(Population structure of Pimelodus maculatus Lacépí­¨de, 1803 (Osteichthyes, Pimelodidae) in Bariri Reservoir, Tietê River, State of São Paulo.)

Abstract

Aspects of the population structure of the mandiuva Pimelodus maculatus Lacépí­¨de, 1803 in the Bariri reservoir located on the middle Tietê River, State of São Paulo, was studied based on 1425 specimens collected between January 1980 and December 1982. During the period under consideration there occurred a slight predominance of males (52.4%). On the other hand, females tended to be larger (total length) than males, and predominant in the upper size classes. Total length at first maturation (pm) of females was 12.0 cm and of males was 12.5 cm. At a total length of approximated 15.5 cm all individual of both sexes are able to participate in reproductive activity ( 100%).