Histological and histochemical features of the oogenesis in the simultaneous protandric hermaphrodite shrimp Exhippolysmata oplophoroides (Decapoda: Caridea).

This study analyzes the dynamics of the vitellogenesis process in the simultaneous protandric hermaphrodite shrimp Exhippolysmata oplophoroides, based on light microscopic observations. The ovotestes of the shrimps at the different gonadal development stages were removed, fixed and submitted an usual histological procedure (HE) and histochemical techniques (Bromophenol Blue, PAS/Alcian Blue, and Von Kossa tests). The germinative cells were classified into oogonias, and oocytes in stages I-IV based on the following features: cell size, cytoplasm appearance, presence of yolk granules, lipid droplets, chorion, and chromatin patterns. In the male initial phase of the gonadal development, the ovotestes present mainly oogonia and oocytes I and II while in the functional hermaphrodite phase, oocytes III and IV predominate in the peripheral zone of the gonads. Oocytes with an atypical appearance of the cellular components indicative of reabsorption were also observed. This study showed an increasing accumulation of proteins, carbohydrates and lipids occurring as the germ cells develop, being the yolk elements deposited in a sequence, in which proteins and carbohydrates are the first to appear both by an endogenous as well as also by an exogenous origin. The presence of calcium was detected mainly in oocytes I, II and inside those in reabsorption, being posteriorly mobilized to chorion constitution and/or to hemolymph due to its role during molting. Although the similarity of the germ cells shape among the crustaceans, this first histochemical characterization of E. oplophoproides ovary increases the comprehension of oogenesis in a caridean simultaneous protandric hermaphrodite species.

Juvenile development of Callinectes danae Smith, 1869 (Crustacea, Decapoda, Brachyura, Portunidae) under laboratory conditions.

The juvenile development of Callinectes danae was investigated from megalopae obtained in neuston samples at Ubatuba, São Paulo, Brazil. The individuals were raised in the laboratory under constant temperature (25 ± 1°C), filtered sea water from the collection location (35‰), and natural photoperiod. Newly hatched Artemia sp. nauplii were offered as food on a daily basis and ornamental-fish food was also provided for the juveniles from the 4th stage on. Twelve stages of the juvenile phase were obtained. The main morphological features that allowed recognition of the first juvenile stage were drawn and described. All the subsequent stages obtained were examined and measured, and the main changes in relation to the first stage were recorded. Sexual dimorphism becomes apparent from the fourth juvenile stage onwards. Some appendages and morphological features proved to be of great importance in the identification of species, including the number of segments of the antennal flagellum and the number of setae on the maxilla and on the 1st, 2nd and 3rd maxillipeds. These can probably be used for future comparisons and species identifications.

Effect of environmental factors on the abundance of decapod crustaceans from soft bottoms off southeastern Brazil.

This study investigated the importance of variations in environmental factors affecting the abundance patterns of decapods on the southeastern Brazilian coast. Sampling was carried out monthly from January 1998 through December 1999 in Ubatumirim and Mar Virado, Ubatuba region, using a commercial shrimp fishing boat equipped with double-rig nets. Six areas adjacent to rocky shores were chosen. Bottom-water samples were collected using a Nansen bottle, to measure the temperature and salinity. Sediment samples were also obtained by means of a Van Veen grab, for determination of texture and organic-matter content. The association of environmental factors with species abundance was evaluated by Canonical Correspondence Analysis (α = 0.05). Forty-one species of Decapoda were used in the multivariate analysis. The analysis indicated that sediment texture (phi) and bottom temperature were the main factors correlated (p < 0.05) with the spatial and temporal abundance of the species. Considering the study region as faunal transition zone, including a mixture of species of both tropical and subantarctic origin, the species responded differently to environmental factors, mainly temperature. It is conceivable that the decapods adjust their distribution according to their intrinsic physiological limitations, possibly as a result of the available resources.