South Africa has two commercial fishing sectors that target tuna – the Large Pelagic Longline and the Tuna Pole-Line (baitboat) sectors. The latter sector mainly targets (Thunnus alalunga) and to a lesser degree yellowfin tuna (Thunnus albacares) and rarely operates in the IOTC Area of Competence. The Large Pelagic Longline sector comprises two fleets with different histories: the South African-flagged Large Pelagic Longline vessels that traditionally used swordfish (Xiphias gladius) targeting methods, and the Japanese-flagged vessels that operate under joint-ventures and fish for South African Rights Holders. The Japanese-flagged vessels typically target tropical tunas and southern bluefin tuna (Thunnus maccoyii) with their effort focused in the Indian Ocean
In 2018, a total of 25 longline vessels were active in the IOTC area of competence, which is more than in 2017. Effort increased marginally - the number of hooks set in 2018 was 1 325 446, compared to 1 284 160 in 2017. Catches also increased from 2017 for swordfish (53%), blue shark (41%), yellowfin tuna (25%) and southern bluefin tuna (19%). The increase in southern bluefin tuna catch is a result of South Africa’s longline fleet actively targeting this species due to the increased nominal TAC from 40 tons in 2015 to 450 tons in 2017/2018. For the same period, decreases in catch were observed in albacore (48%), bigeye tuna (23%) and shortfin mako shark (15%). The high inter-annual variability in catches for species can largely be attributed to a high proportion of longline vessels fishing close to the IOTC/ICCAT boundary line. Skipjack catches continue to be negligible (0.1 metric tons) and the catch of all other species (NEI) also declined from 2017 to 2018.
There were three Japanese foreign-flagged joint-venture vessels that fished in the IOTC area of competence in 2018, all with 100% observer coverage - a combined total of 243 observer days. Nine trips from a local longline vessel were observed, with a combined total of 75 observer days. Observer coverage exceeded all RFMO requirements and 56% (744 415) of hooks set in the IOTC area of competence were set while an observer was onboard. Approximately 37% of all hooks set in the IOTC area of competence were actively observed. There was zero effort in the IOTC area of competence by the South African Tuna Pole-Line fleet in 2018; only a single trip occurred in 2017.