EFFECT OF THE FISHING GEARS ON THE SIZE OF THE FISHES IN AN ESTUARINE SMALL-SCALE FISHERY OF THE COLOMBIAN CARIBBEAN

Abstract

As fundamental support for designing a management system for the fishery in the Ciénaga Grande de Santa Marta and Pajarales Complex (CGSM-PC), the effect of the most used fishing gears on the main five fish species was addressed. The fishes studied were: mapalé sea catfish (Cathorops mapale), striped mojarra (Eugerres plumieri), New Granada sea catfish (Ariopsis sp.), parassi mullet (Mugil incilis), and Nile tilapia (Oreochromis niloticus). Length frequency data for each species were available during 1994-1996 and 2000-2004 to the following gears: cast-nets, encircling gillnets, beach seines, longlines, and gill nets. In order to evaluate the gears’ effect, the mean fish size (MCS) was compared to the size at maturity (MMS) of each species, considered here as limit reference point (LRP). The MCS for each species changed through the years, between landing sites and gears. The five fish species showed an individual size reduction trend. The results indicate that M. incilis, C. mapale, and Ariopsis sp. are at high risk of overfishing, since in all cases their MCS surpass their MMS. Concerning E. plumieri, although its MCS slightly exceeded the MMS, it is not exempted of the jeopardy of overexploitation. Oreochromis niloticus was the only one species without any overfishing hazard. How technological changes affect fish resources is discussed, whereas some management measures for this fishery are proposed.