Contents lists available at ScienceDirect Fisheries Research journal homepage: www.elsevier.com/locate/fishres Development of pilot empirical harvest strategies for tropical tuna in Indonesian archipelagic waters: Case studies of skipjack and yellowfin tuna Eriko Hoshino a, *, Richard Hillary a , Campbell Davies a , Fayakun Satria b , Lilis Sadiyah c , Tri Ernawati b , Craig Proctor a a Oceans and Atmosphere, CSIRO, Hobart, Australia b Research Institute for Marine Fisheries, Indonesia c Centre for Fisheries Research, Indonesia ARTICLEINFO Handled by A.E. Punt Keywords: Harvest strategy Operating model Management strategy evaluation RFMO Developing countries Fishery management ABSTRACT 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. 1. Introduction Located between the Pacific and Indian Oceans, Indonesia is an archipelagic nation consisting of 17,508 islands, of which around 6,000 are inhabited, and approximately 81,000km of coastline (MMAF, 2017). Indonesia is the largest producer of tropical tuna (albacore, bi- geye, skipjack and yellowfin), contributing some 15 % of global pro- duction (FAO, 2019). Its geographic location, and the importance of tuna for economic development, livelihoods, and food security makes Indonesia an important member of three tuna Regional Fisheries Management Organisations (tRFMOs) – the Western and Central Pacific Fisheries Commission (WCPFC), the Indian Ocean Tuna Commission (IOTC) and the Commission for the Conservation of Southern Bluefin Tuna (CCSBT). Tuna RFMOs determine research, monitoring and re- porting requirements that members are obliged to meet. Information underpinning assessments of tuna in Indonesia, however, remains limited, resulting in high levels of uncertainty around status and productivity of stocks. Hence, assessing the sustainability of the current levels of fishing and impacts on future yields at the regional and sub- regional level is problematic. While there has been substantial progress in Indonesia’s participa- tion in tRFMOs and meeting its monitoring and reporting responsi- bilities, there is currently limited capacity for operational management of these important resources to maximise benefits and minimise risks of overfishing. This situation has the potential to generate substantial short- and long-term economic losses, reduced food security and asso- ciated social impacts for Indonesia. Given the highly migratory nature of these fishery resources, there are likely to be commensurate impacts for developing economies in the adjacent Pacific and Indian oceans (Haward and Bergin, 2016). Recognising the importance of effective management of tuna re- sources, Indonesia’s Ministry for Marine Affairs and Fisheries (MMAF), supported by stakeholder groups, initiated discussions on the potential to develop formal harvest strategies for the management of Indonesia’s https://doi.org/10.1016/j.fishres.2020.105539 Received 13 November 2019; Received in revised form 17 February 2020; Accepted 18 February 2020 ⁎ Corresponding author at: CSIRO Oceans and Atmosphere, Castray Esplanade, Hobart, Tasmania, 7001, Australia. E-mail address: eriko.hoshino@csiro.au (E. Hoshino). Fisheries Research 227 (2020) 105539 0165-7836/ © 2020 Elsevier B.V. All rights reserved. T