Sample records for alevins

  1. Histologic and skeletal abnormalities in benzo(a)pyrene-treated rainbow trout alevins

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    Hose, J.E.; Hannah, J.B.; Puffer, H.W.; Landolt, M.L.


    Histological and skeletal examinations were performed on rainbow trout (Salmo gairdneri Richardson) alevins reared in 0.00, 0.08, 0.21, 0.39, 1.48, 2.40 or 2.99 ng/ml aqueous benzo(a)pyrene (BaP). Nuclear pycnosis and karyorrhexis were most common in neuroectodermal and mesodermal derivatives and in liver of BaP-treated alevins. Microphthalmia was observed in 17% of the test fish and was frequently associated with a patent optic fissure. Depressed mitotic rates in the retina and brain (but not liver) were observed in alevins reared in 0.21 to 1.48 ng/ml aqueous BaP. Test alevins had a significantly higher incidence of skeletal malformations in the skull and vertebral column, and abnormalities of vertebral arcualia often corresponded to areas of kyphoscoliotic flexures. 43 references, 3 figures, 4 tables.

  2. Survival of Apache Trout eggs and alevins under static and fluctuating temperature regimes (United States)

    Recsetar, Matthew S.; Bonar, Scott A.


    Increased stream temperatures due to global climate change, livestock grazing, removal of riparian cover, reduction of stream flow, and urbanization will have important implications for fishes worldwide. Information exists that describes the effects of elevated water temperatures on fish eggs, but less information is available on the effects of fluctuating water temperatures on egg survival, especially those of threatened and endangered species. We tested the posthatch survival of eyed eggs and alevins of Apache Trout Oncorhynchus gilae apache, a threatened salmonid, in static temperatures of 15, 18, 21, 24, and 27°C, and also in treatments with diel fluctuations of ±3°C around those temperatures. The LT50 for posthatch survival of Apache Trout eyed eggs and alevins was 17.1°C for static temperatures treatments and 17.9°C for the midpoints of ±3°C fluctuating temperature treatments. There was no significant difference in survival between static temperatures and fluctuating temperatures that shared the same mean temperature, yet there was a slight difference in LT50s. Upper thermal tolerance of Apache Trout eyed eggs and alevins is much lower than that of fry to adult life stages (22–23°C). Information on thermal tolerance of early life stages (eyed egg and alevin) will be valuable to those restoring streams or investigating thermal tolerances of imperiled fishes.

  3. Effect of acidic lake water on survival of aurora trout (Salvelinus fontinalis) embryos and alevins

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    Snucins, E.J.; Liimatainen, V.A.; Gale, P.A.


    During the 1960s the aurora trout, a rare color variant of the brook trout, disappeared from its native waters in northeastern Ontario. Its disappearance was attributed to acidification of the waters by atmospheric deposition of industrial emissions from metal smelters at Sudbury, Ontario. Recently, water quality in the Sudbury area has improved due to emission reductions. These experiments were designed to assess the toxicity of current water quality in the native lakes of aurora trout. During May 1984, hatchery-reared aurora trout alevins were held for 4 days in 3 of their native lakes (Whiligig, Whitepine and Wilderness with pH 4.5-4.8) and a control lake, Regan Lake (pH 6.5), and survival rates were assessed. In a second bioassay, embryos and alevins were buried in the substrate at 3 groundwater upwelling sites, and survival rates were assessed. The final test involved a 14-day exposure of groundwater-reared fish to ambient conditions.

  4. Otolith micro-structure analysis of rainbow trout alevins (Oncorhynchus mykiss under rearing conditions Análisis de la micro-estructura de otolitos en alevines de trucha arcoiris (Oncorhynchus mykiss en cautiverio

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    Guillermo Moyano


    Full Text Available Otolith microstructure (MO analysis was used to back-calculate growth patterns from hatching to the yolk-sac absorption in Rainbow trout alevins (Oncorhynchus mykiss, under experimental conditions, from winter to spring in Central-Chile. MO showed the following main features: (i occurrences of multiple primordia in the central region of otolith (MP; (ii several increments (22 ± 3 rings before a prominent hatch check surrounding MP and (iii existence of a very distinctive check associated to yolk-sac absorption. Further findings were the validation of daily periodicity of micro-increments and a significant linear relationship (P La micro-estructura de otolitos (MO fue utilizada para retro-calcular los patrones de crecimiento, desde la eclosión hasta la absorción del saco vitelino, en alevines de trucha arcoiris (Oncorhynchus mykiss, en la zona central de Chile. La MO mostró tres características principales: (i ocurrencia de múltiples primordios en la región central de los otolitos (MP, (ii formación de varios micro-incrementos antes de la eclosión (22 ± 3 micro-incrementos (iii y existencia de una marca distintiva correspondiente a la absorción del saco vitelino. Otros resultados fueron la validación de la periodicidad diaria de micro-incrementos y la existencia de una relación lineal significativa (P < 0,001; r2 = 0,91 entre la longitud máxima del otolito (LMO y la longitud total de los alevines (L T. La relación lineal L MO-L T validó el uso del método de intercepto biológico, para retro-calcular las tasas diarias de crecimiento (TDC. Las TDC mostraron una tendencia decreciente desde la eclosión hasta 6 días después de la absorción del saco vitelino (16 ± 1 días, las TDC variaron desde los 0,22 mm d-1 a los 0,34 mm d-1 (0,30 ± 0,037. La MO demostró ser una herramienta efectiva para el análisis retrospectivo de los patrones de crecimiento en alevins una vez absorbido su saco vitelino.

  5. Estimation de la survie des alevins de carpe (C. carpio au cours de leur premier mois d'existence

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    Full Text Available Des observations réalisées sur deux stations piscicoles de Madagascar, dans des étangs ne recevant ni engrais ni nourriture, révèlent qu'au cours de leur premier mois les alevins de carpe (C. carpio subissent des mortalités voi-sines de 50 %. Ces dernières sont encore plus élevées en début et en fin de saison de reproduction. Au début, les fortes mortalités sont dues à la température trop basse et aux disponibilités alimentaires insuffisantes ; en fin de saison de reproduction, la température trop élevée et la mauvaise qualité des œufs sont sans doute en cause. Une fumure adéquate des étangs de grossissement des alevins et une alimentation correcte des géniteurs permettront peut-être de diminuer ces mortalités.

  6. Does broodstock nutritional history affect the response of progeny to different first-feeding diets? A whole-body transcriptomic study of rainbow trout alevins. (United States)

    Lazzarotto, Viviana; Corraze, Geneviève; Larroquet, Laurence; Mazurais, David; Médale, Françoise


    The whole-body transcriptome of trout alevins was characterised to investigate the effects of long-term feeding of rainbow trout broodstock females a diet free of fishmeal and fish oil on the metabolic capacities of progeny. Effects were studied before first feeding and after 3 weeks of feeding diets containing different proportions of marine and plant ingredients. Feeding alevins plant-based diets resulted in lower fish body weight, irrespective of maternal nutritional history. No differences in whole-body lipids were found between treatments, and the tissue fatty acid profile strongly reflected that of the respective broodstock or first-feeding diets. We showed that the maternal diet history did not significantly affect expressions of any genes before the first feeding. Interestingly, we found an effect of maternal nutritional history on gene expression in alevins after 3 weeks of feeding. The major differences in the transcriptome of alevins from plant-based diet-fed females compared with those from commercial-fed females were as follows: (i) down-regulation of genes involved in muscle growth/contraction and (ii) up-regulation of genes involved in carbohydrate and energy metabolism related to the delay in growth/development observed with plant-based diets. Our findings also showed an effect of the first-feeding diets, irrespective of maternal nutritional history. Specifically, the introduction of plant ingredients resulted in the up-regulation of genes involved in amino acid/protein and cholesterol metabolism and in differences in the expressions of genes related to carbohydrate metabolism. Information gained through this study opens up avenues for further reduction of marine ingredients in trout diets, including the whole rearing cycle. PMID:27112276

  7. Dévalaison et survie d'alevins de saumon atlantique (Salmo salar L. en milieu semi-naturel contrôlé

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    BEALL E.


    Full Text Available Dans un chenal artificiel expérimental, des œufs de saumon atlantique (Salmo salar L. ont été pondus naturellement ou ont été enfouis au stade embryonné. A la fin de la résorption de la vésicule, une fraction importante des alevins survivants dévale de la zone de frayère. La dévalaison semble stimulée par des baisses de niveau ou des hausses de température et ralentie en période de pleine lune. D'autres facteurs pouvant être responsables de cette dévalaison sont discutés. La survie jusqu'à la collecte de tous les alevins est estimée à 74 p. 100 pour les sujets issus de la reproduction naturelle et est égale à 80 p. 100 pour ceux issus d'œufs introduits dans le gravier au stade embryonné. Des comparaisons entre ces résultats et ceux obtenus dans d'autres chenaux de fraie ou en milieu naturel montrent la validité de cette méthode pour la production d'alevins de saumon atlantique destinés au repeuplement.

  8. Flavobacterium psychrophilum y su patología en alevines de Onchorhynchus mykiss del centro piscícola El Ingenio, Huancayo


    Jorge León; Rita Ávalos; Milagros Ponce


    En el presente trabajo se reporta la presencia de Flavobacterium psychrophilum, como agente causante de la patología “enfermedad bacteriana del agua fría” en alevines de Onchorhynchus mykiss “trucha arco iris” del Centro Piscícola El Ingenio, Junín (3250 m de altitud). La lesión macroscópica externa más frecuente fue la ulceración profunda de la región dorsal del pez acompañado de un ennegrecimiento localizado de la piel. Internamente se observó una marcada esplenomegalia, palidez del hígado,...

  9. Efecto del calcio sobre la toxicidad aguda de aluminio en alevines de trucha arcoiris (Oncorhynchus mykiss expuestos en aguas de diferente pH

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    Rolando Vega


    Full Text Available En la producción de alevines de salmón de la región de la Araucanía (sur de Chile se presentan importantes eventos de mortalidad aguda sin rasgos patológicos aparentes. El problema se focaliza en ejemplares de 0,2 a 1 g y las causas apuntan a procesos de acidificación del pH del agua y a la presencia de ciertos metales pesados, entre los cuales destaca el aluminio, que alcanza concentraciones más allá de los rangos de tolerancia de los peces. La información científica indica que concentraciones de 5 mg Ca L-1 en el afluente son suficientes para mantener a salvo los peces del efectos tóxico del aluminio. Sin embargo, los problemas en la producción de alevines de salmón indican que se requiere un mayor conocimiento científico y evidencia experimental que soporte el desarrollo de procesos y tecnologías para el tratamiento de los afluentes de las pisciculturas chilenas. En este trabajo se evaluó el efecto de cuatro concentraciones de calcio (0, 5, 10 y 20 mg Ca L-1 sobre la toxicidad aguda de 500 μg Al L-1 en alevines de trucha arcoiris (Oncorhynchus mykiss de 0,1 g en agua de cultivo a pH 5, 6 y 7. El objetivo del trabajo fue determinar la dosis de calcio que reduce la toxicidad aguda de aluminio y los tiempos mínimos de reacción que podrían disponer los piscicultores para tomar medidas preventivas ante una concentración aguda de aluminio en el agua de cultivo. Los resultados indican que antes de 8 h de exposición a una concentración tóxica de aluminio los piscicultores deberían asegurar en el agua de cultivo una dosis superior a 10 mg Ca L-1 y un pH >6 como medida remedial para reducir el efecto de intoxicación aguda causada por aluminio.

  10. Stratégies d'utilisation de l'habitat par les alevins post-émergents de truite commune (Salmo trutta et de saumon Atlantique (Salmo salar

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    Full Text Available Des observations réalisées en fluvarium pendant les deux semaines suivant l'émergence d'alevins de truite commune (Salmo trutta et de saumon Atlantique (S. salar, montrent que ces deux espèces développent des stratégies différentes d'utilisation de l'habitat. Les alevins de saumon sont fortement inféodés au substrat, ils passent l'essentiel de leur temps au contact du fond et les tentatives de captures de proies et les comportements agressifs sont rares. Les alevins de truite occupent rapidement un poste de chasse où ils se tiennent en nage statique, bien détachés du substrat, les tentatives de captures de proies et les comportements agressifs sont beaucoup plus fréquents. Ces différences sont discutées en fonction de l'habitat sélectionné par les deux espèces à ce stade de développement.

  11. Flavobacterium psychrophilum y su patología en alevines de Onchorhynchus mykiss del centro piscícola El Ingenio, Huancayo

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    Jorge León


    Full Text Available En el presente trabajo se reporta la presencia de Flavobacterium psychrophilum, como agente causante de la patología “enfermedad bacteriana del agua fría” en alevines de Onchorhynchus mykiss “trucha arco iris” del Centro Piscícola El Ingenio, Junín (3250 m de altitud. La lesión macroscópica externa más frecuente fue la ulceración profunda de la región dorsal del pez acompañado de un ennegrecimiento localizado de la piel. Internamente se observó una marcada esplenomegalia, palidez del hígado, riñón y branquias, inflamación del intestino y acumulación de líquido ascítico en el peritoneo. No se detectó hemorragia interna. En Agar Cytophaga Modificado (ACM según Anaker & Ordal (1959 fueron aisladas inicialmente 29 Gram negativas, de las cuales según la caracterización fenotípica y pruebas bioquímicas 9 fueron consideradas como F. psychrophilum. Pruebas de susceptibilidad antibiótica mostraron alta sensibilidad de las cepas a Gentamicina, Ceftazidina, oxitetraciclina, Norfloxacina, furazolidona, Ciprofloxacina y Cefoxitina.


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    Full Text Available La démographie d’une population de truite (Salmo trutta L. a été étudiée, dans un contexte de repeuplements en alevins nourris, sur le Redon, un affluent du lac Léman. On trouve sur le Redon une situation typique de nombreux affluents du Léman : une zone aval ouverte sur le lac mais rapidement interrompue par un obstacle empêchant la remontée des truites de lac. Des relâchers d’alevins nourris issus d’œufs de géniteurs sauvages de truite de lac ou de géniteurs domestiques, pratiqués en fin de printemps-début été à des densités de 40-60 ind./100 m2, fournissent un recrutement additionnel important pouvant constituer la part dominante du peuplement automnal en 0 +, puis 1 +. Sur les zones ouvertes à la pêche, colonisées ou non par la truite de lac, la densité de la population automnale en place s’effondre entre le stade 1 + et les stades > 1 +. Les résultats comparatifs entre zones ouvertes ou fermées à la pêche indiquent que la pêche peut être un facteur de mortalité important. La dynamique comparée des truites d’origine lacustre ou sédentaire suggère l’existence d’un taux de sédentarisation plus faible pour les 1 + issus de truites de lac comparativement aux 1 + issus de la fraie de truites sédentaires en zone de réserve. Une expérimentation suggère l’existence de mouvements de dévalaison ayant lieu avant octobre et touchant préférentiellement les 0 + d’origine lacustre ayant eu la croissance initiale la plus forte. L’étude montre que : - des alevins nourris d’origine lacustre ou domestique, relâchés en fin de printemps-début été, fournissent des géniteurs de truite de lac remontant dans la rivière de relâcher, avec cependant une proportion moindre (4 fois dans le cas de l’origine domestique comparativement à l’origine lacustre. Malgré leur forte contribution aux stades de juvéniles 0 + et 1 +, les alevins domestiques de pisciculture contribuent peu aux retours de g

  13. Microhabitats utilisés par les alevins 0+ d'une communauté de cyprins rhéophiles : analyse de l'évolution de la communauté et des densités de population

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    BARAS E.


    Full Text Available L'évolution de l'occupation des microhabitats par les alevins de la communauté de cyprins rhéophiles de l'Ourthe a été étudiée au cours de l'été et de l'automne 1994 par échantillonnage ponctuel d'abondance (électrodes fixes prépositionnées, courant continu. 16155 poissons (10-75 mm appartenant à 15 espèces ont été recensés sur 78 sites d'échantillonnage de 2 m2 . Les espèces les plus représentées étaient Leuciscus cephalus, Leuciscus leuciscus et Chondrostoma nasus (respectivement 43,6 %, 20,7 % et 16,7 % des captures estivales. L'analyse factorielle des correspondances d'une matrice site x (espèce x taille met en évidence une subdivision progressive de la communauté au cours de l'été en espèces d'eau vive (B. barbus et L. leuciscus et d'eau lente, davantage associées à un couvert végétal (L. cephalus et C. nasus. La densité maximale observée (fin juin est de 1500 alevins (25 mm m-2, correspondant à une biomasse de 250 g m-2. Le modèle explicatif de la densité généré par analyse de régression multiple pas-à-pas explique 60,0 % de la variabilité de la densité par les variables vitesse de courant, température de l'eau et date d'échantillonnage, cette variable intégrant le concept de mortalité-dispersion au cours de la saison de croissance. Les implications de la méthodologie et des résultats présentés au plan de la gestion des écosystèmes lotiques sont brièvement discutés.

  14. Sistema energéticamente eficiente y de bajo costo para controlar la temperatura y aumentar el oxígeno en estanques de cultivo de alevines de tilapia roja

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    Rubén Darío Vásquez-Salazar


    Full Text Available El artículo expone un sistema automático para controlar la temperatura y aumentar el oxígeno en estanques de cultivo de alevines de tilapia roja en la granja John Jairo González, del Politécnico Colombiano Jaime Isaza Cadavid. El control se realiza a través de un PLC que recibe dos señales de temperatura ubicadas en puntos diferentes del estanque, y una señal de un sensor de nivel. Ejecutando un algoritmo de control, activa o desactiva diferentes circuitos de agua fría, proveniente de la quebrada Guaracú, o caliente, a través de un proceso de bombeo de agua del estanque hacia los colectores solares, y regresándola al estanque, recirculación que se hace hasta obtener una temperatura de 29 °C, un poco por encima de la ideal de 28 °C. El sistema de control es validado comparando temperatura y oxígeno con un tanque sin control. 

  15. Efecto de tres ambientes de transporte sobre el tiempo de aparición de la autólisis en muestras de alevines de trucha arcoíris (Oncorhynchus mykiss Effect of three transport conditions on the appearance time of autolysis in samples of rainbow trout fry (Oncorhynchus mykiss

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    AR Ortloff


    Full Text Available El objetivo de este trabajo fue comparar el efecto de tres tipos de ambiente de transporte sobre el tiempo de aparición y progreso de los cambios autolíticos de muestras de alevines muertos, enviados para ser procesados para análisis histopatológico. Para ello se depositaron 300 cadáveres de alevines completos en tres ambientes de transporte: sumergidos agua a 4 °C, sumergidos agua a 15 °C y ambiente seco a 4 °C. Cada una hora, desde el tiempo cero hasta las 24 horas, grupos de 4 alevines por ambiente fueron fijados en formalina al 10% y procesados con la técnica histológica convencional de hematoxilina&eosina. En todos los grupos se determinó el tiempo de aparición de los cambios autolíticos en los distintos segmentos del riñón e hígado, clasificándose en cambios autolíticos tempranos, avanzados y autólisis completa. Se observó que los cambios autolíticos se evidencian primero en los hígados de los cadáveres a 4 °C en ambiente seco y al último en los cadáveres sumergidos en agua a 4 °C (1 y 6 horas, respectivamente. Respecto al riñón, los primeros cambios autolíticos se presentaron en cadáveres a 4 °C en ambiente seco y al último en los cadáveres sumergidos en agua a 4 °C (3 y 9 horas, respectivamente. De este estudio se concluye que de los tres ambientes de transporte comparados, el que conserva por más tiempo la estructura histológica y citológica de los tejidos de los peces para análisis histológico es la conservación sumergidos en agua a 4 °C, evidenciando el rol clave de la temperatura y humedad ambiental en el progreso de la autólisis de peces.The aim of this work was to compare three types of transport conditions on the appearance and progress of autolytic changes in samples of dead fry sent to be processed for histopathological analysis. 300 whole fry corpses were subjected to three transport conditions: submerged in water at 4 °C, submerged in water at 15 °C and dry atmosphere at 4

  16. Efeito da vitamina C sobre o hematócrito e glicemia de alevinos de tilápia-do-nilo (Oreochromis niloticus em transporte simulado Effect of vitamin C over the haematocrit and glycemia of nile tilapia (Oreochromis niloticus alevins in simulated transport

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    D. Okamura


    Full Text Available Avaliou-se o efeito do ascorbato sobre o hematócrito e glicemia em alevinos de tilápia nilótica (Oreochromis niloticus submetidos à simulação de práticas relacionadas ao transporte. Foram utilizadas três dietas experimentais com diferentes níveis de vitamina C (16, 500 e 1000mg de vitamina C/kg, fornecidas durante os 14 dias anteriores à simulação do transporte que se estendeu por 14 horas. O tratamento que continha 16mg de vitamina C/kg foi o que apresentou a glicemia mais elevada logo após a simulação, 108,5mg/dl imediatamente após a simulação e 91mg/dl 12 horas após a simulação. A concentração de 1000mg de vitamina C/kg foi a mais eficiente no controle do aumento da glicemia, 94,6mg/dl imediatamente após a simulação e 74,4mg/dl 12 horas após a simulação. Para a concentração de 500mg de vitamina C/kg foram observados os níveis de 91,4mg/dl imediatamente após a simulação e 103,8mg/dl 12 horas após a simulação. Os valores do hematócrito não apresentaram variação significativa (P>0,05. A suplementação com 1000mg de vitamina C/kg por 14 dias anteriores ao transporte pode ser utilizada de forma profilática em alevinos de tilápia nilótica para amenizar o aumento da glicemia relacionado ao estresse.The effects of ascorbate on the haematocrit and blood glucose level were evaluated in Nile tilapia alevins (Oreochromis niloticus submitted to a transport simulation. Three experimental diets with different levels of vitamin C (16, 500 and 1000mg/kg were given for 14 days before the simulation of the transport. The treatment containing 16mg of vitamin C showed the highest level of glucose after the simulation (108.5mg/dl immediately after the transport and 91mg/dl 12 hours after the transport. The vitamin C concentration of 1000mg/kg was the most efficient treatment to control glycemia increases (94.6mg/dl immediately after the simulation and 74.4mg/dl 12 hour after simulation. In the 500mg/kg treatment, the

  17. Comparaison des performances de deux souches de truite commune (Salmo trutta L. (domestique et hybride sauvage x domestique introduites au stade alevin dans un ruisseau

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    Full Text Available La production d'un hybride mâle sauvage x femelle domestique, chez la truite commune (Salmo trutta a parfois été proposée pour le repeuplement (CUINAT, 1971. Nos précédents travaux (MAISSE et al., 1983 ont montré que ces sujets sont plus difficiles à élever que ceux dont les deux parents sont domestiques. La présente étude a porté sur la comparaison des performances des hybrides et des domestiques déversés simultanément dans un ruisseau où la reproduction de la truite est compromise par le colmatage du fond. Les déversements ont été effectués sur la totalité du ruisseau, en mai, deux années de suite. Des inventaires ont été réalisés sur des secteurs représentatifs en mai, avant les déversements, et en octobre. Les résultats ont montré que les taux d'implantation, tant en 0+ qu'en 1+, ne différaient pas suivant l'origine des poissons. De plus, sur chacun des secteurs inventoriés, les individus d'origine domestique ont gardé l'avantage de taille qu'ils avaient au moment du déversement. L'intérêt d'un tel croisement est discuté en fonction des diverses stratégies de repeuplement à mettre en œuvre.

  18. La harina de caña proteica como alimento local en la producción de tilapia roja -Oreochromis spp - The cane meal protein like food local in the production red tilapia - Oreochromis spp-

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    Botello A.L.


    Full Text Available ResumenEl presente trabajo se desarrolló con el objetivo de determinar la respuesta biológica de alevines de tilapia roja (Oreochromis spp. alimentados con diferentes niveles de inclusión de harina de caña proteica.SummaryThe present work was developed with the aim of to determine the answerbiological of alevines of red tilapia (Oreochromis spp. fed with different levels of inclusion of cane meal protein.

  19. La harina de caña proteica como alimento local en la producción de tilapia roja -Oreochromis spp - The cane meal protein like food local in the production red tilapia - Oreochromis spp-


    Botello A.L.; Cisneros M.V.L.; Silvera G.S.; Magalis Cutido. E.; Miranda O.M.; Gómez I.A.; Guerra J; Teresa Viana M.C.; Valdivié M.N.; Ariza E.P.; Girón E.T.G.; Valera Y.R.; Botello A.R.


    ResumenEl presente trabajo se desarrolló con el objetivo de determinar la respuesta biológica de alevines de tilapia roja (Oreochromis spp.) alimentados con diferentes niveles de inclusión de harina de caña proteica.SummaryThe present work was developed with the aim of to determine the answerbiological of alevines of red tilapia (Oreochromis spp.) fed with different levels of inclusion of cane meal protein.

  20. Influence de la taille des particules alimentaires sur la croissance du saumon atlantique lors de la prise d'alimentation

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    Full Text Available Les taux de croissance enregistrés sur des saumons atlantiques en période de première alimentation ont permis de montrer que la formule établie pour des parrs par WANKOWSKI : taille des particules à distribuer = taille du saumon x 0,024 est vérifiée pour des alevins de plus de 250 mg pour différents aliments. Pour des alevins de taille inférieure à 250 mg, les résultats dépendent de l'aliment, une taille d'aliment de 400 - 630 μ permet en général des performances satisfaisantes. Pratiquement on détermine une correspondance entre taille d'aliment à distribuer et le poids de l'alevin pour la période d'alevinage.

  1. Effect of background color of tanks on growth and survival of juvenile Yellow Seahorse, Hippocampus kuda (Bleeker 1852), in the pelagic phase

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    Pawar, H.B.; Sanaye, S.V.; Murugan, A.; Sreepada, R.A.; Tanu

    (Naas et al., 1996). While first-feeding Atlantic salmon alevins possess innate color preferences that can be altered by a single associative learning event (Clarke and Sutterlin, 1985), the presence of such innate color preferences has not been... and background color on feeding by Atlantic salmon alevins. Prog. Fish-Cult., 49:141-143. Clarke L.A. and A.M. Sutterlin, 1985. Associative learning, short-term memory, and color preference during first feeding by juvenile Atlantic salmon. Can. J. Zool., 63...

  2. Uso del espacio en pelota vasca en edad escolar: aplicación del análisis secuencia


    Usabiaga, Oidui; Castellano, Julen; Anguera Argilaga, María Teresa


    El presente estudio aborda la búsqueda de patrones de conducta asociados al uso del espacio llevadas a cabo por jugadores benjamines (8-10 años) y alevines (10-12 años) de pelota a mano que participan en deporte escolar. La muestra estuvo compuesta por doce partidos (60 jugadores), seis de benjamines (30 jugadores) y seis de alevines (30 jugadores). El registro se llevó a cabo mediante un instrumento de observación diseñado ad hoc para analizar el uso estratégico del espacio...

  3. Effects of triploidy induction on antioxidant defense status in rainbow trout (Oncorhynchus mykiss) during early development. (United States)

    Taghipoor, Kaveh; Keyvanshokooh, Saeed; Salati, Amir Parviz; Pasha-Zanoosi, Hossein; Babaheydari, Samad Bahrami


    The objective of the present study was to examine the antioxidant status of rainbow trout (Oncorhynchus mykiss) during the early stages of development (fertilized egg, eyed egg, alevin and fry) as an effect of triploidy induction. Eggs and milt were taken from eight females and six males. After insemination, the eggs were incubated at 10°C for 10min. Half of the fertilized eggs were then subjected to heat-shock for 10min submerged in a 28°C water bath to induce triploidy. The remainder were incubated normally and used as diploid controls. Three batches of eggs were randomly selected from each group (control and heat-shocked) and were incubated at 10-11°C under the same environmental conditions in hatchery troughs until the fry stage. Triplicate samples of fertilized eggs from each experimental group were randomly selected 1.5h post-fertilization and at the eyed egg stage of development (18 days post-fertilization, dpf). At 27 dpf, triplicate samples of alevins were chosen from each group. Based on ploidy determination experiment performed on both groups, nine diploid and nine triploid fry (76 dpf) were also selected. The triploidy induction success rate was 87.1%. Vitamin C was in lesser concentrations in fertilized eggs and eyed eggs of the heat-shock treatment group as compared with eggs of the diploid group. Alevins of the heat-shock treatment group had a lower superoxide dismutase (SOD) activity than alevins of the diploid group. Glutathione peroxidase (GPx) level was greater in fertilized eggs and alevins of the heat-shock treatment group as compared to diploids. Catalse (CAT) activity was greater in fertilized eggs, alevins and fry of the heat-shock treatment group than those of the diploid group. Malondialdehyde (MDA), as an index of lipid peroxidation, was in greater concentration in fertilized eggs of the group that was heat-shocked, but it was lesser in alevins and fry of the group in which the eggs were heat-shocked as compared to diploid counterparts

  4. Impacts of Water Level Fluctuations on Kokanee Reproduction in Flathead Lake, 1985 Annual Report.

    Energy Technology Data Exchange (ETDEWEB)

    Beattie, Will; Fraley, John J.; Decker-Hess, Janet (Montana Department of Fish, Wildlife and Parks, Kalispell, MT)


    This study has investigated the effects of the operation of Kerr Dam on the reproductive success of kokanee that spawn along the shores of Flathead Lake. We have estimated the spawning escapement to the lakeshore, characterized spawning habitat, monitored egg and alevin survival in redds, and related survival to length of redd exposure due to lake drawdown. Groundwater discharge apparently attracts kokanee to spawning sites along the lakeshore and is responsible for prolonging egg survival in redds above minimum pool. We have quantified and described the effect of lake drawdown on groundwater flux in spawning areas. This report defines optimal lakeshore spawning habitat and discusses eqg and alevin survival both in and below the varial zone.

  5. Quantifying Temperature Effects on Fall Chinook Salmon

    Energy Technology Data Exchange (ETDEWEB)

    Jager, Yetta [ORNL


    The motivation for this study was to recommend relationships for use in a model of San Joaquin fall Chinook salmon. This report reviews literature pertaining to relationships between water temperature and fall Chinook salmon. The report is organized into three sections that deal with temperature effects on development and timing of freshwater life stages, temperature effects on incubation survival for eggs and alevin, and temperature effects on juvenile survival. Recommendations are made for modeling temperature influences for all three life stages.


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    Full Text Available Les pratiques de repeuplement en truite à des stades précoces (alevins nourris et truitelles 3-5 cm ont été évaluées par la technique de fluoromarquage des otolithes sur le bassin amont du Fier pour trois cohortes (1995, 1996, 1997. La contribution du repeuplement et du recrutement naturel a été suivie à la fois dans la population en place et dans les captures par pêche à la ligne. Au stade 0+ en place à l’automne, la contribution des poissons alevinés est relativement importante pour les trois cohortes considérées. Cependant, l’analyse du rapport entre le nombre d’alevins introduits au printemps et le nombre de truitelles recapturées à l’automne fait apparaître un taux d’implantation très faible des 0+ marqués quelle que soit la densité alevinée. La contribution des marqués chute brutalement au stade 1+ en place (cohorte 95 et 96 et devient très faible. Cette tendance se poursuit au stade 2+ en place pour la cohorte 95 avec des taux de marqués qui diminuent encore. Dans les captures par pêche à la ligne le taux de 2+ marqués est supérieur à celui observé dans la population en place à l’automne mais la contribution du recrutement naturel reste toujours dominante. Ensuite, la contribution de repeuplement suit la même dynamique que dans la population en place puisqu’il diminue avec l’âge. Elle devient négligeable au stade 3+ et nulle à partir de 4+.

  7. Early decrease in dietary protein:energy ratio by fat addition and ontogenetic changes in muscle growth mechanisms of rainbow trout: short- and long-term effects. (United States)

    Alami-Durante, Hélène; Cluzeaud, Marianne; Duval, Carine; Maunas, Patrick; Girod-David, Virginia; Médale, Françoise


    As the understanding of the nutritional regulation of muscle growth mechanisms in fish is fragmentary, the present study aimed to (1) characterise ontogenetic changes in muscle growth-related genes in parallel to changes in muscle cellularity; (2) determine whether an early decrease in dietary protein:energy ratio by fat addition affects the muscle growth mechanisms of rainbow trout (Oncorhynchus mykiss) alevins; and (3) determine whether this early feeding of a high-fat (HF) diet to alevins had a long-term effect on muscle growth processes in juveniles fed a commercial diet. Developmental regulation of hyperplasia and hypertrophy was evidenced at the molecular (expression of myogenic regulatory factors, proliferating cell nuclear antigen and myosin heavy chains (MHC)) and cellular (number and diameter of white muscle fibres) levels. An early decrease in dietary protein:energy ratio by fat addition stimulated the body growth of alevins but led to a fatty phenotype, with accumulation of lipids in the anterior part, and less caudal muscle when compared at similar body weights, due to a decrease in both the white muscle hyperplasia and maximum hypertrophy of white muscle fibres. These HF diet-induced cellular changes were preceded by a very rapid down-regulation of the expression of fast-MHC. The present study also demonstrated that early dietary composition had a long-term effect on the subsequent muscle growth processes of juveniles fed a commercial diet for 3 months. When compared at similar body weights, initially HF diet-fed juveniles indeed had a lower mean diameter of white muscle fibres, a smaller number of large white muscle fibres, and lower expression levels of MyoD1 and myogenin. These findings demonstrated the strong effect of early feed composition on the muscle growth mechanisms of trout alevins and juveniles.

  8. Recherches biologiques et pisciculture expérimentale du goujon (Gobio gobio L.

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    Full Text Available 1.1. Le goujon Gobio gobio L. (sous-espèce gobio est un poisson de rivières peu rapides, à instinct grégaire, vivant sur fond de gravier entre la région salmonicole et la région cyprinicole. Il peut vivre de 5 à 7 années et se reproduire dès la seconde année. 1.2. Le goujon n'est pas un poisson migrateur comme les expériences réalisées par marquage tendent à le démontrer, mais ce poisson à forte capacité reproductrice peut passer par des périodes de prolifération ou de raréfaction. 1.3. Le goujon est un poisson de type Carnivore qui s'alimente normalement durant toute l'année. Les adultes se nourissent principalement à partir du benthos ; les proies sont, en ordre d'importance décroissante, des larves d'Insectes, des Crustacés, des Mollusques, des Vers et des Algues ou détritus végétaux. Les alevins s'alimentent principalement à partir du plancton ; la nourriture est de même nature qualitativement, mais quantitativement les Crustacés y sont beaucoup plus abondants que les Insectes. 1.4. Le goujon est fréquemment parasité par le Plathelminte Monogène du genre Diplozoon ; ce parasite peut infester 90 % de la population. Il est parfois parasité par un grand Nématode du genre Philometra qui envahit la cavité générale. 1.5. Le goujon pond au printemps et en été, mais le début de la ponte est nettement lié à la température de l'eau (minimum de + 16°C à + 17°C; la ponte est fractionnée, mais peut atteindre 4 000 à 5 000 œufs par femelle et par saison. L'œuf, blanc translucide, mesure 1,5 mm de diamètre; l'incubation est de 125 degrés/jour. L'essai d'élevage en aquarium prouve qu'une alimentation artificielle adaptée doit être possible. 1.6. La pisciculture des alevins est réalisée dans la région toulousaine et permet d'indiquer les normes souhaitables. Pour la ponte, des bassins de 1 000 m2 , avec pente de 1 % et fond de gravier, peuvent recevoir 500 géniteurs. La croissance des alevins d'un

  9. Análisis técnico de producción de tilapia Oreochromis niloticus y lechuga acrópolis Lactuca sativa en acuaponia


    Rubio Cabrera, Sheila Guadalupe


    Se evaluó la producción de tilapia Oreochromis niloticus y lechuga romana acropolis Lactuca sativa en sistemas acuapónicos utilizando dos sistemas: recirculación de agua sin recambio (utilizando biofiltración) y sistema sin recirculación con recambio parcial de agua. El cultivo se realizó en 4 etapas. En la primera se colocaron 800 alevines de O. niloticus de 0.2 g de peso inicial en tinas plásticas de 800 L (1600 organismos/m3de agua) durante 39 días. La segunda etapa con u...

  10. Tecnología cubana de cultivo de tilapia y carpa común implementada en la región sur de Namibia


    Millares Dorado, N.; Navarro Jam, M.


    En el Centro de Acuicultura Continental Hardap se implementó un programa de desarrollo de la acuicultura a partir de la formación de tres bancos de reproductores, dos de tilapia mossambica, uno tomado de la presa HARDAP (246 y 216 , y el otro (250 y 215 a partir de alevines seleccionados del segundo ciclo de desove de esta especie logrado en dicho centro. El tercer banco de reproductores formado fue de carpa común (200 y 236 capturado del medio natural...

  11. Cultivo de cachama blanca en altas densidades y en dos sistemas cerrados


    Germán Poleo; José Vicente Aranbarrio; Lismen Mendoza; Oneida Romero


    El objetivo de este trabajo fue evaluar la tolerancia de la cachama blanca, Piaractus brachypomus, a cultivos en altas densidades en sistemas cerrados. Novecientos alevines de 44,3±26 g de peso, se distribuyeron en seis tanques de concreto, con 4,8 m³ de agua. Tres tanques presentaron cero recambio de agua (SCR), y en otros tres, el agua se hizo circular a través de un bioclarificador (SRA). Ambos tratamientos presentaron fuerte aireación para mantener los sólidos en suspensión y suministrar ...

  12. Ionocyte Immunolocalization and the Effects of Ultraviolet Radiation on Their Abundance and Distribution in the Alenins of Caspian Sea Salmon,Salmo Trutta Caspius

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    Saber Khodabandeh


    Full Text Available Objective: On a global scale, stratospheric ozone depletion has caused an increase inUV-B radiation reaching the earth's surface. Ultraviolet radiation has long been suspectedto be harmful to aquatic organisms.Materials and Methods: In order to study ionocyte localization (by Na+/K+-ATPase immunolocalizationand the effects of UV radiation on the ionocytes of skin and gills, the alevinsof Salmo trutta caspius were exposed to different doses of UV radiation [unit low doses(ULD of: 60 μw/cm2 UVC; 100 μw/cm2 UVB and 40 μw/cm2 UVA and unit high doses(UHD of: 90 μw/cm2 UVC; 130 μw/cm2 UVB and 50 μw/cm2 UVA] using two adjustableF8T5 UV-B, 302 nm lamps (Japan for 15 minutes once a day in laboratory conditions.Alevins not subjected to UV exposure served as a control group.Results: In both UV exposure groups, all the alevins died on the ninth day. No mortalitywas observed in the control group. The Na+/K+-ATPase immunolocalization study indicatedthat ionocytes were located, in lessening order, on the yolk sac, trunk, gills, operculaand rarely on the head skin. Immunohistochemical results showed significant reductionin the number of ionocytes on the yolk sac, with lesser reduction on the trunk in both UVexposure groups. In contrast, the number of immunofluorescence cells on the gill wassignificantly elevated. Our results also showed that the size of ionocytes was reduced onthe trunk and yolk sac in the UV exposure groups, but not significantly. Deformation anddestruction of ionocytes on the yolk sac and trunk were observed with scanning electronmicroscope (SEM in the UV exposure groups.Conclusion: Our results showed that ionocytes were located mainly on the yolk sac,in lesser amounts on the trunk, gills and opercula, and rarely also on the head skinof alevins. UV radiation caused deformation and reduction in the number and size ofionocytes on the trunk and yolk sac. As the skin cells of trout alevins possess essentialfunctions for respiration

  13. A genetic test of sexual size dimorphism in pre-emergent chinook salmon.

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    Tosh W Mizzau

    Full Text Available Sex differences in early development may play an important role in the expression of sexual size dimorphism at the adult stage. To test whether sexual size dimorphism is present in pre-emergent chinook salmon (Oncorhynchus tshawytscha, alevins were reared at two temperatures (10 °C and 15 °C and sexed using the OtY1 marker on the Y-chromosome. Linear mixed models were used to test for sex differences in alevin size within families while controlling for the random effects of sire and dam nested within sire. Males and females did not differ in weight at 10 °C but males were heavier than females at 15 °C. Sex accounted for 2% of the within-family variance in weight. In addition, at 15°C, the relationship between weight and sex was greater in families with larger eggs. Whereas male-biased sexual size dimorphism was present at the juvenile stage, female-biased sexual size dimorphism was present at sexual maturity. Males were also younger than females at sexual maturity. A head start on growth by males may underlie their earlier maturation at a smaller size, thus leading to female-biased SSD at the adult stage.

  14. Validación del Protocolo de Reproducción de Colossoma macropomum, Piaractus brachypomus y Prochilodus nigricans en Condiciones Controladas

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    Lorgio Verdi-Olivares


    Full Text Available Protocolos aplicados a las diferentes etapas de la reproducción  inducida: tratamiento hormonal, incubación, manejo de larvas, y manejo de alevines en los peces de consumo humano Colossoma macropomum (gamitana, Piaractus brachypomus (paco y Prochilodus nigricans (boquichico fueron evaluados en el marco del proyecto UNAP “Cátedra CONCYTEC en Acuicultura Tropical” con el propósito de establecer los adecuados procedimientos en la búsqueda de una óptima productividad acuícola y una mejor rentabilidad económica en Loreto. Con este objetivo se utilizaron como inductores: para gamitana, Pituitaria de Carpa con dosis total de 6,0 mg/kg en hembras y 2,0 mg/kg en machos; Para machos y hembras de paco, Conceptal en dosis total de 2,6 ml/kg en hembras y 1,0 ml/kg en machos; y para boquichico, Pituitaria de Carpa con dosis total de 4,0 mg/kg en hembras y 2,0 mg/kg en machos. El desove se produjo en 11±2 horas; la eclosión ocurre después de 22 horas a partir de la fecundación, con  tasas promedios superiores al 70% y tasas de sobrevivencia, aún cundo por debajo del 50%, garantiza una alta producción de alevines.

  15. Avoidance of solar ultraviolet radiation by juvenile coho salmon (Oncorhynchus kisutch)

    International Nuclear Information System (INIS)

    Shade-seeking behavior and avoidance of solar ultraviolet radiation (UVR) by newly emerged coho salmon (Oncorhynchus kisutch) alevins and two-month-old coho juveniles was documented in experimental trials in the Little Qualicum River, British Columbia, using outdoor chambers that provided the fish with a binary choice of photo environments. Under high solar intensifies (i.e., midsummer, cloudless skies) coho of both age classes strongly preferred 50% neutral density shaded conditions to unattenuated full-spectrum (280-700 nm) sunlight (t test, p< 0.025). In addition, coho alevins and juveniles showed a high selective avoidance of UVR (280-400 nm) (t test, p<0.05). Within the UVR spectrum, coho responded significantly to UVA (320-400 nm) (t test, p=0.028). Evidence of UVB (280-320 nm) avoidance was confounded by higher visible and UVA irradiance levels under screens exposing coho to UVB. Under lower solar intensifies (i.e., cloudy skies) coho showed no spectral preference and did not seek neutral density shade. Behavioral avoidance of high intensity UVR, particularly UVA, suggests that shade-seeking behavior of juvenile coho may be linked to avoiding potentially harmful UVR exposure. (author)

  16. Étude expérimentale de la compétition interspécifique entre juvéniles de saumon coho, Oncorhynchus kisutch, et de saumon atlantique, Salmo salar, en eau douce

    Directory of Open Access Journals (Sweden)



    Full Text Available Le risque d'introduction accidentelle du saumon coho dans les rivières peuplées par le saumon atlantique a conduit à développer des recherches en milieu expérimental sur les mécanismes de la compétition entre alevins et juvéniles des deux espèces. Les conséquences possibles de cette compétition ont été évaluées en termes de survie, croissance, prédation, dévalaison et occupation de l'habitat. Les résultats montrent que la présence des saumons cohos n'a pas une influence très marquée sur les alevins ou juvéniles de saumon atlantique si l'environnement trophique est favorable. La microdistribution est différente, les saumons atlantiques occupant plutôt les radiers alors que les saumons cohos préfèrent les profonds. Le comportement pélagique et grégaire des jeunes saumons cohos, nettement plus gros que les saumons atlantiques du même âge dès l'émergence, peut être opposé au comportement benthique et inféodé au substrat de ces derniers. Ces différences s'accentuent en sympatrie, aux dépens du saumon atlantique, désavantagé par la taille. Sous conditions trophiques limitantes, la croissance et la sédentarité des alevins de saumon atlantique sont significativement affectées par la présence des cohos, ce qui justifie d'émettre d'expresses réserves sur l'intérêt de l'introduction du saumon coho dans les rivières françaises.


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    Tamás Molnár


    Full Text Available Market demands and competition force the production of high quality freshwater fish in European aquaculture. In Hungary pike-perch is the most „noble” and perhaps the most sensitive fish species. One of the constraints of the increasing its production in natural waters, reservoirs and ponds is the shortage in adequate sized alevins. The possible solution of this problem can be the elaboration of intensive rearing technics of pond prereared fry. The aims of the present work were to test the growing capacity, feed conversion and survival of pike-perch in intensive circumstances. Fish were kept in 130 l aquaria working in recirculation system at an average water temperature of 220.5 C. Two stocking densities were applied (18 and 36 fish/aquarium. Minced fish (test and live prey (control were offered twice a day till satiation in two replications. The experiment lasted 4 weeks. According to our results minced fish is suitable feed in the intensive rearing of pike-perch alevins. Daily food intake was only influenced significantly by different feeds (2.01g vs.4.53 g, test and control, respectively. Feeding and stocking density had significant effect (P=0.001 and 0.017 on the average weight gain (0.52 g and 1.40 g for minced fish and live feed, respectively, 1.02 g in lower and 0.90 g in higher density. Owning to the high variances treatment effect on feed conversion proved to be not significant. Average survival of the minced fish fed group was 62.2 % vs. 78.8 % of the live fish fed alevins. This difference was significant (P<0.01 in the first two weeks when almost all of the losses happened due to cannibalism and other unknown reasons. Based on our results a period of 10–14 days is needed for pre-reared pike-perch to change gradually their feeding from zooplankton to minced fish diet.

  18. Uso estratégico del espacio en categorías de formación de pelota vasca. [Strategic use of space in basque pelota training categories].

    Directory of Open Access Journals (Sweden)

    Oidui Usabiaga


    Full Text Available La pelota vasca es un deporte de pelota compuesto por varias especialidades. La pelota a mano es una de las más practicadas y se juega tanto en duelos individuales como por equipos. El presente estudio pretende analizar y comparar algunos indicadores de juego del uso estratégico del espacio por parte de jugadores benjamines (8-10 años y alevines (10-12 años que participan en un programa de deporte escolar. La muestra estuvo compuesta por doce partidos, seis de benjamines (30 participantes y seis de alevines (30 participantes. El registro se llevó a cabo mediante un instrumento observacional ad hoc diseñado para analizar el uso estratégico del espacio por parte de los participantes, tanto cuando golpean la pelota como cuando están en situación de espera. Los resultados muestran que los participantes de las dos categorías usan el espacio de la misma forma respecto a las zonas de golpe, la ubicación espacial en situación de espera durante los duelos por parejas y los tipos de saque. Los alevines, en comparación a los benjamines, se posicionan más a la derecha del jugador que golpea durante los duelos individuales, dirigen la pelota a distancias medias y cometen menos faltas tanto en el resto del saque como en el juego de intercambio, dando mayor continuidad al juego (p Abstract The basque pelota is a ball sport composed of various specialties. The hand pelota is one of the most popular and is played in both individual and team matchups. The aim of this study was to analyze and compare some indicators of the strategic use of space by young players, 8-10- and 10-12-year-old students, participating in a school sport program. The sample consisted of twelve games, six for each level (30 participants for each level. Data were recorded with an ad hoc observational instrument designed to analyze the strategic use of space by the participants, both when they hit the ball and when they are on standby. The results show that the participants of

  19. Reversion sexual de las Tilapias Roja (Oreochromis Sp, una guía básica para el acuacultor

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    Duván Andrés Arboleda Obregón


    Full Text Available La tilapia roja es un híbrido distribuido en todo el mundo; atractivo por su color y sus características zootécnicas lo que la convierte en una especie con gran mercado y de gran importancia para investigación, en tilapia es importante el cultivo de machos, para obtener machos se usa la 17alfametiltestosterona que es una hormona que cuando suministrada con el alimento a los alevines los transforma en machos. The red tilapia is a hybrid distribuided in all the world; it is attractive due to its color and its zootechnical characteristic convert in a specie with big market and of many importance for research, in tilapia is important the males culture, for obtain males is used 17alfamethyltestosterone that is an hormone when is supplied with the food to the fingerlings transform in males

  20. Nivel de dominio de las habilidades psicológicas en Jóvenes jugadores de tenis de mesa, bádminton y fútbol


    D\\u00E9bora Godoy-Izquierdo; Mercedes V\\u00E9lez; Francisco Pradas


    El objetivo de este estudio fue conocer el nivel de dominio sobre las habilidades psicológicas de jugadores jóvenes de tenis de mesa, bádminton y fútbol de distintas categorías deportivas y estudiar su posible asociación con el grado de experiencia con el deporte y la competición (años jugando y años compitiendo). Participaron en el estudio 12 jugadores alevines de tenis de mesa (edad, M= 11.09, dt= 1.38), 4 juveniles de bádminton (edad: M= 16.25, dt= 0.5) y 25 jugadores de fútbol, 13 pertene...

  1. Salmo salar: morfología ultraestructural de la pared del corion en ovas normales y con problemas de eclosión Salmo salar: ultrastructural morphology of chorion, from normal and with hatching problems ova

    Directory of Open Access Journals (Sweden)

    R Jaramillo


    Full Text Available El “corion duro” es un fenómeno de reciente ocurrencia y se caracteriza porque algunos alevines con ojo no son capaces de degradar el corion que les rodea o lo hacen sólo de manera parcial, produciéndose en ambos casos la muerte del alevín. Este fenómeno ha causado fracasos reproductivos importantes en algunas pisciculturas del sur de Chile, desconociéndose hasta ahora la razón de su ocurrencia. En este estudio se realizaron mediciones del grosor del corion de Salmo salar así como de las fibras que forman parte de éste en ovas fertilizadas, no fertilizadas, con desarrollo normal y ovas que no lograron eclosionar. Los resultados obtenidos indican que las leves variaciones observadas en el grosor del corion entre los diferentes estados de desarrollo de las ovas estudiadas no explican la ocurrencia del “corion duro”. Sin embargo, la disposición de las fibras proteicas que forman el estrato interno del corion parece ser la respuesta a este fenómeno. Las ovas que no eclosionan presentan “corion duro” y exhiben un estrato interno carente de poros a diferencia de lo que se observa en las ovas que desarrollan normalmente y que logran la eclosión. Se propone que problemas en la síntesis de alguna de las sub-unidades que forman la coriogenina serían los responsables de la formación de un estrato interno carente de poros, siendo ésta la razón del “corion duro”.Either eyed alevins unable to digest the chorion or those digesting it partially, are both suffering the “hard chorion” phenomenon; in both cases alevins can not survive producing high mortality rates. During recent years, the salmon farming industry in Southern Chile has been facing massive mortality events caused by “hard chorion”. Since “hard chorion” is a recently observed phenomenon there are no literature reporting its origin. The aim of this study was to find differences in the ultrastructure of chorion fibers from Salmo salar ova at different

  2. Early enrichment effects on brain development in hatchery-reared Atlantic salmon (Salmo salar): no evidence for a critical period

    DEFF Research Database (Denmark)

    Näslund, Joacim; Aarestrup, Kim; Thomassen, Søren T.;


    In hatcheries, fish are normally reared in barren environments, which have been reported to affect their phenotypic development compared with wild conspecifics. In this study, Atlantic salmon (Salmo salar) alevins were reared in conventional barren hatchery trays or in either of two types...... of structurally enriched trays. We show that increased structural complexity during early rearing increased brain size in all investigated brain substructures. However, these effects disappeared over time after transfer to barren tanks for external feeding. Parallel to the hatchery study, a group of salmon parr...... trajectory. In contrast, our results indicate that brain growth is plastic in relation to environment. In addition, we show allometric growth in brain substructures over juvenile development, which suggests that comparisons between groups of different body size should be made with caution. These results can...

  3. Glucose metabolism ontogenesis in rainbow trout (Oncorhynchus mykiss) in the light of the recently sequenced genome: new tools for intermediary metabolism programming. (United States)

    Marandel, Lucie; Véron, Vincent; Surget, Anne; Plagnes-Juan, Élisabeth; Panserat, Stéphane


    The rainbow trout (Oncorhynchus mykiss), a carnivorous fish species, displays a 'glucose-intolerant' phenotype when fed a high-carbohydrate diet. The importance of carbohydrate metabolism during embryogenesis and the timing of establishing this later phenotype are currently unclear. In addition, the mechanisms underlying the poor ability of carnivorous fish to use dietary carbohydrates as a major energy substrate are not well understood. It has recently been shown in trout that duplicated genes involved in glucose metabolism may participate in establishing the glucose-intolerant phenotype. The aim of this study was therefore to provide new understanding of glucose metabolism during ontogenesis and nutritional transition, taking into consideration the complexity of the trout genome. Trout were sampled at several stages of development from fertilization to hatching, and alevins were then fed a non-carbohydrate or a high-carbohydrate diet during first feeding. mRNA levels of all glucose metabolism-related genes increased in embryos during the setting up of the primitive liver. After the first meal, genes rapidly displayed expression patterns equivalent to those observed in the livers of juveniles. g6pcb2.a (a glucose 6-phosphatase-encoding gene) was up-regulated in alevins fed a high-carbohydrate diet, mimicking the expression pattern of gck genes. The g6pcb2.a gene may contribute to the non-inhibition of the last step of gluconeogenesis and thus to establishing the glucose-intolerant phenotype in trout fed a high-carbohydrate diet as early as first feeding. This information is crucial for nutritional programming investigations as it suggests that first feeding would be too late to programme glucose metabolism in the long term. PMID:26747908

  4. Performance of juvenile steelhead trout (Oncorhynchus mykiss) produced from untreated and cryopreserved milt (United States)

    Hayes, Michael C.; Rubin, Stephen P.; Hensleigh, Jay E.; Reisenbichler, Reginald R.; Wetzel, Lisa A.


    Despite the expanding use of milt cryopreservation in aquaculture, the performance of fish produced from this technique has not been fully explored beyond initial rearing stages. We compared the performance of juvenile steelhead Oncorhynchus mykiss produced from untreated (UM) and cryopreserved milt (CM) and reared for 4–9 months. For the 1996 brood, CM alevins were heavier (∼ 1.7%, P influenced by a significant milt-by-family interaction (P families. No significant differences were found in length or weight (P > 0.05) for 1997 brood alevins and percent yolk was similar for both broods (P > 0.34). In growth and survival experiment I (GSE-I, 1996), UM and CM juveniles reared in separate tanks and fed to satiation (130 days) showed no significant differences in survival, length or weight (P > 0.05) between milt groups. In contrast, for UM and CM siblings reared in the same tank for 210 days on a low food ration (GSE-II), survival was similar (P > 0.05), but length (UM 4% > CM, P  CM, P = 0.08), were influenced by cryopreservation. Fish from the 1997 brood (GSE-III) were reared for 313 days in a repeat of GSE-II and no differences were found in survival (P = 0.47), length (P = 0.75) or weight (P = 0.76) suggesting considerable heterogeneity between broods. Performance of the 1996 brood was also tested for response to stress and a disease challenge. Cortisol responses of juveniles exposed to acute stress were not significantly different (P = 0.19), but mean cortisol was consistently and significantly greater (P families and suggests a cautionary approach to the widespread use of cryopreservation for steelhead.

  5. Ontogeny of the Digestive System of Atlantic Salmon (Salmo salar L. and Effects of Soybean Meal from Start-Feeding.

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    Christian Sahlmann

    Full Text Available Despite a long history of rearing Atlantic salmon in hatcheries in Norway, knowledge of molecular and physiological aspects of juvenile development is still limited. To facilitate introduction of alternative feed ingredients and feed additives during early phases, increased knowledge regarding the ontogeny of the digestive apparatus in salmon is needed. In this study, we characterized the development of the gastrointestinal tract and accessory digestive organs for five months following hatch by using histological, biochemical and molecular methods. Furthermore, the effects of a diet containing 16.7% soybean meal (SBM introduced at start-feeding were investigated, as compared to a fishmeal based control diet. Salmon yolk sac alevins and fry were sampled at 18 time points from hatch until 144 days post hatch (dph. Histomorphological development was investigated at 7, 27, 46, 54 and 144 dph. Ontogenetic expression patterns of genes encoding key digestive enzymes, nutrient transporters, gastrointestinal peptide hormones and T-cell markers were analyzed from 13 time points by qPCR. At 7 dph, the digestive system of Atlantic salmon alevins was morphologically distinct with an early stomach, liver, pancreas, anterior and posterior intestine. About one week before the yolk sac was internalized and exogenous feeding was started, gastric glands and developing pyloric caeca were observed, which coincided with an increase in gene expression of gastric and pancreatic enzymes and nutrient transporters. Thus, the observed organs seemed ready to digest external feed well before the yolk sac was absorbed into the abdominal cavity. In contrast to post-smolt Atlantic salmon, inclusion of SBM did not induce intestinal inflammation in the juveniles. This indicates that SBM can be used in compound feeds for salmon fry from start-feeding to at least 144 dph and/or 4-5 g body weight.

  6. Effets négatifs de pH extrêmes sur le développement embryonnaire et larvaire du brochet Esox lucius L.

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    Full Text Available Parmi les facteurs abiotiques conditionnant la survie au cours de la vie embryonnaire et larvaire des poissons, le pH semble jouer un rôle primordial. La motivation de ce travail provient d'observations sur les importantes variations de ses valeurs au printemps, l'existence de pH très acides en étangs forestiers et des mortalités importantes de brochetons au cours de la même période. L'expérimentation s'est déroulée en aquariums avec une gamme de valeurs allant de 4,5 à 10,5 unités pH. Des tests en bains, continus ou momentanés (1 heure, sont effectués. Deux stades sont étudiés : les oeufs fécondés suivis jusqu'après l'éclosion ; les alevins incubés à pH neutre suivis jusqu'à la résorption de la vésicule vitelline. Les paramètres suivants sont étudiés : survie, déroulement de l'embryogenèse, anomalies éventuelles, performances de nage. Le rythme cardiaque de l'embryon a été mesuré. Les résultats sont les suivants : - Les valeurs létales sont respectivement de 6 et 10 (alevins et 4,5 et 10,5 (embryons. - L'action sur les oeufs est moins forte, même si une mortalité importante (46,7 % et de faibles performances de nage pour un pH inférieur à 6 semblent hypothéquer la réussite du recrutement. La valeur de 10,5 provoque un développement déficient des quelques individus survivants. - Sur les alevins, même en bains d'une heure, la survie est faible : 42,6 % à pH 5, 29,3 % à pH 10. Le rythme cardiaque ne variait pas de façon notable entre les seuils de tolérance. Ces résultats permettent de récapituler pour une espèce largement distribuée les conditions de recrutement liées à l'acidité du milieu. Il faut noter que les hausses brutales du pH au printemps dans des plans d'eau sur substrat cristallin rendent aléatoires la réussite des empoissonnements en brochetons des premiers stades.

  7. Nivel de dominio de las habilidades psicológicas en Jóvenes jugadores de tenis de mesa, bádminton y fútbol

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    D\\u00E9bora Godoy-Izquierdo


    Full Text Available El objetivo de este estudio fue conocer el nivel de dominio sobre las habilidades psicológicas de jugadores jóvenes de tenis de mesa, bádminton y fútbol de distintas categorías deportivas y estudiar su posible asociación con el grado de experiencia con el deporte y la competición (años jugando y años compitiendo. Participaron en el estudio 12 jugadores alevines de tenis de mesa (edad, M= 11.09, dt= 1.38, 4 juveniles de bádminton (edad: M= 16.25, dt= 0.5 y 25 jugadores de fútbol, 13 pertenecientes a la categoría de alevines (edad: M= 11.31, dt= 0.48 y 12 a la categoría juvenil (edad, M= 17.00, dt= 0.85, todos federados. Los participantes respondieron el Cuestionario de Habilidades Psicológicas y Conductas en el Deporte de Competición-Escala infantil-juvenil (Godoy-Izquierdo et al., 2006a, b. El dominio de las habilidades psicológicas por parte de los deportistas jóvenes es, en general, deficiente, no existiendo diferencias significativas entre los jugadores de deportes de raqueta y pala y fútbol, aunque en el caso de los deportistas de categorías inferiores aparecen diferencias significativas en el caso de algunas habilidades psicológicas. Tampoco se han encontrado diferencias significativas en función de la experiencia con el deporte y la competición. Los resultados señalan la necesidad de incluir el entrenamiento psicológico en la preparación deportiva integral de los deportistas, con el fin de dotar a éstos de habilidades psicológicas que les permitan afrontar adecuadamente las crecientes demandas del deporte conforme aumenta su nivel de implicación, tanto en el caso de modalidades individuales como colectivas.

  8. Evaluación del ensilado químico de pescado en la alimentación de Clarias gariepinus (Burchell, 1822 - Fish chemical silage evaluation in Clarias gariepinus (Burchell, 1822 feeding

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    Toledo Pérez, J


    Full Text Available ResumenCon el objetivo de evaluar el efecto biológico y económico del ensilado químico de pescado, como única fuente de proteína animal en la alimentación de alevines de Clarias gariepinus, se ensilo manchuelo entero (Opisthonema oglinum, con tres combinaciones de ácidos orgánicos e inorgánicos: 3% de ácido fórmico; 2% ácido sulfúrico 98% y 2% de ácido fórmico y un tercer ensilado con 2,6% de ácido fosfórico y 2,6% de ácido cítrico. Con cada ensilado se confecciono una dieta húmeda, las cuales fueron comparadas con un Alimento Comercial en la alimentación de alevines de Clarias gariepinus durante 60 días. En los resultados obtenidos no hubo diferencias significativas (P>0.05 en los indicadores de crecimiento, utilización del alimento y supervivencia al sustituir totalmente la harina de pescado por los ensilados químicos de pescado. El análisis económico mostró un ahorro de 20 a 30% de los costos de producción por concepto de alimentaciónAbstractThe objetive of this work was to evaluate the biologic and economic effects of chemical fish silage as a unique animal protein source in Clarias gariepinus feeding. Ensiled Opisthonema oglinum with three combinations of organic and inorganic acids: 3% of formic acid; 2% sulfuric acid 98% and 2% formic acid and other with 2,6% phosphoric acid and 2,6% of citric acid. From each silage moist diets was prepared and were compared with comercial foods in Clarias gariepinus feeding during 60 days. There were not significant differences (P>0.05, in growth, feed utilization and survival indicators. The economic analysis showed a cost production sabe between 20 and 30%.

  9. Lake Roosevelt Fisheries Monitoring Program; Measurement of Thyroxin Concentration as an Indicator of the Critical Period for Imprinting in the Kokanee Salmon (Orcorhynchus Nerka) Implications for Operating Lake Roosevelt Kokanee Hatcheries; 1991 Supplement Report.

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    Scholz, Allan T.; White, Ronald J.; Koehler, Valerie A. (Eastern Washington University, Upper Columbia United Tribes Fisheries Research Center, Cheney, WA)


    Previous investigations have determined that thyroid hormone surges activate olfactory imprinting in anadromous salmonid smolts. The mechanism of action appears to require binding of thyroid hormones to receptors in brain cell nuclei, which stimulates neuron differentiation and wires a pattern of neuron circuitry that allows for the permanent storage of the imprinted olfactory memory. In this study, thyroxine concentrations [T{sub 4}] were measured in 487 Lake Whatcom stock and 70 Lake Roosevelt stock Kokanee salmon to indicate the critical period for imprinting. Eggs, alevins and fry, reared at the Spokane Indian Kokanee Hatchery, were collected from January through August 1991. Sampled fish were flash frozen on dry ice and stored at {minus}80{degrees}C until T{sub 4} was extracted and concentrations determined by radioimmunassay. Mean concentration {+-} SEM of 10--20 individual fish (assayed in duplicate) were determined for each time period. T{sub 4} concentration peaked on the day of hatch at 16.8 ng/g body weight and again at swim-up at 16.0 {+-} 4.7 ng/g body weight. T{sub 4} concentration was 12.5 to 12.9 ng/g body weight in eggs, 7.1 to 15.2 ng/g body weight in. alevins, 4.5 to 11.4 ng/g body weight in 42 to 105 day old fry and 0.1 to 2.9 ng/g body weight in 112 to 185 day old fry. T{sub 4} concentrations were highest in eggs at 13.3 {+-} 2.8 ng/g body weight, then steadily decreased to 0.1 {+-} 0.1 ng/g body weight in older fry. Fry were released in Lake Roosevelt tributaries in July and August 1991, at about 170--180 days post hatching, in order to imprint them to those sites. The results of this study indicate that the time of release was not appropriate for imprinting. If T{sub 4} levels are an accurate guide for imprinting in kokanee, our results suggest that the critical period for imprinting in kokanee is at hatching or swim-up stages.

  10. Relationship between reasons for practicing and sportpersonship behaviors in young handball players

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    David Sánchez Oliva


    Full Text Available AbstractThe main aim of this work was to analyze the relationships among Self-Determination Theory and sportsmanlike and antisocial behaviors in low categories. However, we recruited 127 handball players from alevine, infantile and cadet categories who filled several questionnaires to measure motivation in sport (SMS: Pelletier, Fortier, Vallerand, Tudson, Brière y Blais, 1995, satisfaction of the three psychological needs (EMM: García Calvo, Sánchez Miguel, Leo, Sánchez Oliva, y Gómez, 2010 and sportspersonship behaviors y (MSOS: Vallerand, Brière, Blanchard, y Provencher, 1997. Through the data analysis, we could demonstrate that greater self-determination levels were significantly associated with sportsmanlike conducts, as well as lower self-determination reasons were related with antisocial behaviors. Furthermore, we highlighted the autonomy as the strongest predictor of an adequate participation, whereas external regulation predicted negative critic. Finally, we emphasized the importance to promote self-determinated behaviors in young participants in the sport context, getting more adaptative conducts during the game. Keywords: Self-determination, psychological mediators, sportsmanlike, handball.


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    Francisco Prieto


    Full Text Available En esta investigación se evalúan los efectos de la bioacumulación de arsénico contenido en el "agua potable" de Zimapán, Hidalgo en el pez cebra ( Danio rerio y como indicador del posible daño genotóxico sobre la población de Zimapán, expuesta a la contaminación por arsénico. Los ejemplares fueron estudiados durante 180 días en tres tratamientos: agua del pozo de referencia, agua de referencia adicionada con 5 mg As (V/L, y agua del pozo Zimapán, con 65 especimenes por lote. Se colocó una hembra y un macho en apareamiento en las mismas condiciones de tratamientos, obteniendo que a mayor concentración de As en el agua mayor porcentaje de huevos no viables y óvulos, menor porcentaje de huevos viables y de eclosión, mayor porcentaje de alevines recién eclosionados y juveniles con malformaciones, y menor porcentaje de juveniles sobrevivientes. Los resultados demuestran la genotoxicidad del As en Danio rerio .

  12. Lake Roosevelt Fisheries Monitoring Program; Artificial Imprinting and Smoltification in Juvenile Kokanee Salmon Implications for Operating Lake Roosevelt Kokanee Salmon Hatcheries; 1994 Supplement Report.

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    Tilson, Mary Beth; Scholz, Allan T.; White, Ronald J. (Eastern Washington University, Upper Columbia United Tribes Fisheries Research Center, Cheney, WA)


    At the kokanee salmon hatcheries on Lake Roosevelt, constructed as partial mitigation for effects from Grand Coulee Dam, adult returns have been poor. The reason may be in the imprinting or in the smoltification. A study was initiated in 1992 to determine if there was a critical period for thyroxine induced alfactory imprinting in kokanee salmon; experiments were conducted on imprinting to morpholine and phenethyl alcohol. Other results showed that chemical imprinting coincided with elevated thyroxine levels in 1991 kokanee exposed to synthetic chemicals in 1992. In this report, imprinting experiments were repeated; results showed that imprinting occurred concomitant with elevated thyroxine levels in 1991 kokanee exposed to synthetic chemicals in 1992 and tested in 1994 as age 3 spawners. Imprinting also occurred at the same time as thyroxine peaks in 1992 kokanee exposed to synthetic chemicals in 1993 and tested as age 2 spawners. In both groups fish that had the highest whole body thyroxine content (swimup stage) also had the highest percentage of fish that were attracted to their exposure odor in behavioral tests. So, kokanee salmon imprinted to chemical cues during two sensitive periods during development, at the alevin/swimup and smolt stages. A field test was conducted in Lake Roosevelt on coded wire tagged fish. Smoltification experiments were conducted from 1992 to 1994. Recommendations are made for the Lake Roosevelt kokanee hatcheries.

  13. Écologie et repeuplement des cours d'eau à truites (Deuxième partie

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    Full Text Available Les repeuplements d'entretien en salmonides, comparables à un placement à long terme, se justifient dans les cours d'eau où le recrutement est insuffisant pour une ou deux des raisons suivantes : — déficit de géniteurs, à la suite d'une pollution accidentelle ou d'une pêche excessive ; — rareté ou mauvaise qualité des frayères. En dehors de ce deuxième cas, les taux de fécondation et de survie jusqu'à la résorption de la vésicule sont généralement aussi élevés dans la nature (80 à 90 % qu'en pisciculture. Selon l'importance de la compétition et de la prédation (par l'Anguille notamment, les taux de survie sont ensuite extrêmement variables, surtout dans les six premiers mois de vie de l'alevin (généralement entre 1 et 20 % ; ils sont normalement supérieurs ensuite (entre 10 et 50 % par an.

  14. Activity determination of Na+ K+ - ATPase and Mg++ - ATPase enzymes in the gill of Poecilia vivipara (Osteichthyes, Cyprinodontiformes in different salinities

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    Marcelo da Cunha Amaral


    Full Text Available This work aimed to know the tolerance mechanisms through the salinity variation by Na+ K+ - ATPase and Mg++ - ATPase and enzymes encountered in the gills of Poecilia vivipara. In field, the presence of this species was observed in salinities of 0 and 28‰. In laboratory, these fish were maintained in aquarium with mean salinity of 30‰ and positive responses were obtained. Some adult specimens, collected in a lagoon of the Coqueiros Beach, were utilized as matrixes. In the experiments the specimens used were those born in the test aquarium. For each salinity studied three replicates were made with three specimens for each one. The alevins were maintained in salinities of 5, 10, 15, 20, 25, 30 and 35‰ during a month for adaptation. Gills were extracted in appropriate buffer for isolation of plasma membrane and used for specific dosage of the total enzymatic activity of Na+ K+ - ATPase and Mg++ - ATPase. The relation of alevins to their adaptation towards the salinity variation was also studied. The activity of the two enzymes showed a different result. The major expression of Na+ K+ - ATPase was observed in 20‰ (35 µmoles protein.h-1, the best salinity to cultivate P. vivipara.Este trabalho teve como objetivo conhecer os mecanismos de tolerância às variações de salinidade, pelas enzimas Mg++ - ATPase e Na+ K+ - ATPase, encontrada nas brânquias de Poecilia vivipara. No campo, foi observada a presença desta espécie em salinidades entre 0 e 28‰. No laboratório, os indivíduos foram mantidos em salinidade de 30‰ e responderam positivamente. Os indivíduos adultos, coletados em uma lagoa na praia dos Coqueiros, foram utilizados como matrizes. Nos experimentos foram usados alevinos que nasceram nos aquários testes. Para cada salinidade estudada foram feitas três réplicas com três espécimens em cada uma. Os alevinos foram mantidos em salinidades de 5, 10, 15, 20, 25, 30 e 35‰, durante um mês para total adaptação. As br

  15. Genotype-temperature interaction in the regulation of development, growth, and morphometrics in wild-type, and growth-hormone transgenic coho salmon.

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    Mare Lõhmus

    Full Text Available BACKGROUND: The neuroendocrine system is an important modulator of phenotype, directing cellular genetic responses to external cues such as temperature. Behavioural and physiological processes in poikilothermic organisms (e.g. most fishes, are particularly influenced by surrounding temperatures. METHODOLOGY/PRINCIPAL FINDINGS: By comparing the development and growth of two genotypes of coho salmon (wild-type and transgenic with greatly enhanced growth hormone production at six different temperatures, ranging between 8 degrees and 18 degrees C, we observed a genotype-temperature interaction and possible trend in directed neuroendocrine selection. Differences in growth patterns of the two genotypes were compared by using mathematical models, and morphometric analyses of juvenile salmon were performed to detect differences in body shape. The maximum hatching and alevin survival rates of both genotypes occurred at 12 degrees C. At lower temperatures, eggs containing embryos with enhanced GH production hatched after a shorter incubation period than wild-type eggs, but this difference was not apparent at and above 16 degrees C. GH transgenesis led to lower body weights at the time when the yolk sack was completely absorbed compared to the wild genotype. The growth of juvenile GH-enhanced salmon was to a greater extent stimulated by higher temperatures than the growth of the wild-type. Increased GH production significantly influenced the shape of the salmon growth curves. CONCLUSIONS: Growth hormone overexpression by transgenesis is able to stimulate the growth of coho salmon over a wide range of temperatures. Temperature was found to affect growth rate, survival, and body morphology between GH transgenic and wild genotype coho salmon, and differential responses to temperature observed between the genotypes suggests they would experience different selective forces should they ever enter natural ecosystems. Thus, GH transgenic fish would be expected to

  16. Relationship between fish size and upper thermal tolerance (United States)

    Recsetar, Matthew S.; Zeigler, Matthew P.; Ward, David L.; Bonar, Scott A.; Caldwell, Colleen A.


    Using critical thermal maximum (CTMax) tests, we examined the relationship between upper temperature tolerances and fish size (fry-adult or subadult lengths) of rainbow trout Oncorhynchus mykiss (41-200-mm TL), Apache trout O. gilae apache (40-220-mm TL), largemouth bass Micropterus salmoides (72-266-mm TL), Nile tilapia Oreochromis niloticus (35-206-mm TL), channel catfish Ictalurus punctatus (62-264 mm-TL), and Rio Grande cutthroat trout O. clarkii virginalis (36-181-mm TL). Rainbow trout and Apache trout were acclimated at 18°C, Rio Grande cutthroat trout were acclimated at 14°C, and Nile tilapia, largemouth bass, and channel catfish were acclimated at 25°C, all for 14 d. Critical thermal maximum temperatures were estimated and data were analyzed using simple linear regression. There was no significant relationship (P > 0.05) between thermal tolerance and length for Nile tilapia (P = 0.33), channel catfish (P = 0.55), rainbow trout (P = 0.76), or largemouth bass (P = 0.93) for the length ranges we tested. There was a significant negative relationship between thermal tolerance and length for Rio Grande cutthroat trout (R2 = 0.412, P 2 = 0.1374, P = 0.028); however, the difference was less than 1°C across all lengths of Apache trout tested and about 1.3°C across all lengths of Rio Grande cutthroat trout tested. Because there was either no or at most a slight relationship between upper thermal tolerance and size, management and research decisions based on upper thermal tolerance should be similar for the range of sizes within each species we tested. However, the different sizes we tested only encompassed life stages ranging from fry to adult/subadult, so thermal tolerance of eggs, alevins, and larger adults should also be considered before making management decisions affecting an entire species.

  17. Natural selection constrains personality and brain gene expression differences in Atlantic salmon (Salmo salar). (United States)

    Thörnqvist, Per-Ove; Höglund, Erik; Winberg, Svante


    In stream-spawning salmonid fishes there is a considerable variation in the timing of when fry leave the spawning nests and establish a feeding territory. The timing of emergence from spawning nests appears to be related to behavioural and physiological traits, e.g. early emerging fish are bolder and more aggressive. In the present study, emerging Atlantic salmon (Salmo salar L.) alevins were sorted into three fractions: early, intermediate and late emerging. At the parr stage, behaviour, stress responses, hindbrain monoaminergic activity and forebrain gene expression were explored in fish from the early and late emerging fractions (first and last 25%). The results show that when subjected to confinement stress, fish from the late emerging fraction respond with a larger activation of the brain serotonergic system than fish from the early fraction. Similarly, in late emerging fish, stress resulted in elevated expression of mRNA coding for serotonin 1A receptors (5-HT1A), GABA-A receptor-associated protein and ependymin, effects not observed in fish from the early emerging fraction. Moreover, fish from the early emerging fraction displayed bolder behaviour than their late emerging littermates. Taken together, these results suggest that time of emergence, boldness and aggression are linked to each other, forming a behavioural syndrome in juvenile salmon. Differences in brain gene expression between early and late emerging salmon add further support to a relationship between stress coping style and timing of emergence. However, early and late emerging salmon do not appear to differ in hypothalamus-pituitary-interrenal (HPI) axis reactivity, another characteristic of divergent stress coping styles.

  18. Viabilidad y crecimiento de poblaciones diploides y triploides de tilapia nilotica, oreochromis niloticus, línea Ghana

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    Celis M. Cesar


    Full Text Available The principal aim of this research was to produce triploid offspring of O. niloticus, applying warm thermic shocks (41A-42 oC to eggs during 3,5-4 min., 3,5 mino after fertilization, or cold shocks (10,8-11,3 oC to oocytes during one hour, 5 min after their fertilization. The best tissue to confirm triploids was kidney and brain of larvae and alevines. Then, the survival of fertilized eggs and growth rate were determined. The results show that the warm and cold shocks are efficient to produce 100% triploids, with different rates of survival. Also, that 25,5% oftspring was deformed when cold shocks were applyed, and 32,5% deformities with warm shocks. There were not significant difterences in growth between triploid and diploid populations
    after three months of age.La triploidía se obtuvo aplicando choques térmicos calientes (41.4 - 42 OC a oocitos durante 3.5 - 4 minutos, 3.5 min. después de la fertilización, y choques térmicos fríos (10.8 - 11.3 oC a oocitos durante una hora, 5 minutos de su fertilización. La triploidía se comprobó por análisis cromosomal en larvas y alevinos. Luego se monitoreó la tasa de crecimiento y sobrevivencia de los huevos fertilizados. Los resultados indican que los choques calientes y fríos fueron eficientes para producir ciento por ciento de triploidía, con tasas variables de sobrevivencia. Se observaron deformidades de peces trioloides (25.5% con choques frfos, y 32.5% con choques calientes. No se encontraron diferencias significativas en el crecimiento entre poblaciones triploides y diploides luego de tres meses de cultivo.

  19. Comparison of the growth of males and females of tilapia Oreochromis Niloticus cultured in cages

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    Carlos Alvarado-Ruiz


    Full Text Available With the purpose of evaluating productive performance and potential weight gain capacity of snapper O. Niloticus without reversing, we evaluated the growth of males and females raised in floating cages in captivity grouped by gender. The experiment was conducted for a term of 150 days.  We used a simple 4 836 alevins of 26.2±19.7g, fish that were nourished until they visibly reached sexual differentiation to 119.3±56.5 g to be separated by sex and nourished in floating cages to a final average weight of 387.0±128.9g (harvestto determine differences in growth. The weight distribution of the undefined gender sample showed a decrease in the coefficient of variation (CV of 75.13% to 31.49 and 30.22 for males and females respectively. This indicates that the distribution of sizes of the samples tended to become normal during the cycle of harvest. Significant differences (P=0.05 for the weight of harvest 429.2±135.1g and 339.65±102.64 g.   For the growth rate 2.74±0.86g day y 2.18±0.68 g day were determined between males and females respectively. The standard error of the estimation of the difference of average weight between males and females was 89.62±7.23g for an accuracy level of 95%. Males displayed  better growth rate and weight gain for harvest.

  20. Postprandial kinetics of gene expression of proteins involved in the digestive process in rainbow trout (O. mykiss) and impact of diet composition. (United States)

    Borey, Marion; Panserat, Stephane; Surget, Anne; Cluzeaud, Marianne; Plagnes-Juan, Elisabeth; Herman, Alexandre; Lazzarotto, Viviana; Corraze, Geneviève; Médale, Françoise; Lauga, Beatrice; Burel, Christine


    The impact of increased incorporation of plant ingredients on diets for rainbow trout was evaluated in terms of gene expression of gastric (gastric lipase, pepsinogen) and intestinal (prolidase, maltase, phospholipase A2) digestive enzymes and nutrient transporters (peptide and glucose transporters), as well as of postprandial levels of plasma glucose, triglycerides and total free amino acids. For that purpose, trout alevins were fed from the start of exogenous feeding one of three different experimental diets: a diet rich in fish meal and fish oil (FM-FO), a plant-based diet (noFM-noFO) totally free from fish meal and fish oil, but containing plant ingredients and a Mixed diet (Mixed) intermediate between the FM-FO and noFM-noFO diets. After 16 months of rearing, all fish were left unfed for 72 h and then given a single meal to satiation. Blood, stomach and anterior intestine were sampled before the meal and at 2, 6 and 12 h after this meal. The postprandial kinetics of gene expression of gastric and intestinal digestive enzymes and nutrient transporters were then followed in trout fed the FM-FO diet. The postprandial profiles showed that the expression of almost all genes studied was stimulated by the presence of nutrients in the digestive tract of trout, but the timing (appearance of peaks) varied between genes. Based on these data, we have focused on the molecular response to dietary factors in the stomach and the intestine at 6 and 12 h after feeding, respectively. The reduction in FM and FO levels of dietary incorporation induced a significant decrease in the gene expression of gastric lipase, GLUT2 and PEPT1. The plasma glucose and triglycerides levels were also reduced in trout fed the noFM-noFO diet. Consequently, the present study suggests a decrease in digestive capacities in trout fed a diet rich in plant ingredients. PMID:26920536

  1. The influence of three methods of gravel cleaning on brown trout, Salmo trutta, egg survival (United States)

    Shackle, Victoria J.; Hughes, Simon; Lewis, Vaughan T.


    Siltation of spawning gravels in upland rivers appears to be an increasing hindrance to salmonids' spawning success. River managers seek an effective and non-labour intensive means of loosening gravel and reducing fine material, so improving spawning success; this study compared three practical gravel cleaning techniques, applied at realistic (rather than intensive) levels, by assessing survival to hatching of buried brown trout, Salmo trutta L., ova at five sites on four rivers with gravel substrate in southern England. Each site consisted of six reaches, of which three were cleaned by tractor rotovating, high pressure jet washing and pump washing; these were compared with adjacent, untreated reaches. Brown trout ova were buried in both fine mesh and coarse mesh boxes in each reach.Significant improvements (at P<0·05) in survival (number of live alevins) were found in three of the five pump washed reaches, two of the five tractor rotovated reaches and one pressure washed reach when the data were analysed by site. When data from all five sites were analysed together, all treated reaches showed a significant improvement (at P<0·05) in egg survival to hatching compared with control reaches for fine mesh egg boxes; for coarse mesh boxes only pump washed reaches showed such an improvement.We feel that pump-washing provides the most effective, inexpensive and suitably non labour-intensive means of improving gravel, although ultimately it may be better to reduce the silt load of rivers. Freeze core bed samples taken before and immediately after cleaning were analysed for silt content; pump washing and high pressure washing may have reduced the amount of fine material.

  2. Deuterium depleted water. Present applications and prospects

    International Nuclear Information System (INIS)

    The deuterium depleted water, DDW, is distilled, microbiologically pure water with an isotopic concentration D/(D+H) under 145 ppm, the natural water value. At ICSI Rm Valcea a procedure was developed and a patent was recorded for the method and installation for obtaining DDW. The procedure consists in vacuum distillation of natural water on columns equipped with highly performing ordered packing. The system allows obtaining DDW at isotopic concentration within the range 20-120 ppm. Biological studies showed that treatment with this DDW reduced significantly the high rate in L929 linear fibroblast cells and annihilated the tumoral growth in xenotransplant. It was suggested that the deuterium occurring naturally has an essential in converting the signals regulating the cellular cycling. A vast program based on collaborations of ICSI with different specialized research institutes in Romania was initiated and important results already obtained among which one can mention: - DDW determines an increase of vascular reactivity seemingly endotelio-dependent and implying radical species (superoxides, nitric oxides); - immunity defense reaction represented by the opsonic, bactericide and phagocytic capacity are stimulated; - animals pre-treated with DDW present an increased resistance to both sub-lethal and lethal doses of gamma radiations, suggesting a radioprotective property; - study of artificial fecundation in fishes with fecundating solution containing an 1:1 mixture of DDW and distilled water showed the beneficent effects both in embryonal development and growth in alevins; - an increase of metabolism rate in aquatic macrophytes following the dilution of spectral energy of sea water mixed with DDW was observed; - studies on three genotypes of Zea mays showed significant effects on coleoptile growth. At present programs for studying prevention and treatment of tumors and various cancer forms are underway

  3. Research on Captive Broodstock Programs for Pacific Salmon, 2001-2002 Annual Report.

    Energy Technology Data Exchange (ETDEWEB)

    Berejikian, Barry; Tezak, E.; Endicott, Rick


    The efficacy of captive broodstock programs depends on high in-culture survival and the fitness of cultured salmon after release, either as adults or juveniles. Continuing captive broodstock research designed to improve technology is being conducted to cover all major life history stages of Pacific salmon. The following summarizes some of the work performed and results from the FY 2001 performance period: (1) The incidence of male maturation of age-1 chinook salmon was significantly reduced by reducing growth in the first year of rearing. (2) Experimentally manipulated growth rates of captively-reared coho salmon had significant effects on female maturation rate, egg size, and fecundity, and the effects were stage-specific (i.e., pre-smolt vs. post-smolt). (3) A combination of Renogen and MT239 vaccination of yearling chinook salmon given an acute R. salmoninarum challenge had a significantly longer survival time than the mock-vaccinated group. The survival time was marginally higher than was seen in acutely challenged fish vaccinated with either Renogen or MT239 alone and suggests that a combination vaccine of Renogen and MT239 may be useful as both a prophylactic and therapeutic agent against BKD. (4) Full-sib (inbred) groups of chinook salmon have thus far exhibited lower ocean survival than half-sib and non-related groups. Effects of inbreeding on fluctuating asymmetry did not follow expected patterns. (5) Sockeye salmon were exposed to specific odorants at either the alevin/emergent fry stage or the smolt stage to determine the relative importance of odorant exposure during key developmental periods and the importance of exposure duration. (6) Experimental studies to determine the effects of exercise conditioning on steelhead reproductive behavior and the effects of male body size on chinook salmon fertilization success during natural spawning were completed.

  4. Deuterium depleted water. Romanian achievements and prospects

    International Nuclear Information System (INIS)

    The deuterium depleted water (DDW) is microbiologically pure distilled water with a deuterium content lower than that of natural waters which amounts to 140 - 150 ppm D/(D+H); variations depend on geographical zone and altitude. The procedure of obtaining DDW is based on isotopic separation of natural water by vacuum distillation. Isotope concentration can be chosen within 20 to 120 ppm D/(D+H). The ICSI at Rm. Valcea has patented the procedure and equipment for the production of DDW. According to the document SF-01-2002/INC-DTCI - ICSI Rm. Valcea, the product has a D/(D+H) isotope concentration of 25 ± 5. Studies and research for finding the effects and methods of application in different fields were initiated and developed in collaboration with different institutes in Romania. The following important results obtained so far could be mentioned: - absence of toxicity upon organisms; - activation of vascular reactivity; - enhancement of defence capacity of the organism through non-specific immunity activation; - increase of salmonid reproduction capacity and enhancement of the adaptability of alevins to the environmental conditions; - radioprotective effect to ionizing radiation; - maintaining meat freshness through osmotic shock; - stimulation of growth of aquatic macrophytes; - enhancement of culture plant development in certain ontogenetic stages. Mostly, the results and practical applications of the research were patented and awarded with gold medals at international invention fairs. At present, research-development programmes are undergoing to find active biological features of DDW in fighting cancer, on one hand, and its applicability as food additive of pets or performing animals, on the other hand

  5. Cultivo de cachama blanca en altas densidades y en dos sistemas cerrados

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    Germán Poleo


    Full Text Available El objetivo de este trabajo fue evaluar la tolerancia de la cachama blanca, Piaractus brachypomus, a cultivos en altas densidades en sistemas cerrados. Novecientos alevines de 44,3±26 g de peso, se distribuyeron en seis tanques de concreto, con 4,8 m³ de agua. Tres tanques presentaron cero recambio de agua (SCR, y en otros tres, el agua se hizo circular a través de un bioclarificador (SRA. Ambos tratamientos presentaron fuerte aireación para mantener los sólidos en suspensión y suministrar aire. Los peces se alimentaron a saciedad con pienso comercial por 192 días. Los parámetros de calidad de agua como: oxígeno disuelto, amonio total, nitritos, nitratos, alcalinidad, dureza, temperatura y pH, se midieron semanalmente. Los peces en el SCR crecieron a una tasa de 2,34±0,05 g por día, y tuvieron conversión alimenticia de 1,5±0,06, densidad final de 12,96±0,53 kg m-3, y peso final de 449,5±99 g. En el SRA, los peces crecieron 2,33±0,03 g por día, con conversión alimenticia de 1,6±0,07, densidad final de 12,13±1,12 kg m-3, y peso final de 446,5±10 g. La cachama blanca puede ser cultivada en sistemas cerrados con cero recambio de agua en altas densidades.

  6. Hyporheic Exchange in Gravel-Bed Rivers with Pool-Riffle Morphology: A 3D Model (United States)

    Tonina, D.; Buffington, J. M.


    The hyporheic zone is a saturated band of sediment that surrounds river flow and forms a linkage between the river and the aquifer. It is a rich ecotone where benthic, hyporheic, and groundwater species temporarily or permanently reside. Head gradients along the streambed draw river water into the hyporheic zone and expel pore water into the stream. This process, known as hyporheic exchange, is important for delivering nutrients, oxygen and other solutes to the sediment, and for washing away waste products to support this ecotone. It is an essential component of the carbon and nitrogen cycles, and it controls in-stream contaminant transport. Although hyporheic exchange has been studied in sand-bed rivers with two-dimensional dune morphology, few studies have been conducted for gravel-bed rivers with three-dimensional pool-riffle geometry. The hyporheic zone of gravel-bed rivers is particularly important for salmonids, many of which are currently at risk world wide. Salmon and trout lay their eggs within the hyporheic zone for incubation. After hatching, the alevins live in the gravel before emerging into the stream. The upwelling and downwelling hyporheic fluxes are intense in these streams due to the highly permeable sediment and strong head variations forced by shallow flow over high-amplitude bed forms. Moreover, gravel-bed rivers show a wide range of flow regimes that change seasonally and have strong effects on hyporheic exchange. To study this exchange, we used four sets of pool-riffle geometries in twelve recirculating flume experiments. We kept a constant bed-form wavelength, but changed the bed-form amplitude and imposed three discharges, covering a wide range of hydraulic and geometric characteristics. Hyporheic exchange was predicted from a three-dimensional model based on bedform-induced pumping transport, where the boundary head profile is the pressure head distribution at the sediment interface, measured with an array of mini-piezometers buried within

  7. Premiers résultats de l'élevage intensif de la perche européenne (Perca fluviatilis en bassin : effet de la température et du tri sur la croissance

    Directory of Open Access Journals (Sweden)



    Full Text Available Malgré un marché potentiel important, peu d'études ont examiné les possibilités de développement de l'élevage intensif de la perche (Perca fluviatilis en bassins ou en cages. L'objectif de cette étude initiale était d'évaluer l'effet de la température et du tri en fonction du poids corporel sur la croissance de perches élevées en conditions intensives. Les essais ont été réalisés avec des alevins de perche sevrés (1,9 g sur une alimentation artificielle, placés en bassins alimentés par de l'eau du système de refroidissement d'une centrale nucléaire. La croissance est légèrement supérieure (+ 14,5 % à une température de 26,5 °C par rapport à celle enregistrée à 22,9 °C. Cette différence est non significative (p>0,05, probablement parce que ces 2 températures se situent dans la gamme des températures optimales pour la croissance de la perche. Une infestation (taux de contamination : 24,5 % par le cilié Heteropolaria sp est apparue à une température de 26,5 °C. Les perches, triées et séparées en 3 groupes distincts en fonction du poids corporel au début de l'expérience, ont présenté, après 234 jours d'élevage, une augmentation du polymorphisme de la croissance dans chaque groupe se traduisant par une superposition partielle des distributions des poids corporels. Une analyse de covariance indique que les 3 groupes ont présenté des vitesses de croissance comparables (F = 1,2. En élevage intensif, il apparaît que la perche présente une grande variabilité de croissance, ce qui renforce la nécessité de trier fréquemment les poissons.

  8. Reproducción natural controlada del black bass Micropterus salmoides - Controlled natural reproduction of black bass Micropterus salmoides

    Directory of Open Access Journals (Sweden)

    Amaral Junior, Hilton


    Full Text Available ResumenPara viabilizar la reproducción, larvicutura y alevinaje del Black bass, en la región sur de Brasil, se ha buscado adaptar una tecnología, desarrollada por el Centro Nacional de Acuicultura Piscifactoría las Vegas del Guadiana Badajoz/España. Consiste en controlar el ambiente de desove, utilizando estanques con nidales, para el desove del Black bass. Optimizando esta tecnología, desarrollamos una técnica de adaptación del Black bass al cultivo intensivo durante el período de invierno, ofreciendo un pienso de un 40% de proteína cruda y zooplancton (Daphnia sp.. Se dejan los reproductores en un mismo estanque de engorda en sistema extensivo, y son adaptados para un sistema intensivo de cultivo, en estanques de hormigón con entrada y salida del agua. Se acondicionan reproductores machos y hembras, durante los meses de invierno. En la primavera, se abren sucesivamente las compuertas de comunicación del departamentocentral, con los estanques frezaderos. En estos estanques frezaderos,se colocan nidales de grava para la puesta de las hembras. Pasado elperíodo de ocupación cíclica de los estanques de desove, losreproductores vuelven al departamento central. Después de laeclosión, las larvas son alimentadas con pienso molido a un 48% deproteína cruda con una oferta de un 10% de su peso y zooplancton Daphina sp. Los alevines se quedan alojados en estanques de tierrapara el período de engorda.SummaryIn order to make reproduction, larval and fingerling rearing of BlackBass in the south region of Brazil, we try to adapt a technologydeveloped by Centro Nacional de Aquicultura Piscifactoria Las Vegasdel Guadiana, Badajoz, Espanha. The technique consists in controllingthe spawning environment with a tank containing nests. To optimizethis technology, we develop a technique to adapt the black bass in aintensive culture during winter, providing food with 40% proteine andzooplankton (Daphnia sp.. The spawners are manteined in the

  9. Environmental performance of aquaculture in Rondônia state, Brazil

    Directory of Open Access Journals (Sweden)

    Aurélio Ferreira Borges


    Full Text Available The objective of this study was to analyze the environmental performance of aquaculture in the city of Colorado do Oeste, Rondônia State, Brazil. Fifteen fish farmers were interviewed. For data collection, structured interviews were carried out, using a questionnaire based on information supplied by the United Nations Food and Agriculture Organization (FAO. The questionnaire considered 12 items, organized into three main topics: a social and legal standards b environmental standards c standards of food safety and hygiene. The questionnaire considered 12 items, organized into three main topics: a social and legal standards b environmental standards c standards of food safety and hygiene. Aquaculture in the city of Colorado do Oeste, Rondônia presents two fish production systems: extensive and semi-intensive. In the semi-intensive system, stocking rate was one fish per m3, on average; tambaqui (Colossoma macropomum, tilapias (Oreochromis spp., pirarucu (Arapaima gigas and pintado (Pseudoplatystoma spp. were the species farmed at the largest number. The rate of water renewal was due to the greater availability of natural food in this system. Water renewal was constant in the ponds (1,500 liters per minute. In the semi-intensive system using dug ponds, alevins were stocked and fed during the entire rearing time with natural and exogenous food. The extensive system relied on the natural production of the pond, with stocking density limited by the production of natural food. The little renewal of water made the cultivation tank itself acted as a decantation lake, with the occurrence of oxidation and sedimentation of residual organic matter, consisting of feces, debris and organic fertilizer. Production of reduced effluent volume took place in the extensive system, compared to the cultivation area. In addition, there was high water turbidity, caused by high concentration of planktonic organisms, and low concentrations of dissolved oxygen in the water

  10. Rapid diagnosis and identification by PCR of Yersinia ruckeri isolated of Oncorhynchus mykiss from Canta, Lima, Peru Diagnóstico e identificación rápidos por PCR de Yersinia ruckeri aislada de Oncorhynchus mykiss procedentes de Canta, Lima, Perú

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    Susana Sirvas-Cornejo


    Full Text Available Twenty individuals of rainbow trout were sampled (fry and juveniles from Acochinchan Fishfarm (Canta, Lima - Peru, and analyzed with the Polimerase Chain Reaction test (PCR in order to achieve a rapid identification of Yersinia ruckeri, which is the pathogen agent that causes the enteric red mouth disease (ERM and produces high rates of mortality. Nine fish samples were asymptomatic, while 11 of them showed signs of ERM. In addition, 22 bacterial strains were isolated from the liver, spleen and kidney. PCR and specific primers (16S rRNA, were used to amplified a specific 575 bp DNA fragment of Yersinia ruckeri. Nineteen strains were identified as Yersinia ruckeri by PCR in symptomatic and asymptomatic fishes. It was established a diagnosis time of 26 hours, compared with the 2 or 3 days that would take the diagnosis using biochemical tests.Se muestrearon 20 ejemplares (alevines y juveniles de trucha arco iris cultivados en la piscifactoría Acochinchán (Canta, Lima, Perú, y se les aplico la técnica de la Reacción en Cadena de la Polimerasa (PCR con la finalidad de obtener una identificación rápida del agente patógeno Yersinia ruckeri que produce la enfermedad entérica de la boca roja (ERM y genera elevadas tasas de mortalidad. Nueve ejemplares fueron asintomáticos mientras que 11 presentaron signos de ERM. Se aislaron 22 cepas bacterianas del hígado, bazo y riñón. Se empleó la técnica de la PCR para la amplificación y cebadores específicos (ARNr 16S, que permitieron amplificar un fragmento de ADN de 575 pb de Yersinia ruckeri. Diecinueve cepas fueron identificadas como Yersinia ruckeri mediante la PCR, tanto en peces sintomáticos como asintomáticos. Se estableció un tiempo de diagnóstico de 26 horas, en comparación con los 2 ó 3 días que duraría el diagnóstico empleando las pruebas bioquímicas.

  11. Índices de calidad ambiental de aguas del Arroyo Caañabe mediante tests microbiológicos y ecotoxicológico

    Directory of Open Access Journals (Sweden)

    Tomás López Arias


    Full Text Available El Arroyo Caañabe, es un curso de agua que corre a través de los Departamentos Central y Paraguarí (República del Paraguay. Las descargas de origen agropecuario, urbano e industrial contaminan sus aguas. En este trabajo se evalúa la calidad del arroyo mediante sus características fisicoquímicas, ecotoxicológicas, microbiológicas y se la comparan con la legislación vigente. Se colectaron muestras en los meses de Julio y Setiembre del año 2014. Se estudiaron tres sitios denominados S1, ubicado en aguas arriba de la Ciudad de Carapegua; S2 en la intersección del arroyo con la Ruta 1, y S3, en la zona límite de las ciudades de Carapegua y Nueva Italia. Se realizaron ensayos de toxicidad aguda con Daphnia magna, Lactuca sativa, y alevines de Danio rerio; además de ensayos crónicos en Tetradesmus wisconsinenesis, D. rerio y Allium cepa. Se evaluaron los grupos y especies microbianos siguientes: aerobios mesófilos, enterobacterias, coliformes totales, coliformes fecales, E. coli, Pseudomona aeruginosa, mohos y levaduras; además se determinaron índices de calidad y de contaminación. Los resultados indican que las aguas del arroyo presentaron características de clase II y de clase III según el padrón establecido por la Secretaría del Ambiente del Paraguay. El índice de calidad de agua (ICA arrojó valores comprendidos entre 52 y 62 lo que otorga la clasificación de "regular"; mientras que el índice de contaminación trófica (ICOTRO presentó valores entre 0,12 y 0.26, indicando "eutrofización". Los recuentos de coliformes fueron superiores en el segundo muestreo, aunque dentro lo establecido por la norma. La presencia de P. aeruginosa en los tres puntos constituye un riesgo para la salud. Ensayos ecotoxicológicos agudos mostraron que las aguas presentan escasos efectos letales, no obstante los ensayos crónicos en A. cepa y el test de micronúcleos en D. rerio indican potenciales efectos citotóxicos y genotóxicos de las

  12. Deuterium depleted water. Current and potential applications

    International Nuclear Information System (INIS)

    :1 mixture of DDW and distilled water evidenced beneficial effects both in the embryonic growth period and in growth period in alevins; - DDW causes an increase in metabolism rate of aquatic macrophytes (Tetraselmis suecica) due to the spectral energy diminishing of sea water mixed with DDW; - the studies carried out on three genotypes (one of heterozygote type and two of homozygote type) of Zea mays in parental forms showed that in the presence of DDW the coleoptile growth is enhanced in homozygotes and hindered in heterozygotes, while the root growth is hindered in both. These results and various practical applications were patented and received rewards in many international meetings. Underway are studies concerning DDW use as fodder additive as well as in preventing and treating various forms of cancer

  13. Incidences des extractions de matériaux alluvionnaires et de l'aménagement des cours d'eau sur l'écosystème aquatique

    Directory of Open Access Journals (Sweden)



    Full Text Available Les exploitations de granulats (dragages dans le lit mineur, et/ou rejets, mal décantés, d'eau de lavage des sables et graviers extraits et certains travaux hydrauliques (rectifications, recalibrages, provoquent d'importantes perturbations dans l'écosystème aquatique. Nous avons essayé, entre 1974 et 1978, de les mettre en évidence sur trois cours d'eau du MASSIF CENTRAL : la LOIRE, l'ALLIER, la DORE. LES MODIFICATIONS DU BIOTOPE portent essentiellement sur l'uniformisation et la déstabilisation du lit, l'augmentation du taux de matières en suspension et de la turbidité de l'eau, la réduction de la transmission de lumière en profondeur, le « colmatage » du fond. LES MODIFICATIONS DES COMMUNAUTES VIVANTES résultant des altérations précédentes sont : la réduction des densités numériques de Diatomées et de Macroinvertébrés benthiques (la diversité spécifique est peu affectée, une réduction de la teneur du Périphyton en pigments photosynthétiques, un abaissement de la production primaire, une réduction de la biomasse des Macroinvertébrés un ralentissement de la colonisation du substrat par cette faune, une augmentation de la mortalité des oeufs et alevins de Truites, incubés sous graviers (« colmatage » par les limons déposés, un ralentissement des éclosions des oeufs de Truites, une réduction des effectifs et de la biomasse des populations ichtyaires (prédatrices des Macroinvertébrés. LES MOYENS DE LUTTE contre ce type de nuisances résident dans l'application de la Législation, notamment des nouveaux textes concernant les Carrières. La principale mesure technique pouvant supprimer la pollution mécanique, due aux effluents de lavage des granulats, consiste à laver les matériaux extraits en circuit fermé (recyclage de l'eau. Il convient également d'interdire les extractions dans le lit mineur des cours d'eau. Quant aux aménagements hydrauliques, il est indispensable que leur conception tienne compte

  14. Detección “in vivo” mediante RAPD de alteraciones en el ADN producidas por benzo(apireno

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    C Becerril


    Full Text Available La técnica de RAPD (Amplificación al Azar de ADN Polimórfico permite detectar alteraciones inespecíficas en el ADN procedente de células que poseen una dotación genética idéntica, como son las líneas celulares establecidas, mediante la comparación del patrón de bandas de las células expuestas y no expuestas a la acción de genotóxicos. En los últimos años hemos desarrollado una metodología sensible y reproducible utilizando la línea celular RTG-2, derivada de trucha arco iris (Oncorhynchus mykiss. Sin embargo, es preciso comprobar la capacidad predictiva de este ensayo mediante estudios in vivo. La línea celular RTG-2, como se ha evidenciado en trabajos anteriores, presenta una gran similitud genética con la especie de la que procede. Por ello, en este trabajo, se ha llevado a cabo una exposición subletal a benzo(apireno mediante inyección intraperitoneal de 69 μg/g de p.c. en alevines de trucha arco iris, valorando la aparición de mutaciones mediante la comparación del patrón de bandas obtenido a partir del ADN de células de sangre periférica, a diferentes tiempos (1 - 3 meses. Debido a que la presencia de bandas polimórficas dificulta el análisis entre los grupos de individuos tratados y no tratados, las comparaciones se realizaron en un mismo individuo antes y después del tratamiento. Los análisis cualitativos y cuantitativos mostraron tanto la aparición de nuevas bandas, como alteraciones en su intensidad confirmando, de esta manera, los resultados que previamente habíamos obtenido in vitro tras exposiciones a este mismo genotóxico

  15. RELACIÓN ENTRE LOS MOTIVOS DE PRÁCTICA Y LOS COMPORTAMIENTOS DE DEPORTIVIDAD EN JÓVENES JUGADORES DE BALONMANO [Relationship between reasons for practicing and sportpersonship behaviors in young handball players] Relationship between reasons for practicing and sportpersonship behaviors in young handball players

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    David Sánchez Oliva


    Full Text Available


    El principal objetivo del presente estudio fue analizar las relaciones existentes entre la Teoría de la Autodeterminación y los comportamientos deportivos y antideportivos en categoría inferiores. Para ello, seleccionamos 127 jugadores de balonmano de categorías alevín, infantil y cadete, los cuales rellenaron diversos cuestionarios encaminados a analizar la motivación en el deporte (SMS: Pelletier, Fortier, Vallerand, Tudson, Brière y Blais, 1995, la satisfacción de las necesidades psicológicas básicas (EMM: García Calvo, Sánchez Miguel, Leo, Sánchez Oliva, y Gómez, 2010 y los comportamientos de deportividad (MSOS: Vallerand, Brière, Blanchard, y Provencher, 1997. Tras el análisis de nuestros resultados, se pudo comprobar cómo los niveles altos de autodeterminación se relacionan significativamente con los comportamientos deportivos, así como los motivos de práctica menos autodeterminados con las conductas antideportivas. Del mismo modo, destaca el mediador autonomía como el principal predictor de la participación adecuada, mientras que ocurre lo mismo con la regulación externa al predecir la crítica negativa. Como conclusión, dentro del contexto deportivo, destaca la importancia de fomentar entre los jóvenes comportamientos autodeterminados, consiguiendo que los participantes desarrollen durante el juego conductas más adaptativas. 

    Palabras clave: autodeterminación, mediadores psicológicos, deportividad, balonmano. 



    The main aim of this work was to analyze the relationships among Self-Determination Theory and sportsmanlike and antisocial behaviors in low categories. However, we recruited 127 handball players from alevine, infantile and cadet categories who filled several questionnaires to measure motivation in sport (SMS: Pelletier, Fortier, Vallerand, Tudson, Brière y Blais, 1995, satisfaction of the

  16. Early ontogenesis of the angelfish, Pterophyllum scalare Schultze, 1823 (Cichlidae

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    Agata Korzelecka-Orkisz


    alevines desarrollándose. Adicionalmente, se ha estudiado el efecto del pH básico del agua sobre los primeros estadios de desarrollo y la dependencia entre la cantidad de alimento y la supervivencia de los alevines. Las túnicas ovulares del escalar son finas (1,67-2,18 mm, transparentes, cubiertas de una sustancia viscosa. Los huevos de color ámbar tienen forma ovalada de diámetros medios 1,436 y 1,171 mm y de un volumen medio de 1,033 ± 0,095mm³. El porcentaje de supervivencia de embriones y de larvas en agua con pH aumentado, ligeramente básico, fue muy bajo, ya que sólo el 2% de los embriones sobrevivió, mientras que en agua de parámetros óptimos sólo algunos huevos palidecieron. Las larvas recién salidas del huevo medían 2,60 ± 0,093 mm por término medio y poseían grandes (0,64 ± 0,077 mm³ sacos vitelinos. Se han adherido al substrato mediante una secreción en forma de filamentos finos y viscosos. Esta secreción se ha desprendido de las glándulas ubicadas en la cumbre de la cabeza. Las glándulas desaparecieron al 5º día de vida de las larvas. Las larvas de un día poseían ya las primeras células pigmentarias en el cuerpo, los ojos de las larvas de dos días estaban pigmentadas plenamente. Entre el 4º y 5º día de vida las larvas empezaron a tomar alimento. Las larvas de 23 días se parecían a una versión miniaturizada de los adultos. La mortalidad de las larvas del escalar alimentadas durante los primeros días a partir del desove con larvas de artemia salina (Artemia salina fue mayor que la de las alimentadas con protozoarios y rotíferos.


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    NEVEU A.


    Full Text Available Les écrevisses sont potentiellement une source de nourriture pour les poissons. Le développement géographique et démographique de fortes populations de Pacifastacus leniusculus et de Procambarus clarkii ces 10 dernières années dans les eaux françaises pose le problème des relations avec les populations de poissons en place. En particulier au niveau des espèces carnassières : Esox lucius, Perca fluviatilis et Stizostedion lucioperca. Les interactions entre ces différentes espèces ont été étudiées dans des conditions expérimentales : en mésocosmes, en enclos dans des étangs, dans de petits étangs naturels. En mésocosme, des brochets de 16 à 46 cm consomment régulièrement des Procambarus au cours de l’année. Il y a une relation entre la taille des brochets et celle des Procambarus ingérées. Des brochets de 40 à 50 cm peuvent consommer les adultes d’écrevisses supérieurs à 8 cm. La consommation des écrevisses est régulière même en présence de poissons fourrages et même si chaque individu peut différer dans l’intensité de ses choix. L’intensité de la prédation dépend de la température mais elle perdure l’hiver. En enclos, des alevins de brochets associés à des juvéniles de Pacifastacus détruisent ces dernières au cours de l’été, malgré une croissance en parallèle. La protection par des abris n’est pas efficace, de même que la distribution de poissons fourrages. La même expérience effectuée en étang naturel donne les mêmes résultats, malgré la présence de la protection par des macrophytes. La confrontation de brochets de 1 été avec des Pacifastacus de 1 été donne des résultats semblables : les brochets éliminent la plupart des écrevisses. Dans tous les cas, les quelques écrevisses survivantes ont une croissance réduite et éventuellement une maturité retardée. L’association d’alevins de perches avec des juvéniles de Pacifastacus montre une survie normale des

  18. Biologia do saguirú (Characidae, Curimatinae

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    P. de Azevedo


    stomach are but delineated; the intestine is formed by a cylindric tube, all closed. At the place, where later on there will open the mouth, we find a group of ciliary hairs that produce a liquid current, very evident by the semi-circle formed by attached solid particles. After 36 hours, opening of the mouth and formation of the gill slits begin. At the age of 90 hours (4 mm. the larvas swim well and start to feed themselves; the digestive tube is now all open and the swimbladder works already. During the first days of life, larvas have an adhesive organ situated at their frontal region (fig. 7 in form of a crescent, by means of which they hang to surrounding vegetation (fig. 6. When the larva begins to swim and to feed itself and its yolk are having been absorbed. the adhesive organ retracts and disappears. While larvas and alevins feed themselves with plancton, they have small eye-teeth, which disappear,. when fishes become « ilyophagus ». There exist too, during their life as larvas, pharyngeal-teeth. The lateral line appears in the larva after 16 to 18 days; more or less at the same time all fins are completely developed. Shortly after, first scales appear (20 to 23 days. Evolution of intestines twisting followed (fig. 9. Larvas show at different parts of their bodies small of organs excretory functions, that are constituted by bottons in serial disposition, every one with an excretory canal that opens towards the outside. These formations disappear suddenly when larvas attain their phase of alevin. The existence of a great number of said formations at the caudal fin (fig. 12 is of great interest. In our experiences of breeding we have employed several thousands of C. elegans larvas in different environs and we made conditions of surrounding change (illumination, depth of water, temperature, presence of sand at bottom of aquariums and without sand, food. In this way we could compare the results obtained, estimate the action of each factor for the realisation of a

  19. Pyrethroid toxicity in silver catfish, Rhamdia quelen

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    Francisco P. Montanha


    Full Text Available This study aimed to determine both the lethal and sublethal concentrations of Cypermethrin in young Silver Catfish (Brazilian "Jundiá", Rhamdia quelen on aquatic environment during 96 hours, as well as to determine the Cypermethrin and Deltamethrin sublethal concentrations during the initial embryonic development period of Rhamdia quelen, and to verify their respective rates of fertilization, hatching and survival. Pyrethroid nowadays is a widely used insecticide, which presents a high toxicity to fish. In order to determine lethal and sublethal concentrations, 120 silver catfish were used; each one had an average weight of 59.58±4.50g and an average size of 20.33±2.34cm. Concentrations used were 0, 1.0, 1.5, 2.0, 2.5, 3.0, 5.0, 10.0, 15.0 and 20.0mg of Cypermethrin per liter of water (mg/L. Fish were exposed to the product in 30-liter fish tanks. In each fish tank there were four fishes and the product was applied three times, i.e., a total of twelve fish were exposed to the product at each application, and a total of 120 fish during the entire experiment (n=120. In order to determine the Cypermethrin and Deltamethrin sublethal concentrations during the initial embryonic development, ovulation induction was performed on female fishes using hormones, and then and egg collection was performed. The eggs were then hydrated and fertilized in Cypermethrin and Deltamethrin in different concentrations: 0.001, 0.01, 0.1, 1.0 and 10.0mg/L of Cypermethrin and 0.001, 0.01, 0.1, 0.5 and 1.0mg/L of Deltamethrin, in addition to the control group (0mg/L. After fertilization, the eggs were kept in containers with the respective pesticides of Cypermethrin and Deltamethrin until hatching, when hatching rate was verified. Then the alevins, from the hatching, were kept on their respective concentrations of Cypermethrin and Deltamethrin so that the survival rate could be analyzed regarding the tested insecticides, during both 12-hour and 24-hour periods

  20. Differences in survival and growth in hatchery and stream environments, and in maturation of residuls in a stream, between progeny of hatchery and wild steelhead (Study sites: Brushy Fork Creek and Dworshak Hatchery; Stocks:Dworshak hatchery and Fish Creek wild; Year classes: 1992 and 1993): Chapter 1 (United States)

    Rubin, Stephen P.; Reisenbichler, Reginald R.; Wetzel, Lisa A.; Hensleigh, Jay E.; Leonetti,; Rubin, Stephen P.; Reisenbichler, Reginald R.; Wetzel, Lisa A.; Hayes, Michael C.


    ). Differences between progeny groups were also found for growth (H>W) and condition (H>W) in the hatchery and downstream migration success of hatchery-reared fish after release (H>W), and for growth (HW for the other), condition (H>W), downstream dispersal (H>W for one year-class; H=W for the other), and maturation of residuals (ovaries weight was greater for H than for W females at ages 4 and 5; testes weight was less for H than for W age-3 males of one year-class) in Brushy Fork. A thunderstorm-induced power outage interrupted flow to the incubation trays at the hatchery and compromised a major tenet of the common garden design for the second year-class, possibly contributing to the inconsistency in relative survivals in Brushy Fork between year-classes. The storm caused the incubation environment to differ between the stocks as a result of reduced oxygen levels and substantially higher densities for H alevins. This difference was illustrated by a 55% loss for H fish during the event, about twice that for W fish.

  1. (Danio rerio

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    F Prieto García


    y de eclosión, mayor porcentaje de alevines recién eclosionados y juveniles con malformaciones, y menor porcentaje de juveniles sobrevivientes.

  2. La «loi pêche» (Code rural et l'introduction des espèces piscicoles

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    Full Text Available Les introductions d'espèces piscicoles non représentées et/ou susceptibles de créer des déséquilibres biologiques se développent, ici ou là, pour des considérations halieutiques ou accessoirement scientifiques, ou tout simplement pour se débarrasser de spécimens devenus encombrants. Face à ce phénomène, le droit de la pêche continentale n'offre qu'une réponse partielle qui n'est pas suffisante, à ce jour, pour assurer son contrôle. Ainsi, le chapitre II du titre troisième (pêche en eau douce et gestion des ressources piscicoles du livre II (nouveau du Code rural organise le contrôle des peuplements (section IV : articles L.232-10 à L.232-12, R.*232-3 à R.*232-25 du Code rural. Ce dispositif comporte un ensemble d'interdictions assorties, le cas échéant, d'autorisations : - interdiction d'introduire dans les eaux libres et les piscicultures, et de transporter sans autorisation, des poissons susceptibles de provoquer des déséquilibres biologiques ; - interdiction d'introduire sans autorisation des espèces de poissons qui ne sont pas officiellement représentées dans les eaux douces nationales ; - interdiction d'introduire, dans les eaux classées en 1ère catégorie piscicole, des poissons des espèces carnassières (brochet, perche, sandre et black-bass ; - interdiction d'introduire dans les eaux libres, pour rempoissonner ou aleviner, des poissons qui ne proviennent pas d'établissements agréés. Cette législation est perfectible en tant qu'elle suscite des difficultés d'application : la notion d'introduction n'est pas explicitée par les textes et doit être distinguée de l'emploi d'appâts vifs ou de la remise à l'eau ; le transport des espèces non représentées - autres que celles qui sont de nature à créer des déséquilibres biologiques - n'est pas soumis à autorisation et s'effectue donc librement ; le système de listes d'espèces présente une certaine rigidité et ne permet pas de pr


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    Full Text Available Les comportements d’émigration et d’utilisation de l’espace développés par des civelles ont été observés dans des bacs et plans d’eau expérimentaux. Dans les bacs accueillant 55 ind./m2 sans possibilité d’émigration, la densité d’abris végétaux a été contrôlée (densités d’abris basse, 2 tiges de végétation artificielle par bac ou haute, 9 tiges par bac et le suivi a duré 2 mois et demi. Dans les plans d’eau ouverts, la densité de civelles introduites a été définie selon plusieurs modalités (1,6 - 6 - 9 et 12 ind./m2 et le suivi a duré 1 mois et demi. En bacs, après une période de 5 à 6 jours, les abris sont fortement recherchés pendant environ 6 semaines, les individus montrant alors une forte grégarité. Cette dernière disparaît ensuite, les abris sont alors moins recherchés et des comportements agressifs font leur apparition. En plans d’eau, les sorties concernent en moyenne 17 % du stock initial (mini = 7 %, maxi = 35 %, interviennent rapidement et sont presque toutes dirigées vers l’amont. Leur intensité ne dépend pas de la densité initiale et apparaît plus importante dans les bassins sans herbier. Les tailles et poids moyens des émigrants sont plus importants que ceux du lot initial. Au terme du suivi, la croissance apparaît forte, hétérogène et associée à une faible survie dans les plans d’eau peu ou moyennement alevinés. Elle apparaît plus faible, homogène et associée à une bonne survie dans les bassins à forte densité initiale. Ces observations sont compatibles avec l’expression d’un comportement grégaire en condition de densité importante, comportement favorisant une croissance homogène, ayant pour conséquence de retarder l’apparition d’actes agressifs. Au contraire, dans des contextes de faible densité, l’expression rapide du potentiel de croissance de quelques individus favoriserait l’apparition d’actes agressifs.

  4. Utilización de un anticuerpo monoclonal en el diagnóstico directo e indirecto del virus IPN en peces infectados experimentalmente Utilization of a monoclonal antibody in the diagnosis of infectious pancreatic necrosis virus in fish

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    Full Text Available El virus de la necrosis pancreática infecciosa, virus IPN, es el agente causal de una enfermedad altamente contagiosa que afecta a peces salmonídeos jóvenes, éstos cuando sobreviven pueden convertirse en portadores que pueden transmitir la enfermedad. Para contribuir al diagnóstico rápido y efectivo del virus tanto en peces con la infección aguda, como en peces portadores, es que ensayamos la aplicación de un anticuerpo monoclonal en la detección del virus en animales infectados experimentalmente. Utilizamos alevines de truchas arcoiris (Oncorhynchus mykiss y de salmones coho (Oncorhynchus kisutch infectados con virus IPN aislado en Chile. Para detectar a los antígenos virales empleamos ensayos de ELISA inmunodot e inmunofluorescencia. Los resultados muestran que en los peces con la enfermedad aguda el virus se detecta aplicando directamente los inmunoensayos en extractos de peces enteros. En cambio, para detectar al virus en los peces portadores fue necesario incorporar un paso adicional para amplificar al virus en cultivos celulares. A pesar de lo cual, sin embargo, los métodos se optimizaron de manera que el procedimiento completo se realizó en menos de tres días para ELISA e inmunodot y menos de un día y medio para la inmunofluorescencia. Debido a que la técnica de inmunofluorescencia permite la identificación inequívoca de una o pocas células infectadas, es que ensayamos condiciones para diagnosticar al virus IPN desde improntas de peces portadores del virus. Demostramos que los antígenos virales pueden ser facilmente identificados por medio de la tinción directa de improntas de órganos de peces con el tamaño adecuadoThe infectious pancreatic necrosis virus, IPNV, is the etiological agent of a highly contagious disease that affects young salmon. If they survive, they become carriers and can transmit the disease. To contribute to the fast and effective diagnosis in fish with the acute infection, as well as of carrier

  5. Aclimatação do híbrido da tilápia vermelha Oreochromis niloticus sp. e utilização em ambientes marinhos como isca viva para a pesca de tunideos - Acclimatization of red tilápia hybrids, Oreochromis niloticus sp., and use in sea environments as lively bait in the baitboat fishery of tuna

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    Hilton Amaral Junior


    Full Text Available ResumenLa tilápia roja de Florida Oreochromis sp, obtenido mediante el cruce de O.mossambicus y O. urulepis hornorum, se caracteriza por tener altaresistencia a la salinidad y ser muy tolerante a una variedad de condiciones climáticas. Por lo tanto, es ampliamente utilizado en los cultivos comerciales en algunas partes del mundo tanto en agua dulce y salobre. Se enfrenta actualmente a un problema importante en relación a la disponibilidad de cebo vivo, que usa sardina como atracción a los atunes. Además, crea un conflicto con los pescadores industriales que utilizan el mismo recurso, así como los pescadores artesanales y la sociedad. Este trabajo consistió en una evaluaciónde la resistencia a la salinidad de la tilápia roja, lo que sugiere una nueva técnica para la aclimatación de los juveniles de esta especie. Los lotes de alevines de tilápia roja sexualmente invertido se crearon en el Campo Experimental de Piscicultura de Camboriú - CEPC/Epagri y recreado en el laboratorio de maricultura UNIVALI - EMC, Penha SC. Los parámetros analizados fueron: la tolerancia a la salinidad, la supervivencia y la capacidad de almacenamiento. Los resultados de esta experiencia indican que esta especie responde a las necesidades requeridas para este tipo de pesca. Losjuveniles adaptados a la salinidad, se han utilizado para los ensayos como cebo vivo en la pesca de atún. Este trabajo ofrece una alternativa a cebo vivo en la pesca de atún.ResumoA tilápia vermelha da Flórida (Oreochromis sp, obtida através do cruzamento de O. mossambicus e O. urulepis hornorum, se caracteriza por apresentar grande resistência à salinidade e ser bastante tolerante a uma diversidade de condições climáticas. Sendo assim, é bastante utilizada em cultivos comerciais em algumas partes do mundo, tanto em água doce como salobra. A pesca de atum e afins com vara e isca-viva, atualmente vem enfrentando um grande problema em relação à disponibilidade da isca

  6. Research on Captive Broodstock Programs for Pacific Salmon, 2003-2004 Annual Report.

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    Berejikian, Barry A.; Athos, Jaime I.; Dittman, Andrew H. (National Marine Fisheries Service)


    The success of captive broodstock programs depends on high in-culture survival, appropriate development of the reproductive system, and the behavior and survival of cultured salmon after release, either as adults or juveniles. Continuing captive broodstock research designed to improve technology is being conducted to cover all major life history stages of Pacific salmon. We were able to develop an analytical method for optimizing the detection of spawning events in Chinook salmon using EMG signals. The method developed essentially captured the consistently greater frequency of higher EMG values associated with females cover digging immediately following spawning. However, females implanted with EMG tags retained the majority of their eggs, which significantly reduced their reproductive success compared to non-tagged females. Future work will include increased sample sizes, and modified tagging methods to reduce negative effects on reproductive success. Upper Columbia River sockeye salmon exposed to the odorants PEA, L-threonine, Larginine and L-glutamate were able to learn and remember these odorants as maturing adults up to 2.5 years after exposure. These results suggest that the alevin and smolt stages are both important developmental periods for successful olfactory imprinting. Furthermore, the period of time that fish are exposed to imprinting odors may be important for successful imprinting. Experimental fish exposed to imprinting odors as smolts for six or one weeks successfully imprinted to these odors but imprinting could not be demonstrated in smolts exposed to odors for only one day. A 2-3 C reduction in seawater rearing temperature during the fall and winter prior to final maturation had little effect on reproductive development of spring Chinook salmon. Body size at spawning and total ovary mass were similar between temperature treatments. The percentage of fertilized eggs was significantly higher for females exposed to the ambient temperature compared

  7. Rice-fish farming in Guinée Forestière – outcome of a rural development project

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    D. Simon


    Full Text Available The rice-fish farming project in Guinée Forestière launched in 2000 was, at the outset, a pilot project for the purpose of testing the introduction of a new production technique in an impoverished and landlocked region. It aimed to improve food security for people living in the region and to promote the creation of income through a diversification of activity and better land use. The intervention strategy followed the template used in Côte d’Ivoire for a similar project. It consisted in supporting groups of voluntary producers who were ready to accept the risk of financing lowland developments to produce fish and rice. The project was supported by a small group, mainly composed of volunteers (expatriates and local facilitators recruited as the project activities progressed. A € 1.8 million grant was donated by the Agence Française de Développement, raised between 2000 and 2008, to cover technical assistance and training expenditures. The project gave precedence to the concept of actor autonomy for the development of lowlands and ponds. Investments were financed and implemented by the producers themselves depending on their available resources in funds and labour. Animal husbandry methods, based on extensive mixed cropping, used no other inputs than those available on the farm itself. The fish farmers themselves supplied alevins. To ensure the sustainability of rice-fish farming activities after the project ended, special emphasis was given to providing a structure for the profession in the future by encouraging the members of the groups to sponsor and train new candidates. Although results exceeded the initial targets since, by the end of the project, 350 farmers and 500 ponds were active, lowland rice and fish production is still limited. It does provide, however, regular supplies of fish to approximately 6000 people, calculated according to the low level of local consumption (10 kg/per year/per person.The impact of the

  8. Effect of the Operation of Kerr and Hungry Horse Dams on the Reproductive Success of Kokanee in the Flathead System, 1987 Final Report.

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    Beattie, Will; Zubik, Raymond; Clancey, Patrick


    reproductive success in few sites. Studies of the effects of hydroelectric operations on the reproductive success of kokanee in the Flathead system have been ongoing since 1980. Results of these studies have been published in a series of annual progress reports which are detailed in Appendix G. The reports summarize spawning site inventories and spawning escapement, egg and alevin mortality rates and the mechanisms by which water level fluctuations influence mortality, creel surveys, and investigation of the population dynamics of Flathead kokanee. The Region 1 offices of the Montana Department of Fish, Wildlife and Parks distribute this material to the scientific community and the general public. Until recently, it was considered feasible to recover losses to the Flathead kokanee fishery by enhancing and diversifying natural reproduction. But the establishment of opossum shrimp (M. relicta) in Flathead Lake has reduced the availability of zooplankton forage in the spring and summer, and may reduce the viability of juvenile kokanee. In 1986, research was redirected to quantify this competitive interaction and to investigate artificial means of enhancing the kokanee fishery. The average density of mysid shrimp in Flathead Lake has increased to 108/m{sup 2} in 1987, and at some locations density exceeds 500/m2. Mysid grazing pressure has delayed the pulse of zooplankton production in the spring and reduced zooplankton standing crop in the summer. Cladocerans such as Daphnia thorata, the preferred food of kokanee of all ages, are the most markedly affected species. The peak density of D. thorata in the summer has declined from 4.8/liter in 1983 to O.9/liter in 1987. Growth rates of underyearling and yearling kokanee have declined, apparently as a result of the reduction in their food supply. Spawning escapement has also declined, falling from 150,000 in 1985. to 25,000 in 1986, to 600 in 1987. Fry-to-adult survival has declined from 2.5 percent to near zero. The causes of high

  9. Pyrethroid toxicity in silver catfish, Rhamdia quelen Toxicidade dos piretróides sobre Jundiás, Rhamdia quelen

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    Francisco P. Montanha


    Full Text Available This study aimed to determine both the lethal and sublethal concentrations of Cypermethrin in young Silver Catfish (Brazilian "Jundiá", Rhamdia quelen on aquatic environment during 96 hours, as well as to determine the Cypermethrin and Deltamethrin sublethal concentrations during the initial embryonic development period of Rhamdia quelen, and to verify their respective rates of fertilization, hatching and survival. Pyrethroid nowadays is a widely used insecticide, which presents a high toxicity to fish. In order to determine lethal and sublethal concentrations, 120 silver catfish were used; each one had an average weight of 59.58±4.50g and an average size of 20.33±2.34cm. Concentrations used were 0, 1.0, 1.5, 2.0, 2.5, 3.0, 5.0, 10.0, 15.0 and 20.0mg of Cypermethrin per liter of water (mg/L. Fish were exposed to the product in 30-liter fish tanks. In each fish tank there were four fishes and the product was applied three times, i.e., a total of twelve fish were exposed to the product at each application, and a total of 120 fish during the entire experiment (n=120. In order to determine the Cypermethrin and Deltamethrin sublethal concentrations during the initial embryonic development, ovulation induction was performed on female fishes using hormones, and then and egg collection was performed. The eggs were then hydrated and fertilized in Cypermethrin and Deltamethrin in different concentrations: 0.001, 0.01, 0.1, 1.0 and 10.0mg/L of Cypermethrin and 0.001, 0.01, 0.1, 0.5 and 1.0mg/L of Deltamethrin, in addition to the control group (0mg/L. After fertilization, the eggs were kept in containers with the respective pesticides of Cypermethrin and Deltamethrin until hatching, when hatching rate was verified. Then the alevins, from the hatching, were kept on their respective concentrations of Cypermethrin and Deltamethrin so that the survival rate could be analyzed regarding the tested insecticides, during both 12-hour and 24-hour periods