Research Paper

Mollusc fisheries and length–weight relationship in Tonle Sap flood pulse system, Cambodia

¹ Fisheries Administration, No. 186, Preah Norodom Blvd., Khan Chamcar Morn, PO Box 582, Phnom Penh, Cambodia
² CNRS, Université Toulouse III Paul Sabatier, ENFA, UMR5174 EDB (Laboratoire Évolution and Diversité Biologique), 118 route de Narbonne, 31062 Toulouse, France
³ Relations and Cooperation Office - Chea Sim University of Kamchaymear, No. 157, Preah Norodom Blvd, Khan Chamkarmon, Phnom Penh, Cambodia
⁴ Mekong River Commission, Vientiane, Lao PDR
⁵ Department of Biology, University of Nevada, 1664 N. Virginia Street, Reno, NV 89557, USA

^* Corresponding author: pengbun.ngor@gmail.com

Received: 13 May 2018
Accepted: 20 September 2018

Abstract

Molluscs are important for ecological function, livelihoods and fisheries, but are often forgotten in research and management. Here, we investigated intra-annual variation in the landing and growth patterns of three mollusc species, i.e., Corbicula moreletiana, Pila virescens and Pila ampullacea, using one-year daily data on landing catches and values, recorded in Kampong Chhnang province of Tonle Sap (TS) Lake. Overall, 8330 tonnes with a first sale landing value of US$ 1.4 million for the three species were reported. Also, we found that C. moreletiana was abundant during the dry season with high temperature and less precipitation. By contrast, the two Pila species were abundant from the early rainy to early dry seasons when precipitation and water levels increase. The length–weight relationship analysis indicated that a faster growth in weight of Pila species occurred in the rainy season, and a general negative allometric growth was observed for the three species. This implies that their populations were intensively fished. Our preliminary results suggest that molluscs in the TS Lake (i) are important resources in support of people's livelihoods, (ii) respond differently to intra-annual variation in temperature, precipitation and hydrology and (iii) are being intensively exploited with significant reduction in growth rate. Therefore, it is necessary to conduct further comprehensive research describing status of mollusc stocks and their ecology to support long-term management and conservation of this important aquatic fauna. Our study contributes to establishing the first important baseline data and information on key mollusc species for the TS.