Development of pilot empirical harvest strategies for tropical tuna in Indonesian archipelagic waters: Case studies of skipjack and yellowfin tuna

Indonesia is a member of three tuna Regional Fisheries Management Organisations (RFMOs), but currently has limited capacity to operationally manage its tuna fisheries to maximise benefits and minimise risks of over-fishing. In 2014, the Government of Indonesia initiated discussions on the potential to develop formal harvest strategies for the management of tuna resources within its archipelagic waters. This article summarizes the development of potential empirical tuna harvest strategies for use in Indonesian archipelagic waters (Fisheries Management Areas 713, 714 and 715), using skipjack tuna (Katsuwonus pelamis) and yellowfin tuna (Thunnus albacares) as demonstration case studies. The outputs of area-specific components of Western Central Pacific Ocean stock assessment were used to condition prototype operating models for testing preliminary harvest strategies by management strategy evaluation. The case studies demonstrate the utility of scientific monitoring data to track trends in abundance of adult fish, without requiring complex stock assessment models. They also demonstrate the use of relatively simple, empirical harvest control rules to adjust the levels of fishing intensity of the Indonesian fleet to achieve specific management objectives for archipelagic waters in the context of wider regional management. The approach has a broad applicability to developing coastal nations with multi-gear fisheries and relatively limited data that harvest tuna, as well as participating in RFMOs for internationally managed stocks.