CCSBT CONVENTION AREA.

 

Southern bluefin tuna (Thunnus maccoyii) is assessed and managed by the Commission for the Conservation of Southern Bluefin Tuna (CCSBT). Practically all of the catches are made in the IOTC, ICCAT and WCPFC convention areas (62 percent in the Indian Ocean, 25 percent in the Pacific Ocean and 13 percent in the Atlantic Ocean).

Southern bluefin tuna catches in 2023 were approximately 17 300 tonnes, reflecting a 1 percent increase from 2022. Catches rose sharply from the beginning of the fishery around 1950, reaching a record high of 81 000 tonnes in 1961. However, they then declined continuously until 2011, when the lowest recorded catch of 9 459 tonnes was reported (FIGURE E.1.19). Since then, catches have been gradually increasing to the current level of 17 300 tonnes, largely due to strict catch limits established under the Southern Bluefin Tuna Management Procedure. This procedure, initially known as the “Bali Procedure” (adopted in 2011), was replaced by the “Cape Town Procedure” in 2019. Virtually all catches are made using longline (70 percent) and purse-seine (28 percent) fishing methods. Current catch levels are approximately 20 percent of the peak recorded in 1961 (FIGURE E.1.19).

Southern bluefin tuna catches in 2023 were approximately 17 300 tonnes, reflecting a 1 percent increase from 2022. Catches rose sharply from the beginning of the fishery around 1950, reaching a record high of 81 000 tonnes in 1961. However, they then declined continuously until 2011, when the lowest recorded catch of 9 459 tonnes was reported (FIGURE E.1.19). Since then, catches have been gradually increasing to the current level of 17 300 tonnes, largely due to strict catch limits established under the Southern Bluefin Tuna Management Procedure. This procedure, initially known as the “Bali Procedure” (adopted in 2011), was replaced by the “Cape Town Procedure” in 2019. Virtually all catches are made using longline (70 percent) and purse-seine (28 percent) fishing methods. Current catch levels are approximately 20 percent of the peak recorded in 1961 (FIGURE E.1.19).

The latest full stock assessment was conducted in 2023. Since 2017, CCSBT has measured reproductive capacity as total reproductive output (TRO) rather than SSB. The 2023 stock assessment suggested that the southern bluefin tuna TRO is at 23 percent of its initial value as well as below the level that could produce maximum sustainable yield. According to the 2023 assessment, the current ratio of TRO/ TROMSY is estimated at 0.85, indicating that the stock is in an overfished state. The ratio of Fcurrent/FMSY is estimated at 0.46, indicating that overfishing is not occurring. The estimate of MSY is 30 648 tonnes, well above current catch levels (20 647 tonnes in 2024). Thus, thestock is overfished and overfishing is not occurring (TABLE E.1.6 and FIGURE E.1.20).

The southern bluefin tuna is managed through a management procedure adopted in 2011 (the Bali Procedure) and renewed in 2019 (the Cape Town Procedure). This guides the setting of TACs with the objective of achieving 20 percent of the unfished biomass (20 percent TRO0) with a 70 percent probability by 2035 and 30 percent TRO with a 50 percent probability by 2035. Additionally, if a change to the TAC is recommended, it is subject to a minimum change of 100 tonnes and a maximum change of 3 000 tonnes in either direction.

TACs under the management procedure are set for three-year periods to keep the stock on its planned rebuilding trajectory. The management procedure specifies the minimum and maximum permissible changes in TAC (either an increase or decrease, depending on stock status relative to the rebuilding trajectory). The management procedure was applied in 2022 and recommended that the TAC for the 2024–2026 period be increased by the maximum allowable TAC change of 3 000 tonnes (from 17 647 to 20 647 tonnes). The 2024 ESC found no evidence of exceptional circumstances and therefore confirmed the TAC recommendation for the 2024–2026 period of 20 647 tonnes/year, which the Commission endorsed.