Trends in the Seychelles tuna fishery.
Distant water fishing nations (DWFN) began longlining for tuna in the Western Indian Ocean (WIO) in the early 1950s, initiated by the Japanese soon followed by the Taiwanese (1954) and Koreans (1960). Large scale industrial purse seining began in 1983 when the French and Spanish fleets moved into the Western Indian Ocean from the tropical Atlantic. By 1986 some 6 % of the world tuna catch (143,099t out of 2,400,000t) was coming from the WIO purse seiners; by 1997 this had risen to 14 %. Virtually all the purse seiners active in the WIO are licensed to fish in the Seychelles EEZ; SFA's data therefore reflect the entire WIO purse seine catch (based upon daily catch and effort reports or logbooks which must be provided to SFA by all licensed vessels). At present about 58 vessels per year are licensed. SFA has detailed reports of over 90 % of their total transhipments used to calculate accurate catch figures by correcting estimated catch. Not all licensed longliners provide SFA with catch and effort forms and almost none of those which report catches actually tranship in the Seychelles. In 1985 some 95 % of the WIO purse seine catch was transhipped through Port Victoria; ten years later in 1994, this changed to 60 % of the WIO purse seine catch and, for the first semester of 1998, only 35 % of the total purse seine catch was transhipped in Port Victoria. This reflects a change in the geography of the fishery. In the early 1980s, Mahé was at the centre of the area fished all year round. Purse seiners fish predominantly in the Mozambique during the second quarter of the year and tranship in Antsiranana. Many vessels fish off the Somali coast in the third quarter and tranship in Mombassa. During the fourth quarter of the year, purse seine fishing activities tends to shift from the Somali basin to the Chagos area. By the end of 1997, most vessels moved to the eastern Indian Ocean past the Chagos Archipelago and were transhipping their catch in Phuket, Thailand. A semi-industrial monofilament longline fishery started in Seychelles in October 1995. At present, 6 local longliners are fishing. Swordfish is the targeted species (around 60 %), followed by yellowfin and bigeye tuna. One major problem faced by this fishery is the lost of catch due to predation by marine mammals. The major tuna and tuna like species discussed in this report are: yellowfin (Thunnus albacares), skipjack (Katsuwonus pelamis), bigeye (Thunnus obesus) and swordfish (Xiphias gladius).