Description and analysis of the white shrimp (Litopenaeus schmitti) fisheries in Pearl Lagoon, Atlantic Coast of Nicaragua, with focus on the gear selectivity in the artesanal fleets

摘要

Fishing continues to be the main source of income in the Pearl Lagoon Basin inNicaragua. Currently the fishermen in the area have expressed growing concern about theshrimps stocks. Over the past years it has become increasingly clear that the fish andshrimp stocks are being exhausted, severely over-fished and experiencing a seriousdecline.This thesis examines the catch compositions (shrimps and by-catch) of three mesh sizesof the Cast net gear employed in the fishery through sampling during the months of Julyand August, as well as analyzes the current situation of the shrimp inside the lagoonthrough primary (interviews) and secondary (books, journals, articles, reports, etc.) data.The data samples of the experiment with the different mesh sizes identified in the thesiswere analyzed using standard software applying a trouser trawl method to determine theselectivity curve. Single factor ANOVA testswere use to distinguish significant differences between lengths. Significant differenceswere also tested combining the three different mesh sizes applying the SPSS turkey multicomparison computer program model. The findings were discussed and compared with aprevious selectivity study accomplished in the lagoon.The thesis concludes that gears with ½ inch mesh size were vulnerable to the speciesduring these months by retaining low weight and smaller length shrimp compositions(70% of the capture is between 5 and 8 cm total length). 1 inch and 1½ inch mesh sizesshowed a general improvement in the selective performance of the gear (approximately90% of the captured shrimps were between 11 and 14 cm).The main secondary findings show that local people are employing small gear mesh sizesin the lagoon, especially those whose sustainability livelihoods are significantlythreatened with very few opportunities of survival; most obvious those who live in themore remote areas.