Resumo A aplicação de biotecnologias na reprodução animal tem possibilitado produzir formas jovens em quantidade e qualidade. O aumento da quantidade de gametas viáveis produzidos pelos reprodutores, mediante uma dieta ideal, entre outros fatores, pode garantir uma maior produção. Assim, o objetivo deste trabalho foi determinar o efeito de três dietas quanto à sobrevivência espermática de Macrobrachium acanthurus. Para tanto, 24 machos de M. acanthurus foram utilizados, sendo distribuídos ao acaso e de forma igual entre os tratamentos. As dietas foram compostas por 100% de alimento fresco (músculo de peixe e lula - 14% de proteína), 100% de alimento seco (ração comercial - 50% de proteína) e uma mescla dessas dietas contendo 30% de proteína. Os espermatóforos foram extraídos por eletroestimulação a cada 15 dias, sendo o controle aqueles obtidos diretamente da natureza. Não houve diferença significativa entre as dietas quando comparado os pesos dos camarões e dos espermatóforos. A alimentação 100% fresca proporcionou o melhor desempenho para a sobrevivência espermática.

Abstract The application of biotechnology in animal reproduction has enabled the production of young forms in both quantity and quality. Increasing the number of viable gametes produced by reproducers, among other factors, through an ideal diet, can ensure higher production. Therefore, the aim of this study was to determine the influence of three diets on the sperm survival of Macrobrachium acanthurus. To this end, 24 M. acanthurus males were used, distributed randomly and equally among treatments. Their diets were composed of 100% fresh food (fish and squid muscle - 14% protein), 100% dry feed (commercial feed - 50% protein) and a mixture of these diets containing 30% protein. Spermatophores were extracted through electrical stimulation every 15 days, and the controls consisted of spermatophores obtained directly from nature. No significant difference between diets was observed comparing shrimp and spermatophore weights. The 100% fresh diet provided the best sperm survival performance.

The objective of this work was to get some knowledge about the Guaia stone crab reproduction. The sampling was monthly obtained in the intertidal zone at the Ibicuí Rock Beach. The 638 crabs were collected from August, 1995 to March, 1997. In this total amount 293 were males and 345 (41 ovigerous crabs) were female crabs. Biometrical data informing the total width and length were taken, and gonadal stage was checked macroscopically. The total male width range was between 7.9 to 67.1 mm, while in the female crabs it was between 4.4 to 79.3 mm. The female ones were bigger than the male ones. The ovigerous female crabs were found mainly on Spring and Summer and it probably indicates the reproduction season. The carapace width range of the ovigerous female crabs was about 38.0 and 77.0 mm. The individual fecundity was determined on the number of eggs laid, which were dissociated by means of sodium hipoclorito. The number of eggs laid was about 12,800 and 212,000, according to the female size and the average number of the eggs was 98,800. They were round in shape and their size varied between 0.31 and 0.44 mm. Their average size was 0.37 mm. The five female gonadal stages were determined by the color and the width of the gonads. The estimated mean size of first sexual maturity was 37.8 mm carapace width for female.