Abstract

Almost all Rajiformes are viviparous without placentas, and their embryos are nourished by yolk sacks accompanied in some cases by uterine milk. However, there are few studies of biological aspects of the species in this group in Colombia. This study aimed to analyze some reproductive aspects of Narcine bancroftii (Griffith y Smith, 1834), Diplobatis guamachensis Martin, 1957, and Rhinobatos percellens (Walbaum, 1792), captured as bycatch of the shrimp trawling fishery in two zones (north and south) of the Colombian Caribbean during the second semester of 2004. Samples were caught from the same fleet’s fishing tasks, and corresponded to one-fifth of the homogenized discard, taken randomly from one of the four nets in the ship. Individuals of the three species were brought to the laboratory for further morphometry measurements, taxonomic identification and determination of the maturity state. The maturity state differentiation was based on claspers development and sperm presence for males, and in the size and development of the ovaries, eggs, and embryos for females. Females of N. bancroftii showed immaturity and spawned states, while the males were mature. The individuals of D. guamachensis were represented by maturity females with embryos, and maturity males, whereas those of R. percellens were characterized as maturity females with embryos and spawned states, and maturity males. The presence of uterine milk in individuals of N. bancroftii, and embryos in D. guamachensis were the first known reports in the literature for this country.

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