Improving artisanal fisheries through community-based prawn stock enhancement in a mangrove estuary

Abstract

Tropical seafood, especially prawns, have always been in high demand with high market prices. Because of this, wild prawn resources are often overfished as indicated by the increasing number of fishers, but with overall declining catch volume and sizes through the years. Prawn aquaculture has, as of course, significantly contributed to the total yield in the past decades. However, the expansion of farms and ponds has often negatively affected the natural nursery grounds in the estuaries and mangroves. The economic gains from aquaculture are limited only to those who invested. However, local communities and artisanal fishers are often deprived of such gains. They are still reliant upon the dwindling natural stocks of fisheries resources. This is where the concept of stock enhancement comes in, wherein hatchery-produced juveniles are released into the water body in order to increase capture fisheries yield for local fishers. In this talk, I will present the case of the tiger prawn Penaeus monodon stock enhancement in the New Washington Estuary (NWE), in Aklan, central Philippines. The NWE was a productive fishing ground providing >24 kg/gear/day of catch in the 1970s but steadily declined to <0.7 kg/gear/day in 2010s. Prawn catches declined both in quality and quantity. Meanwhile, mangrove cover was reduced from 4800 ha in 1950s to only <800 ha in 2010s. Site-specific studies were conducted in NWE on prawn nursery rearing, small-scale release and monitoring experiments, as well as social assessments. Our studies produced essential scientific data to guide future stock enhancement activities in NWE. Even at an experimental scale, our releases showed significant increases in catch by at least 8% but can potentially increase daily income by >400%. However, in order to sustain the prawn fisheries and optimize the benefits, long-term management plans by all stakeholders are needed, especially between the communities and the local government.