Biología reproductiva de los tiburones de profundidad Aculeola nigra De Buen, 1959, y Centroscyllium nigrum Garman, 1899 (Chondrichthyes: Etmopteridae), centro-norte de Chile

the reproductive biology of the deep-sea sharks aculeola nigra and centroscyllium nigrum, caught as by-catch in the crustacean fishery, is described. a total of 269 specimens of a. nigra and 284 specimens of c. nigrum obtained in central-northern chile between june and december 2006, were examined. their reproductive condition was assessed considering the characterization of the gonads, the gsi and hsi indices and their size at maturity (l 50%). the results showed that the gsi is highest between august and september in a. nigra and between september and november in c. nigrum, which probably indicates their breeding season. the sexual maturity for both species was determined at 38 cm total length (tl) for males and 39 cm tl in females a. nigra and 32 cm tl for males and females of c. nigrum. pregnant a. nigra showed a fecundity of 5 - 17 embryos while c. nigrum had a fecundity of 4 - 15 embryos, with birth sizes of 16.7 cm tl for a. nigra and 15.7 cm tl for c. nigrum. the histological results showed that the testes of both species are diametric and the ovaries external or carcharhinid.