Desenvolvimento gonadal do jundiá, Rhamdia quelen (Teleostei, Siluriformes), em viveiros de terra, na região sul do Brasil

Abstract

The study characterized the gonadal development of jundiá from approximately 8 g until gonadal maturation, to provide further knowledge for farming jundiá in Southern Brazil. Jundiá fingerlings (average weight 8.00 ± 3.73 g) were stocked in three ponds at 0.6 fish m-2. Fourteen fish were sampled each month from September 2001 to October 2002. Gonadal maturation stages were characterized macroscopically, and samples of ovaries and testicles were fixed in 4-%-buffered formalin for histological examination. One hundred and eighteen fish were analyzed: 60 males e 58 females. Jundiá males matured earlier than females. Testicles and ovaries presented similar morphology to other Siluriformes species. Gonads were classified in four development phases of the ovarian follicle, according to histology: immature, initial maturation, final maturation and mature. The gonadosomatic index varied from 0.29 to 9.16 for males and from 0.11 to 13.03 for females. Mature individuals were observed during summer (December/2001 and January/2002), fall (April and May/2002) and spring (September and October/2002), following the increase in water temperature.