Diferentes estratégias alimentares na larvicultura do acará-bandeira (Peterolophyllum scalare,Cichlidae) / Different feeding strategies on larval rearing of angelfish (Peterolophyllum scalare, Cichlidae)

The hatchery is one of the most critical stages of the development of fish and their success is directly related to food handling that can provide greater survival and growth. The aim of this study was to evaluate the time of dietary transition and providing meta-nauplii of Artemia spp. (MNA) for the angelfish larvae. Two experiments were conducted in a completely randomized design with five treatments and four repetitions. On each experiment there were used 540 fishes, distributed in 20 tanks with 2 liters each. In the first experiment, there were evaluated the dietary transition periods (MNA + Diet) for 1, 2, 3, 4 and 5 days. In the second experiment, there were evaluated the supply of MNA for 5, 10, 15, 20 and 25 days. There were evaluated: weight gain, growth rate and specific development, survival and batch uniformity (only in the experiment to evaluate the time of fish feed with MNA). There was no significant effect of different periods of dietary transition on the growth variables (p>0.05), but survival was higher (p<0.05) in the treatments composed of 3, 4 and 5 days of joint feed. In relation to the time of supply of MNA worse results were observed (p<0.05) when the time of supply of live food was shorter (5, 10 and 15 days). The animals were fed with MNA before feeding transition, for longer time (20 and 25) showed the best results for growth (p<0.05). Therefore, a food transition of three days and a supply of MNA for 20 days is recommended to perform the total replacement of live food for feed.

A larvicultura é uma das etapas mais críticas do desenvolvimento dos peixes e o seu sucesso está diretamente relacionado ao manejo alimentar, que pode proporcionar maiores sobrevivência e crescimento. Objetivou-se avaliar o tempo de transição alimentar e de fornecimento de meta-náuplios de Artemia spp (MNA) na larvicultura do acará-bandeira. Dois experimentos foram conduzidos em delineamento inteiramente casualizado com cinco tratamentos e quatro repetições. Em cada experimento foram utilizados 540 peixes distribuídos em 20 aquários com 2 L. No primeiro experimento, avaliaram-se os períodos de transição alimentar (MNA + ração) por 1, 2, 3, 4 e 5 dias. No segundo experimento, avaliou-se o período de fornecimento de MNA por 5, 10, 15, 20 e 25 dias. Foram avaliados: ganho de peso, taxas de crescimento e desenvolvimento específico, sobrevivência e uniformidade do lote (apenas no experimento para avaliar o tempo de fornecimento de MNA). Não houve efeito significativo dos diferentes períodos de transição alimentar sobre as variáveis de crescimento (p>0,05), porém a sobrevivência foi maior (p<0,05) nos tratamentos compostos por 3, 4 e 5 dias de alimentação conjunta. Em relação ao tempo de fornecimento de MNA, foram observados piores resultados (p<0,05) quando o tempo de fornecimento do alimento vivo foi menor (5, 10 e 15 dias). Os animais que foram alimentados com MNA antes da transição alimentar, por mais tempo (20 e 25 dias), apresentaram os melhores resultados de crescimento (p<0,05). Portanto, recomenda-se uma transição alimentar de três dias e um fornecimento de MNA por 20 dias para realizar a substituição total do alimento vivo pela ração.

Diferentes estratégias alimentares na larvicultura do acará-bandeira (Peterolophyllum scalare,Cichlidae) / Different feeding strategies on larval rearing of angelfish (Peterolophyllum scalare, Cichlidae)

The hatchery is one of the most critical stages of the development of fish and their success is directly related to food handling that can provide greater survival and growth. The aim of this study was to evaluate the time of dietary transition and providing meta-nauplii of Artemia spp. (MNA) for the angelfish larvae. Two experiments were conducted in a completely randomized design with five treatments and four repetitions. On each experiment there were used 540 fishes, distributed in 20 tanks with 2 liters each. In the first experiment, there were evaluated the dietary transition periods (MNA + Diet) for 1, 2, 3, 4 and 5 days. In the second experiment, there were evaluated the supply of MNA for 5, 10, 15, 20 and 25 days. There were evaluated: weight gain, growth rate and specific development, survival and batch uniformity (only in the experiment to evaluate the time of fish feed with MNA). There was no significant effect of different periods of dietary transition on the growth variables (p>0.05), but survival was higher (p<0.05) in the treatments composed of 3, 4 and 5 days of joint feed. In relation to the time of supply of MNA worse results were observed (p<0.05) when the time of supply of live food was shorter (5, 10 and 15 days). The animals were fed with MNA before feeding transition, for longer time (20 and 25) showed the best results for growth (p<0.05). Therefore, a food transition of three days and a supply of MNA for 20 days is recommended to perform the total replacement of live food for feed.(AU)

A larvicultura é uma das etapas mais críticas do desenvolvimento dos peixes e o seu sucesso está diretamente relacionado ao manejo alimentar, que pode proporcionar maiores sobrevivência e crescimento. Objetivou-se avaliar o tempo de transição alimentar e de fornecimento de meta-náuplios de Artemia spp (MNA) na larvicultura do acará-bandeira. Dois experimentos foram conduzidos em delineamento inteiramente casualizado com cinco tratamentos e quatro repetições. Em cada experimento foram utilizados 540 peixes distribuídos em 20 aquários com 2 L. No primeiro experimento, avaliaram-se os períodos de transição alimentar (MNA + ração) por 1, 2, 3, 4 e 5 dias. No segundo experimento, avaliou-se o período de fornecimento de MNA por 5, 10, 15, 20 e 25 dias. Foram avaliados: ganho de peso, taxas de crescimento e desenvolvimento específico, sobrevivência e uniformidade do lote (apenas no experimento para avaliar o tempo de fornecimento de MNA). Não houve efeito significativo dos diferentes períodos de transição alimentar sobre as variáveis de crescimento (p>0,05), porém a sobrevivência foi maior (p<0,05) nos tratamentos compostos por 3, 4 e 5 dias de alimentação conjunta. Em relação ao tempo de fornecimento de MNA, foram observados piores resultados (p<0,05) quando o tempo de fornecimento do alimento vivo foi menor (5, 10 e 15 dias). Os animais que foram alimentados com MNA antes da transição alimentar, por mais tempo (20 e 25 dias), apresentaram os melhores resultados de crescimento (p<0,05). Portanto, recomenda-se uma transição alimentar de três dias e um fornecimento de MNA por 20 dias para realizar a substituição total do alimento vivo pela ração.(AU)

A comparison of abundance estimators for small mammal populations

A major difficulty in the application of probabilistic models to estimations of mammal abundance is obtaining a data set that meets all of the assumptions of the model. In this paper, we evaluated the concordance correlation among three population size estimators, the minimum number alive (MNA), jackknife and the model suggested by the selection algorithm in CAPTURE (the best-fit model), using long-term data on three Brazilian small mammal species obtained from three different studies. The concordance correlation coefficients between the abundance estimates indicated that the probabilistic and enumeration estimators were highly correlated, giving concordant population estimates, except for one species in one of the studies. The results indicate the adequacy of using enumeration estimates as indexes for population size when scarce data do not allow for the use of probabilistic methods. Differences observed in the behavior of enumeration and probabilistic methods among species and studies can be related to the exclusive sampling design of each area, species-specific movement characteristics and whether a significant portion of the population could be sampled.

A comparison of abundance estimators for small mammal populations

A major difficulty in the application of probabilistic models to estimations of mammal abundance is obtaining a data set that meets all of the assumptions of the model. In this paper, we evaluated the concordance correlation among three population size estimators, the minimum number alive (MNA), jackknife and the model suggested by the selection algorithm in CAPTURE (the best-fit model), using long-term data on three Brazilian small mammal species obtained from three different studies. The concordance correlation coefficients between the abundance estimates indicated that the probabilistic and enumeration estimators were highly correlated, giving concordant population estimates, except for one species in one of the studies. The results indicate the adequacy of using enumeration estimates as indexes for population size when scarce data do not allow for the use of probabilistic methods. Differences observed in the behavior of enumeration and probabilistic methods among species and studies can be related to the exclusive sampling design of each area, species-specific movement characteristics and whether a significant portion of the population could be sampled.

A comparison of abundance estimators for small mammal populations

A major difficulty in the application of probabilistic models to estimations of mammal abundance is obtaining a data set that meets all of the assumptions of the model. In this paper, we evaluated the concordance correlation among three population size estimators, the minimum number alive (MNA), jackknife and the model suggested by the selection algorithm in CAPTURE (the best-fit model), using long-term data on three Brazilian small mammal species obtained from three different studies. The concordance correlation coefficients between the abundance estimates indicated that the probabilistic and enumeration estimators were highly correlated, giving concordant population estimates, except for one species in one of the studies. The results indicate the adequacy of using enumeration estimates as indexes for population size when scarce data do not allow for the use of probabilistic methods. Differences observed in the behavior of enumeration and probabilistic methods among species and studies can be related to the exclusive sampling design of each area, species-specific movement characteristics and whether a significant portion of the population could be sampled.(AU)