Adaptive management for southern bluefin tuna: Redevelopment of a replacement management procedure for setting TACs

Abstract

Based on the concept of adaptive management, the Commission for the Conservation of Southern Bluefin Tuna (CCSBT) had been using a management procedure (MP) called Bali Procedure to set total allowable catches (TACs) since 2011. The MP is defined as a harvest control rule that applies pre-agreed procedures (algorithms) and fishing/survey data to specify the TAC. The MP is often developed through an extensive computer simulation called Management Strategy Evaluation (MSE) that tests its robustness to uncertainties about fisheries/fish populations and its performance in achieving management objectives. The scientific aerial survey to obtain recruitment data needed for Bali Procedure was discontinued in 2017. In 2019, the CCSBT redeveloped a replacement MP called Cape Town Procedure (CTP), which utilizes alternative recruitment data. This paper overviews the MSE process for the development of the CTP (the construction of the operating model, the development of candidate MPs, performance comparison among the candidate MPs, and final selection from the candidate MPs) and how the CTP has recently been applied to the management of southern bluefin tuna. Lessons learned from the authors’ experience through the MSE process in the CCSBT and issues related to MP development are discussed.