern Black Sea. Metal and heavy metal concentrations in the Eastern Black Sea mussels were measured using Energy Dispersive X-ray Fluorescence (EDXRF) and Flame Atomic Absorption Spectroscopy (FAAS). The analytical results showed that the tissue of mussel in Eastern Black Sea contains K, Ca, Fe, Cu, Zn, and Sr elements, and the shell of mussel contains Ca, Cu, Sr, and Ba elements. Due to the detection limit of EDXRF, the mussels were analyzed with FAAS for Cr, Mn, Ni, Cd and Pb elements. An ANOVA and Pearson correlation analyses were performed. The results showed although that the mean concentrations of Cu and Zn for the tissue of the mussels were markedly above the permissible levels of the Turkish regulations, Zn concentration is in the limits of the Food and Agriculture Organization (FAO)

  9. Relations of Environmental Factors with Mussel-Species Richness in the Neversink River, New York

    Science.gov (United States)

    Baldigo, Barry P.; Ernst, Anne G.; Schuler, George E.; Apse, Colin D.

    2007-01-01

    INTRODUCTION Declines in the distribution, abundance, and diversity of freshwater-mussel species (family Unionidae1) have been reported worldwide (Bogan, 1993; Strayer and Jirka, 1997). The principal causes of the observed declines are difficult to confirm, however, because only a few of the many factors that affect mussel-species populations have been identified (Strayer and Ralley, 1993; Strayer, 1999; Baldigo and others, 2003; Strayer and others, 2006). The Neversink River, which drains the Catskill Mountains in southeastern New York (fig. 1), contains seven species of mussels (Strayer and Ralley, 1991; Strayer and Jirka, 1997). Populations of the endangered dwarf wedgemussel (Alasmidonta heterodon) and the threatened swollen wedgemussel (Alasmidonta varicosa) coexist with other unionid mussels in the Neversink River (Strayer and Ralley, 1991, 1993; Baldigo and others, 2003). Dwarf wedgemussel populations had previously been found only downstream from the site of an abandoned dam in the lower part of the river at Cuddebackville (fig. 1), and swollen wedgemussels were only found in the lower and middle reaches of the river. The limited distribution of these two species suggests that they may be susceptible to local extinctions. The distribution of mussel populations can be limited by impoundments. Mussel larvae develop in species-specific host fish; thus, impoundments that restrict passage of these host fish also restrict the extent of mussels. The Neversink River is impounded by the Neversink Reservoir [241 square kilometers (km2)], a major source of drinking water for the City of New York, and was also impounded 50 km downstream by the Cuddebackville Dam until 2004, when the latter was removed by The Nature Conservancy (TNC) and the U.S. Army Corps of Engineers to improve fish passage. The removal of this dam has provided previously unavailable habitat for diadromous and other fish species that act as hosts for rare mussel species. In addition, releases from

  10. Preference of redear sunfish on zebra mussels and rams-horn snails

    Science.gov (United States)

    French, John R. P.; Morgan, Michael N.

    1995-01-01

    We tested prey preferences of adult (200- to 222-mm long) redear sunfish (Lepomis microlophus) on two size classes of zebra mussels (Dreissena polymorpha) and two-ridge rams-horns (Helisoma anceps) in experimental aquaria. We also tested physical limitations on consuming these mollusks and determined prey bioenergetic profitability. Redear sunfish strongly preferred rams-horns over zebra mussels, but they displayed no size preference for either prey. Ingestion was not physically limited since both prey species up to 15-mm long fit within the pharyngeal gapes of redear sunfish. Rams-horns were more bioenergetically profitable than zebra mussels and ingestion of rams-horn shell fragments was about three times less than zebra mussels. Rams-horns were somewhat more resistant to shell-crushing, but all size ranges of both prey species tested were crushable by redear sunfish. These studies suggested that the redear sunfish should not be considered a panacea for biological control of zebra mussels.

  11. The mussel filter–pump – present understanding, with a re-examination of gill preparations

    DEFF Research Database (Denmark)

    Riisgård, Hans Ulrik; Funch, Peter; Larsen, Poul Scheel

    2015-01-01

    Filter feeding in mussels is a secondary adaptation where the gills have become W-shaped and greatly enlarged, acting as the mussel filter–pump. Water pumping and particle capture in the blue mussel, Mytilus edulis, have been studied over many years. Here, we give a short status of the present...... understanding of ciliary structure and function of the mussel filter–pump, supplemented with new photo-microscope and scanning electron microscopy (SEM) pictures of gill preparations. Pumping rate (filtration) and pressure to maintain flow have been extensively studied so the power delivered by the mussel pump......-pumping cilia so that continuous feeding with a ‘minimal scaled’ pump is cheaper than discontinuous feeding with a correspondingly larger pump. According to the present view, the pump proper is the beating lateral cilia (lc) on the gill filaments and particle capture is accomplished by the action...

  12. Historical topography of the Tsarev settlement site

    Directory of Open Access Journals (Sweden)

    Glukhov Aleksandr A.

    2014-06-01

    Full Text Available The topography of the Tsarev settlement site, one of major Golden Horde monuments in the Lower Volga region, is analyzed. The first descriptions of the settlement refer to the second half of the 18th century, while the initial large-scale excavations on the monument were conducted in the mid-19th century. By that time, the scientific community had adhered to the opinion that the ruins of Sarai (the city mainly associated with the Tsarev settlement site would stretch to a great distance from the Akhtuba river-head to Kolobovka village. The results of archaeological research of the 20th – early 21st century make it possible to challenge this view. To date, it is an established fact that the size of the actual urban area had constituted 5 x 2.2–2.3 km. The southern part of the city was occupied by the estates of the nobility, the central and northern parts were represented by trade and artisan quarters. Around the city, there were suburban cemeteries, including brick mausoleums (the ruins of which could be mistaken for the remains of dwellings in the 19th century, as well as the areas of irrigated agriculture.

  13. Mitigating Settlement of Structures founded on Peat

    Science.gov (United States)

    Wijeyesekera, D. C.; Numbikannu, L.; Ismail, T. N. H. T.; Bakar, I.

    2016-07-01

    Observations made of two common failures of structures founded on peat/organic soil in Johor, Malaysia is presented. Critical evaluation of current lightweight fill technology to mitigate such settlement is also discussed. Lightweight technology, such as Expanded Polystyrene (EPS), has been used in construction on soft yielding ground for decades. Regrettably, some published information of EPS failures to perform on construction sites are also cited in this paper. This paper outlines some concepts leading to the development of an alternative innovative lightweight fill is that the idealised cellular structure of the GCM permit free flow of water and complemented by the mat structure which evens out any differential settlement A further highlight of this paper is the monitoring of the field performance of this lightweight fill (GCM) as a feasible alternative to fill weight reduction on yielding ground.. Hence, a prime research objective was to compare the fill settlements observed with 1m high fill of surcharge loading on peat ground (comparison of the case of using a partial 0.6m high GCM and that of a total of 1m of conventional sand backfill).

  14. Coral settlement on a highly disturbed equatorial reef system.

    Science.gov (United States)

    Bauman, Andrew G; Guest, James R; Dunshea, Glenn; Low, Jeffery; Todd, Peter A; Steinberg, Peter D

    2015-01-01

    Processes occurring early in the life stages of corals can greatly influence the demography of coral populations, and successful settlement of coral larvae that leads to recruitment is a critical life history stage for coral reef ecosystems. Although corals in Singapore persist in one the world's most anthropogenically impacted reef systems, our understanding of the role of coral settlement in the persistence of coral communities in Singapore remains limited. Spatial and temporal patterns of coral settlement were examined at 7 sites in the southern islands of Singapore, using settlement tiles deployed and collected every 3 months from 2011 to 2013. Settlement occurred year round, but varied significantly across time and space. Annual coral settlement was low (~54.72 spat m(-2) yr(-1)) relative to other equatorial regions, but there was evidence of temporal variation in settlement rates. Peak settlement occurred between March-May and September-November, coinciding with annual coral spawning periods (March-April and October), while the lowest settlement occurred from December-February during the northeast monsoon. A period of high settlement was also observed between June and August in the first year (2011/12), possibly due to some species spawning outside predicted spawning periods, larvae settling from other locations or extended larval settlement competency periods. Settlement rates varied significantly among sites, but spatial variation was relatively consistent between years, suggesting the strong effects of local coral assemblages or environmental conditions. Pocilloporidae were the most abundant coral spat (83.6%), while Poritidae comprised only 6% of the spat, and Acroporidae coral spat. These results indicate that current settlement patterns are reinforcing the local adult assemblage structure ('others'; i.e. sediment-tolerant coral taxa) in Singapore, but that the replenishment capacity of Singapore's reefs appears relatively constrained, which could lead

  15. Body size-dependent Cd accumulation in the zebra mussel Dreissena polymorpha from different routes.

    Science.gov (United States)

    Tang, Wen-Li; Evans, Douglas; Kraemer, Lisa; Zhong, Huan

    2017-02-01

    Understanding body size-dependent metal accumulation in aquatic organisms (i.e., metal allometry) is critical in interpreting biomonitoring data. While growth has received the most attention, little is known about controls of metal exposure routes on metal allometry. Here, size-dependent Cd accumulation in zebra mussels (Dreissena polymorpha) from different routes were investigated by exposing mussels to A.( 111 Cd spiked algae+ 113 Cd spiked river water) or B.( 111 Cd spiked sediments+ 113 Cd spiked river water). After exposure, 111 Cd or 113 Cd levels in mussel tissue were found to be negatively correlated with tissue weight, while Cd allometry coefficients (b values) were dependent on Cd exposure routes: -0.664 for algae, -0.241 for sediments and -0.379 for river water, compared to -0.582 in un-exposed mussels. By comparing different Cd exposure routes, we found that size-dependent Cd bioaccumulation from algae or river water could be more responsible for the overall size-dependent Cd accumulation in mussels, and the relative importance of the two sources was dependent on mussel size ranges: Cadmium obtained from algae (algae-Cd) was more important in size-dependent Cd accumulation in smaller mussels (tissue dry weight  5 mg). In contrast, sediment-Cd contributed only a small amount to Cd accumulation in zebra mussels and may have little effect on size-dependent Cd bioaccumulation. Our results suggest that size-dependent Cd accumulation in mussels could be largely affected by exposure routes, which should be considered when trying to interpret Cd biomonitoring data of zebra mussels. Copyright © 2016 Elsevier Ltd. All rights reserved.

  16. Accumulation and Toxicity of Copper Oxide Engineered Nanoparticles in a Marine Mussel

    Directory of Open Access Journals (Sweden)

    Shannon K. Hanna

    2014-06-01

    Full Text Available Cu is an essential trace element but can be highly toxic to aquatic organisms at elevated concentrations. Greater use of CuO engineered nanoparticles (ENPs may lead to increased concentrations of CuO ENPs in aquatic environments causing potential ecological injury. We examined the toxicity of CuO ENPs to marine mussels and the influence of mussels on the fate and transport of CuO ENPs. We exposed marine mussels to 1, 2, or 3 mg L−1 CuO ENPs for four weeks, and measured clearance rate, rejection, excretion and accumulation of Cu, and mussel shell growth. Mussel clearance rate was 48% less, and growth was 68% less, in mussels exposed to 3 mg L−1 than in control animals. Previous studies show 100% mortality at 1 mg Cu L−1, suggesting that CuO ENPs are much less toxic than ionic Cu, probably due to the slow dissolution rate of the ENPs. Mussels rejected and excreted CuO ENPs in biodeposits containing as much as 110 mg Cu g−1, suggesting the potential for magnification in sediments. Mussels exposed to 3 mg L−1 CuO ENPs accumulated 79.14 ± 12.46 µg Cu g−1 dry weight, which was 60 times more Cu than in control animals. Our results suggest that mussels have the potential to influence the fate and transport of CuO ENPs and potentially cause magnification of CuO ENPs in mussel bed communities, creating a significant source of Cu to marine benthos.

  17. Changes in freshwater mussel communities linked to legacy pollution in the Lower Delaware River

    Science.gov (United States)

    Blakeslee, Carrie J.; Silldorff, Erik L.; Galbraith, Heather S.

    2018-01-01

    Freshwater mussels are among the most-imperiled organisms worldwide, although they provide a variety of important functions in the streams and rivers they inhabit. Among Atlantic-slope rivers, the Delaware River is known for its freshwater mussel diversity and biomass; however, limited data are available on the freshwater mussel fauna in the lower, non-tidal portion of the river. This section of the Delaware River has experienced decades of water-quality degradation from both industrial and municipal sources, primarily as a function of one of its major tributaries, the Lehigh River. We completed semi-quantitative snorkel surveys in 53.5 of the 121 km of the river to document mussel community composition and the continued impacts from pollution (particularly inputs from the Lehigh River) on mussel fauna. We detected changes in mussel catch per unit effort (CPUE) below the confluence of the Lehigh River, with significant declines in the dominant species Elliptio complanata (Eastern Elliptio) as we moved downstream from its confluence—CPUE dropped from 179 to 21 mussels/h. Patterns in mussel distribution around the Lehigh confluence matched chemical signatures of Lehigh water input. Specifically, Eastern Elliptio CPUE declined more quickly moving downstream on the Pennsylvania bank, where Lehigh River water input was more concentrated compared to the New Jersey bank. A definitive causal link remains to be established between the Lehigh River and the dramatic shifts in mussel community composition, warranting continued investigation as it relates to mussel conservation and restoration in the basin.

  18. Effects of shell morphology on mechanics of zebra and quagga mussel locomotion.

    Science.gov (United States)

    Peyer, Suzanne M; Hermanson, John C; Lee, Carol Eunmi

    2011-07-01

    Although zebra mussels (Dreissena polymorpha) initially colonized shallow habitats within the North American Great Lakes, quagga mussels (Dreissena bugensis) are becoming dominant in both shallow- and deep-water habitats. Shell morphology differs among zebra, shallow quagga and deep quagga mussels but functional consequences of such differences are unknown. We examined effects of shell morphology on locomotion for the three morphotypes on hard (typical of shallow habitats) and soft (characteristic of deep habitats) sedimentary substrates. We quantified morphology using the polar moment of inertia, a parameter used in calculating kinetic energy that describes shell area distribution and resistance to rotation. We quantified mussel locomotion by determining the ratio of rotational (K(rot)) to translational kinetic energy (K(trans)). On hard substrate, K(rot):K(trans) of deep quagga mussels was fourfold greater than for the other morphotypes, indicating greater energy expenditure in rotation relative to translation. On soft substrate, K(rot):K(trans) of deep quagga mussels was approximately one-third of that on hard substrate, indicating lower energy expenditure in rotation on soft substrate. Overall, our study demonstrates that shell morphology correlates with differences in locomotion (i.e. K(rot):K(trans)) among morphotypes. Although deep quagga mussels were similar to zebra and shallow quagga mussels in terms of energy expenditure on sedimentary substrate, their morphology was energetically maladaptive for linear movement on hard substrate. As quagga mussels can possess two distinct morphotypes (i.e. shallow and deep morphs), they might more effectively utilize a broader range of substrates than zebra mussels, potentially enhancing their ability to colonize a wider range of habitats.

  19. Economic impacts of zebra mussels on drinking water treatment and electric power generation facilities.

    Science.gov (United States)

    Connelly, Nancy A; O'Neill, Charles R; Knuth, Barbara A; Brown, Tommy L

    2007-07-01

    Invasions of nonnative species such as zebra mussels can have both ecological and economic consequences. The economic impacts of zebra mussels have not been examined in detail since the mid-1990s. The purpose of this study was to quantify the annual and cumulative economic impact of zebra mussels on surface water-dependent drinking water treatment and electric power generation facilities (where previous research indicated the greatest impacts). The study time frame was from the first full year after discovery in North America (Lake St. Clair, 1989) to the present (2004); the study area was throughout the mussels' North American range. A mail survey resulted in a response rate of 31% for electric power companies and 41% for drinking water treatment plants. Telephone interviews with a sample of nonrespondents assessed nonresponse bias; only one difference was found and adjusted for. Over one-third (37%) of surveyed facilities reported finding zebra mussels in the facility and almost half (45%) have initiated preventive measures to prevent zebra mussels from entering the facility operations. Almost all surveyed facilities (91%) with zebra mussels have used control or mitigation alternatives to remove or control zebra mussels. We estimated that 36% of surveyed facilities experienced an economic impact. Expanding the sample to the population of the study area, we estimated 267 million dollars (BCa 95% CI = 161 million dollars - 467 million dollars) in total economic costs for electric generation and water treatment facilities through late 2004, since 1989. Annual costs were greater (44,000 dollars/facility) during the early years of zebra mussel infestation than in recent years (30,000 dollars). As a result of this and other factors, early predictions of the ultimate costs of the zebra mussel invasion may have been excessive.

  20. Socio spatial adaptation as a resilience form of native unplanned settlement in confrontation with new planned settlement development pressure (case study: enclave native settlement in Serpong, Tangerang)

    Science.gov (United States)

    Ischak, Mohammad; Setioko, Bambang; Nurgandarum, Dedes

    2017-12-01

    Urban growth refers to expansion of a metropolitan into sub urban areas as the surrounding environment, with no exception of Jakarta city due to limited availability and high price of land within the city. The city of Jakarta, as a metropolitan, carries of expansion in its surrounding environment including Tangerang. Privat developers may an important role in this urban growth through their large scale of new settlement development project. The formation of establishment of enclave native unplanned sub urban settlement scattered within planned new settlement in Tangerang is to be an consequence of Jakarta urban growth. This fenomena could be comprehended as a form of resilience native settlement in confrontation with the new planned settlement pressure. The aim of this research, presented in this paper is to understand the socio-spatial concept of those enclave native settlement as an adaptation form to the new planned settlement pressure. Through descriptive qualitative research method, with indepth interview as a main research instrument, this research could depict or uncover the facts that there are various form of socio-spatial adaptation as the main theme of resilience native suburban settlement formation.

  1. Biomonitoring of Mercury Contamination at Petroleum Production Platforms in the Gulf of Thailand using Transplanted Green Mussel, Perna viridis

    Directory of Open Access Journals (Sweden)

    Chatree Ritthong

    2011-01-01

    Full Text Available Assessment of mercury contamination was conducted using transplanted green mussels (Perna viridis. Mussels were first exposed to HgCl2 at 0.5, 1.0, 2.5, and 5.0 nmol/L for 8 weeks at laboratory conditions. The result showed that Hg level in the water decreased rapidly, while Hg in mussels increased coincidentally with the applied doses. After 8 weeks the Hg, levels in tissue were a thousand-fold higher than that in the water. Mussels were then transplanted to 3 petroleum production platforms for field study. The result revealed that survival and growth rates of transplanted mussels at all 3 stations were in close to each other but significantly lower than that from the reference site. Hg concentrations in the tissues of transplanted mussels ranged from less than 0.010 to 0.173 µg/g, and Hg concentrations in mussel tissues from all stations were significantly increased within 2 months, while Hg levels in mussel tissues from reference site were not changed. Hg levels of transplanted mussels increased with increasing depths of the water. The transplanted mussels showed no signs of any physical anomalies, indicating that transplanted mussels could be maintained for up to 3 months in an un-natural habitat, such as petroleum production platforms, where food is much less abundant.

  2. Health risk assessments of heavy metal exposure via consumption of marine mussels collected from anthropogenic sites

    International Nuclear Information System (INIS)

    Yap, Chee Kong; Cheng, Wan Hee; Karami, Ali; Ismail, Ahmad

    2016-01-01

    A total of 40 marine mussel Perna viridis populations collected (2002–2009) from 20 geographical sites located in two busy shipping lanes namely the Straits of Malacca (10 sites; 16 populations) and the Straits of Johore (8 sites; 21 populations) and three populations (2 sites) on the east coast of Peninsular Malaysia, was determined for Cd, Cu, Fe, Ni, Pb and Zn concentrations. In comparison with the maximum permissible limits (MPLs) set by existing food safety guidelines, all metal concentrations found in all the mussel populations were lower than the prescribed MPLs. In terms of the provisional tolerable weekly intake prescribed by the Joint FAO/WHO Expert Committee on Food Additives (JECFA) and oral reference doses (ORDs) by the USEPA, all the studied metals (except for Pb) were unlikely to become the limiting factors or unlikely to pose a risk for the consumption of the mussel populations. The estimated daily intake (EDI) for average level mussel (ALM) and high level mussel (HLM) consumers of mussels was found to be lower than the ORD guidelines for Cd, Cu, Fe, Ni and Zn. Furthermore, the target hazard quotient (THQ) was found to be less than 1 for ALM consumers but higher than 1 for HLM consumers in some sites. Therefore, there were no potential human health risks to the ALM consumers of the mussels. However, for Pb THQ values, the Pb levels in some mussel populations could create a health risk problem. Present results indicate that the consumption amounts of mussels should be limited for minimizing potential health risks of heavy metals to the HLM consumers. - Highlights: • Human health risk assessments of heavy metals in Perna viridis were investigated. • All metals in the mussels were below the established seafood safety guidelines. • Pb in mussels could easily reach the percentage of prescribed PTWI value of Pb. • Potential health risk with Pb exposure was found for the mussel consumers. • Consumption rate of mussels should be limited to

  3. Health risk assessments of heavy metal exposure via consumption of marine mussels collected from anthropogenic sites

    Energy Technology Data Exchange (ETDEWEB)

    Yap, Chee Kong, E-mail: yapckong@hotmail.com [Department of Biology, Faculty of Science, Universiti Putra Malaysia (UPM), 43400 Serdang, Selangor (Malaysia); Cheng, Wan Hee [Inti International University, Persiaran Perdana BBN, 71800 Nilai, Negeri Sembilan (Malaysia); Karami, Ali [Laboratory of Aquatic Toxicology, Faculty of Medicine and Health Sciences, Universiti Putra Malaysia (UPM), 43400 Serdang, Selangor (Malaysia); Ismail, Ahmad [Department of Biology, Faculty of Science, Universiti Putra Malaysia (UPM), 43400 Serdang, Selangor (Malaysia)

    2016-05-15

    A total of 40 marine mussel Perna viridis populations collected (2002–2009) from 20 geographical sites located in two busy shipping lanes namely the Straits of Malacca (10 sites; 16 populations) and the Straits of Johore (8 sites; 21 populations) and three populations (2 sites) on the east coast of Peninsular Malaysia, was determined for Cd, Cu, Fe, Ni, Pb and Zn concentrations. In comparison with the maximum permissible limits (MPLs) set by existing food safety guidelines, all metal concentrations found in all the mussel populations were lower than the prescribed MPLs. In terms of the provisional tolerable weekly intake prescribed by the Joint FAO/WHO Expert Committee on Food Additives (JECFA) and oral reference doses (ORDs) by the USEPA, all the studied metals (except for Pb) were unlikely to become the limiting factors or unlikely to pose a risk for the consumption of the mussel populations. The estimated daily intake (EDI) for average level mussel (ALM) and high level mussel (HLM) consumers of mussels was found to be lower than the ORD guidelines for Cd, Cu, Fe, Ni and Zn. Furthermore, the target hazard quotient (THQ) was found to be less than 1 for ALM consumers but higher than 1 for HLM consumers in some sites. Therefore, there were no potential human health risks to the ALM consumers of the mussels. However, for Pb THQ values, the Pb levels in some mussel populations could create a health risk problem. Present results indicate that the consumption amounts of mussels should be limited for minimizing potential health risks of heavy metals to the HLM consumers. - Highlights: • Human health risk assessments of heavy metals in Perna viridis were investigated. • All metals in the mussels were below the established seafood safety guidelines. • Pb in mussels could easily reach the percentage of prescribed PTWI value of Pb. • Potential health risk with Pb exposure was found for the mussel consumers. • Consumption rate of mussels should be limited to

  4. Factors affecting 210Po and 210Pb activity concentrations in mussels and implications for environmental bio-monitoring programmes

    International Nuclear Information System (INIS)

    Carvalho, Fernando P.; Oliveira, Joao M.; Alberto, G.

    2011-01-01

    The activity of 210 Po and 210 Pb was determined in mussels of the same size (3.5-4.0 cm shell length) sampled monthly over a 17-month period at the Atlantic coast of Portugal. Average radionuclide concentration values in mussels were 759 ± 277 Bq kg -1 for 210 Po (range 460-1470 Bq kg -1 dry weight), and 45 ± 19 Bq kg -1 for 210 Pb (range 23-96 Bq kg -1 dry weight). Environmental parameters and mussel biometric parameters were monitored during the same period. Although there was no seasonal variation of radionuclide concentrations in sea water during the study period, the concentration of radionuclide activity in mussels varied seasonally displaying peaks of high concentrations in winter and low concentrations in summer. Analysis of radionuclide data in relation to the physiological Condition Index of mussels revealed that 210 Po and 210 Pb activities in the mussel (average activity per individual) remained nearly constant during the investigation period, while mussel body weight fluctuated due to fat storage/expenditure in the soft tissues. Similar variation of radionuclide concentrations was observed in mussels transplanted from the sea coast into the Tejo Estuary. However, under estuarine environmental conditions and with higher food availability throughout the year, transplanted mussel Condition Index was higher than in coastal mussels and average radionuclide concentrations were 210 ± 75 Bq kg -1 (dry weight) for 210 Po and 10 ± 4 Bq kg -1 (dry weight) for 210 Pb, therefore lower than in coastal mussels with similar shell length. It is concluded that the apparent seasonal fluctuation and inter-site difference of radionuclide concentrations were mostly caused by mussel body weight fluctuation and not by radionuclide body burden fluctuation. This interpretation can be extended to the apparent seasonal fluctuation in concentrations of lipophilic and lipophobic contaminants in mussels, and provides an explanation for occasional high concentrations of 210 Po

  5. Ocean acidification reduces the crystallographic control in juvenile mussel shells.

    Science.gov (United States)

    Fitzer, Susan C; Cusack, Maggie; Phoenix, Vernon R; Kamenos, Nicholas A

    2014-10-01

    Global climate change threatens the oceans as anthropogenic carbon dioxide causes ocean acidification and reduced carbonate saturation. Future projections indicate under saturation of aragonite, and potentially calcite, in the oceans by 2100. Calcifying organisms are those most at risk from such ocean acidification, as carbonate is vital in the biomineralisation of their calcium carbonate protective shells. This study highlights the importance of multi-generational studies to investigate how marine organisms can potentially adapt to future projected global climate change. Mytilus edulis is an economically important marine calcifier vulnerable to decreasing carbonate saturation as their shells comprise two calcium carbonate polymorphs: aragonite and calcite. M. edulis specimens were cultured under current and projected pCO2 (380, 550, 750 and 1000μatm), following 6months of experimental culture, adults produced second generation juvenile mussels. Juvenile mussel shells were examined for structural and crystallographic orientation of aragonite and calcite. At 1000μatm pCO2, juvenile mussels spawned and grown under this high pCO2 do not produce aragonite which is more vulnerable to carbonate under-saturation than calcite. Calcite and aragonite were produced at 380, 550 and 750μatm pCO2. Electron back scatter diffraction analyses reveal less constraint in crystallographic orientation with increased pCO2. Shell formation is maintained, although the nacre crystals appear corroded and crystals are not so closely layered together. The differences in ultrastructure and crystallography in shells formed by juveniles spawned from adults in high pCO2 conditions may prove instrumental in their ability to survive ocean acidification. Copyright © 2014 Elsevier Inc. All rights reserved.

  6. Litigation and the Timing of Settlement: Evidence from Commercial Disputes

    OpenAIRE

    Peter Grajzl; Katarina Zajc

    2015-01-01

    Although an overwhelming proportion of all legal disputes end in settlement, the determinants of the timing of settlement remain empirically underexplored. We draw on a novel dataset on the duration of commercial disputes in Slovenia to study how the timing of settlement is shaped by the stages and features of the litigation process. Using competing risk regression analysis, we find that events such as court-annexed mediation and the first court session, which enable the disputing parties to ...

  7. The urban features of informal settlements in Jakarta, Indonesia.

    Science.gov (United States)

    Alzamil, Waleed

    2017-12-01

    This data article contains the urban features of three informal settlements in Jakarta: A. Kampung Bandan; B. Kampung Luar Batang; And C. Kampung Muara Baru. The data describes the urban features of physical structures, infrastructures, and public services. These data include maps showing locations of these settlements, photography of urban status, and examples of urban fabric. The data are obtained from the statistical records and field surveys of three settlements cases.

  8. Deterring Spoilers: Peace Enforcement Operations and Political Settlements to Conflict

    National Research Council Canada - National Science Library

    Manseau, Nicole C

    2008-01-01

    .... In Somalia, Operation Restore Hope provided a strong peace enforcement operation, but ultimately failed to deter spoilers to United Nations negotiations for a political settlement to the conflict...

  9. The Researches on Cycle-Changeable Generation Settlement Method

    Science.gov (United States)

    XU, Jun; LONG, Suyan; LV, Jianhu

    2018-03-01

    Through the analysis of the business characteristics and problems of price adjustment, a cycle-changeable generation settlement method is proposed to support any time cycle settlement, and put forward a complete set of solutions, including the creation of settlement tasks, time power dismantle, generating fixed cycle of electricity, net energy split. At the same time, the overall design flow of cycle-changeable settlement is given. This method supports multiple price adjustments during the month, and also is an effective solution to the cost reduction of month-after price adjustment.

  10. Trace element concentrations in wild mussels from the coastal area of the southeastern Adriatic, Montenegro

    Directory of Open Access Journals (Sweden)

    Markovic Jelena

    2012-01-01

    Full Text Available The aim of the present investigation was to quantify the levels of trace elements (Zn, Cu, As, Pb, Cd and total Hg in the Mediterranean mussel, Mytilus galloprovincialis (L.. Based on their levels, the quality of Montenegro seawater for future mussel farming was estimated. The mussel M. galloprovincialis (L. was collected from four sites in the Montenegrin costal area in the period of two years to determine trace element concentrations and to classify the quality of the coastal water and possible health risks from its consumption. The mean metal concentrations in the mussels ranged from 133.5-205.9 for Zn, 7.50-14.5 for Cu, 4.42-13.3 for As, 4.70-12.9 for Pb, 1.73-2.41 for Cd and 0.07-0.59 for total Hg in mg/kg dry weight. The levels of toxic metals (except for Pb in the mussels were within the maximum residual levels prescribed by the laws of Montenegro, the EU and the USFDA. In addition, the trace metal concentrations found in the mussels in this study were similar to regional data using this mussel as a biomonitoring agent of seawater quality.

  11. Specificity of the peroxisome proliferation response in mussels exposed to environmental pollutants

    International Nuclear Information System (INIS)

    Cajaraville, Miren P.; Ortiz-Zarragoitia, Maren

    2006-01-01

    Peroxisome proliferation has been proposed as novel biomarker of exposure to organic pollutants in aquatic organisms. Peroxisome proliferator compounds comprise a heterogeneous group of substances known for their ability to cause massive proliferation of peroxisomes and liver carcinogenesis in sensitive species such as rodents. Recently, several marine organisms (mussels and fish) have been shown as target species of peroxisome proliferators. In the present work, we aimed to investigate the specificity of the peroxisome proliferation response in mussels. For this purpose, mussels (Mytilus edulis) were exposed for three weeks to North Sea crude oil (NSO), a mixture of NSO, alkylphenols and extra PAHs (MIX), diallylphthalate (DAP), bisphenol-A (BPA) and tetrabromodiphenylether (TBDE), or transplanted for three weeks to four stations showing different copper concentrations in a copper mine. Peroxisome proliferation was assessed by measuring the activity of the peroxisomal β-oxidation enzyme acyl-CoA oxidase (AOX) and the volume density occupied by peroxisomes (V VP ) in the digestive gland. Mussels exposed to NSO and MIX showed significantly increased AOX activities and V VP compared to control animals. Significantly higher V VP was also found in DAP and TBDE exposed mussels. V VP did not vary in mussels transplanted into a copper concentration gradient. Our results confirm the usefulness and specificity of peroxisome proliferation as a suitable biomarker of exposure to organic contaminants such as oil derived hydrocarbons, phthalate plasticizers and polybrominated flame retardants in mussels

  12. Food habits of diving ducks in the Great Lakes after the zebra mussel invasion

    Science.gov (United States)

    Custer, Christine M.; Custer, T.W.

    1996-01-01

    Zebra mussels (Dreissena polymorpha) invaded the Great Lakes in the mid-1980s and quickly reached high densities. The objective of this study was to determine current consumption of zebra mussels by waterfowl in the Great Lakes region. Feeding Lesser Scaups (Aythya affinis), Greater Scaups (A. marila), Canvasbacks (A. valisineria), Redheads (A. americana), Buffleheads (Bucephala albeola) and Common Goldeneyes (B. clangula) were collected in western Lake Erie and in Lake St. Clair between fall and spring, 1992-1993 to determine food habits. All 10 Redheads, 97% of Lesser Scaups, 83% of Goldeneyes, 60% of Buffleheads and 9% of Canvasbacks contained one or more zebra mussels in their upper gastrointestinal tracts. The aggregate percent of zebra mussels in the diet of Lesser Scaups was higher in Lake Erie (98.6%) than in Lake St. Clair (54.4%). Zebra mussels (aggregate percent) dominated the diet of Common Goldeneyes (79.2%) but not in Buffleheads (23.5%), Redheads (21%) or Canvasbacks (9%). Lesser Scaups from Lake Erie fed on larger zebra mussels ( = 10.7 i?? 0.66 mm SE) than did Lesser Scaups from Lake St. Clair ( = 4.4 i?? 0.22 mm). Lesser Scaups, Buffleheads and Common Goldeneyes from Lake Erie consumed zebra mussels of similar size.

  13. Effects of the exotic zebra mussel (Dreissena polymorpha) on metal cycling in Lake Erie

    International Nuclear Information System (INIS)

    Klerks, P.L.; Fraleigh, P.C.; Lawniczak, J.E.

    1997-01-01

    This research demonstrated the impact of high densities of the zebra mussel (Dreissena polymorpha) on the cycling of copper, nickel, and zinc in a lake environment. Experiments with mussels on sedimentation traps in western Lake Erie and with mussels in flow-through tanks receiving Lake Erie water showed that zebra mussels remove metals from the water column, incorporate metals in their tissues, and deposit metals on the lake bottom. Removal of metals from the water column was estimated at 10-17%·day -1 of the amounts present. This material was largely deposited on the lake bottom; zebra mussels more than doubled the rate at which metals were being added to the lake bottom. Metal biodeposition rates were extremely high (e.g., 50 mg Zn·m -2 ·day -1 ) in high-turbidity areas with elevated metal levels. Two factors contributed to metal biodeposition by zebra mussels. First, their production of feces and pseudofeces increased the rate at which suspended matter was being added to the sediment (accounting for 92% of the increased metal biodeposition). Second, the material coming out of suspension had higher metal concentrations when zebra mussels were present (constituting 8% of the increased biodeposition). (author)

  14. Phytoplankton Communities in Green Bay, Lake Michigan after Invasion by Dreissenid Mussels: Increased Dominance by Cyanobacteria

    Directory of Open Access Journals (Sweden)

    Bart T. De Stasio

    2014-11-01

    Full Text Available Biological invasions of aquatic systems disrupt ecological communities, and cause major changes in diversity and ecosystem function. The Laurentian Great Lakes of North America have been dramatically altered by such invasions, especially zebra (Dreissena polymorpha and quagga (D. rostriformis bugensis mussels. Responses to mussel invasions have included increased water clarity, and decreased chlorophyll and phytoplankton abundance. Although not all systems have responded similarly, in general, mussels have changed nutrient dynamics and physical habitat conditions. Therefore examination of different impacts can help us further understand mechanisms that underlie ecosystem responses to biological invasions. To aid our understanding of ecosystem impacts, we sampled established locations along a well-studied trophic gradient in Green Bay, Lake Michigan, after the 1993 zebra mussel invasion. A strong trophic gradient remained during the period sampled after the mussel invasion (2000–2012. However, mean summer chlorophyll increased and other measures of phytoplankton biomass (microscope and electronic cell counting did not change significantly. Multivariate analyses of phytoplankton community structure demonstrate a significant community shift after the invasion. Cyanobacteria increased in dominance, with Microcystis becoming the major summer taxon in lower Green Bay. Diatom diversity and abundance also increased and Chlorophyta became rare. Phytoplankton responses along the trophic gradient of Green Bay to zebra mussel invasion highlight the importance of mussel effects on nutrient dynamics and phytoplankton diversity and function.

  15. Effects of the exotic zebra mussel (Dreissena polymorpha) on metal cycling in Lake Erie

    Energy Technology Data Exchange (ETDEWEB)

    Klerks, P.L. [Univ. of Southwestern Louisiana, Dept. of Biology, Lafayette, Louisiana (United States)]. E-mail: klerks@usl.edu; Fraleigh, P.C.; Lawniczak, J.E. [Univ. of Toledo, Dept. of Biology, Toledo, Ohio (United States)

    1997-07-15

    This research demonstrated the impact of high densities of the zebra mussel (Dreissena polymorpha) on the cycling of copper, nickel, and zinc in a lake environment. Experiments with mussels on sedimentation traps in western Lake Erie and with mussels in flow-through tanks receiving Lake Erie water showed that zebra mussels remove metals from the water column, incorporate metals in their tissues, and deposit metals on the lake bottom. Removal of metals from the water column was estimated at 10-17%{center_dot}day{sup -1} of the amounts present. This material was largely deposited on the lake bottom; zebra mussels more than doubled the rate at which metals were being added to the lake bottom. Metal biodeposition rates were extremely high (e.g., 50 mg Zn{center_dot}m{sup -2}{center_dot}day{sup -1}) in high-turbidity areas with elevated metal levels. Two factors contributed to metal biodeposition by zebra mussels. First, their production of feces and pseudofeces increased the rate at which suspended matter was being added to the sediment (accounting for 92% of the increased metal biodeposition). Second, the material coming out of suspension had higher metal concentrations when zebra mussels were present (constituting 8% of the increased biodeposition). (author)

  16. Occurrence of zebra mussels in near-shore areas of western Lake Erie

    Science.gov (United States)

    Custer, Christine M.; Custer, T.W.

    1997-01-01

    Zebra mussels (Dreissena polymorpha) invaded the Great Lakes in the mid-1980s and quickly reached high densities. The objective of this study was to determine current consumption of zebra mussels by waterfowl in the Great Lakes region. Feeding Lesser Scaups (Aythya affinis), Greater Scaups (A. marila), Canvasbacks (A. valisineria), Redheads (A. americana), Buffleheads (Bucephala albeola) and Common Goldeneyes (B. clangula) were collected in western Lake Erie and in Lake St. Clair between fall and spring, 1992-1993 to determine food habits. All 10 Redheads, 97% of Lesser Scaups, 83% of Goldeneyes, 60% of Buffleheads and 9% of Canvasbacks contained one or more zebra mussels in their upper gastrointestinal tracts. The aggregate percent of zebra mussels in the diet of Lesser Scaups was higher in Lake Erie (98.6%) than in Lake St. Clair (54.4%). Zebra mussels, (aggregate percent) dominated the diet of Common Goldeneyes (79.2%) but not in Buffleheads (23.5%), Redheads (21%) or Canvasbacks (9%). Lesser Scaups from Lake Erie fed on larger zebra mussels ( = 10.7 i?? 0.66 mm SE) than did Lesser Scaups from Lake St. Clair ( = 4.4 i?? 0.22 mm). Lesser Scaups, Buffleheads and Common Goldeneyes from Lake Erie consumed zebra mussels of similar size.

  17. Metal contamination in zebra mussels (Dreissena polymorpha) along the St. Lawrence River.

    Science.gov (United States)

    Kwan, K H Michael; Chan, Hing Man; de Lafontaine, Yves

    2003-01-01

    In order to evaluate the use of zebra mussels as biomonitors for metal bioavailability in the St. Lawrence River, we tested the hypothesis that the concentrations of 11 metals in zebra mussels vary significantly between sites along the river and that the season of collection and body size affect metal bioaccumulation. Mussels were collected at 14 sites during June 1996 and at monthly intervals at one site. Specimens were grouped in three size classes and their soft tissue was analyzed for As, Ca, Cd, Cr, Hg, Mn, Ni, Pb, Se, and Zn. Significant size effects were found for Ca, Cd, Cr, Cu, Ni and Zn. Spatial and seasonal variations in bioconcentration were significant for all metals. Spatial patterns in contamination that corresponded to known point sources of pollution or hydrology of the river were identified by principal component analysis. Seasonal variations can be attributed to the reproductive cycle of mussels and hydrological variability of the river. In comparison with values reported for zebra mussels in other contaminated sites in North America and Europe, levels of metal in the St. Lawrence River are low or intermediate. Our results show that when controlled for size and seasonal effects, zebra mussels represent a useful biomonitor for metal availability in the river and may offer an interesting alternative to native mussels and fish for such a role. Local contamination by some toxic metals is still a cause for concern in the St. Lawrence River.

  18. Warm season chloride concentrations in stream habitats of freshwater mussel species at risk

    International Nuclear Information System (INIS)

    Todd, Aaron K.; Kaltenecker, M. Georgina

    2012-01-01

    Warm season (May–October) chloride concentrations were assessed in stream habitats of freshwater mussel species at risk in southern Ontario, Canada. Significant increases in concentrations were observed at 96% of 24 long-term (1975–2009) monitoring sites. Concentrations were described as a function of road density indicating an anthropogenic source of chloride. Linear regression showed that 36% of the variation of concentrations was explained by road salt use by the provincial transportation ministry. Results suggest that long-term road salt use and retention is contributing to a gradual increase in baseline chloride concentrations in at risk mussel habitats. Exposure of sensitive mussel larvae (glochidia) to increasing chloride concentrations may affect recruitment to at risk mussel populations. - Highlights: ► Warm season chloride concentrations were assessed in habitats of mussel species at risk. ► Concentrations increased significantly at 96% of 24 long-term monitoring sites. ► Concentrations increased with increases in road density and road salt use. ► Retention of road salt likely contributed to elevated warm season concentrations. ► Glochidia exposure to increasing concentrations may affect mussel reproduction. - Warm season chloride concentrations increased in southern Ontario streams with road salt use, such that reproduction of freshwater mussel species at risk may be affected.

  19. Judging Fairness in Class Action Settlements

    Directory of Open Access Journals (Sweden)

    Catherine Piché

    2010-02-01

    Full Text Available In this paper, I describe the face of modern civil justice and discuss four paradoxes which justify re-evaluating the role of the judge responsible for reviewing class action settlements, in light of modern judicial culture. I also critically evaluate the existing procedures applicable to the fairness review as well as the judicial role described in the caselaw and doctrine, before suggesting a revised, three-parted role for the reviewing judge in the class action settlement context. Ultimately, I suggest that to reach fairness of process and outcome in class action settlements, judges should remain active and creative in their inquisitorial assessment of proposed class action settlements. They should also remain conciliatory, participating in the search for solutions regarding the proposed settlement, always seeking to find the truth (and what is “just” about the proposed settlement, in the utmost respect for the rights of absent class members, the respect of their interests, and the additional consideration of the interests of the defendants and of the public. Dans cet article, je présente l’état de la face de la justice civile moderne et je discute quatre paradoxes qui justifient une réévaluation du rôle du juge responsable de la révision et de l’approbation d’un règlement de recours collectif, à la lumière de la culture juridique moderne. Je propose aussi une évaluation critique des procédures en place s’appliquant à l’évaluation du caracters équitable de la transaction, de même que le rôle du juge décrit dans la jurisprudence et la doctrine, avant de suggérer un rôle révisé. Ce rôle modifié se décline en trois parties. Finalement, je suggère que pour atteindre l’équité de procédure et de résultat dans le cas de règlements en recours collectif, les juges devraient demeurer actifs et créatifs en enquêtant pour évaluer des règlements proposés dans les cas de recours collectifs. Ils et elles

  20. Pathogens and diseases of freshwater mussels in the United States: Studies on bacterial transmission and depuration

    Science.gov (United States)

    Starliper, Clifford E.; Cipriano, R.C.; Bruckner, A.W.; Shchelkunov, I.S.

    2011-01-01

    Unionid mussels are recognized as important contributors to healthy aquatic ecosystems, as well as bioindicators of environmental perturbations. Because they are sedentary, filter feeding animals and require hosts (i.e., fishes) to transform embryonic glochidia, mussels are susceptible to direct adverse environmental parameters, and indirect parameters that restrict the timely presence of the host(s). Their numbers have declined in recent decades to a point that this fauna is regarded as one of the most imperiled in North America. The most significant threat to populations of native unionids in recent years has been the introduction and spread of zebra mussels Dreissena polymorpha. Many federal and state agencies, and private interests are now engaged in mussel conservation efforts, including collecting selected imperiled species from impacted rivers and lakes and propagating them at refuges for future population augmentations. One essential consideration with mussel propagation and their intensive culture at refugia is the prevention of pathogen introductions and control of diseases. Currently, there are few reports of etiological agents causing diseases among freshwater mussels; however, because of increased observations of mussel die-offs in conjunction with transfers of live animals between natural waters and refugia, disease problems can be anticipated to emerge. This review summarizes research to develop bacterial isolation techniques, study pathogen transmission between fish and mussels, identify causes of seasonal mussel die-offs, and develop non-destructive methods for pathogen detection. These efforts were done to develop disease preventative techniques for use by resource managers to avoid potential large-scale disease problems in restoration and population augmentation efforts among imperiled populations.

  1. Cumulative effects of ibuprofen and air emersion in zebra mussels Dreissena polymorpha.

    Science.gov (United States)

    André, C; Gagné, F

    2017-10-01

    Municipal effluents are major source of pharmaceutical products in the environment. The purpose of this study was to examine the toxicity of a largely used drug, ibuprofen (Ibu), in Dresseina polymorpha mussels and its impact on air survival time. The mussels were exposed to increasing concentration of Ibu (0, 1, 10 and 100μg/L) for 96 at 15°C and a sub-group of mussels was maintain in air for another 96h. Post-exposure mussels (Ibu and Ibu+Air) were analyzed for weight loss, total triglycerides, neutral lipids, lipid peroxidation (LPO), arachidonate-dependent cyclooxygenase (COX) and glutathione S-transferase activity. Lipid extracts of mussel tissues were also analyzed by 1 H-nuclear resonance spectroscopy. The data revealed that mussels exposed to Ibu had increased signs of lipid oxidation, neutral lipids and decreased triglycerides, LPO and GST activity. COX activity was significantly reduced by Ibu in keeping with mode of action of the drug. Following exposure to air, increased weight loss, neutral lipids (lipid degradation), were observed in mussels exposed to Ibu but no changes in COX activity were observed. Air stress limited the decrease in triglycerides and the increase in GST in mussels exposed to 100μg/L Ibu indicating decreased anti-oxidant response/phase II biotransformation and limited lipid metabolism. In conclusion, exposure to Ibu has some anti-inflammatory effects to mussels based on COX activity but resulted in increased oxidative damage and lipid catabolism. Exposure to air stress could enhance some of these responses and contribute to decreased resistance to air exposures. Crown Copyright © 2017. Published by Elsevier B.V. All rights reserved.

  2. Housing / Human Settlements Atlas series: continued support towards more sustainable human settlements

    CSIR Research Space (South Africa)

    Goss, H

    2010-09-01

    Full Text Available an answer to the key question of what (shelter type or model and supportive services) should be built where (in the most suitable location with the highest potential to support sustainable human settlements). The investment potential profile indicator has...

  3. Guidelines and criteria for planning Slovenian settlements

    Directory of Open Access Journals (Sweden)

    Andrej Pogačnik

    2001-01-01

    Full Text Available The article deals with proposals for directing settlement development and management in Slovenia on the national level. They should be integrated in the spatial order, a part of the national spatial plan. First a short chronology of research with similar topics and simultaneous critical analysis is presented. The methodology and possible models for structuring directives is elaborated. Based on recent research by domestic authors, European guidelines and own ideas, a manual was devised, dividing guidelines hierarchically between the national, regional and local level. The second part or rather different type of text attached to the manual is a glossary. It also includes an index for further research of various sources.

  4. Public Service Provision in Clientelistic Political Settlements

    DEFF Research Database (Denmark)

    Whitfield, Lindsay; Hirvi, Marja

    2015-01-01

    The politics of public-service delivery continues to be neglected under the supposedly more context-sensitive post-Washington Consensus. Using interviews and documentary evidence from Ghana, this article provides an account of the networks of political interference and informal practices in Ghana......'s public water utility. It argues that, in order to understand why private-sector participation succeeds or fails and why similar arrangements have different outcomes across developing countries, we need to examine the effects of the informal institutional context, particularly the country......-specific political settlement in which public-service provision operates....

  5. Experimental research on fresh mussel meat irradiated by high-dose electron beam

    International Nuclear Information System (INIS)

    Xiao Lin; Lu Ruifeng; Hu Huachao; Wang Chaoqi; Liu Yanna

    2011-01-01

    The sterilization storage of fresh mussel irradiated high-dose electron beam was studied. From the subjective assessment by the weighted average of the test and other determined parameters, it can be concluded that the flavor of fresh mussel meat sealed canned food irradiated by high-dose electron beam has not been significant affected, and various micro-organisms can be killed effectively, which means that the irradiated fresh mussel meat can be preserved for long-term at room temperature. Therefore the method might resolve the problems induced by traditional frozen preservation methods. (authors)

  6. Protection against suspended sand: the function of the branchial membrane in the blue mussel Mytilus edulis

    Science.gov (United States)

    de Vooys, C. G. N.

    2006-09-01

    Blue mussels ( Mytilus edulis) living in estuaries have to cope with varying concentrations of suspended sand. Sand flowing through the inhalant siphons comes into the infrabranchial chamber. The inhalant siphon can be partially closed by the branchial membrane. As a result the inward flow decreases, and suspended sand sinks and can be eliminated. Experiments with mussels from three ecologically different locations showed about the same response of the branchial membrane on contact with suspended sand. The presence and function of the branchial membrane appears to be an adaptation of mussels to their estuarine environment.

  7. HEAVY METALS (Ni, Cu, Zn AND Cd CONTENT IN SERUM OF RAT FED GREEN MUSSELS

    Directory of Open Access Journals (Sweden)

    Muhammad Yudhistira Azis

    2015-11-01

    Full Text Available Green mussel (Perna viridis can playing role as bio-indicator or biomonitoring agent for heavy-metalcontaminations in the sea. In this research, the concentrations of four elements Ni, Cu, Zn and Cd in P. viridis and in the serum of rat which orally feed by P. viridis were determined by Atomic Absorption Spectrometry (AAS following dry acid digestion. Parameter analysis was evaluated by determining confidence limit for the obtained results. The result showed that there was a sequence of heavy-metal content in green mussels sample and laboratory rats serum, such as Ni < Cd < Cu < Zn. Keywords: heavy metals, green mussels, laboratory rats serum, AAS

  8. GROWTH OF MUSSELS (Mytilus galloprovincialis ON THE EAST COAST OF ISTRIA

    Directory of Open Access Journals (Sweden)

    Nives Marušić

    2010-01-01

    Full Text Available Growth rate of mussels depends on ecological factors but largely on the amount of food. Food must be of adequate composition and amount. Other responsible factors are temperature and salinity. Growth of mussels is increased if there is inflow of fresh water. Very low values of salinity have negative influence on growth. The growth of mussels in Budava and Raša Bay is increase with an increase in sea temperature. The slowest growth was at the very lowest salinity values.

  9. The first record of the Chinese pond mussel Sinanodonta woodiana (Lea, 1834 in Montenegro

    Directory of Open Access Journals (Sweden)

    Tomović Jelena

    2013-01-01

    Full Text Available Sinanodonta woodiana (Lea, 1834, Chinese pond mussel (Bivalvia: Unionoida: Unionidae is one of the most invasive aquatic macroinvertebrate species found in Europe. We report the Chinese pond mussel for the first time in Montenegro, in August 2012, in Lake Šasko (Adriatic part of the Central Mediterranean subarea. One specimen of the Chinese pond mussel was observed in a habitat with a predominantly silt-clay substrate. The main pathway of species introduction was evaluated to be via fish stocking. [Projekat Ministarstva nauke Republike Srbije, br. III 43002 i br. ON 173025

  10. Divergent induced responses to an invasive predator in marine mussel populations.

    Science.gov (United States)

    Freeman, Aaren S; Byers, James E

    2006-08-11

    Invasive species may precipitate evolutionary change in invaded communities. In southern New England (USA) the invasive Asian shore crab, Hemigrapsus sanguineus, preys on mussels (Mytlius edulis), but the crab has not yet invaded northern New England. We show that southern New England mussels express inducible shell thickening when exposed to waterborne cues from Hemigrapsus, whereas naïve northern mussel populations do not respond. Yet, both populations thicken their shells in response to a long-established crab, Carcinus maenas. Our findings are consistent with the rapid evolution of an inducible morphological response to Hemigrapsus within 15 years of its introduction.

  11. Freshwater Mussels as Biological Sensors and Cyclers of Aquatic Nitrogen Constituents: An Experimental Investigation

    Science.gov (United States)

    Kruger, A.; Just, C. L.; Mudumbai, R.; Dasgupta, S.; Newton, T. J.; Durst, J.; Boddicker, M. D.; Diken, M. B.; Bril, J.; Baidoo-Williams, H. E.

    2011-12-01

    One of the most extensive manifestations of anthropogenic mismanagement of nitrogen is eutrophication of the Gulf of Mexico. Leaching and runoff transport nitrate compounds-excess agricultural fertilizer and animal waste-via the Mississippi River to the Gulf of Mexico. Phytoplankton then multiplies exponentially, and consumes most of the dissolved oxygen. This hypoxia kills fish and other organisms, leading to so-called dead zones in the Gulf that can cover 6,000-7,000 square miles. Dead zone mitigation plans call for coupling management actions with enhanced monitoring, modeling, and research on nitrogen delivery to, as well as processing within, the Mississippi River. Our vision is to create a biosensor network of native freshwater mussels in a major river to monitor, comprehend, and ultimately model key components of the nitrogen cycle. Native freshwater mussels are a guild of long-lived, suspension feeding bivalves that perform important ecological functions in aquatic systems. Mussels can influence nutrient cycling by transferring nutrients from the water column to the riverbed. A major problem for environmental scientists is that relatively little is known about the diurnal behaviors of freshwater mussels or the impacts these behaviors may have on the aquatic nitrogen cycle. Our multidisciplinary team is performing a series of laboratory experiments exploring the feasibility of using freshwater mussels as sensors of and capacitors for nitrates. For sensing, we place Hall-effect sensors on mussels to monitor the rhythmic opening and closing of their valves (gape). One shortcoming of previous work is that mussels were monitored in artificial conditions: glued fast in laboratory flumes, or tethered in constrained settings. To overcome this shortcoming, our team has built a mussel microhabitat with a constant river water feed stock, solar simulator, and a variety of water chemistry sensor. A main thrust of our work is to develop the technology to monitor mussel

  12. Biomixing in stagnant wate above population of blue mussels (Mytilus edulis)

    DEFF Research Database (Denmark)

    Larsen, Poul Scheel; Andrup, P.; Tang, B.

    2016-01-01

    Dense beds of filter-feeding mussels can exert a considerable grazing impact on phytoplankton in many marine areas depending on downmixing promoted by current, wave- and wind action. But downmixing may also be promoted by biomixing caused by the action of the strong exhalent jets of water from...... a population of 48 ind.m-2 of mussels of shell length 69.5 ± 2.3 mm. Due to the intense agitation (biomixing) generated by exhalant jets of the actively feeding mussels the profiles remained nearly uniform over the full water column while decreasing exponentially with time, reaching a level of about 40...

  13. Uptake of Iodine-131 in mussel (Mytilus smaragdinns) and algae (caulerpa racemosa)

    International Nuclear Information System (INIS)

    Sombrito, E.Z.; Banzon, R.B.; de la Mines, A.S.; Bautista, E.Rb.

    1982-01-01

    The behavior of radionuclides in the environment has been the subject of research. Iodine-131, a beta emitter as one of the radionuclides has been studied. This study describes Iodine-131 uptake in mussel and algae. The bioaccumulation factor C was determined which gave the relationship between the concentration of radioactivity in biota relative to the water environment. Results of the experiments showed that the mussels steadily accumulated I-131 from radioactive medium. Much higher bioaccumulation factor was obtained in algae than in mussel. No attempt was made to measure activity in the soft parts. (ELC)

  14. Considerations of food hygiene in the case of mussels accidentally contaminated by iodine 131

    International Nuclear Information System (INIS)

    Battani, N.; Chambost, Marie-Daniel; Leandri, Marcel

    1969-09-01

    As the transfer to mankind of radioactive pollution by food chains is a matter of concern, the authors report the study of the use of mussels contaminated by iodine 131 in a food preparation in order to follow the evolution of this radionuclide. After their contamination in seawater, mussels are prepared either with or without their shell. Counting is performed after cooking. Results are discussed in terms of presence of the radionuclide in the different parts of the crude or cooked mussels (shell, body, liquid) [fr

  15. PBDEs in freshwater mussels and fish from Flanders, Belgium

    Energy Technology Data Exchange (ETDEWEB)

    Covaci, A.; Voorspoels, S.; Schepens, P. [Antwerp Univ. (Belgium). Toxicological Center; Bervoets, L.; Hoff, P.; Voets, J.; Campenhout, K. van; Blust, R. [Antwerp Univ. (Belgium). Dept. of Ecophysiology, Biochemistry and Toxicology

    2004-09-15

    Polybrominated diphenylethers (PBDEs), a class of brominated flame retardants (BFRs), are widely used in textiles, plastics, electronic equipment and other materials for more than 30 years. Due to their massive use, PBDEs have become ubiquitously present in aquatic organisms and it was recently evidenced that their levels seem to increase rapidly. Higher PBDE concentrations were found in biota from freshwater compared to similar marine species. This is probably due to a higher pollution load found near point pollution sources that are almost exclusively inland located. Zebra mussels (Dreissena polymorpha) fulfil the requirements of a good biomonitoring organism for freshwater ecosystems: they are easy to collect and to handle, are available in sufficient numbers, have a relative long lifespan, are sedentary and resistant to various types of pollution without suffering a too high mortality and have a high filtration rate which favours the bioaccumulation of organic contaminants. Fish species are another suitable tool for the biomonitoring of organic contaminants. The occurrence of PBDEs in fish species from Europe has already received some attention, but the amount of data is still limited. The aim of this study was to evaluate the occurence of PBDEs in zebra mussels and several representative freshwater fish species (eel, carp and gibel carp) at different sites in Flanders, Belgium. In parallel, other organohalogenated contaminants, such as polychlorinated biphenyls (PCBs), p,p'-DDE and hexachlorobenzene (HCB) were also measured and their relationship with PBDEs was investigated.

  16. An 'artificial mussel' for monitoring heavy metals in marine environments

    International Nuclear Information System (INIS)

    Wu, Rudolf S.S.; Lau, T.C.; Fung, Wendy K.M.; Ko, P.H.; Leung, Kenneth M.Y.

    2007-01-01

    A new chemical sampling device, artificial mussel (AM), has been developed for monitoring metals in marine environments. This device consists of a polymer ligand suspended in artificial seawater within a Perspex tubing, and enclosed with semi-permeable gel at both ends. Laboratory and field experiments were carried out to examine the uptake of five metals (Cd, Cr, Cu, Pb and Zn) by the AM. Uptake of metals by AM was proportional to the exposure metal concentrations, and the AM was able to accumulate the ASV labile fractions of metals. Uptake and release of the metals of AM are similar to those of the mussel Perna viridis, but less affected by salinity and temperature. Field studies demonstrated that the AM can not only provide a time-integrated estimate of metals concentrations, but also allows comparisons of metal levels in different environments and geographical areas beyond the natural distribution limits of biomonitors. - A new monitoring device to provide a time-integrated estimate for monitoring metals in marine environments

  17. Phylogeography and systematics of zebra mussels and related species.

    Science.gov (United States)

    Gelembiuk, Gregory W; May, Gemma E; Lee, Carol Eunmi

    2006-04-01

    The genus Dreissena includes two widespread and aggressive aquatic invaders, the zebra mussel, Dreissena polymorpha, and the quagga mussel, Dreissena bugensis. This genus evolved in the Ponto-Caspian Sea basin, characterized by dynamic instability over multiple timescales and a unique evolutionary environment that may predispose to invasiveness. The objectives of this study were to gain insights into the demographic history of Dreissena species in their endemic range, to reconstruct intraspecific phylogeographic relationships among populations, and to clarify systematics of the genus, using DNA sequences from the mitochondrial cytochrome oxidase I (COI) gene. We found four deeply diverged clades within this genus, with a basal split that approximately coincided with the Cretaceous-Tertiary boundary. Divergence events within the four base clades were much more recent, corresponding to geographically disjunct sets of populations, which might represent species complexes. Across all taxa, populations of Dreissena shared a common pattern of genetic signatures indicating historical population bottlenecks and expansions. Haplotype diversity was relatively low in Ponto-Caspian drainages relative to more stable tectonic lakes in Greece, Macedonia, and Turkey. The phylogeographic and demographic patterns in the endemic range of Dreissena might have resulted from vicariance events, habitat instability, and the high fecundity and passive dispersal of these organisms.

  18. Identification of Listeria monocytogenes on Green Mussels and Cockle Shell

    Directory of Open Access Journals (Sweden)

    Winiati Puji Rahayu

    2017-02-01

    Full Text Available AbstractGreen mussel (Perna viridis and cockle shell (Anadara granosa are one of many sources of animal protein which is many cultivated in Indonesia because their price is relatively affordable. This study was conducted to identify the presence of Listeria monocytogenes in 27 samples of green mussels and 3 samples of cockle shells using real-time Polymerase Chain Reaction (real-time PCR and biochemical methods. The target gene for amplification in real-time PCR was an hlyA gene because this gene was a determinant of virulence genes that produce listeriolysin O. Primers used in this study were forward primer DG69 (GTG CCG GGT AAA AGA CCA TA and reverse primer DG74 (CGC CAC TGA GAT ACT AT and fluorescence signals indicator using SYBR Green I. The results of analysis using real-time PCR were negative Listeria monocytogenes in all samples, while using biochemical methods there was one of 30 samples contaminated by Listeria welshimeri.

  19. Developmental plasticity of shell morphology of quagga mussels from shallow and deep-water habitats of the Great Lakes.

    Science.gov (United States)

    Peyer, Suzanne M; Hermanson, John C; Lee, Carol Eunmi

    2010-08-01

    The invasive zebra mussel (Dreissena polymorpha) has quickly colonized shallow-water habitats in the North American Great Lakes since the 1980s but the quagga mussel (Dreissena bugensis) is becoming dominant in both shallow and deep-water habitats. While quagga mussel shell morphology differs between shallow and deep habitats, functional causes and consequences of such difference are unknown. We examined whether quagga mussel shell morphology could be induced by three environmental variables through developmental plasticity. We predicted that shallow-water conditions (high temperature, food quantity, water motion) would yield a morphotype typical of wild quagga mussels from shallow habitats, while deep-water conditions (low temperature, food quantity, water motion) would yield a morphotype present in deep habitats. We tested this prediction by examining shell morphology and growth rate of quagga mussels collected from shallow and deep habitats and reared under common-garden treatments that manipulated the three variables. Shell morphology was quantified using the polar moment of inertia. Of the variables tested, temperature had the greatest effect on shell morphology. Higher temperature (approximately 18-20 degrees C) yielded a morphotype typical of wild shallow mussels regardless of the levels of food quantity or water motion. In contrast, lower temperature (approximately 6-8 degrees C) yielded a morphotype approaching that of wild deep mussels. If shell morphology has functional consequences in particular habitats, a plastic response might confer quagga mussels with a greater ability than zebra mussels to colonize a wider range of habitats within the Great Lakes.

  20. 76 FR 77997 - Proposed CERCLA Administrative Cashout Settlement; The Atlantic Richfield Company

    Science.gov (United States)

    2011-12-15

    ... administrative settlement for recovery of past response costs concerning the Ophir Mills and Smelter Site in Tooele County, Utah with the Atlantic Richfield Company based upon a cash-out settlement. The settlement...

  1. Density and body size of the larval stages of the invasive golden mussel (Limnoperna fortunei in two neotropical rivers Densidade e tamanho dos estágios larvais do molusco invasor mexilhão dourado (Limnoperna fortunei em dois rios neotropicais

    Directory of Open Access Journals (Sweden)

    Vivianne Eilers

    2011-09-01

    Full Text Available AIM: The present study involved an analysis of the monthly variations in the population densities and body sizes of the different stages of planktonic larvae of the invasive golden mussel (Limnoperna fortunei, in the rivers Paraguay and Miranda; METHODS: The study was carried out between February 2004 and January 2005. Monthly collection of the plankton samples was accompanied by physical, chemical and biological analyses of the water; RESULTS: The Miranda River presented higher values of calcium, pH, alkalinity, conductivity and total phosphorous. Larval density varied from 0-24 individuals.L-1 in the Paraguay River, with a peak in March of 2004, while in the Miranda River, densities varied between 0-9 individuals.L-1 with a peak in February of 2004. No larvae were encountered during the coldest months, May and June. No significant correlations were found between environmental variables and larval density in either river. Only the valved larval stages were recorded. The "D" and veliger forms were most abundant; umbonate larvae were rare in the Miranda River samples. Mean body sizes of "D", veliger and umbonate larval stages were, respectively, 111, 135 and 152 µm, in the Paraguay River, and 112, 134 and 154 µm in the Miranda River. Principal Components Analysis indicated positive relationships between "D" larval stage size and the ratio between inorganic and organic suspended solids, while negative relationships were found between larval size and calcium and chlorophyll-; CONCLUSIONS: The larvae were recorded in the plankton during most of the year, with the exception of the two colder months. Neither densities nor larval stage body sizes were significantly different between the two rivers. Possible positive effects of food and calcium concentrations on body size were not recorded. This species may be adapted to grow in environments with elevated sediment concentrations.OBJETIVO: O presente estudo analisou as variações mensais em densidades

  2. 48 CFR 249.110 - Settlement negotiation memorandum.

    Science.gov (United States)

    2010-10-01

    ... 48 Federal Acquisition Regulations System 3 2010-10-01 2010-10-01 false Settlement negotiation memorandum. 249.110 Section 249.110 Federal Acquisition Regulations System DEFENSE ACQUISITION REGULATIONS SYSTEM, DEPARTMENT OF DEFENSE CONTRACT MANAGEMENT TERMINATION OF CONTRACTS General Principles 249.110 Settlement negotiation memorandum. Follow...

  3. Analysis of an Underground Structure Settlement Risk due to Tunneling

    DEFF Research Database (Denmark)

    Vahdatirad, Mohammad Javad; Ghodrat, Hadi; Firouzianbandpey, Sarah

    2010-01-01

    of the underground commercial center structure settlement is estimated using both empirical and numerical methods. The settlement risk level of the commercial center structure is determined based on presented definitions about risk classification of various types of structures. Consequently, tunneling processes...

  4. 12 CFR 308.15 - Opportunity for informal settlement.

    Science.gov (United States)

    2010-01-01

    ... 12 Banks and Banking 4 2010-01-01 2010-01-01 false Opportunity for informal settlement. 308.15 Section 308.15 Banks and Banking FEDERAL DEPOSIT INSURANCE CORPORATION PROCEDURE AND RULES OF PRACTICE RULES OF PRACTICE AND PROCEDURE Uniform Rules of Practice and Procedure § 308.15 Opportunity for informal settlement. Any respondent may, at any time...

  5. Transparency and public participation in WTO dispute settlement

    NARCIS (Netherlands)

    Ahlborn, C.S.; Pfitzer, J.H.

    2009-01-01

    In order to offer a comprehensive analysis of transparency and public participation in the WTO dispute settlement system, this memorandum first considers the current participatory practice throughout the various steps of the dispute settlement process. Secondly, the current state of the DSU

  6. Resilience and social costs: centralised towns vs. distributed settlements?

    DEFF Research Database (Denmark)

    Hendriksen, Kåre

    In government reports and political debates in Greenland it is often stated, that the divided settlement in general and especially the settlements are too costly, and that the outlying districts in general do not contribute sufficiently to the national economy. This presumption is used as an argu...

  7. 47 CFR 1.244 - Designation of a settlement judge.

    Science.gov (United States)

    2010-10-01

    ... Proceedings Presiding Officer § 1.244 Designation of a settlement judge. (a) In broadcast comparative cases... Administrative Law Judge for action. (c) If, in the discretion of the Chief Administrative Law Judge, it appears... Commission's Administrative Law Judges are eligible to act as settlement judges, except that an...

  8. 48 CFR 53.301-1438 - Settlement Proposal (Short Form).

    Science.gov (United States)

    2010-10-01

    ... 48 Federal Acquisition Regulations System 2 2010-10-01 2010-10-01 false Settlement Proposal (Short Form). 53.301-1438 Section 53.301-1438 Federal Acquisition Regulations System FEDERAL ACQUISITION REGULATION (CONTINUED) CLAUSES AND FORMS FORMS Illustrations of Forms 53.301-1438 Settlement Proposal (Short...

  9. 28 CFR 43.3 - Settlement and waiver of claims.

    Science.gov (United States)

    2010-07-01

    ... 28 Judicial Administration 2 2010-07-01 2010-07-01 false Settlement and waiver of claims. 43.3 Section 43.3 Judicial Administration DEPARTMENT OF JUSTICE (CONTINUED) RECOVERY OF COST OF HOSPITAL AND MEDICAL CARE AND TREATMENT FURNISHED BY THE UNITED STATES § 43.3 Settlement and waiver of claims. (a) The...

  10. Conciliation as the traditional method of disputes settlement in PRC

    Directory of Open Access Journals (Sweden)

    Svetlana F. Litvinova

    2011-12-01

    Full Text Available The author of the article researches one of the peculiarities of civil disputes settlement in China. This peculiarity is the conciliatory method that is used during disputes settlement. The using of the method is based on Confucianism. The content of the method has been viewed in the article.

  11. Formalisation of Unplanned Settlements and Its Implications on ...

    African Journals Online (AJOL)

    Formalisation of Unplanned Settlements and Its Implications on Poverty Reduction: The Case of Dar es Salaam City. ... Properties found in these areas are sound or improvable. ... Key words: regularisation, formalisation, land tenure, property rights, unplanned/informal settlements, poverty reduction, Dar es Salaam ...

  12. 32 CFR 536.124 - Settlement authority for maritime claims.

    Science.gov (United States)

    2010-07-01

    ... 32 National Defense 3 2010-07-01 2010-07-01 true Settlement authority for maritime claims. 536.124 Section 536.124 National Defense Department of Defense (Continued) DEPARTMENT OF THE ARMY CLAIMS AND ACCOUNTS CLAIMS AGAINST THE UNITED STATES Maritime Claims § 536.124 Settlement authority for maritime...

  13. 32 CFR 537.18 - Settlement authority for maritime claims.

    Science.gov (United States)

    2010-07-01

    ... 32 National Defense 3 2010-07-01 2010-07-01 true Settlement authority for maritime claims. 537.18 Section 537.18 National Defense Department of Defense (Continued) DEPARTMENT OF THE ARMY CLAIMS AND ACCOUNTS CLAIMS ON BEHALF OF THE UNITED STATES § 537.18 Settlement authority for maritime claims. (a) The...

  14. Engineering approach to model and compute electric power markets settlements

    International Nuclear Information System (INIS)

    Kumar, J.; Petrov, V.

    2006-01-01

    Back-office accounting settlement activities are an important part of market operations in Independent System Operator (ISO) organizations. A potential way to measure ISO market design correctness is to analyze how well market price signals create incentives or penalties for creating an efficient market to achieve market design goals. Market settlement rules are an important tool for implementing price signals which are fed back to participants via the settlement activities of the ISO. ISO's are currently faced with the challenge of high volumes of data resulting from the increasing size of markets and ever-changing market designs, as well as the growing complexity of wholesale energy settlement business rules. This paper analyzed the problem and presented a practical engineering solution using an approach based on mathematical formulation and modeling of large scale calculations. The paper also presented critical comments on various differences in settlement design approaches to electrical power market design, as well as further areas of development. The paper provided a brief introduction to the wholesale energy market settlement systems and discussed problem formulation. An actual settlement implementation framework and discussion of the results and conclusions were also presented. It was concluded that a proper engineering approach to this domain can yield satisfying results by formalizing wholesale energy settlements. Significant improvements were observed in the initial preparation phase, scoping and effort estimation, implementation and testing. 5 refs., 2 figs

  15. Automatic settlement analysis of single-layer armour layers

    NARCIS (Netherlands)

    Hofland, B.; van gent, Marcel

    2016-01-01

    A method to quantify, analyse, and present the settlement of single-layer concrete armour layers of coastal structures is presented. The use of the image processing technique for settlement analysis is discussed based on various modelling
    studies performed over the years. The accuracy of the

  16. Experimental analysis of railway track settlement in transition zones

    NARCIS (Netherlands)

    Wang, H.; Markine, V.L.; Liu, X.

    2017-01-01

    Transition zones in railway tracks are the locations with considerable changes in the vertical support structures. Due to the differential stiffness and settlement in the open track and the engineering structure resulting in the dynamic amplification of the wheel forces, track settlement is usually

  17. Macrofauna Settlement on Pearl Oyster Collectors in Kenya ...

    African Journals Online (AJOL)

    Key words: Pearl oysters, seed collection, macrofauna, bivalves, settlement, monsoon seasons,. Kenya .... have shown that pearl oyster settlement is higher within calm ...... collectors in the Timor Sea, Northern Australia. J. Shellfish ... systems. Aquaculture, 189: 375-388. Urban, H.J. (2000b): Culture potential of the pearl.

  18. Analysis of spatial pattern of settlements in the federal capital ...

    African Journals Online (AJOL)

    Human settlements are important, seemingly static but dynamic, features of the cultural landscape that have attracted several studies due to the important role they play in human life. This paper examined the spatial distribution of settlements in the Federal Capital Territory (FCT) of Nigeria. The analysis uses vector based ...

  19. 47 CFR 64.1002 - International settlements policy.

    Science.gov (United States)

    2010-10-01

    ... (CONTINUED) MISCELLANEOUS RULES RELATING TO COMMON CARRIERS International Settlements Policy and Modification... accounting rate modification, filed pursuant to § 64.1001, that includes a settlement rate that is at or... behavior that is harmful to U.S. customers. Carriers and other parties filing complaints must support their...

  20. 29 CFR 1603.108 - Settlement and alternative dispute resolution.

    Science.gov (United States)

    2010-07-01

    ... 29 Labor 4 2010-07-01 2010-07-01 false Settlement and alternative dispute resolution. 1603.108... Settlement and alternative dispute resolution. (a) The parties are at all times free to settle all or part of... a neutral mediator or to any other alternative dispute resolution process authorized by the...

  1. The development of informal settlements in South Africa, with particular reference to informal settlements around Daveyton on the East Rand, 1970-1999

    OpenAIRE

    2012-01-01

    D.Litt. et Phil. The purpose of the study is to analyse the development of informal settlements in South Africa, with particular reference to the role of the Government in the improvement of informal settlement conditions around Daveyton, especially at the Etwatwa informal settlement. Research has shown that there is common experience in developing countries in Africa, Asia and Latin America in as far as the development of squatter settlements or informal settlements are concerned. This st...

  2. Co-existence of zebra mussels and freshwater unionids: Population dynamics of Leptodea fragilis in a coastal wetland infested with zebra mussels

    Science.gov (United States)

    Nichols, S. Jerrine; Amberg, Jon

    1999-01-01

    In 1996, thousands of live Leptodea fragilis were collected from a marsh located in the western basin of Lake Erie that was infested with zebra mussels (Dreissena polymorpha). Despite the presence of zebra mussels at this site for a number of years, this L. fragilis population showed no signs of competition-induced changes in population dynamics. Biofouling was limited: fewer than 1% of the L. fragilis showed evidence of recent or past zebra mussel colonization. Successful recruitment occurred yearly, with multiple year classes collected that ranged in age from 1 to 12 years. However, age and shell length were not well correlated. Seventy-one percent of the individuals collected were 51-80 mm long, but ranged in age from 2 to 4.5 years. Three different patterns of growth or shell deposition were found. Some individuals grew rapidly, reaching 105 mm in 3.5 years, while others grew only 4.5 mm over the same time period. A few grew poorly during some years but very rapidly in others. Individuals with a shell length of 41 mm or more were sexually mature and females were more common than males. The strong recruitment and steady growth of this population showed no change between the years before and after the zebra mussel invasion, indicating that this marsh is functioning as a natural refugium from potential problems caused by zebra mussels.

  3. The Mass-Dimension Relationships in the Mussels Mytilus Galloprovincialis (Mollusca, Bivalvia from Different Phenotypical Groups in Periphyton Populations near Odessa Coast, the North-Western Part of Black Sea

    Directory of Open Access Journals (Sweden)

    Govorin I. A.

    2016-06-01

    Full Text Available The data of the size-mass indices in the mussels Mytilus galloprovincialis (Lamarck, 1819 from three phenotypic groups - brown, dark violet (black and “zebra” (brown with radial black stripes shells in the periphyton settlements on the concrete traverses near Odessa coast, the North-western part of Black Sea (Ukraine, in March-November 2014-2015 are presented. A comparative evaluation has been made on the relationships of total mass of the mollusks, wet and dry mass of their soft body and mass of the shells on the one hand, and the size of animals (length of its shells on the other hand, in the each of phenotypical groups from the five marine beach areas. It is shown, that in the marine areas with different degrees of isolation from the open sea by coast-protection engineering constructions, the mussels from different phenotypes have almost the same size-mass characteristics. Only the dry weight of soft animal body, which indicated to fatness of mollusk and therefore demonstrated his biological prosperity in specific hydrological conditions, can serve as a reliable criterion which can mark the shellfish habitats with different gradients of environmental factors.

  4. Structured settlement annuities, part 1: overview and the underwriting process.

    Science.gov (United States)

    Schmidt, C J; Singer, R B

    2000-01-01

    Structured settlement underwriting is the underwriting of medically impaired lives for the purchase of an annuity to fund the settlement. Other than risk assessment, structured settlement (SS) underwriting has little in common with traditional life insurance underwriting. Most noteworthy of these differences is the relative lack of actuarial data on which to base decisions about mortality and the necessity for prospective thinking about risk assessment. The purpose of this paper is to provide a foundation for understanding the structured settlement business and to contrast the underwriting of structured settlements with that of traditional life insurance. This is the first part of a two-part article on SS annuities. Part 2 deals with the mortality experience in SS annuitants and the life-table methodology used to calculate life expectancy for annuitants at increased mortality risk.

  5. Residual concentrations of micropollutants in benthic mussels in the coastal areas of Bohai Sea, North China

    International Nuclear Information System (INIS)

    Liu Wenxin; Chen Jianglin; Lin Xiumei; Fan Yongsheng; Tao Shu

    2007-01-01

    Studies of heavy metals and organic pollutants in different benthic mussel species from Bohai Sea show that concentrations of Cd in mussels commonly exceed national biological quality standards. In addition, a site located in Laizhou Bay exhibits higher average concentrations of As, Hg and Pb with respect to the other sites. Residual levels of petroleum hydrocarbons at several sites in Liaodong Bay also exceed quality guidelines. Contents and compositional characteristics of DDT and its metabolites in mussels suggest the probability of recent inputs and potential ecological risks to the local benthic environment. - Residual Cd contents of mussels at many sites in Bohai Sea exceed national marine biological quality standard and compositions of DDT metabolites indicate recent inputs and potential risk

  6. Arsenic speciation in shrimp and mussel from the Mid-Atlantic hydrothermal vents

    DEFF Research Database (Denmark)

    Larsen, Erik Huusfeldt; Quetel, C. R.; Munoz, R.

    1997-01-01

    Specimens of shrimp (Rimicaris exoculata) and mussel (Bathymodiolus puteoserpentis) were collected 3500 m below the ocean surface at the hydrothermal vents of the mid-Atlantic Ridge (TAG and Snake Pit sites, respectively). Arsenic, a potentially toxic element, is among the substances emitted...... by the hydrothermal vents. The hydrothermal vent shrimp, which are known to be a primary consumer of the primary producing chemolithoautotrophic bacteria, contained arsenic at 13 mu g g(-1) almost exclusively as arsenobetaine (AsB). Arsenic was present in the soft:issues of the mussel at 40 mu g g(-1) and the major...... of arsenic species found in the shrimp and mussel species in the deep-sea is similar to that found in their counterparts from the ocean surface. It is concluded that the autotrophic bacteria of the hydrothermal vent ecosystem and the symbiotic bacteria harboured in the mussel species are responsible...

  7. Growth of juvenile shrimp Metapenaeus monoceros fed with squid and mussel

    Digital Repository Service at National Institute of Oceanography (India)

    Achuthankutty, C.T.; Nair, S.R.S.; Krishnakumari, L.

    Small juveniles of both sexes and females of large juveniles of Metapenaeus monoceros attained faster growth with squid diet. Males of large juveniles registered better growth with mussel diet. No significant difference was observed in moult weights...

  8. Culinary preparation as a tool to decrease the radioactive contamination in mussels

    International Nuclear Information System (INIS)

    Arapis, G.; Gasco, C.; Romero, L.; Martinez, A.

    1992-01-01

    The radiation dose to man from the ingestion of contaminated foodstuffs may be lower after culinary preparation than one calculated from raw food. In this study, cesium and cobalt loss from blue mussels contaminated under laboratory conditions was investigated after culinary preparation processes with and without application of corrective measures. A reduction in Cs-137 was observed into drinkable cooking liquids when mussels were previously washed. Part of the Co-60 was eliminated when boiling was introduced. This elimination was greater when the first boiling water was replaced by the final cooking liquid. Culinary preparation could reduce the Cs-137 content in the eatable part of mussels by a factor of 3 to 6. Maximum reduction was obtained when corrective actions were applied. The reduction of Co-60 content in the body of mussels was lower and the corrective actions applied through the cooking processes did not have any significant influence. (author)

  9. Validated methodology for quantifying infestation levels of dreissenid mussels in environmental DNA (eDNA) samples.

    Science.gov (United States)

    Peñarrubia, Luis; Alcaraz, Carles; Vaate, Abraham Bij de; Sanz, Nuria; Pla, Carles; Vidal, Oriol; Viñas, Jordi

    2016-12-14

    The zebra mussel (Dreissena polymorpha Pallas, 1771) and the quagga mussel (D. rostriformis Deshayes, 1838) are successful invasive bivalves with substantial ecological and economic impacts in freshwater systems once they become established. Since their eradication is extremely difficult, their detection at an early stage is crucial to prevent spread. In this study, we optimized and validated a qPCR detection method based on the histone H2B gene to quantify combined infestation levels of zebra and quagga mussels in environmental DNA samples. Our results show specific dreissenid DNA present in filtered water samples for which microscopic diagnostic identification for larvae failed. Monitoring a large number of locations for invasive dreissenid species based on a highly specific environmental DNA qPCR assay may prove to be an essential tool for management and control plans focused on prevention of establishment of dreissenid mussels in new locations.

  10. Substratum type and conspecific density as drivers of mussel patch formation

    KAUST Repository

    Bertolini, Camilla; Geraldi, Nathan R.; Montgomery, W.I.; O'Connor, Nessa E.

    2017-01-01

    , their aggregation rate appeared to be greater when mussel density was higher, suggesting that the encounter rate of individuals is an important factor for aggregation. M. modiolus also formed aggregations with a higher fractal dimension in the high and medium

  11. DNA damage in male gonad cells of Green mussel (Perna viridis) upon exposure to tobacco products

    Digital Repository Service at National Institute of Oceanography (India)

    Nagarajappa; Ganguly, A.; Goswami, U.

    DNA damage (determined by the Comet Assay) and the occurrence of deformed nuclei were measured as endpoints of genotoxicity in male gonad cells of the marine mussel (Perna viridis). Upon exposure of the organism to varying concentrations...

  12. A serine protease inhibitor from hemolymph of green mussel, Perna viridis

    Digital Repository Service at National Institute of Oceanography (India)

    Khan, M.S.; Goswami, U.; Rojatkar, S.R.; Khan, M.I.

    Bioactivity guided fractions of cell-free hemolymph of bacterially challenged marine mussel, Perna viridis led to the isolation of a novel quaternary alkaloid 1, which was identified by its spectral data. The isolated molecule 1 has been found...

  13. A Survey of the Freshwater Mussel Fauna of the Little Kanawha River Basin,

    Science.gov (United States)

    Mussels, * Aquatic biology, Surveys, Rivers, Basins(Geographic), Natural resources, Population, Distribution, Sampling, Environmental impact...Chemical analysis, Pesticides, Metals, Water quality, Waste water , Waste management, Decision making, West Virginia, Fresh water , Workshops

  14. Methallothionein expression on the gills and stomach of Chinese pond mussels exposed to lead (Pb)

    Science.gov (United States)

    Kartikaningsih, H.; Suryanto, A. M.; Arfiati, D.

    2018-04-01

    In freshwaters area, Pb originates from rocks (naturally), industries, and pesticides. The ability of Chinese pond mussels as biofilters to absorb heavy metal (Pb) was demonstrated in water circulation system using ten 8 cm mussels. PbNO3 (0, 10, 20, and 30 ppm) was administered into water containing mussels. Carp culture was done for 30 days, and Pb accumulation in carps was measured every week (week 0, 1, 2, and 3). The results showed that the highest Pb ion accumulation was found in the gills of mussels. The examination using hematoxylin-eosin showed that tissues were damage due to haemorrhage, cell ruptures, and cell deaths. The results of the measurement of metallothionein (MT) showed that MT molecular weight was 12.84 kDa.

  15. The effect of UV-C exposure on larval survival of the dreissenid quagga mussel

    Science.gov (United States)

    Stewart-Malone, Alecia; Misamore, Michael; Wilmoth, Siri K.; Reyes, Alejandro; Wong, Wai Hing; Gross, Jackson

    2015-01-01

    The rapid spread of quagga mussels (Dreissena rostriformis bugensis) has lead to their invasion of Lake Mead, Nevada, the largest reservoir in North America and partially responsible for providing water to millions of people in the southwest. Current strategies for mitigating the growth and spread of quagga mussels primarily include physical and chemical means of removing adults within water treatment, delivery, and hydropower facilities. In the present study, germicidal ultraviolet light (UV-C) was used to target the larval stage of wild-caught quagga mussel. The lethal effect of UV-C was evaluated at four different doses, 0.0, 13.1, 26.2, and 79.6 mJ/cm2. Tested doses were determined based on results from preliminary trials. The results demonstrate that germicidal UV-C is effective in controlling the free-swimming life history stages of larval quagga mussels.

  16. The Effect of UV-C Exposure on Larval Survival of the Dreissenid Quagga Mussel.

    Science.gov (United States)

    Stewart-Malone, Alecia; Misamore, Michael; Wilmoth, Siri; Reyes, Alejandro; Wong, Wai Hing; Gross, Jackson

    2015-01-01

    The rapid spread of quagga mussels (Dreissena rostriformis bugensis) has lead to their invasion of Lake Mead, Nevada, the largest reservoir in North America and partially responsible for providing water to millions of people in the southwest. Current strategies for mitigating the growth and spread of quagga mussels primarily include physical and chemical means of removing adults within water treatment, delivery, and hydropower facilities. In the present study, germicidal ultraviolet light (UV-C) was used to target the larval stage of wild-caught quagga mussel. The lethal effect of UV-C was evaluated at four different doses, 0.0, 13.1, 26.2, and 79.6 mJ/cm2. Tested doses were determined based on results from preliminary trials. The results demonstrate that germicidal UV-C is effective in controlling the free-swimming life history stages of larval quagga mussels.

  17. The Effect of UV-C Exposure on Larval Survival of the Dreissenid Quagga Mussel.

    Directory of Open Access Journals (Sweden)

    Alecia Stewart-Malone

    Full Text Available The rapid spread of quagga mussels (Dreissena rostriformis bugensis has lead to their invasion of Lake Mead, Nevada, the largest reservoir in North America and partially responsible for providing water to millions of people in the southwest. Current strategies for mitigating the growth and spread of quagga mussels primarily include physical and chemical means of removing adults within water treatment, delivery, and hydropower facilities. In the present study, germicidal ultraviolet light (UV-C was used to target the larval stage of wild-caught quagga mussel. The lethal effect of UV-C was evaluated at four different doses, 0.0, 13.1, 26.2, and 79.6 mJ/cm2. Tested doses were determined based on results from preliminary trials. The results demonstrate that germicidal UV-C is effective in controlling the free-swimming life history stages of larval quagga mussels.

  18. Polycyclic aromatic hydrocarbons in sediments and mussels of Corral Bay, south central Chile.

    Science.gov (United States)

    Palma-Fleming, Hernan; P, Adalberto J Asencio; Gutierrez, Elena

    2004-03-01

    PAHs were measured in sediments and mussels (Mytilus chilensis) from Carboneros and Puerto Claro, located in Corral Bay, Valdivia. According to the ratio of phenanthrene/anthracene and fluoranthene/pyrene concentrations, these sites are medium polluted with PAHs originating mainly from pyrolytic sources. Fluoranthene was the major component measured in mussels (3.1-390 ng g(-1) dry weight) and sediments (6.9-74.1 ng g(-1) dry weight). In general, mussels were mainly exposed to the dissolved fraction of the lower molecular weight PAHs (tri- and tetra-aromatics) while the higher molecular ring systems (penta- and hexa-aromatics) were more bioavailable to sediments. Mussel PAHs content was relatively constant, with the exception of the 1999 summer season (March), when higher concentration values were found in both sites; however, PAHs residues in sediments showed a temporal variation.

  19. Growth of the green mussel, Perna viridis L., in a sea water circulating system

    Digital Repository Service at National Institute of Oceanography (India)

    Chatterji, A.; Ansari, Z.A.; Ingole, B.S.; Parulekar, A.H.

    Growth of the green mussel, P. viridis L., was studied in a sea water circulating system for 12 months. The maximum growth rate was recorded during March - May, coinciding with the maximum abundance of phytoplankton. The other hydrological...

  20. Control of modiolid mussels in cooling water systems by continuous chlorination.

    NARCIS (Netherlands)

    Rajagopal, S.; Venugopalan, V.P.; Velde, G. van der; Jenner, H.A.

    2006-01-01

    Abstract. Modiolid mussels such as Modiolus philippinarum and Modiolus metcalfei constitute a numerically significant group in fouling communities, especially in tropical and subtropical industrial cooling water systems. Nevertheless, there are hardly any published reports on the tolerance of these