Fishery status of freshwater clam (Batissa violacea, Corbiculidae) (Bivalvia) (Lamarck, 1818) in Cagayan River, Northern Philippines

Abstract

This study presents an analysis on the fishery status of edible mollusk Batissa violacea collected from Cagayan River, the largest river in the Philippines. The Philippine government recently categorized B. violacea as a threatened species due to its dwindling stocks from 2000 to 2012. Several concerns have been raised on the ongoing uncontrolled harvesting of the bivalve which could likely lead to extinction of the resource. The mean catch per unit effort (CPUE) of the bivalve was 2.04 kg/hr/boat with volume of catch ranging from 3.40-24.77 kg/trip/boat. Majority of the fisherfolk were in agreement that B. violacea harvested starting 2013 were of smaller sizes as compared to years 2002 and 2007. To institute concrete harvesting regulation, it is recommended that a proportion of mature individuals be left in the river so that natural breeding occurs continuously. The recommended minimum size limit of B. violacea to be collected should not be less than 25-49 mm. These policy regulations must be complemented with enhanced information and education campaigns among the locals to enhance their awareness on the current status of the bivalves and its habitats.