Integrated Assessment of Neritic Tuna Resources in Southeast Asia: stock status, population genetics, age estimation, and reproductive patterns

Abstract

The high demand for tuna and tuna-like species, both domestically and internationally, drives economic activity from catch to market, processing, and export. However, escalated fishing pressure on these species can lead to overfishing and depletion, threatening ecosystems and the economic stability of fishing communities, thus calling for sustainable fishing practices. To enhance the effectiveness of sustainable fisheries management policies, an integrated assessment that considers multiple aspects of these species is more accurate as it provides comprehensive information on their current status and helps guide evidence-based management strategies.

From 2020 to 2024, SEAFDEC conducted stock and risk assessments on two neritic tuna species (Euthynnus affinis and Thunnus tonggol) and two tuna-like species (Scomberomorus guttatus and S. commerson), along with genetic stock structure, age determination studies, and reproductive pattern of E. affinis. These studies offer critical insights into stock status, population dynamics, growth rates, and reproductive patterns. These activities align with the provisions of the ASEAN-SEAFDEC Resolution and Plan of Action on Sustainable Fisheries for Food Security for the ASEAN Region Towards 2030 (RES&POA-2030), particularly Resolution No. 12 “Strengthen knowledge, including local knowledge, and science-based development and management of fisheries by enhancing the national capacity to collect, analyze, and share fisheries data and information”; as well as POA No. 4 “Establish reference points, and come up with estimated biomass or capacity level to determine the maximum sustainable yield, allowable biological catch, or allowable effort for marine and inland fisheries”; and No. 27 “Foster cooperation with other countries for the conduct of stock assessment on straddling, transboundary, highly migratory, and shared fishery resources, as appropriate, to serve as inputs for formulating science-based fishery management plan; and strengthen subregional and bilateral cooperation including inter-agency cooperation for management of such resources.” The outputs will support the formulation of science-based fishery management plans and strengthen sub-regional and bilateral cooperation, including inter-agency cooperation, for the management of such resources.