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Sample records for alevins

  1. Production d'alevins de Tilapia (Oreochromis niloticus) avec 3 ...

    African Journals Online (AJOL)

    2015 International Formulae Group. All rights reserved. Mots clés: Alevins, Oreochromis niloticus, aliment, croissance, performance. English Title: Production of young Tilapia fish (Oreochromis niloticus) with 3 foods containing under agroindustrial products in the North of Senegal. English Abstract. The study was carried out ...

  2. Evaluation of the use of cypermethrin in the control of predatory insects of alevins in aquaculture ponds

    OpenAIRE

    Plaul, Silvia E.; García Romero, N.; Barbeito, Claudio Gustavo

    2010-01-01

    Los emprendimientos acuícolas semi-intensivos de cría de peces ornamentales, basan su producción en la siembra de alevines en cavas fertilizadas para el desarrollo de grandes cantidades de zooplancton, alimento de los peces. Los piretroides como la cipermetrina, constituyen una opción económica para combatir distintos insectos que depredan a los alevines. Se utilizaron cuatro cavas las cuales fueron fertilizadas 10 días antes del tratamiento. En ellas, se dispusieron jaulas con alevines de Ca...

  3. Enhancement of growth performance and hematological changes in rainbow trout (Onchorhynchus mykiss alevins fed with Bifidobacterium bacteria

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    Javad Sahandi

    2017-04-01

    Full Text Available The study of probiotic application as an important rearing strategy was started more than 30 years ago and most of these studies were carried out to increase growth and survival of larvae. Effect of Bifidobacterium animalis PTTC-1631 and B. lactis PTTC-1736 as probiotic supplement has been studied on growth performance and hematological changes on rainbow trout, Oncorhynchus mykiss alevins with initial body weight of 0.583 ± 0.197 g. The commercial diet was supplemented with graded levels of probiotics (1×107, 2×107 and 3×107 CFU g-1 dry feed to obtain 3 sets of experimental diets (T1, T2, andT3 respectively and fed four times a day for 60 days. T1 alevin showed the best growth performance in terms of specific growth rate, weight gain, metabolic growth rate, feed conversion ratio and survival rate. The highest red and white blood cell concentrations were noticed in fish fed T2 and T3 diets, respectively, no significant difference was observed in hemoglobin content. T1 showed the significant elevation of serum biochemical parameters and reduction of cortisol level. The results of present study might suggest likely positive effects of probiotic supplements with concentration of 1×107 CFU g-1 dry feed on growth and hematology on rainbow trout alevins.

  4. Metabolic effects of dinoseb, diazinon and esfenvalerate in eyed eggs and alevins of Chinook salmon (Oncorhynchus tshawytscha) determined by 1H NMR metabolomics

    International Nuclear Information System (INIS)

    Viant, Mark R.; Pincetich, Christopher A.; Tjeerdema, Ronald S.

    2006-01-01

    Pesticide pulses in the Sacramento River, California, originate from storm-water discharges and non-point source aquatic pollution that can last from a few days to weeks. The Sacramento River and its tributaries have historically supported the majority of California's Chinook salmon (Oncorhynchus tshawytscha) spawning grounds. Three pesticides currently used in the Sacramento Valley - dinoseb, diazinon, and esfenvalerate - were chosen to model the exposure of salmon embryos to storm-water discharges. Static-renewal (96 h) exposures to eyed eggs and alevins resulted in both toxicity and significant changes in metabolism assessed in whole-embryo extracts by 1 H nuclear magnetic resonance (NMR) spectroscopy based metabolomics and HPLC with UV detection (HPLC-UV). The 96-h LC 5 values of eyed eggs and alevins exposed to dinoseb were 335 and 70.6 ppb, respectively, and the corresponding values for diazinon were 545 and 29.5 ppm for eyed eggs and alevins, respectively. The 96-h LC 5 of eyed eggs exposed to esfenvalerate could not be determined due to lack of mortality at the highest exposure concentration, but in alevins was 16.7 ppb. All esfenvalerate exposed alevins developed some degree of lordosis or myoskeletal abnormality and did not respond to stimulus or exhibit normal swimming behavior. ATP concentrations measured by HPLC-UV decreased significantly in eyed eggs due to 250 ppb dinoseb and 10 and 100 ppb esfenvalerate (p 1 H NMR metabolite fingerprints of eyed egg and alevin extracts revealed both dose-dependent and mechanism of action-specific metabolic effects induced by the pesticides. Furthermore, NMR based metabolomics proved to be more sensitive than HPLC-UV in identifying significant changes in sublethal metabolism of pesticide exposed alevins. In conclusion, we have demonstrated several benefits of a metabolomics approach for chemical risk assessment, when used in conjunction with a fish embryo assay, and have identified significant metabolic perturbations

  5. 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

    2012-09-01

    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.

  6. Hatching time and alevin growth prior to the onset of exogenous feeding in farmed, wild and hybrid Norwegian Atlantic salmon.

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    Monica Favnebøe Solberg

    Full Text Available The onset of exogenous feeding, when juveniles emerge from the gravel, is a critical event for salmonids where early emergence and large size provide a competitive advantage in the wild. Studying 131 farmed, hybrid and wild Norwegian Atlantic salmon families, originating from four wild populations and two commercial strains, we investigated whether approximately 10 generations of selection for faster growth has also resulted in increased somatic growth prior to the onset of exogenous feeding. In addition, we tested whether relaxed selection in farms has allowed for alterations in hatching time between farmed and wild salmon. Across three cohorts, wild salmon families hatched earlier than farmed salmon families, while hybrid families displayed intermediate hatching times. While the observed differences were small, i.e., 1-15 degree-days (0-3 days, as water temperatures were c. 5-6°C, these data suggest additive genetic variation for hatching time. Alevin length prior to exogenous feeding was positively related to egg size. After removal of egg size effects, no systematic differences in alevin length were observed between the wild and farmed salmon families. While these results indicate additive genetic variation for egg development timing, and wild salmon families consistently hatched earlier than farmed salmon families, these differences were so small they are unlikely to significantly influence early life history competition of farmed and wild salmon in the natural environment. This is especially the case given that the timing of spawning among females can vary by several weeks in some rivers. The general lack of difference in size between farmed and wild alevins, strongly suggest that the documented differences in somatic growth rate between wild and farmed Norwegian Atlantic salmon under hatchery conditions are first detectable after the onset of exogenous feeding.

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

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    MOREAU J.

    1979-10-01

    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.

  8. Single and multiple stressor effect of road deicers and Cu on Atlantic salmon (Salmo salar) alevins from hatching till swim-up.

    Science.gov (United States)

    Mahrosh, Urma; Rosseland, Bjørn Olav; Salbu, Brit; Teien, Hans-Christian

    2018-04-01

    Road salts are frequently used for deicing of roads in the Nordic countries. During snow-melt, the road run-off containing high concentrations of road salt and various metals such as Cu remobilized from sand, silt and dust may negatively influence organisms in downstream receiving water bodies. The present work focuses on the impact of road salt (NaCl) and Cu, separately and in mixtures on Atlantic salmon alevins from hatching till swim-up. The results showed that high road salt concentrations could induce a series of negative effects in alevins such as reduced growth, deformities, delayed swim-up and mortality. For alevins exposed to all tested road salt concentrations (100-1000mg/L), mortality was significantly higher compared to control. In exposure to Cu solutions (5-20μgCu/L), no effects on growth, morphology, swim-up or mortality of alevins compared to control were observed. In mixture solutions (road salt and Cu), ultrafiltration of the exposure water demonstrated that only 20%-40% of Cu was present as positively charged low molecular mass (LMM) Cu species assumed to be bioavailable. When exposed to road salt and Cu mixtures, negative effects in alevins such as reduced growth, deformities, delayed swim-up and mortality were observed. The overall results indicated that the road salt application could seriously affect sensitive life stages of Atlantic salmon, and application of road salt should be avoided during the late winter-early spring period. Copyright © 2017. Published by Elsevier B.V.

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

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    BEALL E.

    1983-04-01

    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.

  10. 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

    2015-05-01

    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.

  11. Centrocestus formosanus (Opisthorchiida: Heterophyidae como causa de muerte de alevines de tilapia gris Oreochromis niloticus (Perciforme: Cichlidae en el Pacífico seco de Costa Rica

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    Donald Arguedas Cortés

    2010-12-01

    Full Text Available Centrocestus formosanus es un parásito trematodo zoonótico originario de Asia asociado con muertes de peces principalmente de cultivo. 907 moluscos provenientes de estanques sembrados con tilapias, seleccionados uno por provincia fueron identificados al nivel taxonómico especifico. Se identificaron cuatro gastrópodos y un bivalvo: M. tuberculata, M. turricula, P. flagellata, H. cubensis y A. luteola. Se reporta, por primera vez, la presencia de dos especies de moluscos en Costa Rica. Se identificaron siete morfotipos de cercarias parasitando las cinco especies de moluscos encontradas. En la segunda exposición experimental se demostró que el morfotipo parapleurolofocercus encontrado en M. tuberculata concuerda con el hallazgo de C. formosanus en alevines de tilapia, después del examen clínico, anatomopatológico y parasitológico realizado a los alevines expuestos. Las metacercarias fueron extraídas del quiste utilizando microagujas y micropinzas lavadas en solución salina fisiológica (0.65%, fijadas en formol caliente al 4% y después esquematizadas con una cámara clara adaptada a un microscopio fotónico, estimándose una abundancia e intensidad media de 1018-1027 digeneos por branquia en cada pez parasitado, determinándose así el hospedador intermediario primario y secundario del parásito. En el presente trabajo se reporta por primera vez Centrocestus formosanus en Costa Rica.

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

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    Jorge León

    2008-12-01

    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.

  13. REPEUPLEMENTS EN ALEVINS NOURRIS ET DÉMOGRAPHIE DE LA POPULATION DE TRUITE (SALMO TRUTTA L. DANS LE REDON, UN AFFLUENT DU LAC LÉMAN INTERROMPU PAR UN OBSTACLE

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    CHAMPIGNEULLE A.

    2003-01-01

    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

  14. Centrocestus formosanus (Opisthorchiida: Heterophyidae como causa de muerte de alevines de tilapia gris Oreochromis niloticus (Perciforme: Cichlidae en el Pacífico seco de Costa Rica

    Directory of Open Access Journals (Sweden)

    Donald Arguedas Cortés

    2010-12-01

    Full Text Available Centrocestus formosanus es un parásito trematodo zoonótico originario de Asia asociado con muertes de peces principalmente de cultivo. 907 moluscos provenientes de estanques sembrados con tilapias, seleccionados uno por provincia fueron identificados al nivel taxonómico especifico. Se identificaron cuatro gastrópodos y un bivalvo: M. tuberculata, M. turricula, P. flagellata, H. cubensis y A. luteola. Se reporta, por primera vez, la presencia de dos especies de moluscos en Costa Rica. Se identificaron siete morfotipos de cercarias parasitando las cinco especies de moluscos encontradas. En la segunda exposición experimental se demostró que el morfotipo parapleurolofocercus encontrado en M. tuberculata concuerda con el hallazgo de C. formosanus en alevines de tilapia, después del examen clínico, anatomopatológico y parasitológico realizado a los alevines expuestos. Las metacercarias fueron extraídas del quiste utilizando microagujas y micropinzas lavadas en solución salina fisiológica (0.65%, fijadas en formol caliente al 4% y después esquematizadas con una cámara clara adaptada a un microscopio fotónico, estimándose una abundancia e intensidad media de 1018-1027 digeneos por branquia en cada pez parasitado, determinándose así el hospedador intermediario primario y secundario del parásito. En el presente trabajo se reporta por primera vez Centrocestus formosanus en Costa Rica.Centrocestus formosanus (Opisthorchiida: Heterophyidae as a cause of death in gray tilapia fry Oreochromis niloticus (Perciforme: Cichlidae in the dry Pacific of Costa Rica. Centrocestus formosanus is a zoonotic trematode from Asia and has been mainly associated as cause of death of cultured fish. To identify pathogen trematode species in tilapia fry (Oreochromis niloticus and to determine mollusks hosting these parasites, freshwater mollusks were collected from tilapia cultured ponds and experimental infections were carried out with tilapia fries and

  15. RÉTENTION DES OVULES APRÈS OVULATION DANS LA CAVITÉ OVARIENNE DE LA CARPE HERBIVORE : COMPOSITION DES OVULES ET CAPACITÉ DE DÉVELOPPEMENT DES ŒUFS ET DES ALEVINS.

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    KHARROUBI M.

    2002-04-01

    Full Text Available Pour étudier l’effet de rétention prolongée des ovules dans la cavité ovarienne (in vivo de la carpe herbivore, des extractions d’ovules de 15 femelles (3 à 5,6 kg ont eu lieu à différents intervalles de temps après ovulation (0, 30, 60, 90 et 120 min. Le taux de fécondation, le taux de survie embryonnaire, le taux d’éclosion et la croissance en longueur totale des alevins jusqu’à 5 semaines après éclosion (L1 = Longueur totale mesurée 2 semaines après éclosion, L2 = Longueur totale mesurée 3 semaines après éclosion, L3 = Longueur totale mesurée 4 semaines après éclosion, L4 = Longueur totale mesurée 5 semaines après éclosion sont déterminés pour chaque temps d’extraction des ovules. Il n’y a pas eu de différences significatives entre ces paramètres biologiques observés juste après ovulation et ceux observés 120 min après ovulation. Sont déterminées également quelques caractéristiques de la composition des ovules à savoir la teneur en eau, le poids sec, les cendres brutes, le fer, le calcium, les protéines totales, les lipides totaux, les phospholipides et les sucres. Ces composés demeurent constants quand les ovules sont maintenus au sein de la femelle pour deux heures après ovulation. Chez la carpe herbivore, la rétention post ovulatoire des ovules pendant 2 heures in vivo n’a pas d’effet ni sur leur composition biochimique examinée, ni sur la capacité de développement des œufs ni sur la croissance des alevins en terme de longueur totale. L’absence de changements des constituants des ovules pourrait expliquer la maintenance de la viabilité des œufs et celle de la croissance des alevins. Cependant, il importe de signaler une certaine différence de cette capacité de développement des œufs et des alevins entre les femelles reproduites (p < 0,05 pour chaque paramètre examiné.

  16. 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.

    1995-04-01

    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.

  17. Predicted time from fertilization to maximum wet weight for steelhead alevins based on incubation temperature and egg size (Study site: Western Fishery Research Center, Seattle; Stock: Dworshak hatchery; Year class: 1996): Chapter 4

    Science.gov (United States)

    Rubin, Stephen P.; Reisenbichler, Reginald R.; Slatton, Stacey L.; Rubin, Stephen P.; Reisenbichler, Reginald R.; Wetzel, Lisa A.; Hayes, Michael C.

    2012-01-01

    The accuracy of a model that predicts time between fertilization and maximum alevin wet weight (MAWW) from incubation temperature was tested for steelhead Oncorhynchus mykiss from Dworshak National Fish Hatchery on the Clearwater River, Idaho. MAWW corresponds to the button-up fry stage of development. Embryos were incubated at warm (mean=11.6°C) or cold (mean=7.3°C) temperatures and time between fertilization and MAWW was measured for each temperature. Model predictions of time to MAWW were within 1% of measured time to MAWW. Mean egg weight ranged from 0.101-0.136 g among females (mean = 0.116). Time to MAWW was positively related to egg size for each temperature, but the increase in time to MAWW with increasing egg size was greater for embryos reared at the warm than at the cold temperature. We developed equations accounting for the effect of egg size on time to MAWW for each temperature, and also for the mean of those temperatures (9.3°C).

  18. 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

    2014-01-01

    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. 

  19. 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

    2007-08-01

    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

  20. PRODUCTION D'ALEVINS DE TILAPIA (Oreochromis niloticus L ...

    African Journals Online (AJOL)

    AISA

    protéines dans les aliments composés destinés à l'aquaculture est à l'origine de la surenchère de ces aliments. Gourène et al. (2002) ont abondé dans le même sens. Leurs travaux que le coût de l'alimentation des poissons est plus important (> 50%) que celui de la production totale. Pourtant, Liebert et Portz (2005) ont le.

  1. Intervención para la mejora de las orientaciones hacia la deportividad en futbolistas alevines

    Directory of Open Access Journals (Sweden)

    Javier Lamoneda Prieto

    2017-06-01

    Full Text Available Introducción. El fútbol base demanda de un tratamiento ético que incluya no solo aspectos preventivos frente a la violencia sino también la promoción de conductas prodeportivas. Para ello se requiere de programas debidamente diseñados e instrumentos de evaluación adaptados a cada contexto.Objetivos. Los dos objetivos principales de esta tesis fueron: 1. Diseñar un modelo de intervención para la promoción del juego limpio-deportividad destinada a futbolistas de categoría alevín y verificar su eficacia, y 2. Contextualizar los instrumentos de evaluación existentes para el análisis de las orientaciones hacia la deportividad en el fútbol alevín.Muestra. Participaron ciento ochenta y cuatro futbolistas federados de entre 10 y 12 años de edad (n = 184.Procedimiento. Se diseñó y desarrolló durante dos temporadas consecutivas (2011-2012 y 2012-2013 un programa de educación en valores de diez semanas de duración. Para valorar la eficacia del programa se recurrió a la Escala multidimensional de orientaciones hacia la deportividad (MSOS. Se realizó una adecuación muestral del instrumento a la realidad particular del fútbol alevín. Para ello cada ítem de la versión española fue sustituido por una situación práctica de juego, se redujo el número de ítems y se redactó la quinta subescala en positivo.Análisis estadístico. Para analizar la eficacia del programa de intervención se realizó un análisis descriptivo (media, desviación estándar, de la significatividad intragrupo (prueba de Wilcoxon y de la significatividad intergrupo (test exacto de Fisher’s. Además, se valoraron las propiedades psicométricas del instrumento de evaluación a través del estudio de la fiabilidad mediante el análisis de consistencia interna, se aportó un estudio factorial y se analizó la sensibilidad del instrumento.Resultados. Los participantes en el programa, en comparación con los que no recibieron tratamiento educativo, mejoraron significativamente (p  0.6 y aceptable validez de constructo (KMO = .657; χ2 = 688.5; g.l. 210; p < .000.Conclusiones. Los resultados obtenidos permiten pensar que la inclusión de programas educativos en las planificaciones deportivas resulta beneficiosa como elemento preventivo frente a la tendencia hacia la pérdida de valores en el fútbol.

  2. 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

    Directory of Open Access Journals (Sweden)

    NIHOUARN A.

    1990-10-01

    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.

  3. Centrocestus formosanus (Opisthorchiida: Heterophyidae) como causa de muerte de alevines de tilapia gris Oreochromis niloticus (Perciforme: Cichlidae) en el Pacífico seco de Costa Rica

    OpenAIRE

    Arguedas Cortés, Donald; Dolz, Gaby; J. Romero Zúñiga, Juan; E. Jiménez Rocha, Ana; León Alán, Dennis

    2009-01-01

    Centrocestus formosanus es un parásito trematodo zoonótico originario de Asia asociado con muertes de peces principalmente de cultivo. 907 moluscos provenientes de estanques sembrados con tilapias, seleccionados uno por provincia fueron identificados al nivel taxonómico especifico. Se identificaron cuatro gastrópodos y un bivalvo: M. tuberculata, M. turricula, P. flagellata, H. cubensis y A. luteola. Se reporta, por primera vez, la presencia de dos especies de moluscos en Costa Rica. Se ident...

  4. Une percée qui permet de fournir toute une industrie en petits ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    28 oct. 2010 ... Image. Division des communications, CRDI. DES EFFETS DURABLES. Les pisciculteurs ont besoin d'alevins pour ensemencer leurs étangs ou leurs cages ... En outre, le centre a enseigné à des pêcheurs qui récoltent des alevins sauvages de meilleures méthodes de manipulation et de transport de ces ...

  5. Effects of Replacing Fishmeal with Soyabean in Diets of ...

    African Journals Online (AJOL)

    Des alevins Oreochromis niloticus ont été nourris sur base de quatre régimes isoprotéiques (30% de protéine brute) dans lesquels la farine de soja (FS) a partiellement ou totalement remplacé la farine de poisson (FP) ; et l'effet de ces régimes sur la croissance et l'utilisation des éléments nutritifs par les alevins a été ...

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

    Directory of Open Access Journals (Sweden)

    GAIGNON J. L.

    1982-10-01

    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.

  7. Efecto de la tasa y frecuencia de alimentación en el crecimiento de alevinos de Osteoglossum bicirrhosum (Cuvier, 1829) (PISCES: OSTEOGLOSSIDAE) “arahuana”, en ambientes controlados

    OpenAIRE

    Ribeyro Schult, Bernardo Olaff

    2013-01-01

    El objetivo de este estudio fue evaluar los efectos de dos tasas de alimentación (5% y el 7%), tres frecuencias de alimentación (2, 4 y 6 veces / día) y sus interacciones en el crecimiento de los alevines de la arahuana (Osteoglossum bicirrhosum). Un total de 180 alevines con rangos de pesos entre 2.36 g. a 2.54 g. y rangos de longitudes entre 8.35 cm. a 8.52 cm. fueron criados en 18 de madera-tanques revestidos de plástico y se alimentaron con una dieta extruida con 50% proteína cruda (Purip...

  8. Crossing the Salt Barrier

    Indian Academy of Sciences (India)

    Fry. RIVER. To cross the salt barrier is, therefore, an obligatory part of every amphihaline fish cycle. Figure 2a. Life Cycle of. Salmon. Adult salmon migrate from sea towards the river. After reaching their hatching ground, the eggs are laid in the gravel. The spawned fishes are called kelts. Alevin is a stage from hatching to fry.

  9. Browse Title Index

    African Journals Online (AJOL)

    Vol 8, No 5 (2014), Prevalence of intestinal protozoan parasites in stray and domicile dogs in Ilorin, North Central, Nigeria, Abstract PDF ... Vol 9, No 5 (2015), Production d'alevins de Tilapia (Oreochromis niloticus) avec 3 aliments à base de sous-produits agro-industriels au Nord du Sénégal, Abstract PDF. Serigne Modou ...

  10. 316-IJBCS-Article-Prof Emile Fiogbe

    African Journals Online (AJOL)

    Dr Gatsing

    Thèse de. Doctorat, Facultés Universitaires Notre-. Dame de la Paix, Namur, Belgique, 220p. Kestemont P, Micha J-C, Falter U. 1989. Les. Méthodes de Production d'Alevins de. Tilapia nilotica. ADCP / REP / 89 / 46,. PNUD-FAO, Rome, 132p. Lejeune A, Cagauan A, Van Hove C. 1999. Azolla Research and Development :.

  11. Comportement alimentaire au cours du changement d'habitat lié à l'émergence chez le saumon atlantique Salmo salar L. et la truite commune Salmo trutta L., en conditions semi-naturelles

    Directory of Open Access Journals (Sweden)

    VIGNES J. C.

    1995-04-01

    L'analyse simultanée du déroulement de l'émergence, du degré de résorption de la vésicule, de la croissance des larves et de leurs contenus stomacaux a permis de mettre en évidence que la prise alimentaire est postérieure à l'émergence et démarre, avec la perte de poids de l'alevin, avant la fin de la résorption de la vésicule pour les 2 espèces. Le comportement alimentaire est un peu plus précoce chez les truites. Chez les saumons, la capture des proies est précédée par une phase d'ingestion de débris végétaux liée au positionnement benthique des alevins.

  12. ÉVOLUTION SPATIO-TEMPORELLE DE LA CONTRIBUTION DU REPEUPLEMENT EN TRUITE (SALMO TRUTTA L. RÉALISÉ A DES STADES PRÉCOCES DANS LE BASSIN AMONT DU FIER (74.

    Directory of Open Access Journals (Sweden)

    CAUDRON A.

    2002-04-01

    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+.

  13. 2814-IJBCS-Article-Inoussa Compaoré

    African Journals Online (AJOL)

    hp

    individuel (pmi) avant d'être mis en charge pour le suivi de la croissance. Deux densités de mise en charge (2 et 4 poissons/litres, soit. 2000 et 4000 alevins/m3) sont utilisées pour chacune des espèces. Ces mises en charges se réfèrent aux densités de mise en charge recommandées en phase de pré-grossissement.

  14. L'étude de la croissance de Oreochromis niloticus par la fertilisation ...

    African Journals Online (AJOL)

    SARAH

    31 juil. 2015 ... rendre celui-ci plus productif, c'est notamment le matériel végétal transformé en compost ou du fumier animal. (Hilbrands et Yzerman, 2004). On peut citer pour le matériel ... manioc et pour le fumier animal ; les excréments de porc, les ... de la biomasse des alevins y compris le comportement de poissons ...

  15. Quantifying Temperature Effects on Fall Chinook Salmon

    Energy Technology Data Exchange (ETDEWEB)

    Jager, Yetta [ORNL

    2011-11-01

    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.

  16. Y-chromosomal DNA markers for discrimination of chemical substance and effluent effects on sexual differentiation in salmon.

    OpenAIRE

    Afonso, Luis O B; Smith, Jack L; Ikonomou, Michael G; Devlin, Robert H

    2002-01-01

    Chinook salmon alevins were exposed during their labile period for sex differentiation to different concentrations of bleached kraft mill effluent (BKME), primary sewage effluent, secondary sewage effluent (SE), 17ss-estradiol, testosterone, and nonylphenol. After exposure for 29 days post hatching (DPH), fish were allowed to grow until 103 and 179 DPH, at which time their genetic sex was determined using Y-chromosomal DNA markers and their gonadal sex was determined by histology. Independent...

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

    Directory of Open Access Journals (Sweden)

    BRUNET R.

    1972-07-01

    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

  18. The effects of total dissolved gas on chum salmon fry survival, growth, gas bubble disease, and seawater tolerance

    Energy Technology Data Exchange (ETDEWEB)

    Geist, David R.; Linley, Timothy J.; Cullinan, Valerie I.; Deng, Zhiqun

    2013-02-01

    Chum salmon Oncorhynchus keta alevin developing in gravel habitats downstream of Bonneville Dam on the Columbia River are exposed to elevated levels of total dissolved gas (TDG) when water is spilled at the dam to move migrating salmon smolts downstream to the Pacific Ocean. Current water quality criteria for the management of dissolved gas in dam tailwaters were developed primarily to protect salmonid smolts and are assumed to be protective of alevin if adequate depth compensation is provided. We studied whether chum salmon alevin exposed to six levels of dissolved gas ranging from 100% to 130% TDG at three development periods between hatch and emergence (hereafter early, middle, and late stage) suffered differential mortality, growth, gas bubble disease, or seawater tolerance. Each life stage was exposed for 50 d (early stage), 29 d (middle stage), or 16 d (late stage) beginning at 13, 34, and 37 d post-hatch, respectively, through 50% emergence. The mortality for all stages from exposure to emergence was estimated to be 8% (95% confidence interval (CI) of 4% to 12%) when dissolved gas levels were between 100% and 117% TDG. Mortality significantly increased as dissolved gas levels rose above 117% TDG,; with the lethal concentration that produced 50% mortality (LC50 ) was estimated to be 128.7% TDG (95% CI of 127.2% to 130.2% TDG) in the early and middle stages. By contrast, there was no evidence that dissolved gas level significantly affected growth in any life stage except that the mean wet weight at emergence of early stage fish exposed to 130% TDG was significantly less than the modeled growth of unexposed fish. The proportion of fish afflicted with gas bubble disease increased with increasing gas concentrations and occurred most commonly in the nares and gastrointestinal tract. Early stage fish exhibited higher ratios of filament to lamellar gill chloride cells than late stage fish, and these ratios increased and decreased for early and late stage fish

  19. 2476-IJBCS-Article-Dr Serigne Modou Sarr

    African Journals Online (AJOL)

    hp

    protéines des aliments utilisés, constitue le premier facteur du coût élevé de la production aquacole (Fiogbé et al., 2009 ; Lazard, 2009) en Afrique en général et au Sénégal en particulier. L'espèce O. niloticus est la plus utilisée pour la production d'alevins au. Sénégal avec une biomasse de 322t par rapport à la production ...

  20. 1267-IJBCS-Article-Diane Kpogue

    African Journals Online (AJOL)

    hp

    10% de lipides et 18,5 Kj/g d'Energie Brute. L'aliment a été distribué manuellement ad libitum et 5 fois / jour entre 8 et 18 heures. Des pêches de contrôle ont été faites chaque semaine afin d'estimer l'évolution du poids moyen et d'ajuster la ration à la biomasse. La biomasse totale de tous les alevins par bassin a été alors ...

  1. ASPECTOS MORFOLOGICOS DE LA DEFORMIDAD DE COLUMNA VERTEBRAL EN SALMONES (SALMO SALAR), Y SU ASOCIACION CON HIPOXIA

    OpenAIRE

    CASTRO SANCHEZ, RODRIGO ANDRES; CASTRO SANCHEZ, RODRIGO ANDRES

    2010-01-01

    La deformidad de columna vertebral (DCV) es una patología de alta prevalencia en la salmonicultura nacional y su presentación disminuye la calidad y rentabilidad del producto. Se ha relacionado a hipoxia con la deformidades de diversos órganos, sin embargo, no ha sido asociada con DCV. Este estudio describe, morfológicamente, columnas vertebrales de alevines Salmo salar, cultivados en el Centro de Estudios Acuícolas de la Universidad de Chile (Castro, Chiloé) y expuestos ...

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

    OpenAIRE

    Rubio Cabrera, Sheila Guadalupe

    2014-01-01

    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...

  3. Effets de l’alimentation végétale sur les capacités digestives de la truite arc-en-ciel et sur le microbiote associé à sa muqueuse digestive en fonction de son génotype

    OpenAIRE

    Borey, Marion

    2017-01-01

    Over-fishing pressure and increasing aquaculture production led to an important substitution of fish oil and fish meal with oil and meal from plant origin in feed meant for farming fish. However this replacement has some deleterious incidence on fish. For rainbow trout, which are carnivorous fish, some growth delay often appears from the early life stages when they are fed with plant based diet. The aim of this work was to assess, at alevin and juvenile stages, the impact of a total replaceme...

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

    OpenAIRE

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

    2011-01-01

    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 ...

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

    Directory of Open Access Journals (Sweden)

    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.

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

    Directory of Open Access Journals (Sweden)

    Amaral Marcelo da Cunha

    2001-01-01

    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 Pi.mg protein.h-1, the best salinity to cultivate P. vivipara.

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

    Directory of Open Access Journals (Sweden)

    Lorgio Verdi Olivares

    2014-06-01

    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.

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

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    Lorgio Verdi-Olivares

    2014-07-01

    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.

  9. INVESTIGATIONS ON TECHNOLOGICAL PARAMETERS IN INTENSIVE REARING OF PIKE-PERCH (STIZOSTEDION LUCIOPERCA

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    Tamás Molnár

    2000-06-01

    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.

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

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    HELAND M.

    1997-01-01

    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.

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

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    Sahlmann, Christian; Gu, Jinni; Kortner, Trond M.; Lein, Ingrid; Krogdahl, Åshild; Bakke, Anne Marie

    2015-01-01

    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. PMID:25923375

  12. Morfologia e crescimento do músculo estriado esquelético no pirarucu Arapaima gigas Cuvier, 1817 (Teleostei, Arapaimidae = Morphology and skeletal muscle growth in pirarucu Arapaima gigas Cuvier, 1817 (Teleostei, Arapaimidae

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    Fernanda Regina Carani

    2008-04-01

    Full Text Available O objetivo deste trabalho foi avaliar as características morfológicas e de crescimento do músculo estriado esquelético no pirarucu (Arapaima gigas. Foram utilizados animais em duas fases de crescimento: alevinos, com 50 dias de idade, e juvenis, com umano de idade. Após eutanásia dos animais, fragmentos musculares das regiões dorsal, lateral cranial e lateral caudal foram coletados e congelados em nitrogênio líquido. Cortes histológicos (10 mm foram submetidos às colorações HE e Tricrômico de Gomori, para a análise morfológica, e NADH-TR, para a análise do metabolismo oxidativo das fibras musculares. Foi calculado o menor diâmetro das fibras musculares brancas nas regiões dorsal e lateral cranial. A musculatura dorsal branca mostrou-se mais desenvolvida e, namusculatura lateral, observaram-se compartimentos distintos: superficial vermelho e profundo branco. Nos alevinos, o crescimento muscular ocorreu predominantemente por hiperplasia das fibras e, nos juvenis, predominou o crescimento muscular por hipertrofia.The aim of this work was to evaluate the morphological and growth characteristics of skeletal muscle tissue in pirarucu (Arapaimagigas using alevins (50 days old and juveniles (1 year old. Muscle samples were collected from dorsal, lateral cranial and lateral caudal regions, and then frozen in liquid nitrogen. Histological frozen sections (10μm were stained with HE and Gomori Trichrome formorphological analysis, and NADH-TR to evaluate muscle fiber oxidative metabolism. Morphometric analysis samples were obtained from dorsal and lateral cranial regions, and the smallest-diameter white fibers were measured. White dorsal muscle was thicker, andtwo muscle fiber compartments were identified in the lateral cranial region: red (superficial and white (deep muscle. Hyperplasia muscle growth predominated in alevins and hypertrophy in juveniles.

  13. Morfologia e crescimento do músculo estriado esquelético no pirarucu Arapaima gigas Cuvier, 1817 (Teleostei, Arapaimidae - DOI: 10.4025/actascibiolsci.v30i2.3640 Morphology and skeletal muscle growth in pirarucu Arapaima gigas Cuvier, 1817 (Teleostei, Arapaimidae - DOI: 10.4025/actascibiolsci.v30i3.3640

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    Maeli Dal Pai Silva

    2008-05-01

    Full Text Available O objetivo deste trabalho foi avaliar as características morfológicas e de crescimento do músculo estriado esquelético no pirarucu (Arapaima gigas. Foram utilizados animais em duas fases de crescimento: alevinos, com 50 dias de idade, e juvenis, com um ano de idade. Após eutanásia dos animais, fragmentos musculares das regiões dorsal, lateral cranial e lateral caudal foram coletados e congelados em nitrogênio líquido. Cortes histológicos (10 µm foram submetidos às colorações HE e Tricrômico de Gomori, para a análise morfológica, e NADH-TR, para a análise do metabolismo oxidativo das fibras musculares. Foi calculado o menor diâmetro das fibras musculares brancas nas regiões dorsal e lateral cranial. A musculatura dorsal branca mostrou-se mais desenvolvida e, na musculatura lateral, observaram-se compartimentos distintos: superficial vermelho e profundo branco. Nos alevinos, o crescimento muscular ocorreu predominantemente por hiperplasia das fibras e, nos juvenis, predominou o crescimento muscular por hipertrofia.The aim of this work was to evaluate the morphological and growth characteristics of skeletal muscle tissue in pirarucu (Arapaima gigas using alevins (50 days old and juveniles (1 year old. Muscle samples were collected from dorsal, lateral cranial, and lateral caudal regions, and then frozen in liquid nitrogen. Histological frozen sections (10 µm were stained with HE and Gomori Trichrome for morphological analysis, and NADH-TR to evaluate muscle fiber oxidative metabolism. Morphometric analysis samples were obtained from dorsal and lateral cranial regions, and smallest diameter white fibers were measured. White dorsal muscle was thicker and two muscle fiber compartments were identified in the lateral cranial region: red (superficial and white (deep muscle. Hyperplasia muscle growth predominated in alevins and hypertrophy in juveniles.

  14. Hydrological and thermal effects of hydropeaking on early life stages of salmonids: A modelling approach for implementing mitigation strategies.

    Science.gov (United States)

    Casas-Mulet, Roser; Saltveit, Svein Jakob; Alfredsen, Knut Tore

    2016-12-15

    Alterations in hydrological and thermal regimes can potentially affect salmonid early life stages development and survival. The dewatering of salmon spawning redds due to hydropeaking can lead to mortality in early life stages, with higher impact on the alevins as they have lower tolerance to dewatering than the eggs. Flow-related mitigation measures can reduce early life stage mortality. We present a set of modelling tools to assess impacts and mitigation options to minimise the risk of mortality in early life stages in hydropeaking rivers. We successfully modelled long-term hydrological and thermal alterations and consequences for development rates. We estimated the risk of early life stages mortality and assessed the cost-effectiveness of implementing three release-related mitigation options (A,B,C). The economic cost of mitigation was low and ranged between 0.7% and 2.6% of the annual hydropower production. Options reducing the flow during spawning (B and C) in addition to only release minimum flows during development (A) were considered more effective for egg and alevin survival. Options B and C were however constraint by water availability in the system for certain years, and therefore only option A was always feasible. The set of modelling tools used in this study were satisfactory and their applications can be useful especially in systems where little field data is available. Targeted measures built on well-informed modelling tools can be tested on their effectiveness to mitigate dewatering effects vs. the hydropower system capacity to release or conserve water for power production. Environmental flow releases targeting specific ecological objectives can provide better cost-effective options than conventional operational rules complying with general legislation. Copyright © 2016 Elsevier B.V. All rights reserved.

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

    Science.gov (United States)

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

    2016-03-01

    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. © 2016. Published by The Company of Biologists Ltd.

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

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    LE LOUARN H.

    1998-07-01

    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.

  17. 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)

    1992-05-01

    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.

  18. Efeito da temperatura da água sobre desempenho e perfil de ácidos graxos de tilápia do Nilo (Oreochromis niloticus - DOI: 10.4025/actascianimsci.v27i4.1184 Effect of environmental temperature on fatty acids profile of Oreochromis niloticus (Nile tilapia - DOI: 10.4025/actascianimsci.v27i4.1184

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    Nilson Evelázio de Souza

    2005-03-01

    Full Text Available Neste estudo foram analisados o perfil em ácidos graxos de alevinos de tilápia do Nilo (Oreochromis niloticus, submetidos a dietas enriquecidas com óleo de linhaça a diferentes temperaturas (23, 26, 29 e 32oC. Tilápias em fase inicial de desenvolvimento não apresentaram diferenças significativas (P > 0,05 em sua composição físico-química e lipídica, nas diferentes temperaturas estudadas. O perfil de ácidos graxos, analisados por cromatografia gasosa equipada com coluna capilar, mostrou aproximadamente 15% de ácidos graxos n-3 com valores em torno de 0,12 a 0,18% para o ácido eicosapentaenóico (EPA e de 1,21 a 2,10% para o ácido docosahexaenóico (DHA. Os resultados mostraram que a temperaturas mais baixas 23 e 26oC, as tilápias do Nilo cresceram menos que em temperaturas mais altas 29 e 32oC, mas a variação de temperatura entre 23 a 32oC não influenciou no perfil em ácidos graxos dos alevinosIn this study the fatty acid profile in tilápia Oreochromis niloticus alevins carcass, fed with enriched diets from flaxseed oil, was examined at different temperatures (23, 26, 29 and 32oC. Tilapia in its initial phase of development did not present differences (P >0.05 on physical-chemical and lipids compositions, at the different temperatures studied. The fatty acids profile, analyzed by gas chromatography using a capillary column, showed approximately 15% of n-3 fatty acids, with values around 0.12 to 0.18% for the eicosapentaenoic acid (EPA, and from 1.21 to 2.10% for the docosahexaenoic acid (DHA. Results showed that at lower temperatures 23 and 26oC, Nile tilapia grows less than at higher temperatures around 29 and 32oC. Temperature variation from 23 to 32oC did not influence on fatty acids profile of the alevins

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

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    CUINAT R.

    1971-10-01

    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.

  20. Increasing Benefits from Agroforestry Tree Products in West and Central Africa

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    2012-01-01

    Full Text Available Increasing Benefits from Agroforestry Tree Products in West and Central Africa. Des alevins de tilapia Oreochromis niloticus ont été mis en grossissement dans trois types de fermes piscicoles rurales de Côte d'Ivoire ayant des taux d'observance de mesures de biosécurité respectifs de 5%, 55% et 83%. L'étude a consisté à déterminer et à comparer les valeurs des paramètres physicochimiques de l'eau des étangs et des paramètres zootechniques des poissons entre ces trois types de ferme. Aucune différence significative n'a été observée entre les valeurs moyennes des paramètres physiques et chimiques de l'eau des étangs des différentes fermes piscicoles. Concernant les paramètres zootechniques, la ferme piscicole possédant 83% de taux d'observance des mesures de biosécurité a enregistré les meilleures performances zootechniques avec des différences significatives par rapport aux deux autres types de fermes.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1995-02-01

    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.

  2. El cultivo de tilapias: una amenaza a las especies ícticas nativas en Nicaragua.

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    McCrary, J.K.

    2001-08-01

    Full Text Available El cultivo de tilapia del nilo (oreochromis niloticus, linnoeus previamente alimentados con hormonas para producir machos, en la laguna de Apoyo en Nicaragua ha permitido la introducción a la laguna de individuos, incluyendo hembras fecundas. Discutimos las consecuencias de esta introducción, en términos de amenazas de extinción de especies endémicas nativas a través de destrucción de hábitat, competencia por sitios de cortejo y alimentación, proliferación de parásitos en poblaciones de fauna nativa, y la depredación de alevines nativos. Mientras que una liberación anterior de una especie similar (O. aureus Steindachner en la laguna de Apoyo, en 1983, tuvo poco impacto observado, este segundo incidente, aquí documentado, ha resultado en dramáticos impactos negativos en la laguna, amenazando especies endémicas locales y creando posiblemente riesgos en la salud humana. Abogamos por la remoción total de tilapias de ecosistemas naturales como el de Apoyo, y advertimos sobre el peligro de las introducciones de especies no nativas en ecosistemas naturales, aun donde introducciones previas han sucedido.

  3. Action des feuilles de peuplier dans de petits bassins de pisciculture

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    WURTZ A.

    1955-10-01

    Full Text Available Il a été procédé à des essais dans des bassins de pisciculture de mêmes dimensions (504 m2 en vue d'établir la nocivité des feuilles de peuplier. L'influence de celles-ci ne s'est guère fait sentir par les dosages chimiques effectués dans l'eau. Par contre, les feuilles en décomposition ont provoqué une abondante quantité de vase putride sur le fond du bassin en expérience et le rendement en alevins de poissons a été ortement diminué dans le bassin avec feuilles de peuplier : 10 kilogrammes seulement par rapport aux 27 kg. 200 du bassin-témoin. On peut conclure que les feuilles de peuplier, tombant en abondance dans les étangs sont nettement nocives, tant pour la faune benthique du fond, qui est éliminée par suite de la formation de vase putride, que pour la productivité piscicole. Des observations complémentaires permettent de penser que les étangs et même les cours d'eau dans lesquels tombent des feuilles de peuplier sont moins bons pour l'alevinage et la productivité piscicole que ceux dans lesquels il n'en tombe pas.

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

    Directory of Open Access Journals (Sweden)

    David Sánchez Oliva

    2010-11-01

    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.

  5. The effects of low pH and elevated aluminum on yellowstone cutthroat trout (Oncorhynchus clarki bouvieri)

    International Nuclear Information System (INIS)

    Farag, A.M.; Woodward, D.F.; Little, E.E.; Steadman, B.; Vertucci, F.A.

    1993-01-01

    Although acid deposition is not considered a problem in the western US, surface waters in high elevations and fish inhabiting these waters may be vulnerable to acidification. This study examined the sensitivity of a wester salmonid to acid and aluminum stress. Yellowstone cutthroat trout (Oncorhynchus clarki bouvieri; YSC) were exposed for 7 d during each of four early life stages, or continuously from fertilization to 40 d post-hatch, to decreased pH and elevated Al. The authors monitored survival, growth, whole-body ion content, and behavior of the exposed fish. Sensitivity of early life stages of YSC may be expressed by survival or by survival and sublethal effects. In their study, eggs were the most sensitive life stage of YSC to low pH if survival alone was considered. However, the sublethal effects on growth, tissue ion content, and behavior revealed the alevins and swim-up larvae were more sensitive to reduced pH and increased Al than eggs or eyed embryos. They also observed that survival was significantly decreased if YSC were exposed to pH 6.0 and 50 μg Al per liter continuously from fertilization to 40 d post-hatch

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

    Directory of Open Access Journals (Sweden)

    David Sánchez Oliva

    2010-11-01

    Full Text Available Abstract 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 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.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2002-08-01

    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.

  8. Comparative toxicity of inorganic contaminants released by placer mining to early life stages of salmonids

    Science.gov (United States)

    Buhl, Kevin J.; Hamilton, Steven J.

    1990-01-01

    The acute toxicities of four trace inorganics associated with placer mining were determined, individually and in environmentally relevant mixtures, to early life stages of Arctic grayling (Thymallus arcticus) from Alaska and Montana, coho salmon (Oncorhynchus kitsutch) from Alaska and Washington, and rainbow trout (Oncorhynchus mykiss) from Montana. The descending rank order of toxicity to all species and life stages was copper > zinc > lead > arsenic. For each of the three species, sensitivity to the inorganics was greater in juveniles than in alvenins or in swim-up fry. Arctic grayling from Alaska were more sensitive than the other species tested, including Arctic grayling from Montana. For Arctic grayling, sensitivity to all four inorganics was significantly greater in swim-up fry from Alaska than in alevins from Montana, and sensitivity to arsenic and copper was significantly greater in juveniles from Alaska than in juveniles from Montana. In tests with environmentally relevant mixtures (based on ratios of concentrations measured in streams with placer mining) of these four inorganics, copper was identified as the major toxic component because it accounted for ⩾97% of the summed toxic units of the mixture, and an equitoxic mixture of these inorganics showed less-than-additive toxicity. Total and total recoverable copper concentrations reported in five Alaskan streams with active placer mines were higher than the acutely toxic concentrations, either individually or in mixtures, that the authors found to be acutely toxic to Arctic grayling and coho salmon from Alaska. However, caution should be used when comparing our results obtained in “clear” water to field situations, because speciation and toxicity of these inorganics may be altered in the presence of sediments suspended by placer mining activities.

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

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    Germán Poleo

    2011-04-01

    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.

  10. Influence of fluoride on aluminum toxicity to Atlantic salmon (Salmo salar)

    Science.gov (United States)

    Hamilton, Steven J.; Haines, Terry A.

    1995-01-01

    Atlantic salmon (Salmo salar) alevins were exposed to various aluminum (0–4700 μg/L) and four fluoride (0–500 μg/L) concentrations at two pH values (5.5 and 6.5) for 4- and 30-d periods. In the 4-d tests, aluminum with fluoride was less toxic at pH 6.5 than at pH 5.5, whereas without fluoride, pH had no effect. In the 30-d test, mortality in all treatments was 17–21% at pH 5.5, but only 3–7% at pH 6.5. Fish length and weight after 30 d were reduced in all fluoride–aluminum treatments at pH 5.5, but only in the 200-μg/L aluminum without fluoride treatment at pH 6.5. At pH 5.5 and 6.5 without aluminum, histomorphological examinations revealed no abnormalities in gill tissue. However, in aluminum exposure with no fluoride, gill filaments and secondary lamellae were swollen and thickened. Addition of fluoride at pH 6.5 alleviated some gill damage. At pH 5.5 and 200 μg/L aluminum, addition of 100 μg/L fluoride reduced swelling of gill lamellae, but 200 μg/L fluoride did not reduce swelling. Low fluoride concentrations (aluminum in acidic waters, whereas high fluoride concentrations (> 100 μg/L) may not reduce aluminum-induced effects.

  11. Relationship between fish size and upper thermal tolerance

    Science.gov (United States)

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

    2012-01-01

    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.

  12. 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

    2010-04-01

    Full Text Available 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.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.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 differentially respond and adapt to shifts in environmental

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

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    Carlos Alvarado-Ruiz

    2015-01-01

    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.

  14. Deuterium depleted water. Romanian achievements and prospects

    International Nuclear Information System (INIS)

    Stefanescu, Ioan; Steflea, Dumitru; Titescu, Gheorghe; Tamaian, Radu

    2002-01-01

    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

  15. Effect of developmental stage of unfed fry on survival and growth of steelhead released in a stream and hatchery ponds (Study sites: Dworshak Hatchery and North Fork Palouse River; Stock: Dworshak hatchery; Year class: 1996): Chapter 6

    Science.gov (United States)

    Rubin, Stephen P.; Reisenbichler, Reginald R.; Wetzel, Lisa A.; Stenberg, Karl D.; Rubin, Stephen P.; Reisenbichler, Reginald R.; Wetzel, Lisa A.; Hayes, Michael C.

    2012-01-01

    We tested whether differences in developmental stage of unfed fry at release affected subsequent survival and growth of steelhead Oncorhynchus mykiss in a stream and hatchery ponds. Differences in development were created by artificially spawning hatchery steelhead from the Clearwater River, Idaho, and incubating their progeny at three different temperatures (means=10.9, 11.3, and 11.7°C). Time between fertilization and maximum alevin wet weight (MAWW) was predicted from incubation temperature using a model. MAWW is equivalent to the button - up fry stage of development. Developmental stages at release were “underdeveloped” (97.7% of model - predicted time to MAWW, mean weight=0.177 g, proportion yolk=0.087), “intermediate” (102.5%, 0.179 g, 0.044), and “overdeveloped” (107.9%, 0.156 g, 0.030). Neither survival nor growth in the hatchery to near the end of the standard one year rearing period differed among groups. In the stream, frequency of overdeveloped fish relative to the other two groups decreased fro m release in May to September, probably indicating lower survival for the overdeveloped fish during that interval since emigration of sub - yearlings is typically negligible. Length in September was less for overdeveloped than for intermediate fish and was in between for underdeveloped fish, suggesting that growth between May and September was less for overdeveloped fish than for intermediate fish. Although changes in relative frequency and size occurred among fry development groups from September to one ye ar later, those changes may have reflected differences in emigration rate during the interval rather than differential survival or growth. Our results show a cost to survival and growth in a stream, but not in a hatchery, from overdevelopment characterize d by loss of weight and yolk reserves relative to fry closer to MAWW at release. We didn’t find any cost from underdevelopment; however, our underdeveloped fry were closer to MAWW than the

  16. 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)

    MÉLARD C.

    1995-01-01

    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.

  17. ACUICULTURA DE PARGO LA MANCHA LUTJANUS GUTTATUS (STEINDACHNER, 1869 EN COSTA RICA DENTRO DE UN ENFOQUE ECOSISTÉMICO

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    Angel Herrera-Ulloa

    2011-07-01

    Full Text Available La sobreexplotación pesquera y la búsqueda de alternativas ante la pobreza crónica han llevado a explorar el campo de la maricultura por medio de un enfoque ecosistémico se abrieron dos procesos paralelos: una estrategia e; investigación en laboratorio para el levantamiento larval de peces marinos tropicales y una estrategia de comanejo para desarrollar el cultivo de peces marinos tropicales. El pargo la mancha muestra gran potencial de producción de larvas y posterior cultivo en el mar. No mostró respuestas positivas a la inducción por medio de hormonas, el desarrollo de un ambiente adecuado para su reproducción espontánea, permitió tener desoves frecuentes y de calidad. La fase de levantamiento larval mostró contratiempos por el tamaño reducido de las larvas de pargo la mancha el manejo en tanques apropiados y el uso de enriquecedores permitieran mejorar los procesos y llegar a incrementar la producción de alevines. El enfoque ecosistémico permitió abrir los espacios necesarios que permitieron la operación de un proyecto piloto. La granja se creó con un enfoque productivo, pero también para turismo rural. Overfishing and the search for alternatives to it, led us to the explore mariculture as an option using an ecosystem-based approach through two parallel processes: an in-laboratory research strategy for larval rearing of tropical marine fish, and a strategy of co-management to develop tropical marine fish aquaculture. The spotted rose snapper shows great potential for larvae production and cage culture. This species showed no responses to hormone induction; however, the set up of a suitable environment allowed frequent, high-quality spontaneous spawnings. The larval rearing phase presented problems due to the small size of the larvae; although, management in appropriate tanks and the use of enrichments improved the processes, increasing the production of juveniles. This ecosystem approach allowed the operation of a

  18. 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

    2012-02-01

    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.

  19. Summary of Temperature Data Collected to Improve Emergence Timing Estimates for Chum and Fall Chinook Salmon in the Lower Columbia River, 1998-2004 Progress Report.

    Energy Technology Data Exchange (ETDEWEB)

    Arntzen, E.; Geist, D.; Hanrahan, T.

    2005-10-01

    From 1999 through 2004, Pacific Northwest National Laboratory collected temperature data from within chum and fall Chinook salmon spawning gravels and the overlying river at 21 locations in the Ives Island area approximately 5 km downstream from Bonneville Dam. Sample locations included areas where riverbed temperatures were elevated, potentially influencing alevin development and emergence timing. The study objectives were to (1) collect riverbed and river temperature data each year from the onset of spawning (October) to the end of emergence (June) and (2) provide those data in-season to fisheries management agencies to assist with fall Chinook and chum salmon emergence timing estimates. Three systems were used over the life of the study. The first consisted of temperature sensors deployed inside piezometers that were screened to the riverbed or the river within chum and fall Chinook salmon spawning areas. These sensors required direct access by staff to download data and were difficult to recover during high river discharge. The second system consisted of a similar arrangement but with a wire connecting the thermistor to a data logger attached to a buoy at the water surface. This system allowed for data retrieval at high river discharge but proved relatively unreliable. The third system consisted of temperature sensors installed in piezometers such that real-time data could be downloaded remotely via radio telemetry. After being downloaded, data were posted hourly on the Internet. Several times during the emergence season of each year, temperature data were downloaded manually and provided to management agencies. During 2003 and 2004, the real-time data were made available on the Internet to assist with emergence timing estimates. Examination of temperature data reveals several important patterns. Piezometer sites differ in the direction of vertical flow between surface and subsurface water. Bed temperatures in upwelling areas are more stable during salmon

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

    Directory of Open Access Journals (Sweden)

    BOUCHAUD B.

    1979-04-01

    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

  1. Composición del mercado nacional de alimentos balanceados para tilapia en Costa Rica

    Directory of Open Access Journals (Sweden)

    Ruth Vargas

    2003-01-01

    Full Text Available Se evaluó el origen y proceso de fabricación de los alimentos balanceados para tilapias comercializados en el país e inscritos en el Programa de Registro y Control de Calidad de Alimentos Balanceados para Animales del Ministerio de Agricultura y Ganadería. Además, se determinaron las prescripciones según la fase fisiol ógica y su composición química, así como las relaciones proteína cruda versus energía metabolizable y calcio – fósforo para compararlos contra los requerimientos recomendados. La calidad física fue evaluada en términos del tamaño de part ícula versus el tamaño del pez. El estudio de mercado consider ó el precio de venta de cada unidad de nutriente y su relaci ón que aportan los alimentos disponibles. Se determinó que un 82,35% de los registros son de origen nacional, un 88,23% de los alimentos son producidos por extrusión, y un 41% de las fórmulas son ofrecidas para todos los estadios, lo que provoca poca sustentación para comparar contra los requerimientos; a manera de ejemplo metodológico se determinó que los contenidos de proteína cruda de aquéllas fórmulas que son ofrecidas para alevines concuerdan con los niveles recomendados por la literatura. La situación de la calidad fí- sica es más crítica, por cuanto solamente un 23,53% de las garantías indican el tamaño del gránulo. Dado que el estudio de mercado arrojó que de las 17 garantías solamente se comercializan cinco se concluyó que comparar los alimentos por los precios unitarios de los nutrientes no coadyuva tampoco en la escogencia del alimento de manera importante.

  2. Reproductive strategy of Oreochromis niloticus (Pisces: Cichlidae in Opa reservoir, Ile-Ife, Nigeria

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    O.O Komolafe

    2007-06-01

    Full Text Available The fish family Cichlidae has a large diversity and dominates African freshwater bodies, with over 200 species reported in inland waters. Sampling for the fish Oreochromis niloticus (Linnaeus in Opa reservoir, Nigeria, started in October 1997 and extended until February 2000. The fishing methods employed for collecting the 1 430 specimens were cast netting and gillnetting. Egg diameter varied between 2.12 mm and 2.69 mm with a mean of 2.47±0.02. Female gonadosomatic index was 1.34±0.01 (0.12-4.06, n= 637. The male gonadosomatic index was 0.39±0.02 (0.03-1.67, n= 789. In Opa reservoir, O. niloticus bred throughout the study period. The species was a maternal mouth brooder with the female fish carrying eggs and fry in the buccal cavities. The sex ratio of O. niloticus was approximately 1:1 in the reservoir. The fecundity of the species was between 73 eggs and 1 810 eggs per female with a mean fecundity of 815 eggs. Rev. Biol. Trop. 55 (2: 595-602. Epub 2007 June, 29.Estudiamos la tilapia, Oreochromis niloticus (Linnaeus en la reserva de Opa, Nigeria, desde octubre 1997 hasta febrero del 2000. Recolectamos 1 430 especímenes con red lanzada y red de arrastre. El diámetro de los huevos varía entre los 2.12 mm y 2.69 mm con un promedio de 2.47±0.02. El índice gonadosomático de las hembras fue de 1.34±0.01 (0.12-4.06, n= 637, y en machos fue de 0.39±0.02 (0.03-1.67, n= 789. En la reserva este pez se reprodujo durante todo el periodo de estudio. Hay cuido materno: la hembra lleva los huevos y alevines en la boca. La proporción machos/hembras fue aproximadamente 1:1. La fecundidad varía entre 73 y 1 810 huevos por hembra con un promedio de 815 huevos.

  3. Efectos negativos del cambio climático aceleran la extinción de la principal población de la náyade Margaritifera margaritifera L., 1758 en la cuenca del Duero

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    Morales, J., Lizana, M.

    2014-01-01

    Full Text Available El río Negro alberga una metapoblación de la náyade Margaritifera margaritifera L. 1758 que no es demográficamente funcional. Su estructura poblacional está desequilibrada hacia tallas muy grandes y no se han detectado juveniles en más de una década de estudio. En el río existen graves problemas de conservación derivados del aterramiento, extensibles a la trucha Salmo trutta L. 1758, único hospedador de sus larvas. Entre 2002 y 2009 sucedieron de forma consecutiva graves riadas y la mayor sequía registrada en la cuenca. La mayor avenida en 100 años del año 2006 produjo el movimiento de gran parte de la población de náyades, con un impacto mortal que según tramos afectó entre el 5 y el 34% de los efectivos. Se comprobó una mortandad diferencial en relación con la topografía local y composición granulométrica del lecho, pero independiente de la densidad y la talla de los individuos. La sequía afectó al tercio final del cauce y supuso la pérdida del 37% de ejemplares del tramo. La aplicación de modelos poblacionales permite estimar que estos eventos estocásticos agravan significativamente el proceso de extinción, anticipando el presumible colapso demográfico teóricamente esperable para 2027-2032, provocado por la actuación continuada del resto de problemas. La aplicación de un plan de restauración del cauce, enfocado a las náyades y sus hospedadores, así como el rescate de adultos tras los eventos extremos, su asentamiento temporal en zonas favorables y la propagación de la especie sobre alevines de trucha son medidas urgentes que deberían desarrollarse antes de poder afrontar un programa de cría en cautividad que evite la extinción de la especie en la Cuenca del Duero.

  4. Environmental performance of aquaculture in Rondônia state, Brazil

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    Aurélio Ferreira Borges

    2015-04-01

    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

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

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    Tomás López Arias

    2016-06-01

    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

  6. LES POISSONS CARNASSIERS LOCAUX PEUVENT-ILS CONTENIR L’EXPANSION DES ÉCREVISSES ÉTRANGÈRES INTRODUITES ? EFFICACITÉ DE 3 ESPÈCES DE POISSONS FACE À 2 ESPÈCES D’ÉCREVISSES DANS DES CONDITIONS EXPÉRIMENTALES.

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    NEVEU A.

    2001-04-01

    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

  7. Biologia do saguirú (Characidae, Curimatinae

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    P. de Azevedo

    1938-01-01

    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

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

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    Agata Korzelecka-Orkisz

    2012-09-01

    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.

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

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    D. Simon

    2010-09-01

    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

  10. Pyrethroid toxicity in silver catfish, Rhamdia quelen

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    Francisco P. Montanha

    2012-12-01

    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

  11. 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)

    2004-07-01

    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

  12. Le black-bass (Micropterus salmoides Lacép. dans les eaux italiennes. Un antagoniste du brochet ?

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    ALESSIO G.

    1984-01-01

    Full Text Available Le black-bass à grande bouche est largement répandu dans les eaux italiennes et fait l'objet de repeuplement. Les alevins et estivaux nécessaires proviennent le plus souvent de la vidange automnale des étangs à cyprinidés avec lesquels ils sont élevés. Il n'y a pas vraiment d'élevage contrôlé de cette espèce en Italie, mais seulement une série d'essais qui portent sur la reproduction naturelle en étangs-frayères, l'introduction de nids artificiels dans le milieu et l'induction de la ponte par traitement hypophysaire (avec HCG, essais qui donnent des résultats satisfaisants. Dans le milieu naturel, la croissance en longueur et en poids du black-bass en Italie est comparable et quelquefois meilleure que celle enregistrée sur ses lieux d'origine. La croissance annuelle est d'abord lente (printemps, puis rapide (été, ensuite à nouveau lente (automne pour être finalement modeste ou pratiquement nulle en hiver. La population qui, avec des fluctuations annuelles, représente 0,5 à 1,6 % de l'ichthyofaune des eaux étudiées (fleuves Pô, Sesia et Ticino, est constituée surtout de sujets jeunes : environ 40 % des individus sont âgés de 2 hivers et ne dépassent pas un poids de 400 g et une longueur totale de 28 cm. La survie est considérée comme bonne avec une durée de vie de 8 à 9 hivers. La nourriture présente un spectre très large et est basée de préférence sur des petits poissons et sur les amphibiens, avec une large partie d'invertébrés (surtout des insectes. La reproduction intervient aux mois de mai et juin, mais elle peut être aussi plus précoce et, le plus souvent, plus tardive. Le black-bass est très sensible aux pollutions, mais ne semble pas particulièrement affecté par des épizooties ou du parasitisme. Par rapport à la niche écologique occupée, à son spectre trophique, à son rôle dans les équilibres biologiques et à ses caractéristiques éthologiques, le black-bass ne peut pas être consid

  13. ÉTUDE EXPÉRIMENTALE DES COMPORTEMENTS DE CIVELLES D’ANGUILLA ANGUILLA L. INFLUENCE DE LA DENSITÉ ET DE LA DISPONIBILITÉ EN ABRIS

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    BARDONNET A.

    2005-10-01

    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.

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

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    GUEVEL B.

    1997-01-01

    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

  15. Effect of the Operation of Kerr and Hungry Horse Dams on the Reproduction Success of Kokanee in the Flathead River System, 1986 Annual Progress Report.

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    Beattie, Will; Clancey, Patrick

    1987-03-01

    The 1985 kokanee spawning run in the Flathead system was the strongest in five years. Escapement to the Flathead River system was 147,000 fish, including 123,000 in McDonald Creek and an estimated 20,000 in the main stem. Enumeration of spawners and redds in the Flathead River was hindered by high fall flows and early freezing in November. The upstream spawning migration from Flathead Lake began in late August. Schools of kokanee were seen six miles above the lake on September 4. We counted 1,156 redds in Flathead Lake, distributed primarily along the southeastern shore. An unusually high proportion (90 percent) of lakeshore spawning occurred in the zone above minimum pool, where egg mortality is very high because of exposure from drawdown. Escapement to the Swan River was 1,350 fish. Four year old (III+) fish comprised 95 percent of the spawning run in the Flathead system. This continues a five-year trend toward dominance of the III+ year class. The age composition of spawners has varied considerably for the past 15 years. The average size of spawning fish was 365 mm, which is identical to the average size of the parent year class in 1981. One of the goals of managing Flathead kokanee is to produce mature fish 300-330 mm in length. In the main stem Flathead River, pre-emergent survival was 80 percent. Survival in McDonald Creek, unaffected by hydroelectric operations, was 83 percent. Sampling showed few hatched alevins, probably due to unusually cold winter temperatures. Egg survival at Blue Bay, a spawning area on Flathead Lake where redds are concentrated below minimum pool, varied in relation to depth and dissolved oxygen concentration in the substrate. Eggs survived 78 days at 2,880 feet where dissolved oxygen was 5.7 mg/l. Eggs survived 35 days at 2,870 feet where dissolved oxygen concentration averaged 2.9 mg/l. Low dissolved oxygen contributed to poor survival to emergence at all elevations in Blue Ray. Experiments in Skidoo Bay confirmed that survival of

  16. 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

    1988-05-01

    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

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

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    Francisco P. Montanha

    2012-12-01

    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