Reproduction of the electric ray Narcine bancroftii en Santa Marta, Caribe Colombiano

This paper provides information about reproductive aspects of the electric ray Narcine bancroftii, caught as bycatch with beach seines in two beaches of El Rodadero, Santa Marta, Colombian Caribbean, between August (2005) and October (2006). The electric rays obtained were separate by sex, weighed and measured; the development of reproductive stage was identified by external and internal characteristics. The reproductive condition was determinate by (gonadosomatic GSI and hepatosomatic HSI) indexes and the size at sexual maturity ([l.sub.50%]). The results showed that the GSI has one peak at year between September and December when probably the copulation carried out, the HSI presented its highest value in January, which corresponds to the end of the reproductive period. The size at sexual maturity was 32.2 cm in females and it was between 20.2 and 22.9 cm in males. We propose that the gestation period extends during four months, starting with the birth of individuals in February and finishing in April. Keywords: electric ray, reproduction, fecundity, maturity, Caribbean sea, Colombia. Se analizaron aspectos reproductivos de la raya electrica Narcine bancroftii, capturada como bycatch con una red playera de cerco en dos playas del sector de El Rodadero, Santa Marta, Caribe colombiano. Los ejemplares fueron sexados, pesados y medidos, se identifico su estado de desarrollo gonadal mediante caracteristicas morfologicas externas e internas. Se evaluo la condicion reproductiva con el comportamiento de los indices biologicos (gonadosomatico IGS y hepatosomatico IHS) y la talla a la madurez sexual ([l.sub.50%]). Los resultados obtenidos mostraron que el IGS tiene un maximo anual entre septiembre y diciembre cuando probablemente ocurre la copula. El IHS presento su mayor valor en enero, cuando termina su periodo reproductivo. La talla media de madurez en hembras fue de 32,2 cm y en machos de 20,2 a 22,9 cm. El periodo de gestacion es de cuatro meses y las crias nacen de febrero a abril. Palabras clave: raya electrica, reproduccion, fecundidad, mar Caribe, Colombia.