Portal de Periódicos da CAPES

TRAÇOS DE HISTÓRIA DE VIDA DE TRÊS ESPÉCIES DE PEIXES EM RIACHOS DA BACIA DO RIO CORUMBATAÍ-SP

2013; Linguagem: Inglês

2639-6459

Luzia da Silva Lourenço,

Fish Biology and Ecology Studies

The present study has as aim to assess the reproductive traits of the life history and biometrics relationships of the three fish species of the streams, as well as the spatial variation on growth one of the species. The samplings were performed monthly from April 2010 to March 2011 in streams belonging to four sub-basins in the Corumbatai river basin (Cabeca, Corumbatai, Passa Cinco e Ribeirao Claro), located in the south-eastern Brazil. Based on gonadosomatic index, the maturation time of the Geophagus brasiliensis and Astyanax altiparanae varied between seasons (dry and rainy), while for Piabina argentea there was spatial variation (among sub-basins), and temporal. Part of the variation in the gonadosomatic index of the A. altiparanae is related to the alteration in depth, turbidity and precipitation, and for G. brasiliensis in rainfall, conductivity and turbidity. However for P. argentea only oxygen and conductivity explained part of the variation in gonadosomatic index. The length at first maturation showed spatial variation for all species. For the biometrics relationships the estimated of the specific weight using the weight and volume data, was above of the specific weight of the water 1.00 g/cm for G. brasiliensis and A. altiparanae, therefore for P. argentea was below. The weight and volume increase similar in function of length. Thus the dispersion of the points of the volume and length and weight and length relationship is very close. The results about the somatic growth of the G. brasiliensis give evidence that the growth is a trait of the life history which can vary even when a small spatial scale is used. Models with individuals nested in sites and with individuals nested in sites and sub-basins fitted better the length-at-age data than the model with individual level. Therefore in growth analysis is important take in account the space and hierarchical design of the aquatic system, because growth trajectories can be generated with more robustness. Key-words: Growth, reproduction, spatial variation, temporal variation, biometrics relationships.