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Crab fecundity is widely known to vary proportionallyto female size, but the female's nutritional state also has an important effect on egg production. This study evaluates intraspeci c variability of reproductive output by monthly sampling Uca vocator populations from the Itapanhaú, Indaiá, and Itamambuca mangroves on the southeastern coast of Brazil. The presence of ovigerous crabs, their carapace width (CW) and their number of eggs were recorded. Additionally, the productivity of the mangroves and the content of organic matter of the sediments were analysed in order to estimate food availability in each locality. Size-speci c fecundity relationships were obtained for each population and compared among the three populations. Ovigerous females from Itamambuca are the largest and their fecundities are also the highest among the populations studied. These results probably are associated with the favourable environmental conditions in Itamambuca, as this is a young mangrove with a high productivity level. RESUMENLa fecundidad de los cangrejos es muy variable respecto a la talla de la hembra, pero su estado nutricional también puede tener importantes efectos en la producción de huevos. Este estudio estudia la variabilidad intraespecí ca del potencial reproductor de Uca vocator mediante muestreos mensuales de poblaciones provenientes de los manglares de Itapanhaú, Indaiá e Itamambuca, en el litoral sudeste de Brasil. Se registró la presencia de hembras ovígeras, su anchura del caparazón (CW) y número de huevos. Asimismo, se analizó la productividad del manglar y el contenido en materia orgánica de los sedimentos con el n de evaluar la disponibilidad del alimento en cada localidad. La relación talla-fecundidad se obtuvo para cada población, comparándose las tres poblaciones. Las hembras ovígeras de Itamambuca son las que tienen mayor talla y fecundidades más elevadas de las tres poblaciones estudiadas. Estos resultados están probablemente asociados a las buenas condiciones ambientales existentes en Itamambuca, que es un manglar joven de elevada productividad.

The effect of density on growth, sex ratio, survival, and biochemical composition of the red cherry shrimp, Neocaridina davidi Bouvier, 1904, was studied to determine optimum rearing conditions in this ornamental species. It was tested whether gender segregation affected growth and survival of the species. To test the effect of density (Experiment 1), hatched juvenile shrimp were kept at three different densities: 2.5, 5, and 10 individuals l-1 (D 2.5 , D 5 and D 10 , respectively). To test the effect of gender segregation (Experiment 2), 30-day juveniles were reared in three conditions: culture with only females, culture with only males, and mixed culture (females: males 1:1) at 5 individuals l-1 density. Experiments lasted 90 days, and shrimp were weighted either every 30 days (Experiment 1) or 15 days (Experiment 2). At day 90, females kept at D 2.5 weighted 45% more than females stocked at D 10 (P < 0.05), whereas females from D 5 did not differ from those of other densities (P > 0.05). Males at D 2.5 weighted 29% more than D 5 and D 10 (P < 0.05). Survival was high and unaffected by treatment. Sexual differentiation did not differ among treatments. Females from D 2.5 had the lowest lipid and protein content, which would occur if they had a higher spawning. Males from D 2.5 had higher content of proteins, probably due to their larger size. Gender segregation had no effect over growth and survival; females grew up to a larger size than males both in monosex and mixed culture. It was shown that given to their non-aggressive behavior, N. davidi is tolerant to a highdensity condition, which makes it feasible as an ornamental species.

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