RESUMO
The queen conch fishery in Jamaica is sustained by Pedro Bank, which is the main harvesting site located approximately 80 km south-west from Kingston. Due to its relative size, Pedro Bank has been subdivided into zones for management purposes by the Fisheries Division and the Veterinary Services Division. Understanding whether these sub-divisions reflect different sub-populations is critical for managing exploitation levels because fisheries management must demonstrate that harvesting does not endanger the future viability of the population as queen conch are on Appendix II of the Convention in Trade in Endangered Species of Wild Fauna and Flora (CITES). This determination is essential for the continued export to international markets such as the European Union. Two hundred and eight samples were collected across the entire Pedro Bank and were genetically characterized using nine polymorphic microsatellite loci. Population structure analysis for Lobatus gigas from Pedro Bank yielded low but significant values (FST = 0.009: p = 0.006) and suggested a high magnitude of gene flow indicative of a fit and viable population throughout the bank. Analysis of molecular variance (AMOVA) indicated a 100% variation within individual samples with little variation (0.9%) between populations. In contrast pairwise genetic comparisons identified significant differences between populations located to the south eastern and eastern region of the bank to those in the central and western locations. Bayesian clustering analysis also indicated the likelihood of two population sub-divisions (K = 2) on Pedro Bank. The results provided evidence of a weak but significant population structure which has crucial implications for the fishing industry as it suggests the use of ecosystem based management (EBM) in setting quotas to promote sustainable harvesting of L. gigas within each monitoring zone on Pedro Bank.
Assuntos
Gastrópodes/genética , Animais , Espécies em Perigo de Extinção , Pesqueiros , Fluxo Gênico , Variação Genética , Jamaica , Repetições de Microssatélites , Polimorfismo GenéticoRESUMO
Spearfishing was becoming an increasingly important economic activity in the Caribbean as a result of socioeconomic factors related to underemployment and the low capital outlay for equipment. For a year (2011) we surveyed spearfishing in 23 Jamaican beaches. Spearfishing has expanded from approximately 1% of fishers in 1991 to about 10% in 2011. The fishery is larger than expected and probably produced 4 000tons per year. Though reef fishes dominated catches, other resources such as lobsters, conch and octopus were regularly taken. Many small juvenile fishes were observed in catches well below their adult or optimum sizes. A total of 58% of spear-fishers reported they would have significant difficulty finding alternative employment if spearfishing was banned. Spearfishers reported exploiting the entire island shelf and also nearly all the offshore banks, especially Pedro Bank. Night spearfishing was common and targeted sleeping reef fishes. The activity is banned and should be enforced. Our recommendations include: register all spearfishers, actively manage spearfishing, a partial ban for part of the year and a ban on using scuba and hookah gear for spearfishing.
Un estudio de la pesca submarina en Jamaica durante el 2011 reveló una pesquería mayor que la esperada, que produce aproximadamente 4 000 toneladas por año de todos los tipos de recursos pesqueros. Este nivel de producción esta por encima de lo que se pensaba era una actividad pesquera de pequeña escala. Esta pesquería especializada se ha ampliado aproximadamente en 1% de pescadores a al menos el 10%, en un periodo de 20 años (1991 a 2011). Aunque los peces de coral se dominaran como otros recursos tales como langostas, concha y pulpo. Aunque no era un objetivo del censo se observaron muchos peces juveniles en las capturas con tamaños muy por debajo de su tamaño adulto u óptimo. Un total de 58% pescadores informaron que tendrían dificultad para encontrar otra opción de empleo si la pesca submarina se prohibe. Los pescadores explotan recursos en la plataforma de la isla y también en casi todos los bancos de la costa sobre todo en el Banco de Pedro. Este estudio también muestra que comunmente se práctica la pesca submarina durante la noche con el fin de capturar peces de coral durmiendo. A pesar de que esta actividad es prohibida. Se recomienda que los pescadores se registren y que se regule la actividad. Posibles acciones incluyen considerar la prohibición parcial durante el año o prohibir el uso de equipo de buceo y narguile.