The monofilament longline fishery targeting swordfish and tuna is practised actually in Seychelles by 8 local longliners (average length of 16 metres) and foreign longliners fishing under Seychelles licenses ( French and Indonesian longliners , averaging 34 metres and 25 metres in total length). Experimental trips by SFA’s research vessel were undertaken in 1994 and commercial trips started in 1995. The total landing catch increased from 215 mt in 1996 to 456 mt in 1999. The estimated catch rates varied from 0.64 kg/hook in 1996 to 0.92 kg/hook in 1999. Loss of catch due to predation by marine mammals (pseudorca crassidens) remains one of the major problem of this fishery. In 1999, 24 % of the total catch (109 mt of fish) was lost due to predation. The main species caught by the Seychellois longliners are : swordfish (xiphias gladius) 60%, Yellowfin tuna (Thunnus albacares) 19%, Bigeye tuna (Thunnus obesus) 13% and other species (billfishes, sharks & common dolphin fish) 8%. Length frequency data are taken at the landing sites for the different species. Analysis of the length frequency distribution of swordfish from 1995 to 1999 shows that the average length has remained stable throughout the 5 years (139 cm fork length). The females have larger sizes than the males. Published