Reproduction of the surubim catfish (Pisces, Pimelodidae) in the Sao Francisco River, Pirapora Region, Minas Gerais, Brazil

The reproductive biology of the surubim, P. coruscans of the Sao Francisco River, in the Pirapora region was studied from December/98 to November/99. Reproduction occurred between October and January with high frequency of fishes in the advanced ripening/mature and spawned/spent stages along with higher values of the gonadosomatic index. Macroscopic and microscopic analyses indicated that P. coruscans presents total spawning. The reproductive period coincided with highest rainfall and water turbidity values in the region. The smallest male captured had a total length of 63.3cm and the smallest female 92.0cm in total length. The largest male in the maturation stage was recorded to be 97.0cm and the largest female 144.1cm in total length. Surubim were more frequently captured than females, at a proportion of approximately one female to three males. The gonadosomatic, hepatosomatic, stomach repletion, and coelomic fat indexes, as well as the condition factor were related to stages of the reproductive cycle.