GROWTH OF Litopenaeus schmitti (BURKENROAD, 1936) AND Farfantepenaeus paulensis (PEREZ-FARFANTE, 1967) SHRIMP REARED IN RECIRCULATION CULTURE SYSTEM

Os camarões Litopenaeus schmitti e Farfantepenaeus paulensis capturados pela pesca artesanal nos estuários são comercializados como iscas vivas na pesca esportiva. Como alternativa à atividade extrativista foi avaliado o cultivo dessas espécies em sistema de recirculação de água. Para cada espécie foram realizados dois ciclos de produção de 120 dias, utilizando 3300 juvenis em cada um, com média de 25 mm de comprimento e 0.9 gramas em peso, dispostos em 12 tanques de 1500L e 1.32 m2, na densidade de 208.3 camarões m2. Os parâmetros de crescimento foram obtidos utilizando-se o modelo de von Bertalanffy baseado nos dados de comprimento (mm) e idade (semanas). Os ajustes foram feitos no ambiente R utilizando o método não-linear de mínimos quadrados. O modelo de von Bertalanffy apresentou ajuste adequado, com coeficientes de determinação de 0.900 para L. schmitti e 0.841 para F. paulensis. Os valores de L∞ e k foram 172.66 mm e 0.027 para L. schmitti e 110.13 mm e 0.050 para F. Paulensis, respectivamente. No presente estudo L. schmitti apresentou crescimento alométrico negativo (p=4.314x10-18) e F. paulensis crescimento isométrico (p=0.267). O crescimento obtido dos camarões no sistema de recirculação proposto atende ao mercado de iscas vivas da pesca esportiva.The Litopenaeus schmitti and Farfantepenaeus paulensis shrimp captured in estuaries are marketed as live bait for recreational fishing. As an alternative to shrimp extractive activities, the authors evaluated the rearing of these species in a recirculation culture system. For each species, the grow-out study was carried out in two 120-day production cycles, using 3,300 juveniles of an average length of 25 mm and weight of 0.9 grams in each, distributed in 12 tanks of 1,500 liters and 1.32 m2, at a population density of 208.3 shrimp per m2. The growth parameters were obtained using the von Bertalanffy model based on the length (mm) and age (weeks) data. The adjustments were made in the R environment of the non-linear least-square method. The von Bertalanffy growth model showed a proper fit, with determination coefficients of 0.900 for L. schmitti and 0.841 for F. paulensis. The values of L∞ and k were 172.66 and 0.027 mm for L. schmitti and 110.13 mm and 0.050 for F. paulensis, respectively. In the current study, L. schmitti showed negative allometric growth (p=4,314x10-18) and F. paulensis isometric growth (p=0.267). The growth of shrimp obtained in the proposed recirculation system can supply live bait for the sport fishing market

GROWTH OF Litopenaeus schmitti (BURKENROAD, 1936) AND Farfantepenaeus paulensis (PEREZ-FARFANTE, 1967) SHRIMP REARED IN RECIRCULATION CULTURE SYSTEM

The Litopenaeus schmitti and Farfantepenaeus paulensis shrimp captured in estuaries are marketed as live bait for recreational fishing. As an alternative to shrimp extractive activities, the authors evaluated the rearing of these species in a recirculation culture system. For each species, the grow-out study was carried out in two 120-day production cycles, using 3,300 juveniles of an average length of 25 mm and weight of 0.9 grams in each, distributed in 12 tanks of 1,500 liters and 1.32 m2, at a population density of 208.3 shrimp per m2. The growth parameters were obtained using the von Bertalanffy model based on the length (mm) and age (weeks) data. The adjustments were made in the R environment of the non-linear least-square method. The von Bertalanffy growth model showed a proper fit, with determination coefficients of 0.900 for L. schmitti and 0.841 for F. paulensis. The values of L∞ and k were 172.66 and 0.027 mm for L. schmitti and 110.13 mm and 0.050 for F. paulensis, respectively. In the current study, L. schmitti showed negative allometric growth (p=4,314x10-18) and F. paulensis isometric growth (p=0.267). The growth of shrimp obtained in the proposed recirculation system can supply live bait for the sport fishing market

GROWTH OF Litopenaeus schmitti (BURKENROAD, 1936) AND Farfantepenaeus paulensis (PEREZ-FARFANTE, 1967) SHRIMP REARED IN RECIRCULATION CULTURE SYSTEM

The Litopenaeus schmitti and Farfantepenaeus paulensis shrimp captured in estuaries are marketed as live bait for recreational fishing. As an alternative to shrimp extractive activities, the authors evaluated the rearing of these species in a recirculation culture system. For each species, the grow-out study was carried out in two 120-day production cycles, using 3,300 juveniles of an average length of 25 mm and weight of 0.9 grams in each, distributed in 12 tanks of 1,500 liters and 1.32 m2, at a population density of 208.3 shrimp per m2. The growth parameters were obtained using the von Bertalanffy model based on the length (mm) and age (weeks) data. The adjustments were made in the R environment of the non-linear least-square method. The von Bertalanffy growth model showed a proper fit, with determination coefficients of 0.900 for L. schmitti and 0.841 for F. paulensis. The values of L∞ and k were 172.66 and 0.027 mm for L. schmitti and 110.13 mm and 0.050 for F. paulensis, respectively. In the current study, L. schmitti showed negative allometric growth (p=4,314x10-18) and F. paulensis isometric growth (p=0.267). The growth of shrimp obtained in the proposed recirculation system can supply live bait for the sport fishing market

Maintenance of filtering molluscs in aquaria for sub-chronic studies

This work determined the best survival conditions for the clam Mytella guyanensis and the mussel Perna perna in the estuary and sea aquaria respectively over at least 12 days, which could enable their use in the ecotoxicological studies. The aquaria were set up with the appropriate water and sedimen, and allowed to establish for a minimum of one month before adding the organisms. The best survival conditions for M. guyanensis required more time for the aquarium stabilization, addition of inocula and more frequent water changes than for P. perna. The organisms' lipid contents increased and their condition index was maintained indicating the good conditions of the aquaria, hence, their possible use in the sub-chronic studies.<br>Estudos sobre a dinâmica de contaminação de organismos marinhos devem ser feitos sob condições controladas pelo tempo necessário para que os organismos possam responder à presença do agente contaminante. No entanto, a manutenção de organismos em aquários por determinado período pode ser difícil porque todas as outras variáveis do ambiente precisam ser próximas às condições naturais. Este trabalho determinou as melhores condições de sobrevivência do marisco Mytella guyanensis e do mexilhão Perna perna, respectivamente em aquários de estuário e de mar, por período de até 12 dias. Os aquários foram montados com água e sedimento de estuário ou de mar e estabilizados por, no mínimo, um mês antes da colocação dos respectivos organismos. As melhores condições de sobrevivência de M. guyanensis requisitaram mais tempo de estabilização do aquário, adição de inóculos e trocas de água mais freqüentes do que para os P. perna. Os conteúdos de lipídios aumentaram com o tempo e o índice de condição dos organismos foi mantido, indicando as boas condições dos aquários e, conseqüentemente, a possibilidade de uso em pesquisas ecotoxicológicas