Revista de Biología Tropical (Jun 2013)
Composición, abundancia y distribución de las poblaciones de gasterópodos de importancia comercial en La Guajira, Caribe colombiano Composition, abundance and distribution of populations of commercially important gastropods in La Guajira, Colombian Caribbean
Abstract
En el Caribe continental colombiano el aprovechamiento del recurso caracol y el estado de sus poblaciones han sido poco estudiados, esto se refleja en la carencia de un ordenamiento pesquero. Se evaluó la composición, densidad poblacional y distribución de las especies que conforman ese recurso en La Guajira. Se realizaron censos visuales entre septiembre y noviembre 2009 en 145 transectos de 100x4m (400m²), abarcando un área de 56 920m² entre Riohacha y el Cabo de la Vela. También se evaluó la composición, abundancia y talla de conchas de gasterópodos en depósitos de conchas vacías en 13 playas. En octubre 2010 se evaluaron 40 transectos más (16 000m²), desde el sur de Riohacha hasta Camarones. Se encontraron 9 911 caracoles de 12 especies, siendo Strombus pugilis el más abundante con 8 912 individuos y densidad de 1 538.4±3 662.6 ind./ha, seguido por Vasum muricatum con 374 individuos y densidad de 51.8±91.2 ind./ha. El índice de valor de importancia (IVI) de caracoles vivos y de conchas en las playas, muestran a Turbinella angulata como la especie más aprovechada por pescadores artesanales. Los resultados denotan la urgencia de realizar planes de manejo pesquero para este recurso en la región.In the continental Colombian Caribbean the conch resource exploitation and the status of snails populations has been poorly studied, which are reflected in the lack of fisheries management. This study assesses composition, population density and distribution of the gastropods species that make conch resource in La Guajira region. Underwater visual censuses for snails were performed between September-November 2009 in 145 100x4m (400m²) transects, spanning a total area of 56 920m² between Riohacha and Cabo de la Vela. The study was complemented with the evaluation of composition, abundance and size of gastropods conch found in the discarded-by-fishermen shell mounds in 13 beaches. In October 2010 another 40 transects were evaluated (16 000m²) from the Southern of Riohacha to the Camarones village (La Guajira). We found a total of 9 911 snails belonging to 12 species, the most abundant being Strombus pugilis with 8 912 individuals and an average density of 1 538.4±3 662.6 ind./ha , followed by Vasum muricatum with 374 individuals and an average density of 51.8±91.2 ind./ha. Calculating the importance value index (IVI) for both living organisms as the empty shells on beaches, shows that Turbinella angulata is the most used species by artisanal fishermen in the region. Cassis madagascariensis and Cassis tuberosa are also important snail resources in the region (as suggested by the number of empty shells found in beaches), but its densities were low. Strombus gigas, with only three living organisms found in the area, presented the lowest abundance ever found in the Colombian Caribbean (0.52±3.6 ind./ha), showing that queen conch population in La Guajira can- not support commercial exploitation. The abundance of discarded S. gigas shells on beaches suggests resource exploitation in the recent past. Results remarks the urgency of implementing management plans for snail fisheries in the region.
