Longline Fisheries

pelagikos has been working with the Seafood Exporters’ Association of Sri Lanka (SEASL), the DFAR and the Multiday Boat Owners’ Association – on and off – since 2014. The first collaboration with SEASL and the Sustainable Fisheries Partnership ended in January 2015, when the European Commission banned the importation of Sri Lankan seafood to the European Union due to concerns about illegal, unreported and unregulated (IUU) fishing. The second collaboration ended in 2021. The third collaboration between the SEASL, DFAR, multiday day boat owners and pelagikos to improve the biological and ecological status and the management effectiveness of Sri Lanka’s longline fisheries for tuna and billfish started in May, 2025. Fingers crossed, it will continue..

Biology & Ecology: Indian Ocean yellowfin tuna (Thunnus albacares) are marine, oceanic, highly migratory fish that live up to nine years, measure more than 203 cm and weigh up to 200 kilos. Yellowfin tuna form schools by size, either with other yellowfin tuna, other pelagic, oceanic fish species or as adults with marine mammals. Yellowfin tuna are found to a depth of 250 m in tropical waters. Schools of yellowfin tuna often associate with flotsam, jetsam and other floating objects. Yellowfin tuna are apex predators feeding on other fish species, squid and crustaceans.

Fisheries & Status: Sri Lanka’s large fleet of longline, multiday fishing deploy short, drifting longlines (< XX km) with up to 1,000 hooks (No. XX) per set, at depths of between XX m and XX m to target yellowfin tuna. Big-eye tuna (Thunnus obesus), swordfish (Xiphias gladius), sailfish (Istiophorus platypterus), blue marlin (Makaira nigricans), black marlin (Istiompax indica) and striped marlin (Kajikia audax) are an important part of the retained non-target species (bycatch) from the longline fishery, comprising roughly XX%, XX%, XX%, XX%, XX% and XX% of the longline catch respectively. Yellowfin tuna, big-eye tuna, swordfish, sailfish and marlin species are all managed by the IOTC. The IOTC’s assessment of the Indian Ocean yellowfin tuna fishery in 2024 determined that the probability of the stock being in the green Kobe quadrant was 89% i.e. the fishery was sustainable. On the weight-of-evidence available in 2024, the yellowfin tuna stock was determined to be not-overfished and not-subject to overfishing

Sustainable Sri Lankan Seafood: The majority of the catch and all of the sailfish, blue, black and striped marlin are sold to domestic seafood markets. Yellowfin tuna, big-eye tuna and swordfish amounting to less than 10% of the total catch are exported fresh (chilled) or frozen to seafood markets in the EU and North America. The export value of tuna and billfish was US$ 200 million in 2024.

Useful links, downloads & videos
Sri Lanka Tuna Fisheries Improvement Project. FisheryProgress
Executive Summary: Yellowfin tuna (2024). Indian Ocean Tuna Commission
Executive Summary: Big-eye tuna (2024). Indian Ocean Tuna Commission
Executive Summary: Swordfish (2024). Indian Ocean Tuna Commission