~ 500 ~ International Journal of Fisheries and Aquatic Studies 2016; 4(3): 500-506 ISSN: 2347-5129 (ICV-Poland) Impact Value: 5.62 (GIF) Impact Factor: 0.352 IJFAS 2016; 4(3): 500-506 © 2016 IJFAS www.fisheriesjournal.com Received: 11-03-2016 Accepted: 12-04-2016 Aeron D Mayor School of Environmental Science and Management, University of the Philippines Los Baños, College, Los Baños, Laguna, Philippines 4031 Rico Ancog School of Environmental Science and Management, University of the Philippines Los Baños, College, Los Baños, Laguna, Philippines 4031 Correspondence Aeron D Mayor School of Environmental Science and Management, University of the Philippines Los Baños, College, Los Baños, Laguna, Philippines 4031 Fishery status of freshwater clam (Batissa violacea, Corbiculidae) (Bivalvia) (Lamarck, 1818) in Cagayan River, Northern Philippines Aeron D Mayor and Rico Ancog 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. Keywords: Batissa violacea; freshwater clam; Cagayan River; fishery status 1. Introduction The freshwater clam (Batissa violacea, Corbiculidae) (Lamarck, 1818), is a non-marine edible mollusk indigenous of Cagayan River, the largest river in the Philippines, reported to also occur across the western Pacific including Malaysia, Indonesia, Northwestern Australia, Fiji, and Papua New Guinea [16, 19, 20, 26, 27] . The clam can be found in sandy or muddy beds of freshwater and brackishwater rivers and mangrove swamps [9, 24] . This indigenous freshwater clam B. violacea is ecologically important and has socio-economic and cultural values [2, 16, 17] just like other mollusks [11] . However, the bivalve is currently categorized as endangered or threatened species in Cagayan River by the Bureau of Fisheries and Aquatic Resources (BFAR) Region 02 [19] because wild stocks in Cagayan River have dwindled in 2000 and continuously declined in 2012 due to over-harvesting [15] . The highest B. violacea production of 75.00 MT was in 2003 and declined continuously up to 21.95 MT in 2012 [6] . Hence, It has seen that continuous uncontrolled and regular harvesting of the resource may lead to resource extinction similar to several economically important bivalve species population in the Philippines such as Anadara, Modiolus, Crassostrea, Placuna, Phacoides, Periglypta, Tapes, Mactra and Haliotis [18] , Strombus [10] and Paphia textilis [1, 14] . Hence, this study analyzed the status of the fishery of B. violacea in selected communities in terms of catch per unit effort and perception of collectors on abundance of the clam. This will serve as a basis in the development of conservation and management plan of the resource in order to prevent its extinction. 2. Materials and Methods 2.1 Study Area The Cagayan River is the longest and largest river in the Philippines located in the Cagayan Valley region in northeastern part of Luzon Island and traverses the provinces of Nueva Vizcaya, Quirino, Isabela and Cagayan [25] . With an estimated length of 505 kilometers, the river's headwaters are at the Caraballo Mountains of the Central Luzon at an elevation of approximately 1,524 meters and flows north to the Babuyan Channel near the town of Aparri, Cagayan dropping rapidly to 91 meters at the river mouth. Its principal tributaries are the Chico, Siffu, Mallig, Magat and Ilagan Rivers (Figure 1).