RESUMO

This study evaluates the influence of marine and freshwater conditions on the timing of river entry and upstream migration of sea trout (Salmo trutta) in the Grande River of Tierra del Fuego, Patagonia. We analysed the in-river catch-and-release records from a group of fishing lodges that dominate the Grande River fishery during January-April 2008 (n = 5029 fish) as a function of environmental variables: tidal amplitude, stage in the lunar cycle, river discharge, and river water temperature along the homeward migration season. We discuss the value of the daily catch rate as an abundance index in the Grande river, then analyse the temporal structure of the tidal cycle in the Grande River estuary, a macro-tidal environment with a mean tidal amplitude of 5.7 m, and analyse the fit of a generalized additive model to trout catches on a daily basis in four sections along the river to identify the environmental variables that may affect trout abundance throughout the homeward migration. Fish catches in each section of the river were differentially affected by specific environmental variables: tidal amplitude had a positive and significant effect on catches in the lower river sections, whereas water temperature and river discharge significantly affected catches in upper sections (positive effect of temperature; negative effect of discharge). Catches in the lower section clearly reflect the river entry stage of the homeward migration, with a bi-modal shape significantly correlated with the tidal cycle. The first peak was composed mainly of larger multi-sea-winter trout that move upstream, whereas the second one had a wider range of fish lengths, including a large proportion of small and maybe nonreproductive trout that overwinter in the lower river. Based on our results, we conclude that the large tides in the Grande River estuary strongly affect the river entry timing of sea trout. The underlying mechanisms of this effect may be a combination of increased olfactory recognition and increased tidal transport modulated by the seasonal tidal cycle, which operates on trout during coastal migration to produce the pulses observed in the Grande River sea trout run. In the middle and upper sections of the river, where the tidal effect at river entry was dissipated as upstream migration progressed, trout catches increased with water temperature and decreased with river discharge, which may operate through their influence on in-river migration rate and abundance, but also through changes in catchability.

Assuntos

RESUMO

Abstract 20 pieces of all-female (produces by using Gynogenesis process via gamma irradiation) Caspian salmon (Salmo trutta caspius) with dosage of 450, 600, 750, 900 and 1050 Gy by gamma irradiation (Co60) with average weight of 2.31 ± 0.22 in a randomized design was transferred to 300 liters tanks (n =3). For 6 months, growth indices including weight gain, feed conversion ratio, specific growth rate were examined. At the end of the period, 3 pieces from each experimental unit were caught and after anesthesia were used using clove oil (100 ppm) and blood sampling and sera isolation, immunological indices (lysozyme activity, complement activity and total immunoglobulin) were measured in fish of different groups. The results showed that the growth rate in the gynogen groups were higher than the control group (p<0.05). The feed conversion ratio in the control treatment was significantly increased compared to experimental groups. The specific growth indices including of final weight 47.2%, FCR 13.46% and SGR 10.9% were improved significantly in the experimental groups in comparison with the control group (p<0.05). Immunological indices (lysozyme, complement activity and, immunoglobulin) in different groups weren't show significant changes (p>0.05). Therefore, the use of gynogenesis by using gamma irradiation concluded in Caspian Sea salmon, due to the lack of immunological indices and growth improvement.

RESUMO

ABSTRACT: Body composition (total crude protein, lipid, ash, dry matter and moisture) and fatty acid profiles were compared between wild and farmed brown trout and between farmed rainbow trout. Farmed brown trout contained the highest amount of crude protein (18.39%), whereas farmed rainbow trout contained higher levels of crude lipid (2.35%). Thirty six fatty acids were found, including sixteen saturated fatty acids (SFA), nine monounsaturated fatty acids (MUFA) and eleven polyunsaturated fatty acids (PUFA). The most abundant SFA in all fish were palmitic acid and stearic acid. However, the most abundant fatty acids in all trout samples were MUFA and PUFA. MUFA were the most abundant fatty acid in farmed brown trout because of high abundance of oleic acid in this samples (35.46g / 100g fatty acids). PUFA were predominating in the samples of wild brown trout and of rainbow trout 56.16 and 56.29g/100g fatty acids, respectively). Linoleic acid was the most abundant fatty acid reported in the rainbow trout (47.17g/100g fatty acids). Significantly higher amounts of docosahexaenoic acid, α-linolenic acid, arachidonic acid and eicosapentaenoic acid were observed in the wild trout samples. Wild brown trout contained significantly more docosahexaenoic acid, α-linolenic acid, Eicosapentaenoic acidArachidonic acid. Sensory quality evaluation, by a consumers' panel, revealed all samples were equally well accepted.

RESUMO: A composição corporal (teores de proteína, gordura total, cinzas, matéria seca e humidade) e os perfis de ácidos gordos da truta-fário (selvagem e proveniente de aquacultura) e da truta-arco-íris (cultivada) foram comparados. A truta-fário cultivada continha a maior quantidade de proteína bruta (18,39%), enquanto a truta arco-íris possuía teores mais elevados de lípidos (2,35%). Foram detectados 36 ácidos graxos, incluindo 16 ácidos graxos saturados (SFA), nove ácidos graxos monoinsaturados (MUFA) e 11 ácidos graxos poliinsaturados (PUFA). Os SFA mais abundantes foram o ácido palmítico e o ácido esteárico. No entanto, os ácidos graxos mais abundantes em todas as amostras de truta foram os MUFA e os PUFA. A grande abundância de ácido oleico existente nas amostras de truta-fário cultivada (35,46g/100g de ácidos graxos) faz com que os MUFA sejam os ácidos graxos mais abundantes nesta variedade de truta (42,43g/100g de ácidos graxos) Nas amostras de truta-fário selvagem e nas de truta arco-íris predominaram os PUFA (56,16 e 56,29g/100g de ácidos graxos, respetivamente), sendo o ácido linoleico o mais abundante na truta-arco-íris (47,17g/100g de ácidos graxos). Nas amostras truta-fário selvagem foram observadas quantidades significativamente mais elevadas de ácido docosahexaenóico, ácido α-linolênico, ácido acidoaraquidônico e ácido eicosapentaenóico. Todas as amostras foram igualmente bem aceitas por um painel de consumidores.

RESUMO

ABSTRACT: Body composition (total crude protein, lipid, ash, dry matter and moisture) and fatty acid profiles were compared between wild and farmed brown trout and between farmed rainbow trout. Farmed brown trout contained the highest amount of crude protein (18.39%), whereas farmed rainbow trout contained higher levels of crude lipid (2.35%). Thirty six fatty acids were found, including sixteen saturated fatty acids (SFA), nine monounsaturated fatty acids (MUFA) and eleven polyunsaturated fatty acids (PUFA). The most abundant SFA in all fish were palmitic acid and stearic acid. However, the most abundant fatty acids in all trout samples were MUFA and PUFA. MUFA were the most abundant fatty acid in farmed brown trout because of high abundance of oleic acid in this samples (35.46g / 100g fatty acids). PUFA were predominating in the samples of wild brown trout and of rainbow trout 56.16 and 56.29g/100g fatty acids, respectively). Linoleic acid was the most abundant fatty acid reported in the rainbow trout (47.17g/100g fatty acids). Significantly higher amounts of docosahexaenoic acid, -linolenic acid, arachidonic acid and eicosapentaenoic acid were observed in the wild trout samples. Wild brown trout contained significantly more docosahexaenoic acid, -linolenic acid, Eicosapentaenoic acidArachidonic acid. Sensory quality evaluation, by a consumers panel, revealed all samples were equally well accepted.

RESUMO: A composição corporal (teores de proteína, gordura total, cinzas, matéria seca e humidade) e os perfis de ácidos gordos da truta-fário (selvagem e proveniente de aquacultura) e da truta-arco-íris (cultivada) foram comparados. A truta-fário cultivada continha a maior quantidade de proteína bruta (18,39%), enquanto a truta arco-íris possuía teores mais elevados de lípidos (2,35%). Foram detectados 36 ácidos graxos, incluindo 16 ácidos graxos saturados (SFA), nove ácidos graxos monoinsaturados (MUFA) e 11 ácidos graxos poliinsaturados (PUFA). Os SFA mais abundantes foram o ácido palmítico e o ácido esteárico. No entanto, os ácidos graxos mais abundantes em todas as amostras de truta foram os MUFA e os PUFA. A grande abundância de ácido oleico existente nas amostras de truta-fário cultivada (35,46g/100g de ácidos graxos) faz com que os MUFA sejam os ácidos graxos mais abundantes nesta variedade de truta (42,43g/100g de ácidos graxos) Nas amostras de truta-fário selvagem e nas de truta arco-íris predominaram os PUFA (56,16 e 56,29g/100g de ácidos graxos, respetivamente), sendo o ácido linoleico o mais abundante na truta-arco-íris (47,17g/100g de ácidos graxos). Nas amostras truta-fário selvagem foram observadas quantidades significativamente mais elevadas de ácido docosahexaenóico, ácido -linolênico, ácido acidoaraquidônico e ácido eicosapentaenóico. Todas as amostras foram igualmente bem aceitas por um painel de consumidores.

RESUMO

Body composition (total crude protein, lipid, ash, dry matter and moisture) and fatty acid profiles were compared between wild and farmed brown trout and between farmed rainbow trout. Farmed brown trout contained the highest amount of crude protein (18.39%), whereas farmed rainbow trout contained higher levels of crude lipid (2.35%). Thirty six fatty acids were found, including sixteen saturated fatty acids (SFA), nine monounsaturated fatty acids (MUFA) and eleven polyunsaturated fatty acids (PUFA). The most abundant SFA in all fish were palmitic acid and stearic acid. However, the most abundant fatty acids in all trout samples were MUFA and PUFA. MUFA were the most abundant fatty acid in farmed brown trout because of high abundance of oleic acid in this samples (35.46g / 100g fatty acids). PUFA were predominating in the samples of wild brown trout and of rainbow trout 56.16 and 56.29g/100g fatty acids, respectively). Linoleic acid was the most abundant fatty acid reported in the rainbow trout (47.17g/100g fatty acids). Significantly higher amounts of docosahexaenoic acid, α-linolenic acid, arachidonic acid and eicosapentaenoic acid were observed in the wild trout samples. Wild brown trout contained significantly more docosahexaenoic acid, α-linolenic acid, Eicosapentaenoic acidArachidonic acid. Sensory quality evaluation, by a consumers panel, revealed all samples were equally well accepted.(AU)

A composição corporal (teores de proteína, gordura total, cinzas, matéria seca e humidade) e os perfis de ácidos gordos da truta-fário (selvagem e proveniente de aquacultura) e da truta-arco-íris (cultivada) foram comparados. A truta-fário cultivada continha a maior quantidade de proteína bruta (18,39%), enquanto a truta arco-íris possuía teores mais elevados de lípidos (2,35%). Foram detectados 36 ácidos graxos, incluindo 16 ácidos graxos saturados (SFA), nove ácidos graxos monoinsaturados (MUFA) e 11 ácidos graxos poliinsaturados (PUFA). Os SFA mais abundantes foram o ácido palmítico e o ácido esteárico. No entanto, os ácidos graxos mais abundantes em todas as amostras de truta foram os MUFA e os PUFA. A grande abundância de ácido oleico existente nas amostras de truta-fário cultivada (35,46g/100g de ácidos graxos) faz com que os MUFA sejam os ácidos graxos mais abundantes nesta variedade de truta (42,43g/100g de ácidos graxos) Nas amostras de truta-fário selvagem e nas de truta arco-íris predominaram os PUFA (56,16 e 56,29g/100g de ácidos graxos, respetivamente), sendo o ácido linoleico o mais abundante na truta-arco-íris (47,17g/100g de ácidos graxos). Nas amostras truta-fário selvagem foram observadas quantidades significativamente mais elevadas de ácido docosahexaenóico, ácido α-linolênico, ácido acidoaraquidônico e ácido eicosapentaenóico. Todas as amostras foram igualmente bem aceitas por um painel de consumidores.(AU)

Assuntos