Reproductive Output of Uca Vocator (Herbst, 1804) (Brachyura, Ocypodidae) from Three Subtropical Mangroves in Brazil

Abstract

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.

Decapod crustaceans from a marine tropical mangrove ecosystem on the Southern Western Atlantic, Brazil

“…In addition, U. (L.) leptodactyla prefers high salinities (Crane, 1975;Barnwell, 1986;Thurman, 1998) and muddy sand substrata (Colpo and Negreiros-Fransozo, 2003;Benetti and Negreiros-Fransozo, 2004;Castiglioni and Negreiros-Fransozo, 2004), as observed in the present study, showing that the studied marine mangrove location has ideal characteristics as a habitat for this species. The family Grapsidae was represented by two very frequent but non-abundant species, Pachygrapsus transversus and P. gracilis.…”

Comparison of the population structure of the fiddler crab <i>Uca vocator</i> (Herbst, 1804) from three subtropical mangrove forests

“…The interstitial community from Indaiá and Itamambuca may be more abundant than at Itapanhaú, so the source seems to be greater in those areas. Specific environmental conditions are likely to affect important biological processes in macroinvertebrates, such as growth and reproduction, as described for U. vocator by Colpo and Negreiros-Fransozo (2003). Such environmental constraints are thus reflected in population structure.…”

Sampling technique affects the population structure assessments of fiddler crab Minuca vocator (Herbst, 1804) (Ocypodidae: Gelasiminae)

“…These proportions were compared each month by calculating the z statistic for a paired comparison using the normal approximation of the binomial distribution (Sokal and Rohlf, 1979). We considered as juveniles any crabs with CW smaller than the smallest ovigerous female in each population (Colpo and Negreiros-Fransozo, 2003). The proportion of ovigerous crabs was calculated monthly from the total adult females captured with each sampling procedure.…”