Eels and moray eels are among the species that lack commercial value but that are important as bait. However, little information is available about Colombian fishing by-products. Between 2005 and 2009, field work was done in Gorgona National Natural Park and its surrounding areas, with a fishing line made of traditional "J" and circular or curve hooks. We analyzed the catch composition, comparing both types of hooks, emphasizing whether the circular hook modified or not non-commercial captures. Overall, 189 fishing throws where analyzed, standardizing the Catch Per Effort (CPUE) in number of individuals and in kilograms per 100 hooks per hour of task. A total of 50 species where captured, of which 14 are part of the non-commercial category. There were no significant differences for hook types (U=25228, P>0.1), and Gymnothorax equatorialis and Echiophis brunneus were the most abundant species. Both were concentrated in the northern sector of the study area, a rocky banks sector. The mean sexual maturity size was 57.0cm in G. equatorialis, and at 85.6cm in E. brunneus. Rev. Biol. Trop. 62 (Suppl. 1): 391-405. Epub 2014 February 01.