SANBI IDentifyIt - Species SANBI IDentifyIt - Species Yellowfin Tuna - Thunnus albacares Yellowfin Tuna - Thunnus albacares Geographic location / distribution Geographic location / distribution Habitat : Yellowfin is found worldwide in open water in tropical and subtropical seas. They prefer warm water and are commonly found in water of 22°C (not below 8°C). Although they can dive to 350m depths, they are usually found in the top 100m of the sea surface. Found in SA waters: In the Atlantic, Yellowfin are predominantly found in the SW Cape region from spring to summer. By June they move south due to the increased north west wind in the winter months, which is reflected in the catches and the seasonality of the tuna pole fishery. Generally Yellowfin is more abundant in the Agulhas Current. It is suspected that the Indian and Atlantic Ocean populations around South Africa are separate stocks. Fishery Fishery Yellowfin is targeted by both the tuna longline and tuna pole fisheries in South Africa. The tuna pole fishery is a small fishery which lands the majority of yellowfin fresh for the export market, and has a fishing season from September - April each year, coinciding with the best seasons for Albacore and Yellowfin. Using a pole and line is a selective form of fishing and not much bycatch is caught. However, seabirds and sharks do occasionally get caught on the line and should be released alive. Other fish species are caught and are managed by catch limits: Daily bag limit of 10 yellowtail per crew member Species not allowed to be caught: Chokka and Mackerel spp. Longlining is not a very selective form of fishing and many species are caught accidentally on the the hooks. Bycatch species in this fishery include: billfishes (swordfish, marlins etc), seabirds, turtles and sharks. Recent assessments show that eleven species of seabird, four species of turtle and 20 species of shark are caught incidentally by this fishery. The FAO estimates that approximately 28% of the catch is discarded. Local studies indicate that discards comprise approximately 22% of the catch. Bycatch restrictions therefore exist to protect vulnerable species: The bycatch of billfish cannot exceed 10% of the total tuna catch A precautionary catch limit of 25 seabirds has been set for tuna longline vessels, after which further management restrictions are enforced Shark fins need to be landed with their trunks, with the fins not exceeding 5% of the weight of the trunk Any Bigeye, Swordfish or Southern Bluefin tuna landed must be accompanies by the relevant RFMO (ICCAT, IOTC or CCSBT) catch statistical document. Size limits Size limits Southern bluefin tuna >6.4kg Bigeye tuna >3.2kg Yellowfin tuna >3.2kg Swordfish >119cm LJFL / >18kg dressed Marlins >210cm LJFL Stock status Stock status Indian ocean - Overfished Atlantic ocean - Overfished in recent years, and showing signs of recovery, although this is uncertain Fisheries management Fisheries management Yellowfin falls within the management of the large pelagic fishery, and due to its widespread and migratory habits in