Efeito do tamanho da presa e do acréscimo de ração na larvicultura de pacamã

Abstract

RESUMO -Objetivou-se estudar o efeito do tamanho da presa, com ou sem adição de ração na larvicultura do pacamã (Lophiosilurus alexandri), espécie nativa da bacia do Rio São Francisco ameaçada de extinção. As larvas foram cultivadas em aquários por 16 dias e alimentadas com zooplâncton natural, selecionado em malhas de 650 e 1.300 μm, com ou sem ração.A oferta de zooplâncton de maior tamanho resultou em melhor desenvolvimento das larvas de pacamã, comprovando a vantagem do fornecimento de partículas alimentares maiores para o potencial de crescimento da espécie. O aumento na quantidade de ração não influenciou o desempenho das larvas, evidenciando a baixa ou falta de capacidade das larvas em digerir a ração ofertada. O fornecimento de ração diminuiu o pH e aumentou a condutividade elétrica, prejudicando a qualidade da água, o que não afetou o desempenho das larvas.Palavras-chave: cultivo de larvas, espécie nativa, extinção, manejo alimentar, repovoamento, sistema intensivo Effect of prey size selection and feeding on the larviculture of pacamãABSTRACT -The effect of prey size selection and feeding on pacamã Lophiosilurus alexandri larvae culture (native specie of San Francisco basin classified as threatened of extinction) was evaluated. The larvae were cultivated in aquariums during 16 days and fed with natural zooplankton, screened in 650 and 1300 μm sieve, with and without ration. The offer of zooplankton of largest size provided a better development of the pacamã larvae, demonstrating the need of alimentary particles larger for the growth potential of the species. The increase of the amount of ration did not affect the performance of the larvae, evidencing low or lack of capacity in digesting the offered ration. The ration fed reduced the pH and increased the electric conductivity, worsening water quality, which did not affect the performance of the larvae.

Larviculture of two neotropical species with different distributions in the water column in light- and dark-colored tanks

“…Water quality parameters (Table 2) were similar to those observed by other authors for the culture of larvae of pacamã (Pedreira et al, 2008a;Pedreira et al, 2009) and curimatá-pioa , and were similar between treatments, not interfering with the observed differences. The luminosity (L*) differed between tanks with different colors, which influenced the development and survival of pacamã and curimatá-pioa larvae alike.…”

“…Larvae of pacamã ate the same amount of prey when subjected to aquaria of different colors and showed differences in growth between those cultivated in green and black tanks. Pedreira et al (2008a) observed differences in the survival rate and growth of pacamã fed the same number of prey. Luz & Zaniboni-Filho (2001), while subjecting fish larvae to different concentrations of food plankton, did not find a significant difference in survival and growth of larvae.…”

Effect of daily Artemia nauplii concentrations during juvenile production of Lophiosilurus alexandri

“…Some researches focusing on the juvenile production using Artemia nauplii has been done with success for this species (LUZ and SANTOS, 2008;PEDREIRA et al, 2008PEDREIRA et al, , 2009SANTOS and LUZ, 2009;LUZ et al, 2011).…”

Allometric larval growth of the bottom-dwelling catfish Lophiosilurus alexandri Steindachner, 1876 (Siluriformes: Pseudopimelodidae)

“…They are likely ready to search and capture for prey, which is corroborated by the much faster yolk sac consumption after 11 mm TL. Moreover, experimental exogenous feeding initiates at this length (Pedreira et al, 2008). The period between the IP of mouth length and the end of the yolk sac could be linked to the development and improvement of suction and prey capture before relying fully on exogenous energy for survival (Hunt von Herbing et al, 1996).…”

“…Ecomorphological and culture experiments have been conducted envisaging the establishment of pacamã larval culture protocols (López & Sampaio, 2000;Pedreira et al, 2008;Guimarães-Cruz et al, 2009;Pedreira et al, 2009;Luz et al, 2011). Recently, Santos et al (2013) published a valuable set of data on reproductive parameter of hormonally induced spawning pacamãs obtained in hatchery conditions.…”