Sample records for sardinops sagax jenyns

  1. Anchovy Engraulis capensis and sardine Sardinops sagax currently ...

    African Journals Online (AJOL)


    within-season variability in factors affecting sardine Sardinops sagax and anchovy Engraulis capensis recruitment. .... variogram. ... formerly SF, unpublished data) were based on length ..... the front offshore, along with many eggs and larvae.

  2. Worldwide, where anchovies Engraulis spp. and sardine Sardinops ...

    African Journals Online (AJOL)


    sardine Sardinops sagax co-occur, the two species alternate in ... the west coasts of South America and southern Africa, ... of extinction in the wild within 100 years (Croxall et al. 1996) ..... able to penguins year-round, compared to the seasonal.

  3. Dinámica poblacional de la sardina del pacifico Sardinops sagax (Jenyns 1842) (clupeiformes: clupeidae), en la costa oeste de la península de Baja California y el sur de California


    Félix Uraga, Roberto


    Tres stocks de sardina del Pacífico fueron identificados utilizando datos mensuales de captura y temperatura superficial del mar de Bahía Magdalena, Isla Cedros y Ensenada en México, y San Pedro en EUA. Un stock parece estar adaptado a temperaturas mayores de 22 ºC (stock cálido), otro a temperaturas entre 17-22 ºC (stock templado) y el tercero a temperaturas menores de 17 ºC (stock frío). Se elaboró un modelo conceptual para describir la distribución espacio temporal de est...

  4. Traditionally, sardine Sardinops sagax has been the backbone of ...

    African Journals Online (AJOL)


    Grant Program, San Diego, California, USA, in cooperation with Centro de Investigaciones ... maturity of Baltic cod (Gadus morhua) during a period of large variations in stock .... Trudy– AtlantNIRO 73: 77–85 (in Russian). ROCHET, M. J. 1998 ...

  5. Although South African sardine (or pilchard, Sardinops sagax) were ...

    African Journals Online (AJOL)


    (iii) as anchovy and sardine frequently shoal together during their first ... Fishery Resources Division, Food and Agricultural Organization, Via delle Terme di Caracalla 00100, Rome, Italy. ...... risk and “scope for growth” as performance criteria.

  6. Anchovy Engraulis capensis, sardine Sardinops sagax and round ...

    African Journals Online (AJOL)


    all years in the recruitment time-series from 1985 to. 1994. ... Forecasts of anchovy recruitment from multiple cruises may produce a different result from the forecast ... abundance, phyto- and zooplankton biomass, copepod ...... estuarine lake.

  7. The southern African sardine Sardinops sagax (also known as ...

    African Journals Online (AJOL)


    mental factors that affect stock dynamics primarily through recruitment, and .... school-groups contributed an increasing proportion ..... of a recovery in the stock in the early 1990s were not ..... must strive to promote a healthy spawning stock,.

  8. The southern African sardine Sardinops sagax supports major purse ...

    African Journals Online (AJOL)


    Echo-Integrator post-processing system (Foote et al. 1991). ... noise-reduction filters at weak, and with frequency ..... approach based on acoustic image simulation. Aquat. ... GERLOTTO, F., SORIA, M. and P. FRÉON 1999 — From 2D to.

  9. 2012 Joint U.S.-Canada Integrated Acoustic and Trawl Survey of Pacific Hake (Merluccius productus) and Pacific Sardine (Sardinops sagax) (SH1204, EK60) (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Scientists from the Fishery Resource Analysis and Monitoring (FRAM) division at the NOAA Fisheries Northwest Fisheries Science Center (NWFSC), the Fishery Resources...

  10. The 2012 Joint U.S.-Canada Integrated Acoustic and Trawl Survey of Pacific Hake (Merluccius productus) and Pacific Sardine (Sardinops sagax) (SH1204, ME70) (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Scientists from the Fishery Resource Analysis and Monitoring (FRAM) division at the NOAA Fisheries Northwest Fisheries Science Center (NWFSC), the Fishery Resources...

  11. Characteristics of infection of Diplectanum sp. (Monogenea: Monopisthocolytea: Diplectanidae in Cynoscion analis Jenyns (Pisces: teleostei: Scianidae

    Directory of Open Access Journals (Sweden)

    José Iannacone


    Full Text Available 120 Cynoscion analis Jenyns were collected from Chorrillos fishmarket, Lima, Perú, between January and February 2000 and necropsied to study ectoparasite monogenean Diplectanum sp. from branchial filaments. This parasite was considered a core specie, because it parasites 2/3 hosts examined. Of the fishes collected 80 were female and 40 male. Females and males showed a standard length between 16,4-27,0 cm (mean = 21,08 ± 2,24 and 16,5-26,3 cm (mean = 20,47 ± 2,06, respectively. The prevalence of infection of Diplectanurn was 72,5%, mean intensity and abundance were 3,16 ± 2,84 and 2,29 ± 2,80 respectively. This monogenean showed an overclispersal spatial distribution (2,55 at level of fish hosts. We observed a correlation between mean intensity of infestation and standard length of C. analis. Males (4,14 ± 3,75 showed a higher mean intensity than females (2,67 ± 2,14. A high prevalence, intensity and abundance of Diplectanum to 11 gill was found. However, we did not find neither preference when we separated each gill in three parts (fore, middle and hind respectively. Finally, we compared our results of population assemblages of other ectoparasite monogeneans in marine fishes. Diplectanurn sp. is a new record to C. analis and to Peru.

  12. Constant harvest rate for the Pacific sardine (Sardinops caeruleus) fishery in the Gulf of California based on catchability-at-length estimations



    Constant harvest rate as a management strategy for the Pacific sardine (Sardinops caeruleus) fishery in the Gulf of California is supported by an analysis of variations in the catchability coefficient (q), stock abundance and commercial catch. Catchability was analyzed based on population length-structured data standard length (SL), expressed as CPUE, for 26 fishing seasons (1972-1973 to 1997-1998). We used a deterministic model of catchability to estimate the catchability-at-length assuming ...

  13. Stomach Chitinase from Japanese Sardine Sardinops melanostictus: Purification, Characterization, and Molecular Cloning of Chitinase Isozymes with a Long Linker. (United States)

    Kawashima, Satoshi; Ikehata, Hiroki; Tada, Chihiro; Ogino, Tomohiro; Kakizaki, Hiromi; Ikeda, Mana; Fukushima, Hideto; Matsumiya, Masahiro


    Fish express two different chitinases, acidic fish chitinase-1 (AFCase-1) and acidic fish chitinase-2 (AFCase-2), in the stomach. AFCase-1 and AFCase-2 have different degradation patterns, as fish efficiently degrade chitin ingested as food. For a comparison with the enzymatic properties and the primary structures of chitinase isozymes obtained previously from the stomach of demersal fish, in this study, we purified chitinase isozymes from the stomach of Japanese sardine Sardinops melanostictus, a surface fish that feeds on plankton, characterized the properties of these isozymes, and cloned the cDNAs encoding chitinases. We also predicted 3D structure models using the primary structures of S. melanostictus stomach chitinases. Two chitinase isozymes, SmeChiA (45 kDa) and SmeChiB (56 kDa), were purified from the stomach of S. melanostictus. Moreover, two cDNAs, SmeChi-1 encoding SmeChiA, and SmeChi-2 encoding SmeChiB were cloned. The linker regions of the deduced amino acid sequences of SmeChi-1 and SmeChi-2 (SmeChi-1 and SmeChi-2) are the longest among the fish stomach chitinases. In the cleavage pattern groups toward short substrates and the phylogenetic tree analysis, SmeChi-1 and SmeChi-2 were classified into AFCase-1 and AFCase-2, respectively. SmeChi-1 and SmeChi-2 had catalytic domains that consisted of a TIM-barrel (β/α)₈-fold structure and a deep substrate-binding cleft. This is the first study showing the 3D structure models of fish stomach chitinases.

  14. Variação geográfica em Corydoras paleatus (Jenyns (Siluriformes, Callichthyidae do sul do Brasil Geographic variation in Corydoras paleatus (Jenyns (Siluriformes, Callichthyidae from southern Brazil

    Directory of Open Access Journals (Sweden)

    Oscar A. Shibatta


    Full Text Available A espécie Corydoras paleatus (Jenyns, 1842 está amplamente distribuída na região Sul do Brasil, ocorrendo desde o Rio Grande do Sul até o norte do Paraná. Estudos populacionais nessa espécie são considerados importantes devido à sua distribuição em uma região com forte interferência ambiental humana e pelo interesse comercial, uma vez que é vendida como peixe ornamental. Dezesseis caracteres morfométricos e seis caracteres merísticos foram utilizados para avaliação morfológica das populações das bacias dos rios Tibagi e Iguaçu (Paraná e Lagoa dos Quadros (Rio Grande do Sul. Apesar do número de placas laterais ser mais variável nos exemplares do rio Iguaçu, a sobreposição das contagens tanto das placas quanto dos raios das nadadeiras não permitiu a discriminação segura das populações. Entretanto, foi observado com a análise dos componentes principais, que essas podem ser diferenciadas pelo crescimento alométrico dos caracteres morfométricos. Além disso, a amostra do rio Iguaçu ficou discriminada morfometricamente do rio Tibagi e Lagoa dos Quadros no primeiro eixo canônico, enquanto estas ficaram separadas no segundo eixo. A variação intraespecífica, observada nessa espécie, evidencia que análises morfométricas populacionais podem ser úteis na análise da diversidade biológica de determinada região. As diferenças morfométricas, aliadas ao isolamento geográfico, são indícios de que essas populações estão sujeitas a diferentes processos seletivos.The species Corydoras paleatus (Jenyns, 1842 is widely distributed in Southern Brazil, occurring from Rio Grande do Sul to the north of Paraná State. Studies related to this species populations are considered important once this fish is distributed in a region with great anthropogenic interference and also because its economic importance, given that this species is commercialised as ornamental fish. In the present study sixteen morphometric characters

  15. Bases biológicas para el cultivo del puye Galaxias maculatus (Jenyns, 1842: una revisión

    Directory of Open Access Journals (Sweden)

    Rolando Vega


    Full Text Available Galaxias maculatus (Jenyns, 1842 es un pez gourmet de importancia comercial cuyas pesquerías están sobre-explotadas, siendo esencial el estudio de su biología para desarrollar su tecnología de cultivo (galaxicultura, que se encuentra en etapa piloto. Los objetivos de éste trabajo son: 1 entregar una síntesis de la información de la literatura sobre la biología de la especie, y 2 identificar la carencia de conocimiento científico y puntos críticos para el desarrollo de su tecnología de cultivo comercial. G. maculatus es un pequeño pez carnívoro, con poblaciones eurihalinas diferenciadas en diadrómicas y dulceacuícolas. Las poblaciones diadrómicas desovan en los estuarios y la larva migra al mar, retornando a la edad de seis meses para metamorfosearse en adulto. Son escasos los estudios de su sistemática, poblaciones y estado larvario en aguas chilenas, pero los correspondientes a alimentación, reproducción y enfermedades son más numerosos. Las hembras de un año desovan, aproximadamente, 1.200 huevos adhesivos pero un número importante muere después del primer desove (40%. La especie tiene un crecimiento rápido (1,1% dia-1 y alto metabolismo, con un promedio de vida de dos años. Se puede cultivar en cautividad, desovar, incubar sus huevos y obtener larvas; los adultos comen starter pelletizado de salmón y crecen en estanques. El protozoo ciliado Ichtyophthirius multifilis (ich produce altas mortalidades, en ejemplares en cautiverio, que pueden ser controladas con baños de sal. Los problemas de investigación a resolver para una futura piscicultura comercial son: identificar y seleccionar las poblaciones adecuadas para cultivo, aumentar el número de huevos desovados por hembra, desarrollar alimentos para larvas y reproductores, y controlar las enfermedades ectoparasitarias. El punto crítico es la masificación de la producción mediante el mejoramiento de las técnicas de reproducción y larvicultura.

  16. Single-cell gel electrophoresis assay in the ten spotted live-bearer fish, Cnesterodon decemmaculatus (Jenyns, 1842), as bioassay for agrochemical-induced genotoxicity. (United States)

    Vera-Candioti, Josefina; Soloneski, Sonia; Larramendy, Marcelo L


    The ability of two 48 percent chlorpyrifos-based insecticides (Lorsban* 48E® and CPF Zamba®), two 50 percent pirimicarb-based insecticides (Aficida® and Patton Flow®), and two 48 percent glyphosate-based herbicides (Panzer® and Credit®) to induce DNA single-strand breaks in peripheral blood erythrocytes of Cnesterodon decemmaculatus (Jenyns, 1842) (Pisces, Poeciliidae) exposed under laboratory conditions was evaluated by the single-cell gel electrophoresis (SCGE) assay. In those fish exposed to Lorsban* 48E®, CPF Zamba®, Aficida®, Patton Flow®, Credit®, and Panzer®, a significant increase of the genetic damage was observed for all formulations regardless of the harvesting time. This genotoxic effect was achieved by an enhancement of Type II-IV comets and a concomitant decrease of Type 0-I comets over control values. A regression analysis revealed that the damage varied as a negative function of the exposure time in those Lorsban* 48E®- and Aficida®-treated fish. On the other hand, a positive correlation between damage increase and exposure time was achieved after Patton Flow® and Credit® treatment. Finally, no correlation was observed between increase in the genetic damage and exposure time after treatment with CPF Zamba® or Panzer®. These results highlight that all agrochemicals inflict primary genotoxic damage at the DNA level at sublethal concentrations, regardless of the exposure time of the aquatic organisms under study, at least within a period of 96 h of treatment.

  17. La dieta y fauna de endoparásitos del pejesapo Gobiesox marmoratus Jenyns, 1842 (Pisces: Gobiesocidae en el litoral central de Chile están conectadas pero no correlacionadas Feeding habits and endoparasite fauna of the clingfish Gobiesox marmoratus Jenyns, 1842 (Pisces: Gobiesocidae on the central coast of Chile are intertwined, but not correlated

    Directory of Open Access Journals (Sweden)

    M. Cecilia Pardo-Gandarillas


    Full Text Available Se documenta una alta similitud en la composición de la fauna parasitaria y de la dieta de 108 ejemplares del pejesapo Gobiesox marmoratus Jenyns, 1842 recolectados de la costa de la zona centro-sur de Chile, desde tres localidades separadas por al menos 400 km de su(s vecina(s. La longitud total de los pejesapos fue similar entre localidades y su parasitofauna estuvo compuesta por 16 taxa de metazoos (incluyendo cinco Myxozoa. En el 38,8 % de los 108 pejesapos se encontraron parásitos, en tanto que en el 32,4 % de los mismos ejemplares había contenido estomacal, en los que se determinaron 37 ítems presa. La aún más baja ocurrencia conjunta de parásitos y presas imposibilitó el uso de parejas de datos parasitarios y dietarios, para evaluar, por ejemplo, si había correlación entre la amplitud dietaria y la riqueza parasitaria. Aunque la composición de la fauna de endoparásitos necesariamente depende de la composición de la dieta de los pejesapos, encontramos muy pocos parásitos en uno de los sitios de estudio. Es decir, las propiedades numéricas de este sistema hospedador-parásito limitaron la posibilidad de hallar asociaciones entre ambos tipos de variables. Tanto la composición de la dieta como de las infracomunidades de parásitos variaban con la ontogenia del huésped. La dieta de los pejesapos juveniles y adultos consistía principalmente de anfípodos, crustáceos decápodos y moluscos en las tres localidades. La similitud de los descriptores numéricos de la dieta y de las infracomunidades (abundancia total, diversidad y riqueza entre las localidades, en parte puede deberse al escaso tamaño corporal máximo alcanzado por G. marmoratus, a la escasa longitud total del tracto digestivo, a las diferencias en las tasas de ingreso y tiempo de residencia de parásitos y presas, al nivel de resolución taxonómica alcanzado en presas y/o parásitos, y al efecto de decidir excluir o no de los análisis a las especies rarasA high

  18. A fuzzy-logic tool for multi-criteria decision making in fisheries: the case of the South African pelagic fishery

    DEFF Research Database (Denmark)

    Paterson, B.; Jarre, Astrid; Moloney, C.L.


    The present study presents an electronic decision-support tool that uses a fuzzy-logic model of expert knowledge to assist in multi-criteria decision-making in the context of an Ecosystem Approach to Fisheries (EAF). The prototype model integrates the multiple goals and objectives related...... to the evaluation of the ecosystem performance of the South African sardine Sardinops sagax fishery into a NetWeaver knowledge base and provides intuitive visual outputs to communicate results to managers and stakeholders. The software tool was developed in a consultative process with key experts and follows...... on expert opinion. Results show that the model is robust and conservative. The strength of the approach lies in the ability to include variables that are difficult to measure. It provides a means of rendering value judgements explicit and transparent. The tool synthesises a large amount of information...

  19. Isolation Driven Divergence in Osmoregulation in Galaxias maculatus (Jenyns, 1848 (Actinopterygii: Osmeriformes.

    Directory of Open Access Journals (Sweden)

    Ignacio Ruiz-Jarabo

    Full Text Available Marine species have colonized extreme environments during evolution such as freshwater habitats. The amphidromous teleost fish, Galaxias maculatus is found mainly migrating between estuaries and rivers, but some landlocked populations have been described in lakes formed during the last deglaciation process in the Andes. In the present study we use mtDNA sequences to reconstruct the historical scenario of colonization of such a lake and evaluated the osmoregulatory shift associated to changes in habitat and life cycle between amphidromous and landlocked populations.Standard diversity indices including the average number of nucleotide differences (Π and the haplotype diversity index (H indicated that both populations were, as expected, genetically distinctive, being the landlocked population less diverse than the diadromous one. Similarly, pairwise GST and NST comparison detected statistically significant differences between both populations, while genealogy of haplotypes evidenced a recent founder effect from the diadromous stock, followed by an expansion process in the lake. To test for physiological differences, individuals of both populations were challenged with a range of salinities from 0 to 30 ppt for 8 days following a period of progressive acclimation. The results showed that the landlocked population had a surprisingly wider tolerance to salinity, as landlocked fish survival was 100% from 0 to 20 ppt, whereas diadromous fish survival was 100% only from 10 to 15 ppt. The activity of ATPase enzymes, including Na+/K+-ATPase (NKA, and H+-ATPase (HA was measured in gills and intestine. Activity differences were detected between the populations at the lowest salinities, including differences in ATPases other than NKA and HA. Population differences in mortality are not reflected in enzyme activity differences, suggesting divergence in other processes.These results clearly demonstrate the striking adaptive changes of G. maculatus osmoregulatory system, especially at hyposmotic environments, associated to a drastic shift in habitat and life cycle at a scale of a few thousand years.

  20. Phylogeography in Galaxias maculatus (Jenyns, 1848) along Two Biogeographical Provinces in the Chilean Coast (United States)

    González-Wevar, Claudio A.; Salinas, Pilar; Hüne, Mathias; Segovia, Nicolás I.; Vargas-Chacoff, Luis; Astorga, Marcela; Cañete, Juan I.; Poulin, Elie


    Major geologic and climatic changes during the Quaternary exerted a major role in shaping past and contemporary distribution of genetic diversity and structure of aquatic organisms in southern South America. In fact, the northern glacial limit along the Pacific coast, an area of major environmental changes in terms of topography, currents, and water salinity, represents a major biogeographic transition for marine and freshwater species. We used mitochondrial DNA sequences (D-loop) to investigate the consequences of Quaternary glacial cycles over the pattern of genetic diversity and structure of G. maculatus (Pisces: Galaxiidae) along two biogeographical provinces in the Chilean coast. Extreme levels of genetic diversity and strong phylogeographic structure characterize the species suggesting a low amount of influence of the last glacial cycle over its demography. However, we recognized contrasting patterns of genetic diversity and structure between main biogeographical areas here analyzed. Along the Intermediate Area (38°–41° S) each estuarine population constitutes a different unit. In contrast, Magellanic populations (43°–53° S) exhibited low levels of genetic differentiation. Contrasting patterns of genetic diversity and structure recorded in the species between the analyzed biogeographic areas are consistent with the marked differences in abiotic factors (i.e., different coastal configurations, Quaternary glacial histories, and oceanographic regimes) and to inherent characteristics of the species (i.e., salt-tolerance, physiology, and reproductive behavior). PMID:26161896

  1. Efecto de la salinidad en la supervivencia embrionaria de puye Galaxias maculatus (Jenyns, 1842

    Directory of Open Access Journals (Sweden)

    Juan Barile


    Full Text Available Se evaluó e l efecto de la salinidad en la supervivencia embrionaria, período embrionario y período de eclosión de puye, Galaxias maculatus. Se utilizaron ocho tratamientos, con salinidades de 0, 4, 8, 12, 16 y 20 obteniéndose supervivencias embrionarias promedios respectivas de 84,9; 84,0; 85,5; 86,1; 82,6 y 75,8%, sin diferencias significativas entre ellas, mientras que con salinidad de 24 se obtuvo sobrevivencia de 10,4%, significativamente diferente al resto de los tratamientos y con salinidad de 28 causó 100% de mortalidad. A diferencia del estado juvenil y adulto, el embrión es incapaz de resistir la salinidad marina y su umbral de tolerancia se encuentra entre salinidades de 24 y 28. Las mayores supervivencias promedios larvales a 10 días de vida fueron con salinidades intermedias de 8, 12 y 16 de 79,3; 80,3 y 74,6% respectivamente, sin diferencias significativas entre ellas, demostrando alta viabilidad del embrión post-eclosión. Los períodos embrionarios promedios (50% más breves fueron a bajas salinidades 0, 4, 8, 12 con 28,7; 28,0; 29,7 y 29,7 días y los más extensos en los tratamientos con salinidades de 16 y 20, con 34,0 y 34,3 días, sin diferencias significativas entre ellos. Los períodos de eclosión promedio (50% con salinidades de 0, 4, 8, 12, 16, 20 y 24 fueron de 5,0; 5,5; 7,5; 8,8; 13,0; 14,3 y 15,8 días respectivamente, sin diferencias significativas entre ellos.

  2. Habitat use by Astyanax taeniatus (Jenyns, 1842 (Characiformes: Characidae in a coastal stream from Southeast Brazil

    Directory of Open Access Journals (Sweden)

    Luisa Resende Manna

    Full Text Available The habitat use of a stream-dwelling Astyanax taeniatus from the State of Rio de Janeiro was investigated. We performed 12 h of underwater observation in a 200 m long stretch in the upper Roncador stream and quantified the following microhabitat descriptors: (i water velocity, (ii distance from the stream bank, (iii substratum, and (iv water column depth. Microhabitat selectivity was analyzed by comparing the microhabitat used by fish and the microhabitat available in the study site as well as by applying the Ivlev Electivity Index to the microhabitat use data. Differences in the use and availability of the various microhabitats revealed non-stochastic patterns of spatial occupation by A. taeniatus, which was selective for two of the four analyzed microhabitats. Our findings indicated that A. taeniatusis associated with habitats that have higher depths, low water velocity, and sand and bedrock substratum.

  3. Occurrence of intersexuality in " Lambaris" , Astyanax scabripinnis (Jenyns, 1842, small characids from the Brazilian streams

    Directory of Open Access Journals (Sweden)

    Maria de Fátima Pereira de Sá


    Full Text Available During studies carried out with a small characid (Astyanax scabripinnis, from the Brazilian streams located in Cerrado biome, some gonads of fishes exhibited sparse oocytes in perinucleolar stage embedded in normally developing testicular tissues. Another pattern of gonad intersex with vitellogenic oocytes and mature lobules was observed in the gonads of fishes collected from a reservoir supplied by the Atlantic Forest stream. These gonads in different stages of maturation were examined histologically. The results revealed the patterns occurring in fishes of the same species, from four different populations.Durante estudos efetuados com pequenos caracídeos (Astyanax scabripinnis de riachos do Cerrado brasileiro, localizados nos Estados de Minas Gerais e de São Paulo, foram encontrados alguns peixes com gônadas exibindo oócitos em estágio perinucleolar dispersos, embebidos em tecidos testiculares em desenvolvimento. Em exemplares da mesma espécie, provenientes de um riacho situado na Mata Atlântica do Estado de São Paulo, outro padrão de gônadas intersexuadas foi registrado, mostrando oócitos vitelogênicos e lóbulos maduros presentes na mesma gônada. As gônadas em diferentes estágios de maturação foram submetidas a análises histológicas. Os resultados obtidos mostram os padrões morfológicos e as freqüências de ocorrência dos intersexos encontrados em peixes do " complexo" A. scabripinnis provenientes de quatro diferentes populações. São discutidas as prováveis causas ambientais responsáveis por estas alterações.

  4. Effect of UV radiation on the genetic inactivation of sperm of the bullseye puffer Sphoeroides annulatus (Jenyns, 1842); Efecto de la radiacion UV en la inactivacion genetica del esperma de botete diana Sphoeroides annulatus (Jenyns, 1842)

    Energy Technology Data Exchange (ETDEWEB)

    Arias-Rodriguez, Lenin; Rodriguez-Ibarra, Luz Estela; Del Valle-Pignataro, Gabriela [Laboratorio de Genetica, Centro de Investigacion en Alimentacion y Desarrollo, A. C., Sinaloa (Mexico)


    Genetic (DNA) inactivation of fish sperm with ultraviolet irradiation is generally accompanied by a paradoxical effect on survival rates (Hertwig effect). In the present study, sperm samples from ten males bullseye puffer fish (Sphoeroides annulatus) were diluted 1:50 using Cortland's extender solution and used to test the effect of nine ultraviolet doses (0.2-1.0 J cm{sup -}2 ) on motility time in seconds, motility index, and embryo survival rate after fertilizing eggs from five bullseye puffer females. Motility time of sperm irradiated with 0.2-0.9 J cm{sup -}2 were not statistically different from the controls, but sperm irradiated with a dosage of 1.0 J cm{sup -}2 dosage had significant lower motility time. Motility indices (MI) allowed for the statistical differentiation of four groups in relation to their response to different radiation doses: the first had high MI, and included the controls and 0.2-0.3 J cm{sup -}2 treatments; the second had lower MI and included the 0.4-0.7 J cm{sup -}2 treatments; the third showed recovery of MI and included the 0.8-0.9 J cm{sup -}2 treatments; and the fourth showed the lowest MI with the 1.0 J cm{sup -}2 treatment. Embryo survival was highest for the controls and 0.2 J cm{sup -}2 treatment, decreasing in the 0.3-0.4 J cm{sup -}2 treatments, increasing again in the 0.5-0.8 J cm{sup -}2 treatments, until reaching lowest survival in the 0.9-1.0 J cm{sup -}2 treatments. These results indicate that the best ultraviolet dosage to achieve genetic inactivation of sperm of this species is close to 0.7 J cm{sup -}2, a dosage in which fish fry showed typical haploid syndrome characteristics. [Spanish] La inactivacion genetica (ADN) del esperma de peces se realiza mediante luz ultravioleta que, en irradiaciones crecientes, genera efectos paradojicos (efecto Hertwig) en los porcentajes de supervivencia. En este trabajo se diluyeron muestras de semen provenientes de diez machos de botete diana (Sphoeroides annulatus) en solucion extendedora Cortland modificada en dilucion 1:50, y se utilizaron para probar el efecto de nueve dosis de radiacion ultravioleta (0.2-1.0 J cm{sup -}2 ) sobre la duracion de la motilidad en segundos, el indice de motilidad del esperma, y los porcentajes de superviviencia de embriones obtenidos de la fertilizacion de huevos provenientes de cinco hembras de la misma especie. Los tiempos de motilidad del esperma en las muestras irradiadas con 0.2-0.9 J cm{sup -}2 resultaron estadisticamente no diferentes de los controles, mientras que las muestras irradiadas con 1.0 J cm{sup -}2 fueron significativamente menores. El indice de motilidad (IM), por otra parte, permitio la diferenciacion estadistica de cuatro grupos en cuanto a su respuesta a diferentes dosis de radiacion. El primer grupo se caracterizo por valores altos del IM, e incluyo a los controles y a las muestras irradiadas con 0.2-0.3 J cm{sup -}2; el segundo agrupo a las irradiaciones de 0.4 a 0.7 J cm{sup -}2, en las cuales se observo un descenso del IM; en el tercer grupo (0.8-0.9 J cm{sup -}2 ) el IM aumento nuevamente; y en el ultimo (1.0 J cm{sup -}2) se observo el menor IM. En cuanto a los porcentajes de supervivencia, se observo una curva descendente con valores altos de supervivencia en los controles y en las muestras irradiadas con 0.2 J cm{sup -}2, con un descenso en los tratamientos de 0.3 a 0.4 J cm{sup -}2, y una recuperacion significativa a partir del tratamiento de 0.5 y hasta 0.8 J cm{sup -}2, observandose nuevamente un decremento en la supervivencia de los tratamientos de 0.9 a 1.0 J cm{sup -}2 . Ambos resultados, IM y supervivencia, indican que la dosis optima para la produccion de organismos haploides se encuentra cercana a 0.7 J cm{sup -}2. En el tratamiento de 0.7 J cm{sup -}2 se observaron larvas con las caracteristicas tipicas del sindrome haploide, indicando nuevamente que esta puede ser la dosis mas adecuada para producir organismos ginogeneticos.

  5. An Empty Donut Hole: the Great Collapse of a North American Fishery

    Directory of Open Access Journals (Sweden)

    Kevin M. Bailey


    Full Text Available Walleye pollock (Theragra chalcogramma is North America's most abundant and lucrative natural fishery, and is the world's largest fishery for human food. The little-known demise of the "Donut Hole" stock of pollock in the Aleutian Basin of the central Bering Sea during the 1980s is the most spectacular fishery collapse in North American history, dwarfing the famous crashes of the northern cod and Pacific sardine (Sardinops sagax. This collapse has received scant recognition and became evident only in 1993 when fishing was banned by an international moratorium; nearly 20 years later it has not recovered. The history of fishing in the North Pacific Ocean after World War II offers some insights into how the Donut Hole pollock fishery developed, and the societal and economic pressures behind it that so influenced the stock's fate. Overfishing was, without a doubt, the greatest contributor to the collapse of the Aleutian Basin pollock fishery, but a lack of knowledge about population biocomplexity added to the confusion of how to best manage the harvest. Unfortunately, the big scientific questions regarding the relationship of Donut Hole fish to other stocks are still unanswered.

  6. Fish larvae retention linked to abrupt bathymetry at Mejillones Bay (northern Chile during coastal upwelling events

    Directory of Open Access Journals (Sweden)

    Pablo M Rojas


    Full Text Available The influence of oceanic circulation and bathymetry on the fish larvae retention inside Mejillones Bay, northern Chile, was examined. Fish larvae were collected during two coastal upwelling events in November 1999 and January 2000. An elevated fish larvae accumulation was found near an oceanic front and a zone of low-speed currents. Three groups of fish larvae were identified: the coastal species (Engraulis ringens and Sardinops sagax, associated with high chlorophyll-a levels; larvae from the families Phosichthyidae (Vinciguerria lucetia and Myctophidae (Diogenichthys laternatus and Triphoturus oculeus, associated with the thermocline (12°C, and finally, larvae of the families Myctophidae (Diogenichthys atlanticus and Bathylagidae (Bathylagus nigrigenys, associated with high values of temperature and salinity. The presence of a seamount and submarine canyon inside Mejillones Bay appears to play an important role in the circulation during seasonal upwelling events. We propose a conceptual model of circulation and particles retention into Mejillones Bay. The assumption is that during strong upwelling conditions the flows that move along the canyon emerge in the centre of Mejillones Bay, producing a fish larvae retention zone. Understanding the biophysical interactions responsible to trap and/or concentrate particles is essential to protect these fragile upwelling ecosystems.


    Directory of Open Access Journals (Sweden)



    Full Text Available Both the preservation of the poorly mineralized skeleton of sharks and the preservation of stomach contents are rarely observed in the fossil record. Here we report on a partial skeleton of a lamniform shark, including portions of the visceral arches and the anterior segment of the vertebral column, collected from the late Miocene beds of the Pisco Formation exposed at Cerro Yesera (Ica Desert, South Peru. Based on the morphology of the preserved teeth, this specimen was determined as a juvenile of the extinct lamnid species Cosmopolitodus hastalis. The shark skeleton includes remains of fish (featuring a pilchard determined as Sardinops sp. cf. S. sagax in the abdominal region. These fish remains are interpreted herein as the fossilized stomach contents of the shark. For the first time, piscivory is demonstrated in a juvenile individual of Cosmopolitodus hastalis. This result is consistent with the current knowledge about the feeding habits of immature individuals of extant lamniform shark species (including Carcharodon carcharias and Isurus oxyrinchus. Our report further outlines the fundamental role of schooling pilchards in the late Miocene trophic chains of the highly productive coastal waters off present South Peru. Moreover, the find of this well preserved shark skeleton strengthens the qualification of the Pisco Formation as a Fossil-Lagerstätte, and emphasizes the role of early mineralization processes in cases of exceptional preservation.

  8. Macro-Scale Patterns in Upwelling/Downwelling Activity at North American West Coast (United States)

    Saldívar-Lucio, Romeo; Di Lorenzo, Emanuele; Nakamura, Miguel; Villalobos, Héctor; Lluch-Cota, Daniel; Del Monte-Luna, Pablo


    The seasonal and interannual variability of vertical transport (upwelling/downwelling) has been relatively well studied, mainly for the California Current System, including low-frequency changes and latitudinal heterogeneity. The aim of this work was to identify potentially predictable patterns in upwelling/downwelling activity along the North American west coast and discuss their plausible mechanisms. To this purpose we applied the min/max Autocorrelation Factor technique and time series analysis. We found that spatial co-variation of seawater vertical movements present three dominant low-frequency signals in the range of 33, 19 and 11 years, resembling periodicities of: atmospheric circulation, nodal moon tides and solar activity. Those periodicities might be related to the variability of vertical transport through their influence on dominant wind patterns, the position/intensity of pressure centers and the strength of atmospheric circulation cells (wind stress). The low-frequency signals identified in upwelling/downwelling are coherent with temporal patterns previously reported at the study region: sea surface temperature along the Pacific coast of North America, catch fluctuations of anchovy Engraulis mordax and sardine Sardinops sagax, the Pacific Decadal Oscillation, changes in abundance and distribution of salmon populations, and variations in the position and intensity of the Aleutian low. Since the vertical transport is an oceanographic process with strong biological relevance, the recognition of their spatio-temporal patterns might allow for some reasonable forecasting capacity, potentially useful for marine resources management of the region. PMID:27893826

  9. Molecular epidemiology of viral haemorrhagic septicaemia virus (VHSV) in British Columbia, Canada, reveals transmission from wild to farmed fish. (United States)

    Garver, Kyle A; Traxler, Garth S; Hawley, Laura M; Richard, Jon; Ross, Jay P; Lovy, Jan


    Viral haemorrhagic septicaemia virus (VHSV) is a fish pathogen found throughout the Northern Hemisphere and is capable of infecting and causing mortality in numerous marine and freshwater hosts. In the coastal waters of British Columbia, Canada, the virus has been detected for 20 yr with many occurrences of mass mortalities among populations of Pacific herring Clupea pallasii (Valenciennes) and sardine Sardinops sagax as well as detections among cultured Atlantic Salmo salar and Chinook Oncorhynchus tshawytscha salmon. We compared nucleotide sequence of the full glycoprotein (G) gene coding region (1524 nt) of 63 VHSV isolates sampled during its recorded presence from 1993 to 2011 from 6 species and a total of 29 sites. Phylogenetic analysis showed that all isolates fell into sub-lineage IVa within the major VHSV genetic group IV. Of the 63 virus isolates, there were 42 unique sequences, each of which was ephemeral, being repeatedly detected at most only 1 yr after its initial detection. Multiple sequence types were revealed during single viral outbreak events, and genetic heterogeneity was observed within isolates from individual fish. Moreover, phylogenetic analysis revealed a close genetic linkage between VHSV isolates obtained from pelagic finfish species and farmed salmonids, providing evidence for virus transmission from wild to farmed fish.

  10. No deep diving: evidence of predation on epipelagic fish for a stem beaked whale from the Late Miocene of Peru (United States)

    Lambert, Olivier; Collareta, Alberto; Landini, Walter; Post, Klaas; Ramassamy, Benjamin; Di Celma, Claudio; Urbina, Mario; Bianucci, Giovanni


    Although modern beaked whales (Ziphiidae) are known to be highly specialized toothed whales that predominantly feed at great depths upon benthic and benthopelagic prey, only limited palaeontological data document this major ecological shift. We report on a ziphiid–fish assemblage from the Late Miocene of Peru that we interpret as the first direct evidence of a predator–prey relationship between a ziphiid and epipelagic fish. Preserved in a dolomite concretion, a skeleton of the stem ziphiid Messapicetus gregarius was discovered together with numerous skeletons of a clupeiform fish closely related to the epipelagic extant Pacific sardine (Sardinops sagax). Based on the position of fish individuals along the head and chest regions of the ziphiid, the lack of digestion marks on fish remains and the homogeneous size of individuals, we propose that this assemblage results from the death of the whale (possibly via toxin poisoning) shortly after the capture of prey from a single school. Together with morphological data and the frequent discovery of fossil crown ziphiids in deep-sea deposits, this exceptional record supports the hypothesis that only more derived ziphiids were regular deep divers and that the extinction of epipelagic forms may coincide with the radiation of true dolphins. PMID:26354940

  11. Metals and metalloids in Little Penguin (Eudyptula minor) prey, blood and faeces. (United States)

    Finger, Annett; Lavers, Jennifer L; Dann, Peter; Kowalczyk, Nicole D; Scarpaci, Carol; Nugegoda, Dayanthi; Orbell, John D


    Piscivorous species like the Little Penguin (Eudyptula minor) are particularly at risk of being negatively impacted by pollution due to their heightened exposure through aquatic food chains. Therefore, determining the concentration of heavy metals in the fish prey of seabirds is an essential component of assessing such risk. In this study, we report on arsenic, cadmium, mercury, lead and selenium concentrations in three fish species, which are known to comprise a substantial part of the diet of Little Penguins at the urban colony of St Kilda, Melbourne, Australia. Metal concentrations in the fish sampled were generally within the expected limits, however, arsenic and mercury were higher than reported elsewhere. Anchovy (Engraulis australis) and sandy sprat (Hyperlophus vittatus) contained higher Hg concentrations than pilchard (Sardinops sagax), while sandy sprat and pilchard contained more selenium. We present these findings together with metal concentrations in Little Penguin blood and faeces, sampled within weeks of the fish collection. Mercury concentrations were highest in the blood, while faeces and fish prey species contained similar concentrations of arsenic and lead, suggesting faeces as a primary route of detoxification for these elements. We also investigated paired blood - faecal samples and found a correlation for selenium only. Preliminary data from stable isotope ratios in penguin blood indicate that changes in penguin blood mercury concentrations cannot be explained by trophic changes in their diet alone, suggesting a variation of bioavailable Hg within this semi-enclosed bay.

  12. A recent increase of swift terns Thalasseus bergii off South Africa - The possible influence of an altered abundance and distribution of prey (United States)

    Crawford, Robert J. M.


    In the 2000s, there were large increases in the numbers of swift terns Thalasseus bergii breeding in the Western and Eastern Cape Provinces of South Africa, which are most plausibly attributed to good recruitment and to an increase in the proportion of mature birds breeding. Numbers increased coincidentally with a greatly increased abundance of two of the main prey species of swift terns, sardine Sardinops sagax and anchovy Engraulis encrasicolus, and remained high as these resources decreased. After 2005, numbers of swift terns breeding in the north and central portions of the Western Cape decreased, whereas numbers breeding farther south in that province increased. This followed displacements to the south and east of sardine and anchovy. In southern Africa, swift terns show low fidelity to breeding localities, which enables a rapid adjustment of the location of breeding to an altered availability of prey. For two seabirds that feed mainly on sardine and anchovy, but once breeding show high fidelity to colonies, African penguin Spheniscus demersus and Cape gannet Morus capensis, proportions breeding in the south and east also increased, but there were substantial decreases in overall numbers breeding in the Western Cape.

  13. Composition, abundance, distribution and seasonality of larval fishes in the shallow nearshore of the proposed Greater Addo Marine Reserve, Algoa Bay, South Africa (United States)

    Pattrick, Paula; Strydom, Nadine A.


    The larval fish assemblage was investigated in the shallow, nearshore region of a proposed marine protected area in eastern Algoa Bay, temperate South Africa, prior to proclamation. Sampling was conducted at six sites along two different depth contours at ˜5 m and ˜15 m to assess shore association. Larvae were collected by means of stepped oblique bongo net tows deployed off a ski-boat, twice per season for 2 years between 2005 and 2007. In total, 6045 larval fishes were collected representing 32 families and 78 species. The Gobiidae, Cynoglossidae, Clupeidae, Engraulidae and Sparidae were the dominant fish families. Catches varied significantly among seasons peaking in spring with a mean of ˜200 larvae/100 m 3. Mean overall larval density was higher along the deeper contour, at ˜15 m (40 larvae/100 m 3). The preflexion stage of development dominated catches at the ˜5 m (80%) and ˜15 m (73%) depth contours. Body lengths of Argyrosomus thorpei, Caffrogobius gilchristi, Diplodus capensis, Heteromycteris capensis and Solea turbynei, all estuary associated species, were larger at the shallow sites nearer to shore. Larvae of coastal species that produce benthic eggs dominated catches (75%) in the shallow sites (˜5 m) but were less abundant (32%) farther from shore at the deeper (˜15 m) sites. All developmental stages of D. capensis, Engraulis capensis, H. capensis, Sardinops sagax and two Pomadasys species were found in the study area. It appears that some species use the shallow nearshore as a nursery area.

  14. Influence of ocean winds on the pelagic ecosystem in upwelling regions. (United States)

    Rykaczewski, Ryan R; Checkley, David M


    Upwelling of nutrient-rich, subsurface water sustains high productivity in the ocean's eastern boundary currents. These ecosystems support a rate of fish harvest nearly 100 times the global mean and account for >20% of the world's marine fish catch. Environmental variability is thought to be the major cause of the decadal-scale biomass fluctuations characteristic of fish populations in these regions, but the mechanisms relating atmospheric physics to fish production remain unexplained. Two atmospheric conditions induce different types of upwelling in these ecosystems: coastal, alongshore wind stress, resulting in rapid upwelling (with high vertical velocity, w); and wind-stress curl, resulting in slower upwelling (low w). We show that the level of wind-stress curl has increased and that production of Pacific sardine (Sardinops sagax) varies with wind-stress curl over the past six decades. The extent of isopycnal shoaling, nutricline depth, and chlorophyll concentration in the upper ocean also correlate positively with wind-stress curl. The size structure of plankton assemblages is related to the rate of wind-forced upwelling, and sardine feed efficiently on small plankters generated by slow upwelling. Upwelling rate is a fundamental determinant of the biological structure and production in coastal pelagic ecosystems, and future changes in the magnitude and spatial gradient of wind stress may have important and differing effects on these ecosystems. Understanding of the biological mechanisms relating fisheries production to environmental variability is essential for wise management of marine resources under a changing climate.

  15. Extended incubation affects larval morphology, hatching success and starvation resistance in a terrestrially spawning fish, Galaxias maculatus (Jenyns 1842). (United States)

    Semmens, D; Swearer, S E


    The effect of extended incubation (delayed hatching) on larval morphology in the terrestrially spawning common galaxias Galaxias maculatus was investigated by inducing larvae to hatch 1 and 2 weeks after the normal 2 week incubation period. After 1 week of extended incubation, larvae were larger (longer in standard length, L(S), and greater in body depth) compared to controls (larvae that experienced normal incubation durations). After 2 weeks of extended incubation, larvae were smaller (shorter in L(S) and smaller in body depth) than larvae that experienced 1 week of extended incubation. Furthermore, eye area increased while yolk-sac size decreased monotonically with increasing incubation duration. These results suggest that larvae experiencing long periods of extended incubation are using somatic tissue to meet their metabolic demands. Larvae that experienced 2 weeks of extended incubation succumbed to starvation sooner than control larvae, but hatching success was not significantly different. Temperature mediated the effect of extended incubation on the morphology of larvae at hatching, most likely, through its effects on developmental rate and efficiency of yolk utilization. This study demonstrates some of the consequences of terrestrial spawning with extended incubation, which will assist in determining why this intriguing behaviour has evolved several times in a diverse range of taxa.

  16. So Long and Thanks for All the Fish: Overexploitation of the Regionally Endemic Galapagos Grouper Mycteroperca olfax (Jenyns, 1840) (United States)

    Friedlander, Alan M.; Koike, Haruko; Zimmerhackel, Johanna; Schuhbauer, Anna; Eddy, Tyler; Salinas-de-León, Pelayo


    The regionally endemic Galapagos Grouper, locally known as bacalao, is one of the most highly prized finfish species within the Galapagos Marine Reserve (GMR). Concerns of overfishing, coupled with a lack of fishing regulations aimed at this species raises concerns about the current population health. We assessed changes in population health over a 30-year period using three simple indicators: (1) percentage of fish below reproductive size (Lm); (2) percentage of fish within the optimum length interval (Lopt); and (3) percentage of mega-spawners in the catch. Over the assessed period, none of the indicators reached values associated with healthy populations, with all indicators declining over time. Furthermore, the most recent landings data show that the vast majority of the bacalao caught (95.7%,) were below Lm, the number of fish within the Lopt interval was extremely low (4.7%), and there were virtually no mega-spawners (0.2%). Bacalao fully recruit to the fishery 15 cm below the size at which 50% of the population matures. The Spawning Potential Ratio is currently 5% of potential unfished fecundity, strongly suggesting severe overfishing. Our results suggest the need for bacalao-specific management regulations that should include minimum (65 cm TL) and maximum (78 cm TL) landing sizes, slot limits (64–78 cm TL), as well as a closed season during spawning from October to January. It is recognized that these regulations are harsh and will certainly have negative impacts on the livelihoods of fishers in the short term, however, continued inaction will likely result in a collapse of this economically and culturally valuable species. Alternative sources of income should be developed in parallel with the establishment of fishing regulations to limit the socio-economic disruption to the fishing community during the transition to a more sustainable management regime. PMID:27780213

  17. Contrasting Genetic Structure and Diversity of Galaxias maculatus (Jenyns, 1848) Along the Chilean Coast: Stock Identification for Fishery Management. (United States)

    González-Wevar, Claudio; Salinas, Pilar; Hüne, Mathias; Segovia, Nicolás; Vargas-Chacoff, Luis; Oda, Esteban; Poulin, Elie


    Galaxias maculatus (Pisces: Galaxiidae) commonly known as "puye" has a disjunct distribution along the Southern Hemisphere including landlocked and migratory populations at latitudes over 30°S in South America, Australia, Tasmania, and New Zealand. Chilean artisanal fishery of G. maculatus has become less important as a resource due to multiple factors including overexploitation, pollution, introduction of predators, and competitors. At the same time, the current conservation status of the species in Chile is still uncertain. Here, we used mtDNA control region sequences (925bp) to investigate main patterns of genetic diversity and structure in populations from 2 biogeographic areas along the Chilean coast. Extremely high levels of genetic diversity characterize the species, suggesting a low amount of influence of the last glacial cycle over its demography compared with other studies in freshwater and marine South American fishes. However, we recognized contrasting genetic patterns between the Intermediate Area (between 30°S and 42°S) and the Magellanic Province (between 42°S and 56°S). On the one hand, over a narrow geographical range (stock units for G. maculatus and this information should be integrated in future management strategies and aquaculture programs for this species. © The American Genetic Association 2015. All rights reserved. For permissions, please e-mail:

  18. Coupling between the environment and the pelagic resources exploited off northern Chile: ecosystem indicators and a conceptual model Acoplamiento entre el ambiente y los recursos pelágicos explotados en el norte de Chile: un modelo conceptual

    Directory of Open Access Journals (Sweden)

    Eleuterio Yáñez


    Full Text Available The eastern boundary of the Chile-Peru Current System constitutes one of the most biologically productive ecosystems in the world, due largely to coastal upwelling and the horizontal advection of nutrients. In this ecosystem, El Niño events are of great importance in the interannual variability of the environment. A change was observed in the environmental regime at the beginning of the 1970s with the onset of the 1972-1973 El Niño, marking an important decrease in the anchovy fishery (Engraulis ringens. After the mid-1970s, sardine (Sardinops sagax landings increased noticeably. A second regime shift at the end of the 1980s was seen mostly in the noticeable recovery of anchovy and the decline of sardine. Herein, we present an integrated conceptual model of the different local and large-scale phenomena that affect the marine environment off northern Chile and the distribution and abundance of pelagic resources. The model considers an analysis of environmental and bio-fishery data on different scales and describes how the interdecadal (associated with re-gime shifts and interannual (associated with El Niño events fluctuations in the Equatorial Pacific are mani-fested in the eastern South Pacific and, therefore, in the northern zone off Chile, affecting the annual eyele, the dynamic of the coastal trapped waves, and coastal upwelling. In this framework, interdecadal fluctuations play an important role in the anchovy-sardine-anchovy replacement sequence.El borde oriental del Sistema de Corrientes de Chile-Perú constituye uno de los ecosistemas de mayor productividad biológica del mundo, debido principalmente a la surgencia costera y advección horizontal de nutrientes. En este ecosistema, los eventos El Niño son de mayor importancia en la variabilidad interanual del ambiente. No obstante, un cambio de régimen ambiental es observado a inicio de los 70's el que hubiera comenzado con El Niño 1972-73 y que marca la gran disminución de la

  19. Biomasa acústica y distribución del jurel Trachurus murphyien el Perú

    Directory of Open Access Journals (Sweden)

    Marceliano Segura


    Full Text Available Se analizan los resultados de las evaluaciones hidroacústicas del recurso jurel Trachurus murphyi Nichols 1920 realizadas en aguas peruanas entre 1983 – 2012. Desde 1983 se incluyó al T. murphyicomo especie de estudio durante los cruceros de evaluación de recursos pelágicos ejecutados por el Instituto del Mar del Perú. Debido al énfasis en la estimación de biomasa de la anchoveta Engraulis ringens y de la sardina Sardinops sagax cuando esta última es más abundante, los cruceros se llevan a cabo durante el verano austral y las áreas de evaluación están circunscritas a las zonas más costeras hasta 100 mn, con sólo algunas exploraciones en otras estaciones y hasta 200 millas. El máximo valor de biomasa de 8.51 millones de toneladas de T. murphyien aguas peruanas estimado con las evaluaciones hidroacústicas fue encontrado durante el crucero realizado en otoño (marzo-mayo de 1983. En los años siguientes los estimados de biomasa acústica fluctuaron entre 180 mil toneladas en 1985 y otro máximo de 8.47 millones de toneladas en 1993, para luego disminuir gradualmente hasta un mínimo de 1239 t en 2010, con una ligera recuperación en los años 2011 y 2012. El área de distribución de T. murphyifue muy fluctuante en todo el periodo observado.

  20. Dynamic height: A key variable for identifying the spawning habitat of small pelagic fishes (United States)

    Asch, Rebecca G.; Checkley, David M., Jr.


    Small pelagic fishes off southern California exhibit interannual variations in the regions they occupy. An enhanced understanding of these fluctuations could improve fisheries management and predictions of fish's responses to climate change. We investigated dynamic height as a variable for identifying the spawning habitat of northern anchovy (Engraulis mordax), Pacific sardine (Sardinops sagax), and jack mackerel (Trachurus symmetricus). During cruises between 1998 and 2004, dynamic height was calculated from temperature and salinity profiles, while fish egg concentration was measured with obliquely towed bongo nets and the Continuous, Underway Fish Egg Sampler. Dynamic height ranged between 68 and 108 cm, with values increasing offshore. The greatest probability of encountering anchovy, sardine, and jack mackerel eggs occurred at dynamic heights of 79-83 cm, 84-89 cm, and 89-99 cm, respectively. Four mechanisms were proposed to explain how dynamic height affects egg distribution: (1) dynamic height is a proxy for upper water column temperature and salinity, which are known to influence spawning habitat. (2) Low dynamic heights are indicative of coastal upwelling, which increases primary and secondary productivity. (3) Egg concentration is greater at dynamic heights coincident with geostrophic currents that transport larvae to favorable habitats. (4) Eddies delineated by dynamic height contours retain eggs in productive habitats. To evaluate these mechanisms, a generalized linear model was constructed using dynamic height, temperature, salinity, chlorophyll, zooplankton volume, geostrophic currents, and eddies as independent variables. Dynamic height explained more variance than any other variable in models of sardine and anchovy spawning habitat. Together temperature, salinity, and chlorophyll accounted for 80-95% of the dynamic height effect, emphasizing the importance of the first two mechanisms. However, dynamic height remained statistically significant in the

  1. Immunological cross-reactivity between four distant parvalbumins-Impact on allergen detection and diagnostics. (United States)

    Sharp, Michael F; Stephen, Juan N; Kraft, Lukas; Weiss, Thomas; Kamath, Sandip D; Lopata, Andreas L


    Fish are the largest and most diverse group of vertebrates. Fish are also a part of the eight food groups that cause the majority of IgE mediated food reactions. Detection tools for fish allergens are however limited due to the great diversity of fish species, despite fish allergy and its major allergen parvalbumin being well documented. The most commonly studied fish are frequently consumed in North America and Europe. However, much less is known about fish allergens in the Australasian region although fish is widely consumed in this region. A comprehensive phylogenetic analysis was performed of known parvalbumin amino acid sequences to determine possible candidate antigens for new cross-reactive antibodies to be used to detect most fish parvalbumins. Polyclonal rabbit antibodies were raised against parvalbumins from frequently consumed barramundi (Lates calcarifer), basa (Pangasius bocourti), pilchard (Sardinops sagax) and Atlantic salmon (Salmo salar). These were evaluated for cross-reactivity against a panel of 45 fish extracts (raw, heated and canned fish). Anti-barramundi parvalbumin proved to be the most cross-reactive antibody, detecting 87.5% of the 40 species analyzed, followed by anti-pilchard and anti-basa antibody. In contrast the anti-salmon antibody was very specific and only reacted to salmonidae and a few other fish. All analyzed fish species, except mahi mahi, swordfish, yellowfin tuna and all 5 canned fish had parvalbumin detected in raw extracts. However antibody reactivity to many fish was heat liable or susceptible to denaturation, demonstrating that some parvalbumins have most likely conformational epitopes, which lose antibody reactivity after heat treatment. We have demonstrated the generation of highly cross-reactive anti-parvalbumin antibodies that could be used for the detection of allergenic fish parvalbumin in contaminated food products. This cross-reactivity study thus shows processing of fish, especially canning, can have on impact

  2. Managing small-scale commercial fisheries for adaptive capacity: insights from dynamic social-ecological drivers of change in Monterey Bay.

    Directory of Open Access Journals (Sweden)

    Stacy E Aguilera

    Full Text Available Globally, small-scale fisheries are influenced by dynamic climate, governance, and market drivers, which present social and ecological challenges and opportunities. It is difficult to manage fisheries adaptively for fluctuating drivers, except to allow participants to shift effort among multiple fisheries. Adapting to changing conditions allows small-scale fishery participants to survive economic and environmental disturbances and benefit from optimal conditions. This study explores the relative influence of large-scale drivers on shifts in effort and outcomes among three closely linked fisheries in Monterey Bay since the Magnuson-Stevens Fisheries Conservation and Management Act of 1976. In this region, Pacific sardine (Sardinops sagax, northern anchovy (Engraulis mordax, and market squid (Loligo opalescens fisheries comprise a tightly linked system where shifting focus among fisheries is a key element to adaptive capacity and reduced social and ecological vulnerability. Using a cluster analysis of landings, we identify four modes from 1974 to 2012 that are dominated (i.e., a given species accounting for the plurality of landings by squid, sardine, anchovy, or lack any dominance, and seven points of transition among these periods. This approach enables us to determine which drivers are associated with each mode and each transition. Overall, we show that market and climate drivers are predominantly attributed to dominance transitions. Model selection of external drivers indicates that governance phases, reflected as perceived abundance, dictate long-term outcomes. Our findings suggest that globally, small-scale fishery managers should consider enabling shifts in effort among fisheries and retaining existing flexibility, as adaptive capacity is a critical determinant for social and ecological resilience.

  3. Managing small-scale commercial fisheries for adaptive capacity: insights from dynamic social-ecological drivers of change in Monterey Bay. (United States)

    Aguilera, Stacy E; Cole, Jennifer; Finkbeiner, Elena M; Le Cornu, Elodie; Ban, Natalie C; Carr, Mark H; Cinner, Joshua E; Crowder, Larry B; Gelcich, Stefan; Hicks, Christina C; Kittinger, John N; Martone, Rebecca; Malone, Daniel; Pomeroy, Carrie; Starr, Richard M; Seram, Sanah; Zuercher, Rachel; Broad, Kenneth


    Globally, small-scale fisheries are influenced by dynamic climate, governance, and market drivers, which present social and ecological challenges and opportunities. It is difficult to manage fisheries adaptively for fluctuating drivers, except to allow participants to shift effort among multiple fisheries. Adapting to changing conditions allows small-scale fishery participants to survive economic and environmental disturbances and benefit from optimal conditions. This study explores the relative influence of large-scale drivers on shifts in effort and outcomes among three closely linked fisheries in Monterey Bay since the Magnuson-Stevens Fisheries Conservation and Management Act of 1976. In this region, Pacific sardine (Sardinops sagax), northern anchovy (Engraulis mordax), and market squid (Loligo opalescens) fisheries comprise a tightly linked system where shifting focus among fisheries is a key element to adaptive capacity and reduced social and ecological vulnerability. Using a cluster analysis of landings, we identify four modes from 1974 to 2012 that are dominated (i.e., a given species accounting for the plurality of landings) by squid, sardine, anchovy, or lack any dominance, and seven points of transition among these periods. This approach enables us to determine which drivers are associated with each mode and each transition. Overall, we show that market and climate drivers are predominantly attributed to dominance transitions. Model selection of external drivers indicates that governance phases, reflected as perceived abundance, dictate long-term outcomes. Our findings suggest that globally, small-scale fishery managers should consider enabling shifts in effort among fisheries and retaining existing flexibility, as adaptive capacity is a critical determinant for social and ecological resilience.

  4. Different Levels of Hypoxia Tolerance during Early Life History Stages of Key Fish Species from the Northern Benguela Upwelling Ecosystem Inferred from the Comparison of Eco-Physiological Traits (United States)

    Geist, S. J.; Imam, R. M.; Kunzmann, A.; Ekau, W.


    Global change factors such as a pronounced Oxygen Minimum Zone and the shoaling of hypoxic waters are assumed to play a major role in controlling the recruitment of fish stocks in Upwelling Systems by affecting the planktonic early life history stages. Ecological and ecophysiological traits in the larval stages of five key fish species in the Northern Benguela Upwelling System (Sardine, Sardinops sagax; Anchovy, Engraulis encrasicolus; Cape horse mackerel, Trachurus capensis; Cape hake, Merluccius sp.; Pelagic goby, Sufflogobobius bibarbatus) were investigated during the GENUS (Geochemistry and Ecology of the Namibian Upwelling Ecosystem) research project . Analysis of vertical larval distributions in relation to the depth of hypoxic water layers showed gradual interspecific differences, suggesting lower hypoxia tolerance levels of the small pelagics Sardine and Anchovy. Cape horse mackerel juveniles and larvae exhibited very high tolerance levels to short-term hypoxia in respirometry stress experiments, close to the levels of the extremely hypoxia-tolerant Pelagic goby. In the latter two species, we also measured the highest activities of anaerobic enzymes (pyruvate kinase and lactate dehydrogenase) in early and late larval stages, compared to very low activities in Sardine larvae. A higher amount of anaerobic enzymatic activity is related to a higher capacity to break down metabolites that build up during phases of oxygen debt and thus help the larvae to quickly recover from hypoxia exposure. In consequence, a high hypoxia tolerance during their early life stages allows Cape horse mackerel and Pelagic goby to successfully reproduce in an environment characterized by frequent hypoxic events. The low hypoxia tolerance of Sardine larvae, eventually resulting in higher mortality rates, is likely to be an important factor to understand the poor reproductive success and continuing recruitment failures of this formerly dominant fish species of the NBUS during the last

  5. Quantifying mercury isotope dynamics in captive Pacific bluefin tuna (Thunnus orientalis

    Directory of Open Access Journals (Sweden)

    Sae Yun Kwon


    Full Text Available Abstract Analyses of mercury (Hg isotope ratios in fish tissues are used increasingly to infer sources and biogeochemical processes of Hg in natural aquatic ecosystems. Controlled experiments that can couple internal Hg isotope behavior with traditional isotope tracers (δ13C, δ15N can improve the applicability of Hg isotopes as natural ecological tracers. In this study, we investigated changes in Hg isotope ratios (δ202Hg, Δ199Hg during bioaccumulation of natural diets in the pelagic Pacific bluefin tuna (Thunnus orientalis; PBFT. Juvenile PBFT were fed a mixture of natural prey and a dietary supplement (60% Loligo opalescens, 31% Sardinops sagax, 9% gel supplement in captivity for 2914 days, and white muscle tissues were analyzed for Hg isotope ratios and compared to time in captivity and internal turnover of δ13C and δ15N. PBFT muscle tissues equilibrated to Hg isotope ratios of the dietary mixture within ∼700 days, after which we observed a cessation in further shifts in Δ199Hg, and small but significant negative δ202Hg shifts from the dietary mixture. The internal behavior of Δ199Hg is consistent with previous fish studies, which showed an absence of Δ199Hg fractionation during Hg bioaccumulation. The negative δ202Hg shifts can be attributed to either preferential excretion of Hg with higher δ202Hg values or individual variability in captive PBFT feeding preferences and/or consumption rates. The overall internal behavior of Hg isotopes is similar to that described for δ13C and δ15N, though observed Hg turnover was slower compared to carbon and nitrogen. This improved understanding of internal dynamics of Hg isotopes in relation to δ13C and δ15N enhances the applicability of Hg isotope ratios in fish tissues for tracing Hg sources in natural ecosystems.

  6. Anchovies to Whales: tracking vertebrate biodiversity in Monterey Bay by metabarcoding environmental DNA (eDNA) (United States)

    Closek, C. J.; Starks, H.; Walz, K.; Boehm, A. B.; Chavez, F.


    The oscillation between the dominance of Sardinops sagax (pacific sardine) and Engraulis mordax (northern anchovy) has been documented in the California Coastal Ecosystem for more than 100 years. These two species are strong drivers of trophic interactions in the region. As part of the Marine Biodiversity Observational Network (MBON) initiative, we used archived filtered seawater samples collected late-summer to mid-fall over a span of 8 years from Monterey Bay, CA to examine the change in marine vertebrate environmental DNA (eDNA). Water samples were collected from a nearshore location in Monterey Bay (C1) during the years of 2008-15. The water was then filtered, and the filter was archived at -80°C. DNA was extracted from the filters, and the 12S rRNA gene present in mitochondrial DNA was PCR amplification using primers designed to amplify 12s rRNA genes from marine vertebrates. The amplicons were subsequently sequenced with an Illumina MiSeq and the data processed using an analysis pipeline for sequence annotation. More than 20 fish genera were noted in the sequences from 2008-12, with Engraulis the dominant fish genus from 2013-15. Anchovy and Megaptera novaeangliae (humpback whale) were present in temporal patterns similar to those noted during visual observations where anchovy and humpback whale were more abundant during the years of 2013-2015 than the other years. This study demonstrates our ability to detect megafauna and fish species that are important to the Monterey Bay ecosystem from coastal water samples and determine community structural differences over time.

  7. Oxygen: a fundamental property regulating pelagic ecosystem structure in the coastal southeastern tropical Pacific.

    Directory of Open Access Journals (Sweden)

    Arnaud Bertrand

    Full Text Available BACKGROUND: In the southeastern tropical Pacific anchovy (Engraulis ringens and sardine (Sardinops sagax abundance have recently fluctuated on multidecadal scales and food and temperature have been proposed as the key parameters explaining these changes. However, ecological and paleoecological studies, and the fact that anchovies and sardines are favored differently in other regions, raise questions about the role of temperature. Here we investigate the role of oxygen in structuring fish populations in the Peruvian upwelling ecosystem that has evolved over anoxic conditions and is one of the world's most productive ecosystems in terms of forage fish. This study is particularly relevant given that the distribution of oxygen in the ocean is changing with uncertain consequences. METHODOLOGY/PRINCIPAL FINDINGS: A comprehensive data set is used to show how oxygen concentration and oxycline depth affect the abundance and distribution of pelagic fish. We show that the effects of oxygen on anchovy and sardine are opposite. Anchovy flourishes under relatively low oxygen conditions while sardine avoid periods/areas with low oxygen concentration and restricted habitat. Oxygen consumption, trophic structure and habitat compression play a fundamental role in fish dynamics in this important ecosystem. CONCLUSIONS/SIGNIFICANCE: For the ocean off Peru we suggest that a key process, the need to breathe, has been neglected previously. Inclusion of this missing piece allows the development of a comprehensive conceptual model of pelagic fish populations and change in an ocean ecosystem impacted by low oxygen. Should current trends in oxygen in the ocean continue similar effects may be evident in other coastal upwelling ecosystems.

  8. Medidas de conservación y ordenación pesquera del jurel Trachurus murphyien el Perú

    Directory of Open Access Journals (Sweden)

    Jorge Zuzunaga


    Full Text Available Las pesquerías peruanas como actividades realizadas sobre recursos naturales renovables son reguladas por un marco jurídico, cuyo objetivo es asegurar su conservación y uso sostenible. La Ley General de Pesca (DL N°. 25977 señala que para cada tipo de pesquería y según la situación del recurso explotado debe establecerse un sistema de ordenamiento que concilie el principio de sostenibilidad de los recursos pesqueros o conservación en el largo plazo, con la obtención de los mayores beneficios económicos y sociales. En el ordenamiento pesquero del jurel Trachurus murphyi, las medidas incluyen entre otras, el régimen de acceso constituido por las autorizaciones de incremento de flota y permisos de pesca, que se otorgan solo a los buques cuyas capturas son destinadas únicamente para el consumo humano directo, de acuerdo a lo dispuesto en el Reglamento de Ordenamiento Pesquero (DS N.° 011-2007-PRODUCE. La obligación de destinar los recursos sardina Sardinops sagax, jurel T. murphyiy caballa Scomber japonicus al consumo humano directo rige desde septiembre 2002 (DS N°. 001-2002-PRODUCE. Otras medidas vigentes restringen el tamaño mínimo de malla de las redes, prohíben la captura de ejemplares menores de 31 cm de longitud total, determinan el inicio y cierre de las temporadas de pesca, los límites de captura o cuotas anuales. Estas disposiciones son complementadas por medidas de seguimiento, control y vigilancia para la efectiva conservación y uso sostenido del recurso.

  9. [Fatty acid composition and cholesterol content in naturally canned jurel, sardine, salmon, and tuna]. (United States)

    Romero, N; Robert, P; Masson, L; Luck, C; Buschmann, L


    To obtain more information about fatty acid profile and cholesterol content of fat extracted from canned fish in brine habitually consumed in Chile, four different species Jurel (Trachurus murphyi), Sardine (Sardinops sagax), Salmon (Oncorhynchus kisutch) and Tuna (Thunnus alalunga) were analyzed. The GLC of fatty acid methyl esters showed that the main group of fatty acids belongs to polyunsaturated, being omega-3 family the more important. The principal representants were eicosapentaenoic (EPA) and docosahexaenoic acids (DHA), with percentages between 5%-11% and 12%-22% respectively. Omega-6 family was represented mainly by arachidonic acid (AA) with percentages between 2%-4%. Cholesterol content was similar to the values found in other animal origen meats. The figures were between 41-86 mg of cholesterol per 100 g of edible product, Tuna in brine, was the product with the lowest content of cholesterol. The calculated amount of EPA, DHA and total omega-3 fatty acids indicated values between 95-604, 390-1163 and 609-2775 mg respectively per 100 g of edible product. Due these results is important to emphasize the consumption of this type of canned fish in brine, that they really represent a good dietary source of mainly polyunsaturated omega-3 fatty acids. The international recommendations indicate to increase the consumption of fish, due the beneficial effects described in relation with cardiovascular disease, which is the mean cause of death in Chile, country with a wide variety of marine origen foods, but with a contradictory answer about its consumption which is not incorporated in the current diet.

  10. Long-term variation in a central California pelagic forage assemblage (United States)

    Ralston, Stephen; Field, John C.; Sakuma, Keith M.


    A continuous 23 year midwater trawl survey (1990-2012) of the epipelagic forage assemblage off the coast of central California (lat. 36°30‧-38°20‧ N) is described and analyzed. Twenty taxa occurred in ≥ 10% of the 2037 trawls that were completed at 40 distinct station locations. The dominant taxa sampled by the 9.5 mm mesh net included a suite of young-of-the-year (YOY) groundfish, including rockfish (Sebastes spp.) and Pacific hake (Merluccius productus), two clupeoids (Engraulis mordax and Sardinops sagax), krill (Euphausiacea), cephalopods (Doryteuthis opalescens and Octopus sp.), and a variety of mesopelagic species, i.e., Diaphus theta, Tarltonbeania crenularis, "other" lanternfish (Myctophidae), deep-sea smelts (Bathylagidae), and sergestid shrimp. Annual abundance estimates of the 20 taxa were obtained from analysis of variance models, which included year and station as main effects. Principal components analysis of the abundance estimates revealed that 61% of assemblage variance was explained by the first three components. The first component revealed a strong contrast in the abundance of: (a) YOY groundfish, market squid (D. opalescens), and krill with (b) mesopelagics and clupeoids; the second component was associated with long-term trends in abundance. An evaluation of 10 different published oceanographic data sets and CTD data collected during the survey indicated that seawater properties encountered each year were significantly correlated with abundance patterns, as were annual sea-level anomalies obtained from an analysis of AVISO satellite information. A comparison of our findings with several other recent studies of biological communities occurring in the California Current revealed a consistent structuring of forage assemblages, which we conjecture is primarily attributable to large-scale advection patterns in the California Current ecosystem.

  11. Observación de la velocidad de los cardúmenes de anchoveta (Engraulis ringens JENYNS) en el mar peruano


    Peraltilla Neyra, Salvador


    Da a conocer las observación sobre la velocidad de natación de los cardúmenes de la anchoveta peruana, para comprender los desplazamientos latitudinales y longitudinales que realizan debido a la influencia de las condiciones oceanográficas del mar peruano. Por lo que se debería continuar con el estudio de la velocidad de natación de estos cardúmenes en función a sus características como tallas y pesos. Proyecto GEF -PNUD - GEMCH

  12. Feeding ω-3 PUFA enriched rotifers to Galaxias maculatus (Jenyns, 1842 larvae reared at different salinity conditions: effects on growth parameters, survival and fatty acids profile

    Directory of Open Access Journals (Sweden)

    Patricio Dantagnan


    Full Text Available Despite the well known importance of ω-3 polyunsaturated fatty acids (PUFA in marine and freshwater fish larvae, there are few studies on how essential fatty acid requirements and composition on whole body can be altered by changes in water salinity. The present study aimed to determine the effect of salinity on ω-3 PUFA requirements, larval growth survival and fatty acid composition of Galaxias maculatus larvae cultured at two different salinities (0 and 15 g L-1 for 20 days while fed rotifers containing two different levels of ω-3 PUFA (1.87 and 3.16%. The results denoted a marked difference in ω-3 PUFA requirements and in the pattern of fatty acid deposition in the whole body of larvae reared at different salinities, depending of ω-3 PUFA in diets. Thus, to improve growth and survival larvae of G. maculatus reared at 0 g L-1 require higher levels of ω-3 PUFA, principally 18:3 ω-3. Larvae reared at salinities of 15 g L-1 require low levels of ω-3 PUFA for optimal survival, especially 18:3 ω-3. Eicosapentaenoic acid and docosahexaenoic acid content in the whole body of larvae was also affected by water salinity.

  13. Genotoxic effects of the herbicide Roundup(®) in the fish Corydoras paleatus (Jenyns 1842) after short-term, environmentally low concentration exposure. (United States)

    de Castilhos Ghisi, Nédia; Cestari, Marta Margarete


    The glyphosate-based herbicide, Roundup(®), is one of the most used pesticides worldwide. In concert with the advent of transgenic crops resistant to glyphosate, the use of this pesticide has led to an increase in agricultural yields. The objective of this study was to evaluate the genotoxic effect that the herbicide Roundup(®) (at a concentration of 6.67 μg/L, corresponding to 3.20 μg/L glyphosate) can have on the fish Corydoras paleatus. Treatment groups were exposed for 3, 6, and 9 days, and effects were analyzed using the piscine micronucleus test (PMT) and comet assay. A group subjected to filtered water only was used as a negative control. The PMT did not show differences between the control and exposed groups for any of the treatment times. In contrast, the comet assay showed a high rate of DNA damage in group exposed to Roundup(®) for all treatment times, both for blood and hepatic cells. We conclude that for the low concentration used in this research, the herbicide shows potential genotoxic effects. Future research will be important in evaluating the effects of this substance, whose presence in the environment is ever-increasing.

  14. Population structure and reproductive aspects of puffer fish Sphoeroides annulatus (Jenyns, 1842 (Osteichthyes: Tetraodontidae, landed in Teacapán, Sinaloa, Mexico

    Directory of Open Access Journals (Sweden)

    María Candelaria Valdez-Pineda


    Full Text Available The puffer fish Sphoeroides annulatus is an important target species for the artisanal fishing fleets of NW Mexico. To obtain information on population structure of the local stock, we determined the total length and total weight (TL and TW ranges, sex ratio and reproductive stages of 745 specimens of this species, landed from May 2010 to April 2011 in Teacapán, Sinaloa, NW Mexico. TL ranged from 15 to 40 cm and TW from 100 to 1600 g. There were no differences between mean TL (27.41 ± 4.14 cm and TW (534.5 ± 226.0 g of males and females respectively. Sex ratio was not significantly different (χ2 = 0.03, P > 0.05 from 1F:1M. The length-weight relationship for both sexes was TW = 0.044TL2.815, R² = 0.895. The value of the slope b was significantly lower than 3 (P < 0.05, and indicated negative allometric growth. The distribution of maturity stages indicated one main reproductive period from June to September and one less intense, from November to December for females, and in December for males. Size at first maturity (L50% of females was 26.52 cm and that of males was 27.41 cm.

  15. Blood cytology of the common jollytail (Galaxias maculatus) (Jenyns, 1842) (Osmeriformes: Galaxiidae) at postlarval and adult stages Estudio de la citología sanguínea del puye (Galaxias maculatus) (Jenyns, 1842) (Osmeriformes: Galaxiidae) en estado postlarval y adulto


    I Valdebenito; Busse, K; N. Jaramillo; Hernández, A.


    “Puye” (Galaxias maculatus) is a small freshwater fish species of great interest to Chilean aquaculture diversification, because of the high commercial value reached by its transparent larvae or “cristalino”. This study presents the first data with regard to blood cytology in larvae and adults of this specie. Blood smears stained with May Grünwald-Giemsa were analysed through optical microscopy. The results show that in G. maculatus larvae the flowing blood has a trans...

  16. Blood cytology of the common jollytail (Galaxias maculatus (Jenyns, 1842 (Osmeriformes: Galaxiidae at postlarval and adult stages Estudio de la citología sanguínea del puye (Galaxias maculatus (Jenyns, 1842 (Osmeriformes: Galaxiidae en estado postlarval y adulto

    Directory of Open Access Journals (Sweden)

    I Valdebenito


    Full Text Available “Puye” (Galaxias maculatus is a small freshwater fish species of great interest to Chilean aquaculture diversification, because of the high commercial value reached by its transparent larvae or “cristalino”. This study presents the first data with regard to blood cytology in larvae and adults of this specie. Blood smears stained with May Grünwald-Giemsa were analysed through optical microscopy. The results show that in G. maculatus larvae the flowing blood has a transparent look and mature erythrocytes were not observed, as opposed to the adults of this species where the complete erythrocyte developmental line could be observed. In leucocytes, there was no presence of coarse grain cells such as basophils and eosinophyls. In general, the morphology of the blood cells found in larvae and adults of G. maculatus have the same characteristic traits as described elsewhere in reports of other teleosts.El puye (Galaxias maculatus es un pequeño pez nativo de gran interés para la diversificación de la acuicultura chilena, debido al alto valor comercial de su estado postlarval cristalino. La presente investigación entrega los primeros antecedentes respecto de la citología sanguínea de postlarvas y adultos de esta especie, determinada mediante microscopía óptica utilizando frotis sanguíneos preparados con May Grünwald-Giemsa. Los resultados muestran que en la sangre circulante de G. maculatus en estado de postlarva no se observan eritrocitos maduros y la sangre es de aspecto transparente. Sin embargo, en adultos se pudo observar la línea eritrocitaria completa y en leucocitos no se observó la presencia de células de grano grueso como son los basófilos y eosinófilos. La morfología de las células encontradas en ambos estados del desarrollo del puye mantienen las características propias entregadas en la literatura para peces teleósteos.

  17. Efecto de la ración alimenticia sobre la maduración gonadal y acumulación de grasa de anchoveta peruana (Engraulis ringens Jenyns, 1842 en cautiverio Effect of feeding ration on gonad maturation and fat accumulation in Peruvian anchovy (Engraulis ringens Jenyns, 1842 in captivity

    Directory of Open Access Journals (Sweden)

    Carlos Espinoza


    Full Text Available Se evaluó el efecto de la ración alimenticia sobre la tasa de maduración gonadal, el desempeño de las gónadas maduras y la redistribución de la energía consumida en gónada, músculo o grasa corporal en ejemplares de anchoveta peruana Engraulis ringens en condiciones de cautiverio Estos resultados ayudan a comprender los procesos reproductivos ocurridos en el medio natural ante alteraciones de factores ambientales tales como los eventos El Niño y La Niña, de gran implicancia en el ecosistema y las pesquerías del Pacífico oriental. El tiempo trascurrido desde el estadio inmaduro hasta vitelogénico fue de 45 días bajo condiciones alimenticias energéticamente óptimas y temperatura alrededor de 16,5°C (46,1 cal g-1 pez día-1 . Las hembras alimentadas con 138,3 cal g-1 pez día-1 alcanzaron la máxima vitelogénesis en 30 días y, aunque el alimento fue excesivo, no incrementaron su masa muscular pero si presentaron mayor acumulación de grasa corporal y presencia de ovocitos más grandes, lo cual indica un incremento en el almacenamiento energético en la hembra y su progenie. Los ovocitos vitelogénicos de los peces alimentados con 46,1 cal g-1 pez día-1 presentaron atresia más rápido que los ovocitos vitelogénicos de peces alimentados con 138,3 cal g-1 pez día-1 . Aunque la cantidad de alimento fue adecuada, las hembras no desovaron durante el experimento. En machos, la disponibilidad de alimento también aceleró la maduración gonadal pero la expulsión de espermatozoides parece haber estado condicionada por la presencia de hembras con ovocitos en máximo estado de vitelogénesis.We analyzed the effect that feeding rations have on gonad maturation, mature gonad performance, and the redistribution of the energy taken up by the gonads, muscle, and body fat in captive specimens of Peruvian anchovy (Engraulis ringens. These results help us understand the reproductive processes occurring in the natural environment given changes in the environmental factors such as El Niño and La Niña events, which heavily affect the ecosystem and fisheries in the East Pacific. The specimens required 45 days under optimal feeding conditions (46.1 cal g-1 fish day-1 and at a temperature of 16,5°C to go from an unyoked to a vitellogenic stage. Those females fed 138.3 cal g-1 fish day-1 reached maximum vitellogenesis in 30 days. Despite the excessive amount of food, the specimens' muscle mass did not increase. However, greater body fat accumulation and larger vitellogenic ovocytes were observed, indicating augmented energy storage for the female and her offspring. The yoked oocytes from fish fed 46.1 cal g-1 fish day-1 became atretic earlier than oocytes from fish fed 138.3 cal g-1 fish day-1. Although the food supply was adequate, the females did not spawn during the experiment. In males, food availability also accelerated gonad maturation, but the release of sperm was apparently conditioned by the presence of females with ovocytes in the advanced vitellogenic stage.

  18. Impact of El Niño events on pelagic fisheries in Peruvian waters (United States)

    Ñiquen, Miguel; Bouchon, Marilú


    Using data from stock assesment surveys on pelagic resources during El Niño events of 1972/73, 1982/83, 1997/98, we analyze biological changes on pelagic ecosystems and pelagic fisheries during different stages of development of El Niño phenomenon: emergence, full, final and post-Niño. Results indicate changes in spatial distribution of resources, their concentration and size structure. In anchovy (Engraulis ringens) a decrease in biomass was observed, which was estimated at 1.2 million tons in September 1998, the lowest throughout the 1990s. This resource showed an asymmetric distribution towards the south of Peru. Other pelagic resources increased their biomass during or after Niño events, primarily sardine (Sardinops sagax), jack mackerel (Trachurus murphyi), pacific mackerel (Scomber japonicus), and longnose anchovy (Anchoa nasus). At the end of the El Niño phenomenon we found less productivity but more diversity in the pelagic ecosystem. During the 1997/98 El Niño, the diversity index (Manual de Ecologia, 1a Edition, Editorial Trillas, Mexico, 267pp) increased from 0.87 to 1.23-1.70. In both the emergence stage and fully developed stages of El Niño we found large numbers of sardine and longnose anchovy present simultaneously. Size structure of sardine, jack mackerel, and pacific mackerel showed an increase in juveniles. Anchovy during El Niño showed a single modal group composed of adults, but the post-Niño phase indicated an increase in juveniles with an average length of 6-7 cm. In El Niño conditions spawning among anchovy was low, but among sardine and pacific mackerel it was high. We observed, for the first time during full spawning, juvenile sardines with a total length of 18-20 cm. The anchovy spawning season during the post-Niño phase was considerably lengthened, from April to December 1998. Drastic change occurred in fisheries when monospecific fisheries, based on anchovy before El Niño, became multispecific fisheries based on sardine, jack

  19. Preservación y abundancia de escamas de peces en sedimentos del margen continental de Chile (21-36° S Fish scale preservation and abundance in sediments from the continental margin off Chile (21-36° S

    Directory of Open Access Journals (Sweden)



    Full Text Available Con el objetivo de evaluar la relación entre la preservación de escamas de peces y las variaciones en las condiciones redox en sedimentos del margen continental de Chile, este trabajo presenta recuentos de escamas de peces y concentraciones normalizadas de elementos redox sensibles (Mo/Al, S/Al, Fe/Al en ocho testigos de sedimento recolectados en la zona de minimo oxígeno frente a Chile (Iquique: 20°15' S, bahía de Mejillones: 23° S y Concepción: 36° S. En el norte de Chile (Iquique y Mejillones predominan las escamas de anchoveta (Engraulis ringens y de peces de la familia Myctophidae (media = 90 y 120 escamas 1.000 cm-3, respectivamente mientras que en Chile centro-sur (Concepción son más abundantes las escamas de jurel (Trachurus murphy; media = 140 escamas 1.000 cm-3. La abundancia de escamas de merluza común (Merluccius gayi gayi y de sardina (Sardinops sagax es aproximadamente un orden de magnitud más baja que la de anchoveta o jurel. En general, los valores más altos y los rangos más amplios de variación en las razones Mo/Al, S/Al y Fe/Al se encuentran en Mejillones (Mo/Al ~0,8-12 mg g-1, S/Al 0,2-4,6 g g-1, Fe/Al 0,3-0,7 g g-1 seguidos por Iquique (Mo/Al -0,2-1,8; S/Al 0,2-0,7, Fe/Al 0,5-0,8, mientras que Concepción revela valores más bajos y poco variables (Mo/Al ~0,07, S/Al ~0,15 y Fe/Al ~0,5. La razón Mo/Al, utilizada como indicador de paleo-oxigenación, permite inferir condiciones reductoras relativamente más intensas en los sedimentos de la Bahía de Mejillones e Iquique que en Concepción. En las tres localidades de muestreo se evidencia una asociación estadísticamente significativa entre la abundancia de escamas de anchoveta y el logaritmo de la razón Mo/Al (r²= 0,46; P 1 mg g-1.The relationship between fish scale preservation and variations in the sediment redox conditions on Chile's continental shelf are evaluated herein through fish scale counts and normalized concentrations of redox sensitive elements

  20. Trends in spatio-temporal distribution of Peruvian anchovy and other small pelagic fish biomass from 1966-2009 Tendencias espacio-temporales en la distribución de la biomasa de anchoveta peruana y de otros peces pelágicos pequenos entre 1966 y 2009

    Directory of Open Access Journals (Sweden)

    Mariano Gutiérrez


    Full Text Available Changes in abundance and distribution of anchovy and other species of pelagic fish of the Northern Humboldt Current System (NHCS are driven by environmental forcing variations in different time and spatial scales between the coastal 'cold' ecosystem and the 'warm' oceanic one. Data to study these fluctuations have come mostly from the fishery to show how anchovy (Engraulis ringens increases when sardine (Sardinops sagax declines and vice versa. However, using acoustic data on latitudinal biomass we show that other species as mackerel (Scomber japonicus and jack mackerel (Trachurus murphyi also follow the same opposed trend, then the fishery data hides the true dimension of the balance of abundance among species. Based on Hovmoller diagrams we scrutinized the changes in interannual latitudinal acoustic biomass, landings and influence of El Nino events from 1966 to 2009 in order to describe: 1 how the anchovy decadal distribution pattern moved from south to north since the 1960's; 2 how there have been produced concomitant changes in the latitudinal abundance and distribution of other species such as sardine, jack mackerel and mackerel before, during and after El Nino events; and 3 what was the overall effect of the succession of El Nino events on all these pelagic species. We concluded that: a every El Nino event has had an effect on the expansion or contraction of pelagic species distribution and abundance, with different latitudinal effects; and b the El Nino 1997-98 did not trigger but accelerated a decline phase on the abundance of sardine, jack mackerel and mackerel by a reduction of their ideal habitat due to an expansion of the coastal ecosystem caused by a shallower location of the upper limit of the Oxygen Minimum Zone (OMZ These findings observed using past data might be taken into consideration for fishery management purposes when considering future scenarios.Los cambios en la abundancia y distribución de anchoveta y de otras especies

  1. Biogeochemical and ecological impacts of boundary currents in the Indian Ocean (United States)

    Hood, Raleigh R.; Beckley, Lynnath E.; Wiggert, Jerry D.


    , though local wind forcing can lead to transient near shore current reversals and localized coastal upwelling. The poleward direction of this eastern boundary current is unique. Due to its high kinetic energy the Leeuwin Current sheds anomalous, relatively high chlorophyll, warm-core, downwelling eddies that transport coastal diatom communities westward into open ocean waters. Variations in the Leeuwin transport and eddy generation impact many higher trophic level species including the recruitment and fate of rock lobster (Panulirus cygnus) larvae. In contrast, the transport of the Agulhas Current is very large, with sources derived from the Mozambique Channel, the East Madagascar Current and the southwest Indian Ocean sub-gyre. Dynamically, the Agulhas Current is upwelling favorable; however, the spatial distribution of prominent surface manifestations of upwelling is controlled by local wind and topographic forcing. Meanders and eddies in the Agulhas Current propagate alongshore and interact with seasonal changes in the winds and topographic features. These give rise to seasonally variable localized upwelling and downwelling circulations with commensurate changes in primary production and higher trophic level responses. Due to the strong influence of the Agulhas Current, many neritic fish species in southeast Africa coastal waters have evolved highly selective behaviors and reproductive patterns for successful retention of planktonic eggs and larvae. For example, part of the Southern African sardine (Sardinops sagax) stock undergoes a remarkable northward migration enhanced by transient cyclonic eddies in the shoreward boundary of the Agulhas Current. There is evidence from the paleoceanographic record that these currents and their biogeochemical and ecological impacts have changed significantly over glacial to interglacial timescales. These changes are explored as a means of providing insight into the potential impacts of climate change in the Indian Ocean.

  2. Effects of Climate Change on Sardine Productivity in the California Current System (United States)

    Baumgartner, T. R.; Auad, G.; Miller, A. J.


    The Pacific sardine (Sardinops sagax caeruleus) is one of several coastal pelagic, planktivorous species of fish that provide important trophic links within the ecosystems of the major eastern and western boundary currents. Significant and persistent change in sardine productivity has occurred in the California Current over interdecadal periods in response to reorganization of basin-wide, ocean-atmosphere circulation. Less extreme, but still significant changes in sardine productivity are associated with interannual to decadal-scale climate variability. A precipitous decline of the sardine population began in the mid-1940s with a shift in climate leading to cooling of the California Current system. While the decline, and ultimately the collapse of the population, was exacerbated by intensive fishing, the sardine also suffered a severe reduction in productivity with the southward contraction of favorable thermal habitat that led to restriction of the population to the waters off Southern California and Baja California. This southward displacement resulted in geographic separation of the population from the region off central and northern California that is characterized by significantly higher concentrations of zooplankton that supported the previous levels of success in spawning and larval development. The climate shift in 1976-77 led to the recovery of the population and extension of its range of distribution northwards into the waters off British Columbia. The relation of reproductive success of the sardine population to interannual and decadal climate change was examined for the period 1982-2005 using a suite of seasonal indices representing climate processes and habitat conditions (including zooplankton food levels) occurring through the different stages in the sardine life cycle. We used both stepwise regression and EOF analyses to determine the association between levels of recruitment success and seasonal indices of the Pacific Decadal Oscillation, Ekman

  3. Effects of Ocean Climate on Transboundary Movement of Coastal Pelagic Resources Between the EEZs of Mexico and the United States (United States)

    Baumgartner, T. R.; Garcia, J.; Sanchez, C.; Lo, N. C.; Charter, R.


    Interannual to multidecadal changes in ocean climate directly impact access to transboundary coastal pelagic resources between fisheries operating in U.S. and Mexican waters. This study provides a preliminary analysis of the scale of year-to-year shifts in the distribution of the Pacific sardine (Sardinops sagax caeruleus) with data from 2002 and 2003. One of the purposes of this initiative is to provide a template for collaborative research to guide regional policy development for responsible and sustainable utilization of the shared resource. This work is based on coordinated quarterly ocean surveys run by Mexican (the IMECOCAL program=Investigaciones Mexicanas de la Corriente de California) and U.S. scientists (the CalCOFI program=California Cooperative Oceanic Fisheries Investigations) allowing us to evaluate the annual state of the pelagic ecosystem from northern California to southern Baja California. The subject of this study is the "subarctic stock" of the Pacific sardine which is centered off California in the U.S. and extends southwards to the region off central Baja California. Estimates of sardine biomass in U.S. and Mexican waters, based on the rates of egg production measured during the IMECOCAL and CalCOFI surveys of April 2002 and April 2003, show order of magnitude differences in the relative proportions of biomass in the Mexican EEZ that is associated with the contrasts in ocean climate resulting from the regional effects of El Niño during April 2003. Results indicate a significant northward shift of the sardine stock off Mexico during 2003: we estimate that approximately 20 percent of the total biomass of the stock was located in the Mexican EEZ during spring of 2002 while the shift in ocean climate resulted in the presence of only 2 percent of the biomass of the stock in Mexican waters during April, 2003. A second, more southerly sardine stock extended from southern to central Baja California in April, 2003, but it was out of reach of the fleet

  4. Download this PDF file

    African Journals Online (AJOL)


    which feeds primarily on the large populations of sardine. Sardinops .... 1930 and 1971, with the bulk of the construction completed by .... guanay cormorants were best fitted by the equation ..... Clearly, the population dynamics of seabirds in ...

  5. Diet of Cnesterodon decemmaculatus (Poeciliidae and Jenynsia multidentata (Anablepidae in a hypertrophic shallow lake of Uruguay Dieta de Cnesterodon decemmaculatus (Poeciliidae y Jenynsia multidentata (Anablepidae en un lago hipereutrófico de Uruguay

    Directory of Open Access Journals (Sweden)

    Federico Quintans


    Full Text Available Se analizaron las dietas de Cnesterodon decemmaculatus (Jenyns, 1842 y Jenynsia multidentata (Jenyns, 1842 en el Lago Rodó, un lago urbano hipereutrófico de Montevideo, Uruguay. Ambas especies mostraron un comportamiento omnívoro. Los ítems más consumidos por C. decemmaculatus fueron zooplancton, perifiton, fitoplancton y detritos; la dieta de J. multidentata incluyó zooplancton, insectos, crustáceos y peces juveniles. Estos resultados sugieren que ambas especies pueden actuar como planctívoros facultativos. La comunidad de peces de este lago se caracteriza por la dominancia de C. decemmaculatus y J. multidentata. Bajo esta condición, la depredación sobre el zooplancton de gran tamaño podría indirectamente estar contribuyendo a una alta abundancia de fitoplancton y una baja transparencia del agua.Diet of Cnesterodon decemmaculatus (Jenyns, 1842 and Jenynsia multidentata (Jenyns, 1842 were analysed in Lake Rodó, an urban hypertrophic lake from Montevideo, Uruguay. Both species displayed omnivory. The most consumed items for C. decemmaculatus were zooplankton, periphyton, phytoplankton and detritus; the diet of J. multidentata included zooplankton, insects, crustaceans and juvenile fish. Our results suggest that both species could be acting as facultative planktivores. The fish community of this lake is characterised by the dominance of C. decemmaculatus and J. multidentata. Under this condition, predation on large-bodied zooplankton could indirectly be contributing to maintain a high phytoplankton abundance and a low water transparency.

  6. Feeding of two Cichlidae species (Perciformes in an hypertrophic urban lake

    Directory of Open Access Journals (Sweden)

    Yafe Alejandro


    Full Text Available Diet of two cichlid species, Cichlasoma facetum (Jenyns, 1842, and Gymnogeophagus rhabdotus Hensel, 1870, was studied in Rodó Lake, an urban hypertrophic lake in Uruguay. The stomach contents from 192 individuals of C. facetum and 202 of G. rhabdotus, obtained through seasonal sampling in the year 2000, were analyzed. The occurrence frequency and the alimentary importance index of each food item were calculated for each season and size class in both species. Cichlasoma facetum fed upon insects (mainly chironomid larvae and pupae, fish (Cnesterodon decemmaculatus Jenyns, 1842, and vegetals (algae, periphyton and macrophytes debris; large individuals also fed upon the freshwater shrimp Palaemonetes argentinus Nobili, 1901. Gymnogeophagus rhabdotus consumed zooplankton (mainly copepods, vegetals (algae and detritus and Chironomidae larvae in a lesser extent.

  7. Investigation of the midgut structure and ultrastructure in Cimex lectularius and Cimex pipistrelli (Hemiptera: Cimicidae)


    Rost-Roszkowska, M. M.; Vilimova, J; Włodarczyk, A; Sonakowska, L; Kamińska, K; Kaszuba, F; Marchewka, A; Sadílek, D


    Cimicidae are temporary ectoparasites, which means that they cannot obtain food continuously. Both Cimex species examined here, Cimex lectularius (Linnaeus 1758) and Cimex pipistrelli (Jenyns 1839), can feed on a non-natal host, C. lectularius from humans on bats, C. pipistrelli on humans, but never naturally. The midgut of C. lectularius and C. pipistrelli is composed of three distinct regions—the anterior midgut (AMG), which has a sack-like shape, the long tube-shaped middle midgut (MMG), a...

  8. Abundancia y distribución de las especies ícticas (Osteichthyes del río San Francisco-Cosquín, Córdoba, Argentina Abundance and distribution of fish species (Osteichthyes from San Francisco - Cosquín river in Córdoba, Argentina

    Directory of Open Access Journals (Sweden)

    Andrea Cecilia Hued

    Full Text Available It was made the characterization of the San Francisco-Cosquín Mountain River fish community, Córdoba, Argentina. Samples of fish were taken from selected sites from November 1998 to November 1999. Eleven species were recorded, eight of which are first reports for this river. Relative abundance for each species, species richness, diversity and dominance were estimated. Bryconamericus iheringi (Boulenger, 1887 y Jenynsia multidentata (Jenyns, 1842 were the most abundant.

  9. The life history of Pygidiopsis macrostomum Travassos, 1928 (Digenea: Heterophyidae

    Directory of Open Access Journals (Sweden)

    Susana Balmant Emerique Simões


    Full Text Available The life history of the trematode Pygidiopsis macrostomum Travassos, 1928 is described for the first time. Rediae and cercariae were obtained from naturally infected snails Heleobia australis (d´Orbigny, a new first intermediate host. Metacercariae were found encysted in the mesenteries of three naturally infected guppies, Phalloptychus januarius (Hensel, Jenynsia multidentata (Jenyns (new host records and Poecilia vivipara Bloch and Schneider. Experimental infections were successfully completed in the intermediate hosts H. australis and Poe. vivipara reared in the laboratory and hamsters Mesocricetus auratus Waterhouse were utilised as a definitive host.

  10. Osteologia comparada entre as espécies de peixes-rei Odontesthes Evermann & Kendall (Osteichthyes, Atherinopsidae do sistema lagunar Patos-Mirim, no extremo sul do Brasil Comparative osteology among the species of silverside Odontesthes Evermann & Kendall (Osteichthyes, Atherinopsidae in the Patos-Mirim lagoons systems, in the Southern of Brazil

    Directory of Open Access Journals (Sweden)

    Marlise de A. Bemvenuti


    Full Text Available Uma comparação osteológica é apresentada e discutida entre sete espécies de peixes-rei que ocorrem no complexo lagunar Patos-Mirim, no extremo sul do Brasil. Cinco espécies habitam ambientes de água doce: Odontesthes bonariensis (Valenciennes, 1835, O. humensis De Buen, 1953, O. retropinnis (De Buen, 1953, O. perugiae Evermann & Kendall, 1906, O. mirinensis Bemvenuti, 1995. Outras duas, O. incisa (Jenyns, 1842 e O. argentinensis (Valenciennes, 1835, ocorrem no estuário e na região costeira adjacente.An osteological comparison of seven species of silversides that occur from the Patos-Mirim lagoons systems is presented and discussed. Five species inhabit freshwater environments, Odontesthes bonariensis (Valenciennes, 1835, O. humensis De Buen, 1953, O. retropinnis (De Buen, 1953, O. perugiae Evermann & Kendall, 1906, and O. mirinensis Bemvenuti, 1995. The other species, O. incisa (Jenyns, 1842 and O. argentinensis (Valenciennes, 1835, inhabit in coastal and brackish waters.

  11. O impacto da pesca do camarão-rosa Farfantepenaeus paulensis (Perez-Farfante (Decapoda, Penaeidae nas assembléias de peixes e siris do Parque Nacional da Lagoa do Peixe, Rio Grande do Sul, Brasil The impact of the Pink Shrimp Farfantepenaeus paulensis (Perez-Farfante (Decapoda, Penaeidae fishery on the fish and crab assemblages of Lagoa do Peixe National Park, Rio Grande do Sul, Brazil

    Directory of Open Access Journals (Sweden)

    Daniel Loebmann


    Full Text Available Este trabalho avaliou do impacto da pesca do camarão-rosa Farfantepenaeus paulensis (Perez-Farfante, 1967 sobre a assembléia de peixes e crustáceos do Parque Nacional da Lagoa do Peixe. Constatou-se que, em média, a composição nas capturas da pesca do camarão-rosa, com a arte de pesca aviãozinho, é semelhantes àquelas descrita em para outros estuários do Rio Grande do Sul, quando considerada apenas a proporção das grandes categorias analisadas (espécie alvo - camarão-rosa 53%: captura acessória 24%: rejeito 23%. A composição da fauna acompanhante (captura acessória + rejeito apresente diferenças pronunciadas ao longo do gradiente salino da laguna. No geral, ao nível específico, as espécies de peixes capturadas com maior intensidade - Brevoortia pectinata (Jenyns, 1842, Micropogonias furnieri (Desmarest, 1823 e Jenynsia multidentata (Jenyns, 1842 - diferem daquelas capturadas em outros estuários do Rio Grande do Sul, onde, além de M. furnieri, os bagres Genidens barbus (Lacepède, 1803 e Genidens genidens (Cuvier, 1829 dominam nas capturas. As estimativas do potencial de impacto das capturas acessório e do rejeito apresentaram valores, do ponto de vista pesqueiro, bastantes satisfatórios, quando comparados com outras artes de pesca do camarão, o que sugere que a decisão de proibir a pesca no Parque Nacional da Lagoa do Peixe não deve ser baseada no impacto da pesca do camarão-rosa sobre a fauna acompanhante, mas sim na atividade pesqueira em si, uma vez que a legislação Brasileira vigente proíbe a pesca dentro de Parques Nacionais.This work evaluates the impact of the pink shrimp Farfantepenaeus paulensis (Perez-Farfante, 1967 fishery on fish and crab assemblages of Lagoa do Peixe National Park, Brazil. We observed that composition of catches is similar to shrimp fisheries using fyke-net at others estuaries of Rio Grande do Sul State: pink shrimp (53%, accessory catches (24% and bycatch (23%. However, fishery

  12. Plasticity in the diet of Astyanax taeniatus in a coastal stream from south-east Brazil

    Directory of Open Access Journals (Sweden)

    LR. Manna

    Full Text Available In this work we aimed to characterise the diet of Astyanax taeniatus (Jenyns 1842 (Characiformes, Characidae along the Mato Grosso stream and we hypothesised that the diet of this species would vary according to spatial, seasonal and ontogenetic differences. Specimens were collected every second month at three sites with different physical attributes. The feeding habits of 651 specimens were analysed using the Alimentary Index (IAi. Analysis of the diet showed an effect of spatial, temporal and ontogenetic factors. Vegetal allochthonous items were more important in the diet of Astyanax taeniatus in upstream sites while animal autochthonous items were more important downstream. Ontogenetic differences in the diet were significant only in upstream sites, where adults consumed a greater amount of vegetal matter than juveniles. These results reinforce the idea that Astyanax species are opportunistic and show trophic plasticity.

  13. Piscivory in a Miocene Cetotheriidae of Peru: first record of fossilized stomach content for an extinct baleen-bearing whale. (United States)

    Collareta, Alberto; Landini, Walter; Lambert, Olivier; Post, Klaas; Tinelli, Chiara; Di Celma, Claudio; Panetta, Daniele; Tripodi, Maria; Salvadori, Piero A; Caramella, Davide; Marchi, Damiano; Urbina, Mario; Bianucci, Giovanni


    Instead of teeth, modern mysticetes bear hair-fringed keratinous baleen plates that permit various bulk-filtering predation techniques (from subsurface skimming to lateral benthic suction and engulfment) devoted to various target prey (from small invertebrates to schooling fish). Current knowledge about the feeding ecology of extant cetaceans is revealed by stomach content analyses and observations of behavior. Unfortunately, no fossil stomach contents of ancient mysticetes have been described so far; the investigation of the diet of fossil baleen whales, including the Neogene family Cetotheriidae, remains thus largely speculative. We report on an aggregate of fossil fish remains found within a mysticete skeleton belonging to an undescribed late Miocene (Tortonian) cetotheriid from the Pisco Formation (Peru). Micro-computed tomography allowed us to interpret it as the fossilized content of the forestomach of the host whale and to identify the prey as belonging to the extant clupeiform genus Sardinops. Our discovery represents the first direct evidence of piscivory in an ancient edentulous mysticete. Since among modern mysticetes only Balaenopteridae are known to ordinarily consume fish, this fossil record may indicate that part of the cetotheriids experimented some degree of balaenopterid-like engulfment feeding. Moreover, this report corresponds to one of the geologically oldest records of Sardinops worldwide, occurring near the Tortonian peak of oceanic primary productivity and cooling phase. Therefore, our discovery evokes a link between the rise of Cetotheriidae; the setup of modern coastal upwelling systems; and the radiation of epipelagic, small-sized, schooling clupeiform fish in such highly productive environments.

  14. Piscivory in a Miocene Cetotheriidae of Peru: first record of fossilized stomach content for an extinct baleen-bearing whale (United States)

    Collareta, Alberto; Landini, Walter; Lambert, Olivier; Post, Klaas; Tinelli, Chiara; Di Celma, Claudio; Panetta, Daniele; Tripodi, Maria; Salvadori, Piero A.; Caramella, Davide; Marchi, Damiano; Urbina, Mario; Bianucci, Giovanni


    Instead of teeth, modern mysticetes bear hair-fringed keratinous baleen plates that permit various bulk-filtering predation techniques (from subsurface skimming to lateral benthic suction and engulfment) devoted to various target prey (from small invertebrates to schooling fish). Current knowledge about the feeding ecology of extant cetaceans is revealed by stomach content analyses and observations of behavior. Unfortunately, no fossil stomach contents of ancient mysticetes have been described so far; the investigation of the diet of fossil baleen whales, including the Neogene family Cetotheriidae, remains thus largely speculative. We report on an aggregate of fossil fish remains found within a mysticete skeleton belonging to an undescribed late Miocene (Tortonian) cetotheriid from the Pisco Formation (Peru). Micro-computed tomography allowed us to interpret it as the fossilized content of the forestomach of the host whale and to identify the prey as belonging to the extant clupeiform genus Sardinops. Our discovery represents the first direct evidence of piscivory in an ancient edentulous mysticete. Since among modern mysticetes only Balaenopteridae are known to ordinarily consume fish, this fossil record may indicate that part of the cetotheriids experimented some degree of balaenopterid-like engulfment feeding. Moreover, this report corresponds to one of the geologically oldest records of Sardinops worldwide, occurring near the Tortonian peak of oceanic primary productivity and cooling phase. Therefore, our discovery evokes a link between the rise of Cetotheriidae; the setup of modern coastal upwelling systems; and the radiation of epipelagic, small-sized, schooling clupeiform fish in such highly productive environments.

  15. Metacercariae of Centrocestus formosanus (Trematoda: Heterophyidae in Australoheros facetus (Pisces: Cichlidae in Brazil Metacercárias de Centrocestus formosanus (Trematoda: Heterophyidae em Australoheros facetus (Pisces: Cichlidae no Brasil

    Directory of Open Access Journals (Sweden)

    Hudson Alves Pinto


    Full Text Available Heterophyid metacercariae were found in the gills of Australoheros facetus (Jenyns, 1842 collected from the Pampulha reservoir, Belo Horizonte, Minas Gerais, Brazil, between February and April 2010. The cysts were counted and used to perform experimental studies (artificial excystment and infection of mice. Fifty specimens of A. facetus were analyzed and it was found that the prevalence of infection was 100% and mean infection intensity was 134 metacercariae/fish (range: 4-2,510. Significant positive correlations were seen between total fish length and intensity of infection; between fish weight and intensity of infection, and between parasite density and fish length. Morphological analyses on metacercariae and adult parasites obtained from experimentally infected mice made it possible to identify Centrocestus formosanus (Nishigori, 1924. This is the first report of C. formosanus in A. facetus in Brazil.Metacercárias de Heterophyidae foram encontradas nas brânquias de Australoheros facetus (Jenyns, 1842 coletados na represa da Pampulha, Belo Horizonte, Minas Gerais, Brasil, entre fevereiro e abril de 2010. Os cistos obtidos foram contados e utilizados em estudos experimentais (desencistamento artificial e infecção de camundongos. Cinquenta exemplares de A. facetus foram analisados, sendo verificada prevalência de infecção de 100% e intensidade média de infecção de 134 metacercárias/peixe (variando entre 4 e 2510. Verificou-se correlação positiva entre a intensidade de infecção e comprimento total dos peixes; entre a intensidade de infecção e o peso dos peixes e entre a densidade parasitária e o comprimento total. A análise morfológica das metacercárias e dos parasitos adultos obtidos em camundongos experimentalmente infectados permitiu a identificação de Centrocestus formosanus (Nishigori, 1924. Este é o primeiro relato de C. formosanus em A. facetus no Brasil.

  16. Caracterización del consumo de larvas de culícidos (Diptera en dos especies de peces indígenas de la zona central de Argentina

    Directory of Open Access Journals (Sweden)

    Alejo F. Bonifacio


    Full Text Available Los mosquitos representan una amenaza para la salud del hombre y de los animales debido a que actúan como vectores de distintas enfermedades. Especies de peces nativos son potenciales candidatos a tenerse en cuenta para control biológico de poblaciones de culícidos. Experiencias de consumo de media hora y de 24 horas por Cnesterodon decemmaculatus (Jenyns, 1842 y Jenynsia multidentata (Jenyns, 1842 se llevaron a cabo con larvas de Culex pipiens (Linnaeus, 1758, midiéndose longitud estándar, ancho de boca y peso en individuos de las dos especies. En ambas pruebas, J. multidentata consumió más C. pipiens que C. decemmaculatus, consumiendo las hembras de esta última especie más que los machos (e igual a ambos sexos de J. multidentata en la prueba de 24 horas de duración. Estos resultados no variaron cuando se compararon tantos consumos absolutos o relativos para las pruebas de media hora, sin embargo cuando se compararon los consumos relativos al peso no se encontraron diferencias entre las especies para las pruebas de 24 horas. Análisis de regresión entre las tasas de consumo versus las variables morfométricas y el peso mostraron poco valor explicativo en las pruebas de media hora de duración, mientras que en las pruebas de 24 horas de duración los análisis de regresión tuvieron un mayor valor explicativo, especialmente con el ancho de la boca. Por último, pruebas de media hora de duración fueron llevadas a cabo exponiendo a hembras de C. decemmaculatus con larvas de C. pipiens y Aedes aegypti (Linnaeus, 1742 observándose una fuerte preferencia por las últimas. Este trabajo permitió evidenciar que las especies de peces en estudio presentan grandes diferencias en las tasas de consumo de C. pipiens en periodos cortos. Estas diferencias se atenuaron cuando las tasas de consumo se prolongaron y hasta llegar a desaparecer cuando el peso se tuvo en cuenta.

  17. Variação espaço-temporal da ictiofauna da zona de arrebentação da Praia do Cassino, Rio Grande do Sul, Brasil Spatiotemporal variation in the fish fauna of Praia do Cassino, Rio Grande do Sul, Brazil

    Directory of Open Access Journals (Sweden)

    Mauro Sergio Pinheiro Lima


    Full Text Available This study analyzes the spatiotemporal variation of the ichthyofauna of the surf zone of Praia do Cassino, municipality of Rio Grande (state of Rio Grande do Sul, Brazil from October 2005 to September 2006. Fishes were collected monthly and during daytime using a large beach seine net (30 m x 1.8 m, with 12 mm uniform mesh manufactured with monofilament nylon wire. Five hauls were conducted on each of three sampling sites: one near the jetties of Patos Lagoon and two located 5 km and 10 km south from the jetties, respectively. We caught 10,066 fishes, weighting 128,486 g, distributed in 37 species belonging to 18 families that are similar in species composition to the dominant fish fauna - Trachinotus marginatus (Cuvier, 1832, Atherinella brasiliensis (Quoy & Gaimard, 1825, Brevoortia pectinata (Jenyns, 1842, Mugil platanus (Gunther, 1880, Menticirrhus americanus (Linnaeus, 1758, Menticirrhus littoralis (Holbrook, 1847, and Oncopterus darwinii (Steindachner, 1874 - usually collected in the beaches of Rio Grande do Sul with a smaller net. The dominant size classes were between 50 and 100 mm TL and represent 43% of total catch. Based on CCA analysis we suggested that the ichthyofauna is primarily structured by seasonal variation in the physicochemical and environmental parameters and secondarily by the spatial difference between areas nearer ( approximately 10 km from the Patos Lagoon's jetties. The composition and dominance of the fish community of the surf zone of Cassino Beach changed little in the latest 20 years, indicating a possible stability of the system.

  18. Estrutura populacional, aspectos da reprodução e alimentação dos Cyprinodontiformes (Osteichthyes de um riacho do sudeste do Brasil Population structure, reproductive aspects and feeding of Cyprinodontiformes fishes (Osteichthyes from a coastal stream in southeastcrn Brazil

    Directory of Open Access Journals (Sweden)

    José Marcelo Rocha Aranha


    Full Text Available The population structure, reproductive aspects and feeding of Phalloceros caudimaculatus (Hensel, 1868, Poecilia vivipara Bloch & Schneider (1801, Phalloptychus januarius (Hensel, 1868 e Jenynsia lineata (Jenyns, 1842 were studied in five sampling stations in the Ubatiba stream, municipality of Maricá (State of Rio de Janeiro, Brazil. In relation to the population structure, P. caudimaculatus was more representative upstream; P. vivipara mid-stream and downstream; P. januarius and J. lineata downstream. The species presented preponderance of females, except in the intermediate length classes. The occurence of imatures and females with young pointed out a long reproductive period and favoured areas for reproduction of the four species. The young forms of P. caudimaculatus were more abundant in station 1 (upstream, P. vivipara in station 4 (downstream and P. januarius and J. lineata in station 5 (Maricá coastal lagoon. The higher occurences of females with young belong to P. caudimaculatus, in station 1 (upstream and P. vivipara and P. januarius in station 5 (Maricá lagoon. The four studied species presented herbivorous diet and the differences found in the feeding may reflect the differences in the food availability in the microhabitats used by the species. So, we concluded that the studied species presented evident segregation in several levels of the different available resources in the environment.

  19. Investigation of the midgut structure and ultrastructure in Cimex lectularius and Cimex pipistrelli (Hemiptera: Cimicidae). (United States)

    Rost-Roszkowska, M M; Vilimova, J; Włodarczyk, A; Sonakowska, L; Kamińska, K; Kaszuba, F; Marchewka, A; Sadílek, D


    Cimicidae are temporary ectoparasites, which means that they cannot obtain food continuously. Both Cimex species examined here, Cimex lectularius (Linnaeus 1758) and Cimex pipistrelli (Jenyns 1839), can feed on a non-natal host, C. lectularius from humans on bats, C. pipistrelli on humans, but never naturally. The midgut of C. lectularius and C. pipistrelli is composed of three distinct regions-the anterior midgut (AMG), which has a sack-like shape, the long tube-shaped middle midgut (MMG), and the posterior midgut (PMG). The different ultrastructures of the AMG, MMG, and PMG in both of the species examined suggest that these regions must fulfill different functions in the digestive system. Ultrastructural analysis showed that the AMG fulfills the role of storing food and synthesizing and secreting enzymes, while the MMG is the main organ for the synthesis of enzymes, secretion, and the storage of the reserve material. Additionally, both regions, the AMG and MMG, are involved in water absorption in the digestive system of both Cimex species. The PMG is the part of the midgut in which spherites accumulate. The results of our studies confirm the suggestion of former authors that the structure of the digestive tract of insects is not attributed solely to diet but to the basic adaptation of an ancestor.

  20. Variability and evolutionary implications of repetitive DNA dynamics in genome of Astyanax scabripinnis (Teleostei, Characidae) (United States)

    Barbosa, Patrícia; Leal, Eliza Viola; da Silva, Maelin; de Almeida, Mara Cristina; Moreira-Filho, Orlando; Artoni, Roberto Ferreira


    Abstract DNA sequences of multiple copies help in understanding evolutionary mechanisms, genomic structures and karyotype differentiation. The current study investigates the organization and distribution of different repetitive DNA in the standard complement and B chromosomes in Astyanax scabripinnis (Jenyns, 1842) chromosomes from three allopatric populations in Campos do Jordão region, São Paulo State, Brazil. The location of microsatellite sequences showed different chromosome distribution between Lavrinha Farm Stream (LFS) and Lake of Pedalinho (LP) populations. However, the karyotype of these populations basically followed the pattern of dispersed distribution in the A complement, conspicuous in telomeric/interstitial regions and preferential accumulation in the B chromosome. The B chromosome showed heterogeneous location of microsatellite probes CA, CAC and GA. The H3 and H4 histone genes were isolated from the total genome of the species and then the chromosomal mapping was performed by fluorescence in situ hybridization (FISH). The FISH signals showed high similarity for the probes H3 and H4 mapping in genomes of the populations analyzed. The sequences (GATA)n revealed a sex-specific trend between the chromosomal location in males and females at (LFS) and (LP) populations. Although species that comprise the Astyanax scabripinnis complex do not have morphologically differentiated sex chromosomes, the preferential GATA location – sex-associated – may represent a sex chromosome in differentiation. PMID:28919955

  1. Impairments in aromatase expression, reproductive behavior, and sperm quality of male fish exposed to 17β-estradiol. (United States)

    Guyón, Noelia F; Roggio, María A; Amé, María V; Hued, Andrea C; Valdés, María E; Giojalas, Laura C; Wunderlin, Daniel A; Bistoni, María A


    Growing evidence shows that environmental estrogen can reach levels that are high enough to exert adverse reproductive effects on wild fish populations. The authors report different parameters of male reproductive behavior, brain, and gonadal aromatase expression, as well as sperm quality in an internally fertilizing fish species (Jenynsia multidentata, Jenyns) exposed to environmentally relevant concentrations of 17β-estradiol (E(2) ). Adult males were exposed to 0, 50, 100, and 250 ng/L E(2) over 28 d. The authors' findings demonstrate that E(2) exposure resulted in a very clear increase in brain aromatase transcript abundance at all assayed concentrations compared with control; however, no effects on gonadal aromatase expression were observed. Behavioral measures revealed increased sexual activity at 50 ng/L but not 100 or 250 ng/L E(2) . In contrast to the molecular and behavioral responses, the condition factor, gonadosomatic index, and sperm quality were unaltered by E(2) exposure. The results from the present work suggest that E(2) affects some aspects of the reproductive biology of J. multidentata. These modifications in the reproductive biology caused by exposure to E(2) could potentially lead to long-term effects at population levels that may not always be immediately evident. To the best of the authors' knowledge, this is the first report on the combined effect of E(2) on aromatase expression, sexual behavior, and sperm parameters in fish.

  2. Highly Similar Morphologies Between Chromosomes Bearing U2 snRNA Gene Clusters in the Group Astyanax Baird and Girard, 1854 (Characiformes, Characidae): An Evolutionary Approach in Species with 2n = 36, 46, 48, and 50. (United States)

    Piscor, Diovani; Centofante, Liano; Parise-Maltempi, Patricia Pasquali


    Repetitive sequences and their chromosomal locations have been widely studied in species of the Astyanax genus. However, the chromosomal organization of U2 snDNA remains largely unknown. The aims of this study were to examine the chromosomal contexts of U2 snRNA and 5S rRNA genes in Astyanax species and determine the degree of chromosome morphological similarity between species with different diploid numbers. Clusters of U2 snDNA and 5S rDNA were determined in nine species of Astyanax, including two karyomorphs of Astyanax fasciatus Cuvier, 1819. All species exhibited U2 snDNA clusters on two chromosome pairs, except Astyanax mexicanus De Filippi, 1853 (one pair). The 5S rDNA clusters were located on one chromosome pair in Astyanax altiparanae Garutti and Britski, 2000, and Astyanax marionae Eigenmann, 1911, two pairs in Astyanax abramis Jenyns, 1842, Astyanax asuncionensis Géry, 1972, Astyanax bockmanni Vari and Castro, 2007, Astyanax eigenmanniorum Cope, 1894, A. fasciatus (karyomorphs I and II), and Astyanax schubarti Britski, 1964, and four pairs in A. mexicanus. The relationships between the repetitive sequences in different species suggest that A. schubarti and A. mexicanus exhibit an unusual U2 snDNA chromosomal format as a result of events occurring in the evolutionary history of the Astyanax group.

  3. Morphological development of Corydoras aff. paleatus (Siluriformes, Callichthyidae and correlation with the emergence of motor and social behaviors

    Directory of Open Access Journals (Sweden)

    Daniel Rodríguez-Ithurralde


    Full Text Available Here we examine major anatomical characteristics of Corydoras aff. paleatus (Jenyns, 1842 post-hatching development, in parallel with its neurobehavioral evolution. Eleutheroembryonic phase, 4.3-8.8 days post-fertilization (dpf; 4.3-6.4 mm standard length (SL encompasses from hatching to transition to exogenous feeding. Protopterygiolarval phase (8.9-10.9 dpf; 6.5-6.7 mm SL goes from feeding transition to the commencement of unpaired fin differentiation, which marks the start of pterygiolarval phase (11-33 dpf; 6.8-10.7 mm SL defined by appearance of lepidotrichia in the dorsal part of the median finfold. This phase ends with the full detachment and differentiation of unpaired fins, events signaling the commencement of the juvenile period (34-60 dpf; 10.8-18.0 mm SL. Eleutheroembryonic phase focuses on hiding and differentiation of mechanosensory, chemosensory and central neural systems, crucial for supplying the larval period with efficient escape and nutrient detection-capture neurocircuits. Protopterygiolarval priorities include visual development and respiratory, digestive and hydrodynamic efficiencies. Pterygiolarval priorities change towards higher swimming efficacy, including carangiform and vertical swimming, necessary for the high social interaction typical of this species. At the end of the protopterygiolarval phase, simple resting and foraging aggregations are seen. Resting and foraging shoals grow in complexity and participant number during pterygiolarval phase, but particularly during juvenile period.

  4. A review of Kudoa-induced myoliquefaction of marine fish species in South Africa and other countries

    Directory of Open Access Journals (Sweden)

    Sun S. Henning


    Full Text Available Myoliquefaction of fish musculature results in customer quality complaints and in huge economic losses, especially with regard to Pacific hake (Merluccius productus, farm-reared Atlantic salmon (Salmo salar, South African pilchards (Sardinops ocellatus and Cape snoek (Thyrsites atun. Myoliquefaction, or jelly flesh, is caused by proteolytic enzymes released by the marine myxosporean parasite,Kudoa thyrsites, after the death of the fish. Currently there are no fast methods of detection for this microscopic parasite, and because myoliquefaction is evident only after 38-56 h post-mortem, infected fish inevitably reach the processor and/or consumer. Several methods of detection have been investigated, but most of these methods are time-consuming and/or result in destruction of the fish, and are thus impractical for fishing vessels and fish processors. Limited research is available on possible means of destroying or inhibiting the post-mortem activity of the parasitic proteolytic enzyme. Means such as manipulating post-mortem pH and temperature control have been suggested; leaving opportunities for research into food technology applications such as cold-chain management and ionising radiation.

  5. Satellite remote sensing prediction of Japanese pilchard fishing ground in the Huanghai Sea and the East China Sea

    Institute of Scientific and Technical Information of China (English)

    杨纪明; 顾传宬; 李丽云; 李军; 高崇义; 李文泽


    The thermophily, fishing season and central fishing ground of Japanese pilchard (Sardinops melanosticta) were studied by using satellite remote sensing (SRS) and other methods in Haizhou Bay and Tsushima waters during 1986 -1990. A rapid prediction method of fishing ground is presented. Moreover. the results indicated that the thermophilic values of the fish stock are 11 - 20℃ and both fishing grounds are in increasing temperature process from the beginning to the end of the fishing period. The Japanese pilchards gather vigorously at the sea surface temperature of 15-17℃. The water temperature is a key factor affecting the fishing season and the catch of the fishing ground. The increasing temperature process restricts the fishing season development and central fishing ground formation. The accuracy of 15 predictions made in the Haizhou Bay fishing ground is up to 91.3%, and 37 predictions made in the Tsushima fishing ground shorten the fish detection time by 13.4% - 22% on the average.

  6. Mixed layer depth variations in the Kuroshio Extension in relation to Japanese sardine (United States)

    Yasuda, I.; Nishikawa, H.; Itoh, S.


    Mixed layer depths in and south of the Kuroshio Extension changed from deep to shallow states in the late- 1980s and early-1990s. This change corresponded to the collapse of Japanese sardine (Sardinops melanostictus). This mixed layer shoaling was accompanied by lower temperature in 200-400m depths and higher temperature near the surface. Wintertime field survey in 2006 (Hakuho-maru KH06-1 cruise) demonstrated that late winter maximum mixed layer depth reach deeper with the greater isothermal depth of 14-15degC and higher temperature in 300-400m depth. High-resolution ocean model hindcast data suggests that the accelerated near-surface Kuroshio/Kuroshio Extension associated with the elevated sea-surface height anomaly enhanced the heat transport near the surface. This greater heat advection near the surface overrides the cooler subtropical mode water that was created in the previous years possibly causes the shallower winter mixed layer and collapse of the Japanese sardine.

  7. Fish larvae from the Gulf of California

    Directory of Open Access Journals (Sweden)

    Gerardo Aceves-Medina


    Full Text Available Taxonomic composition of fish larvae was analysed from 464 plankton samples obtained during 10 oceanographic surveys in the Gulf of California between 1984 and 1988. We identified 283 taxa: 173 species, 57 genera, and 53 families. Tropical and subtropical species predominated except during the winter, when temperate-subarctic species were dominant. The most abundant species were the mesopelagic Benthosema panamense, Triphoturus mexicanus and Vinciguerria lucetia, but the coastal pelagic species Engraulis mordax, Opisthonema spp., Sardinops caeruleus and Scomber japonicus were also prominent. The taxonomic composition of the ichthyoplankton shows the seasonality of the Gulf as well as environmental changes that occurred between the 1984-1987 warm period and the 1956-1957 cool period previously reported. The presence of E. mordax larvae as one of the most abundant species in the Gulf provides evidence of the reproduction of this species two years before the development of the northern anchovy fishery and the decline of the sardine fishery in the Gulf of California.

  8. Daily food intake of Kajikia audax (Philippi, 1887 off Cabo San Lucas, Gulf of California, Mexico Tasa de consumo diario de alimento de Kajikia audax (Philippi, 1887 frente a Cabo San Lucas, golfo de California, México

    Directory of Open Access Journals (Sweden)

    Leonardo A Abitia-Cárdenas


    Full Text Available The daily food intake rates of the striped marlin, Kajikia audax (Perciformes: Istiophoridae, were estimated using qualitative and quantitative analyses of their trophic spectrum. We analyzed the stomach contents of 505 striped marlin caught by the sport fishing fleet off Cabo San Lucas, Baja California Sur, Mexico, sampled from October 1987 through December 1989. The most important preys were chub mackerel (Scomber japonicus, California pilchard (Sardinops caeruleus, and jumbo squid (Dosidicus gigas; together these represented ~55% of the striped marlin diet. The daily food consumption was estimated to be 2 kg per day, or ~3.6% of the mean body weight of K. audax. The total biomass of the prey consumed by the striped marlin during the 27 months of sampling around Los Cabos was estimated at 24.8 ton, of which the chub mackerel represented ~29% (7.2 ton, California pilchard just under 16% (3.9 ton, and jumbo squid ~10% (2.5 ton. The feeding habits of K. audax are discussed in terms of the distribution of the epipelagic (neritic and oceanic zones, demersal, and benthic prey, confirming that striped marlin migrate vertically and horizontally in search of their food.Se estimó la tasa de consumo diario de alimento del marlín rayado Kajikia audax (Perciformes: Istiophoridae, sobre la base de análisis cualitativos y cuantitativos de su espectro trófico. Se analizó el contenido estomacal de 505 ejemplares capturados por la flota deportiva frente a Cabo San Lucas, Baja California Sur, México muestreados de octubre 1987 a diciembre 1989. Las presas más importantes fueron la macarela del Pacífico (Scomber japonicus, sardina monterrey (Sardinops caeruleus y calamar gigante (Dosidicus gigas, que en conjunto representaron aproximadamente el 55% de la dieta. La tasa de consumo de alimento fue estimado en 2 kg diarios, lo cual representó aproximadamente el 3,6% del peso corporal de K. audax. La biomasa total de presas consumidas por el marlín rayado

  9. Fish community structure in San Agustín Bay, Huatulco, Mexico Estructura comunitaria de peces en bahía San Agustín, Huatulco, México

    Directory of Open Access Journals (Sweden)



    Full Text Available San Agustín bay is one of the most important bays in the Huatulco National Park because it includes the broadest coral reef surface of this park, which supports a great diversity of fish species. The importance of the present work is that describes quantitatively, for first time, the fish assemblage of this reef area. Visual censuses were realized on transects, according to the coral reef size, on coral and rocky reefs, and coral rubble environments. 64 species, 46 genus and 29 families were registered. Seasonal variation in fish assemblage was observed; reflecting the influence of pelagic shoaling species associated with the Gulf of Tehuantepec upwelling, during the dry season. Thus species were Selar crumenophthalmus, Caranx caninus, and Sardinops caeruleus. For species more closely associated to the reef habitat little seasonal variation was observed for each species, except Chromis atrilobata, which exhibited high density during the dry season. Pomacentrids exhibited more affinity for coral reef, labrids and haemulids for coral rubble environments. The highest diversity values were on coral rubble and the highest density was on the coral reef. Our study suggests that in this region, the Gulf of Tehuantepec upwelling is an important factor as well as the heterogeneity of habitats in shaping the fish assemblages, which must be protected to maintain the biodiversity of this important ecosystemLa bahía de San Agustín es una de las más importantes del Parque Nacional Huatulco debido a que incluye al arrecife coralino más grande de este parque, el cual alberga una gran diversidad de especies de peces. La importancia del presente trabajo es describir cuantitativamente, por primera vez, la comunidad de peces de este habitat de arrecifes. Para ello se realizaron censos visuales en transectos de acuerdo al tamaño de los ambientes coralino, rocoso y de escombros. 64 especies, 46 géneros y 29 familias fueron registrados. Se observaron cambios

  10. Cestodes of the blue shark, Prionace glauca (Linnaeus 1758), (Carcharhiniformes: Carcharhinidae), off the west coast of Baja California Sur, Mexico. (United States)

    Méndez, Oscar; Galván-Magaña, Felipe


    The cestode species recovered from the spiral intestines of 27 blue sharks (Prionace glauca) (Linnaeus, 1758) are reported from the western coast of Baja California Sur (BCS). The sampling was undertaken on a monthly basis from January 2003 to January 2004. The helminthological examination indicated the presence of four species of cestodes: Platybothrium auriculatum Yamaguti, 1952; Prosobothrium japonicum Yamaguti, 1934; Anthobothrium caseyi (Yamaguti, 1934) Ruhnke & Caira, 2009; and Paraorygmatobothrium prionacis (Yamaguti, 1934) Ruhnke, 1994. Of all the 27 sharks examined, 88.8% were infected with at least one cestode species. The most frequent species was P. auriculatum infecting 85% of the spiral intestines examined. In contrast the species with the highest mean intensity was P. prionacis (80.4 200). The species richness of cestodes in P. glauca is very similar in other regions of the world despite its wide distribution; however, this richness is low compared with other species of sharks within the same family. The feeding and host-specific are important factors that influence the parameters of infection of cestodes in this shark. On the west coast of BCS, Prionace glauca feeds mainly on red crab Pleuroncodes planipes Stimpson, 1860; squids Gonatus californiensis Young, 1972, Ancistrocheirus lesueurii (D'Orbigny, 1842), Haliphron atlanticus Steenstrup, 1861, and low proportion of fish teleosts as Merluccius productus (Ayres, 1855), Sardinops sp. Hubbs, 1929 and Scomber japonicus Houttuyn, 1872. We speculate that these prey could be involved as the second intermediate hosts of these cestodes, as in other members of these genera, although the life cycles of none are known.

  11. Basic cytogenetics and physical mapping of ribosomal genes in four Astyanax species (Characiformes, Characidae) collected in Middle Paraná River, Iguassu National Park: considerations on taxonomy and systematics of the genus (United States)

    Paiz, Leonardo Marcel; Baumgärtner, Lucas; da Graça, Weferson Júnio; Margarido, Vladimir Pavan


    Abstract Karyotypes and chromosomal characteristics of both minor and major rDNAs in four fish species known popularly as “lambaris”, namely Astyanax abramis (Jenyns, 1842), Astyanax asuncionensis Géry, 1972, Astyanax correntinus (Holmberg, 1891) and Astyanax sp. collected from downstream of the Iguassu Falls (Middle Paraná River basin), preservation area of the Iguassu National Park, were analyzed by conventional and molecular protocols. Astyanax abramis had diploid chromosome number 2n=50 (4m+30sm+8st+8a) and single AgNORs (pair 22), Astyanax asuncionensis had 2n=50 (8m+24sm+6st+12a) and single AgNORs (pair 20), Astyanax sp. had 2n=50 (4m+26sm+8st+12a) and single AgNORs (pair 25), and Astyanax correntinus had 2n=36 (12m+16sm+2st+6a) and multiple AgNORs (pairs 12, 15, 16, 17). FISH with 18S rDNA showed a single site for Astyanax abramis, Astyanax asuncionensis and Astyanax sp. and multiple for Astyanax correntinus (14 sites). FISH with 5S rDNA showed single 5S-bearing loci chromosome pair only for Astyanax asuncionensis and multiple for Astyanax abramis (four sites), Astyanax correntinus (five sites) and Astyanax sp. (four sites). Distinct distribution patterns of heterochromatin were observed for karyotypes of all species, with the exception of the first acrocentric chromosome pair characterized by centromeric, interstitial-proximal and telomeric blocks of heterochromatin on the long arm, which may represent homeology between karyotypes of Astyanax abramis and Astyanax asuncionensis. Our study showed species-specific characteristics which can serve in diagnosis and differentiation between Astyanax abramis and Astyanax asuncionensis, considered cryptic species, as well as strengthening the occurrence of a species of Astyanax not yet described taxonomically. In addition, the data obtained from first cytogenetic studies in Astyanax correntinus suggest a high similarity with Astyanax schubarti Britski, 1964, suggesting that these species may belong to the same

  12. Ocorrência e ecologia trófica de quatro espécies de Astyanax (Characidae em diferentes rios da bacia do rio Tibagi, Paraná, Brasil Occurrence and trophic ecology of four species of Astyanax (Characidae in different rivers of the Tibagi River Basin, Paraná, Brazil

    Directory of Open Access Journals (Sweden)

    Sirlei Terezinha Bennemann


    Full Text Available Na bacia do rio Tibagi, trechos dos rios Fortaleza, Iapó e Tibagi foram amostrados mensalmente, de maio de 2001 a abril de 2002, com tarrafas e redes de espera de diferentes malhagens. Foram capturados indivíduos de quatro espécies de Astyanax. Para conhecer como essas espécies utilizam o hábitat desses rios, foi calculada a constância, e as freqüências em número de exemplares foram comparadas pela análise de similaridade Bray-Curtis. A composição percentual dos alimentos consumidos foi ordenada usando-se a Análise de Componentes Principais (ACP. As proporções dos recursos alimentares foram avaliadas e classificadas quanto à natureza (animal ou material vegetal e origem (alóctone e autóctone. A constância e a baixa similaridade na abundância revelaram que as espécies têm preferências quanto ao porte do rio ou por determinado hábitat. Astyanax altiparanae Garutti & Britski, 2000 e A. fasciatus (Cuvier, 1819 ocorreram nos de maior porte, mas foram constantes somente no rio Tibagi. Astyanax eigenmanniorum (Cope, 1894 ocorreu em todos os rios, mas prefere hábitats próximos às desembocaduras de afluentes de grandes rios. Astyanax scabripinnis (Jenyns, 1842 esteve restrita ao Fortaleza, o rio de menor porte, subafluente do rio Tibagi. O número de itens alimentares consumidos variou de 11 a 23. Entre os alimentos principais, três itens foram comuns para as quatro espécies: restos de plantas (folhas e sementes de plantas terrestres, restos de insetos (de diferentes origens e não identificados e plantas aquáticas. Os vegetais e os insetos foram os principais alimentos para todas as espécies. A maior distinção na composição da dieta foi constatada para A. eigenmaniorum, devido à sua habilidade em explorar as plantas aquáticas, presentes em abundância, consumidas junto com carvão/sedimento, que estavam nas margens rochosas do rio Iapó. A similaridade quanto à origem e ao tipo de alimento consumido pelas quatro esp

  13. Elucidating dynamic responses of North Pacific fish populations to climatic forcing: Influence of life-history strategy (United States)

    Yatsu, A.; Aydin, K. Y.; King, J. R.; McFarlane, G. A.; Chiba, S.; Tadokoro, K.; Kaeriyama, M.; Watanabe, Y.


    In order to explore mechanistic linkages between low-frequency ocean/climate variability, and fish population responses, we undertook comparative studies of time-series of recruitment-related productivity and the biomass levels of fish stocks representing five life-history strategies in the northern North Pacific between the 1950s and the present. We selected seven species: Japanese sardine ( Sardinopus melanostictus) and California sardine ( Sardinopus sagax) (opportunistic strategists), walleye pollock ( Theragra chalcogramma, intermediate strategist), pink salmon ( Oncorhynchus gorbuscha, salmonic strategist), sablefish ( Anoplopoma fimbria) and Pacific halibut ( Hippoglossus stenolepis) (periodic strategists) and spiny dogfish ( Squalus acanthias, equilibrium strategist). The responses in terms of productivity of sardine, pink salmon, sablefish and halibut to climatic regime shifts were generally immediate, delayed, or no substantial responses depending on the particular regime shift year and fish stock (population). In walleye pollock, there were some periods of high productivity and low productivity, but not coincidental to climatic regime shifts, likely due to indirect climate forcing impacts on both bottom-up and top-down processes. Biomass of zooplankton and all fish stocks examined, except for spiny dogfish whose data were limited, indicated a decadal pattern with the most gradual changes in periodic strategists and most intensive and rapid changes in opportunistic strategists. Responses of sardine productivity to regime shifts were the most intense, probably due to the absence of density-dependent effects and the availability of refuges from predators when sardine biomass was extremely low. Spiny dogfish were least affected by environmental variability. Conversely, spiny dogfish are likely to withstand only modest harvest rates due to their very low intrinsic rate of increase. Thus, each life-history strategy type had a unique response to climatic

  14. Latitudinal variation in the recruitment dynamics of small pelagic fishes in the western North Pacific (United States)

    Watanabe, Yoshiro


    The subarctic Oyashio Current flows south-westward and the subtropical Kuroshio Current flows north-eastward in the western North Pacific, converging in the waters off northern Japan to form the Kuroshio-Oyashio transition region. Some small pelagic fishes inhabit the subarctic or subtropical waters, and others seasonally migrate north and south across the major ocean fronts. Environmental conditions in the subarctic and transition waters are variable, whereas in the subtropical Kuroshio waters conditions are relatively stable. Latitudinally different environmental conditions may affect vital parameters and recruitment variability of small pelagic fishes inhabiting the various waters. Pacific saury Cololabis saira migrate seasonally from the Kuroshio to Oyashio waters and spawn in the transition waters in autumn and spring and in the Kuroshio waters in winter. During 1990-1999, the coefficients of variation (CVs) of daily growth rates (G) and instantaneous mortality coefficients (M) were large for larvae and juveniles spawned in the northern transition waters, but relatively small for those from the southern Kuroshio waters. The Pacific stock of chub mackerel Scomber japonicus spawns in the Kuroshio waters in spring and early summer and migrates to the subarctic Oyashio waters in summer for feeding, whereas the Tsushima Warm Current stock spawns in the East China Sea in spring and fish remain in the subtropical warm waters throughout their lifetime. The Pacific stock had CVs > 100% for the fish aged 0-5 during 1970-2002. In contrast, the Tsushima Warm Current stock had CVs of 34-40% during 1973-2002. Pacific herring Clupea pallasii, which inhabits subarctic waters, had CVs of 118-178% for the fish aged 3-8 y during 1910-1954. Japanese sardine Sardinops melanostictus, which spawn in the subtropical Kuroshio waters and migrate to the subarctic Oyashio waters in summer for feeding, had CVs > 120% for the fish aged 0-4 during 1976-2003. Contrasting with these subarctic

  15. 九种鲱科鱼类线粒体DNA细胞色素b基因相对速率测试及分歧时间估计%Phylogenetic analysis and relative-rate test of nine Clupeidae fishes ( Osteichthyes: Clupeiformes) inferred from cytochrome b gene sequence of mitochondrial DNA

    Institute of Scientific and Technical Information of China (English)

    程起群; 卢大儒


    对鲱科9种鱼类的线粒体细胞色素b(cytb)基因序列进行综合分析.结果表明:(1)用NeighbourJoining(NJ)法构建的分子系统树显示盖纹沙丁鱼属的3种鱼类形成一个单系类群,鲱属2种鱼类形成一个单系类群,它们的bootstrap支持率均为100%.金色小沙丁鱼和短体小沙丁鱼形成一个单系类群,在NJ树中的支持率达到或超过50%.欧洲黍鲱与太平洋鲱和大西洋鲱是单系起源,其bootstrap支持率高达100%.系统发育结果还支持沙丁鱼属鱼类与盖纹沙丁鱼属鱼类是单系类群,支持率分别为87%和95%.但单系类群Ⅰ(包括大西洋鲱、太平洋鲱、欧洲黍鲱)和单系类群Ⅱ(包括欧洲沙丁鱼、加州沙丁鱼、南美拟沙丁鱼、斑点盖纹沙丁鱼)之间的系统发育关系尚不明确,因为它们之间的支持率很低.(2)dN/dS的比值显著的小于1(Ztest),提示由于功能限制,cytb基因受到强烈的负选择作用.(3)基于Tajima的1D和2D相对速率测试表明,分子钟假说在鲱科鱼类中是成立的;鲱科鱼类的分歧时间是0.12至13.45百万年间.%Phylogenetic analysis and relative- rate test of 9 Clupeidae fishes were performed using the cytochrome b(cytb) gene sequence data. Based on Kimura-2-Parameter(K2P) distance, bootstrapped NJ tree ( 1000 replicates) was generated from these 9 cytb gene sequences of Clupeidae fishes. Three species of genus Sardinops are monophyletic group, 2 species of genus Clupea are monophyletic group, and their bootstrap values are both 100%. Sardinella aurita and Sardinella maderensis are monophyletic group, their bootstrap value reached or exceed 50%. Sprattus sprattus which is a species of genus Sprattus, has a monophyletic origin with genus Clupea, their bootstrap value was 100%. The number of synonymous nucleotide substitution per synonymous site (dS) and the number of nonsynonymous nucleotide substitution per nonsynonymous site (dN) of cytb gene among Clupeidae fishes were calculated