Spawning and hatching performance of the silvery black porgy Sparidentex hasta under hypersaline conditions

Abu Al Abyad island is characterized by harsh environmental conditions. A preliminary trial conducted at the island to investigate the spawning and hatching performance of the blue finned sea bream Sparidentex hasta indicated that the fish can be successfully bred at high salinity levels exceeding 50 ppt

Spawning and hatching performance of the silvery black porgy Sparidentex hasta under hypersaline conditions

Abu Al Abyad island is characterized by harsh environmental conditions. A preliminary trial conducted at the island to investigate the spawning and hatching performance of the blue finned sea bream Sparidentex hasta indicated that the fish can be successfully bred at high salinity levels exceeding 50 ppt.Salinity tolerance, Spawning, Hatching, United Arab Emirates, Sparidentex hasta

Efeito da densidade de estocagem no desempenho de rã-touro (Rana catesbeiana) em recria Effects of stocking density on performance of bullfrog (Rana catesbeiana) in the post-metamorphic phase

Este trabalho foi realizado com o objetivo de avaliar quatro densidades de estocagem na recria de rã-touro em mini-baias. As densidades estudadas foram: D1: 75 rãs/m&sup2; (inicial) e 35 rãs/m&sup2; (final); D2: 105 rãs/m&sup2; (inicial) e 50 rãs/m&sup2; (final); D3: 125 rãs/m&sup2; (inicial) e 60 rãs/m&sup2; (final); e D4: 160 rãs/m&sup2; (inicial) e 75 rãs/m&sup2; (final). No ensaio de desempenho, foram utilizadas 558 rãs com peso médio de 26,80 g durante 56 dias, distribuídas em um delineamento em blocos casualizados, com seis repetições. Houve efeito das densidades sobre o ganho de peso, que foram inversamente proporcionais. Menores densidades resultaram em maior consumo de alimento, de modo que, com o uso das densidades iniciais de 75 e 105 rãs/m&sup2;, obteve-se maior consumo de alimento que o uso de 125 e 160 rãs/m&sup2;. A conversão alimentar aparente também variou; a densidade inicial de 160 rãs/m&sup2; proporcionou a pior média desse parâmetro. Os tratamentos foram avaliados economicamente, segundo os custos com alimentação, a receita bruta e a receita líquida parcial proporcionados. Concluiu-se que a densidade final de 50 rãs/m&sup2; aumentou a receita líquida parcial, proporcionando resultados mais adequados para produção de rãs.<br>This work was carried out with the objective of evaluate four stocking densities of bullfrog (post-metamorphic) in mini-stalls. The densities studied were D1: 75 bullfrogs/m&sup2; (initial) and 35 bullfrogs/m&sup2; (finishing); D2: 105 bullfrogs/m&sup2; (initial) and 50 bullfrogs/m&sup2; (finishing); D3: 125 bullfrogs/m&sup2; (initial) and 60 bullfrogs/m&sup2; (finishing); and D4: 160 bullfrogs/m&sup2; (initial) and 75 bullfrogs/m&sup2; (finishing). The performance trial was carried out with 558 bullfrogs averaging initial weight of 26.80 g, during 56 days, according to a completely randomized blocks design with six replicates. Inversely proportional effects of densities on weight gain were observed. Smaller densities resulted in greater values of feed intake, and the initial densities of 75 and 105 bullfrogs/m&sup2; resulted in higher values of feed intake than 125 and 160 bullfrogs/m&sup2;. The apparent feed conversion also varied , showing the worst average on initial density of 160 bullfrogs/m&sup2;. Economic analysis was performed with the costs with feeding, gross income and partial net income. It was concluded that the final density of 50 bullfrogs/m&sup2; increased the partial net income and was indicated for production of bullfrogs