The level of gonadal development of a species can be evaluated by the determination of the gonadossomatic (GSI) and the hepatossomatic (HSP) indices. The hepatopancreas is the most important centre for storage of reserves in decapods, which can be transferred to the gonads during their development. The aim of this study was to estimate gonadal development of Parastacus varicosus Faxon, 1898 by means of macro and microscopic observations, as well by the inspection of the variations of gonadossomatic and hepatossomatic indices. The crayfishes were collected in the Gravataí hydrographic basin, Cova do Touro locality, State of Rio Grande do Sul, Brazil. Female's gonads were weighted for the recognition of the gonadossomatic index and histological analysis. Hepatopancreas weight was also obtained to determine the hepatossomatic index. The results showed a decrease of the hepatossomatic index and an increase of the gonadossomatic index in females during the seasonal transition period from spring to summer, suggesting a possible transfer of the hepatopancreatic reserves to the gonads during the reproductive period. However, considering that this decrease did not show significance at p>0.05 level, it is likely that other tissues contribute for this transfer, as hemolymph, for instance.
Crayfish; gonadossomatic index; maturation
