ALGUNS ASPECTOS DO COMPORTAMENTO BIOLÓGICO DE Rhamdia branneri HASEMAN, 1911. (OSTEICHTHYES, SILURIFORMES, PIMELODIDAE)

Resumo

This study concentrates on the Pimelodidae, Rhamdia branneri Haseman, 1911. The samples were collected in holes on the bank of the Iguaçu River, Curitiba, Paraná, in the following location: 23°38' Lat. S - 49°20' Long. WG. The analysis deals with sex-ratio, frequency distribution, relation total weight/total length, condition coefficient in 550 females and 447 males. The data were collected between March/77 and February/78. Fishing nets of different sizes were used. The fishes were measured and weighted at Zoology Laboratory of the Federal University of Paraná.

In the data collected it was detected predominance of one sex over the other.

In considering the frequency distribution it was observed that the males reaches one size which is near to that of the females.

The relation total weight/total lenght differs significantly between the sexes. It is shown by the following equation:

Females: W_t = 0,0100 x L_t^2,97

Males: W_t = 0,0106 x L_t^2,94

The analysis of the conditional coefficient for both sexes revealed a relation between conditionnal coefficient (K) and the sexual development.