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Data used to generate the tables and figures presented here are based on daily catch and effort forms (logbooks) returned from fishing vessels which are licensed to fish in the Seychelles EEZ. Sometimes there is a delay in these being received at SFA, especially during and just after the second quarter of the year when most vessels are fishing in the Mozambique Channel. Readers should be aware that many of the figures presented here (especially the most recent) are subject to revision (usually upwards) as more data become available. The date upon which the SFA database was closed prior to the generation of the statistical tables is shown at the head of each table. Purse seiners. PRINCIPAL POINTS: The total purse seine tuna catch for the Western Indian Ocean in 1997 is now 271,031 t. This catch was achieved by an average of 58 vessels licensed per month. The total effort recorded for the purse seine fleet during 1997 was 15,573 fishing days, thus giving a mean catch rate of 17.36 t/fishing day, The highest recorded catch so far was in 1995 when 307,135 t of tuna were caught. The 1995 catch was the result of an average of 52 vessels licensed per month at an annual CPUE of 21.27 t/fishing day. The highest annual CPUE on record was obtained in 1992 at 22.27 t/fishing day. The catch dui-gin the first semester of 1998, was 128,368 t. This comprised 32,748 t (26%) of yellowfin (Thunnus albacares) and 81,902 t (64%) skipjack (Katsuwonus pelarnis). The remaining 13,718 t (10%) was mainly bigeye (Thunnus obesus) and albacore (Thunnus atalunga). This compares with the catch during the first semester of 1997 when some 41,333 t (34%) of yellowfin was caught, together with 67,317 t (55%) of skipjack and 14,393 t (11%) of bigeye and albacore. Some 7,393 days were fished in the first semester of 1998 compared to 7,405 days for the equivalent period of 1997, The effort recorded for the first semester of 1998 is almost equivalent to that recorded for the same period in 1997, Readers should be well aware that the catch compositions given here are NOT based on scientific sampling but on the assessment of the fishermen who write the daily catch and effort reports and who decide into which group fish should be placed. They may be biased especially for bigeye tuna which generally is underestimated. The CPUE within the first semester of 1998 was 17.36 t/fishing day compared to 16.44 t/fishing day in the equivalent semester of the previous year. It should be noted that the figures in table 3 (purse seiner transhipment statistics by harbour of transhipment) represent the transhipments of vessels whose trips ENDED in the month indicated and NOT the actual month of physical transhipment of the catch. Transhipments through Victoria for the whole of 1997 was 200,279 t compared to 163,657 t in 1996. The overall decrease in transhipment in Port Victoria during 1996 is the result of the lower catch during 1996 rather than a decrease in importance of Port Victoria. Within the first semester of 1998, transhipment in Port Victoria totalled 44,846 t. This is a dramatic decrease compared to figures obtained in the first semester of 1997, when 82,258 t of tuna were transhipped. During the first semester of 1998 fishing was more widespread than in the same period for 1997. In 1997 fishing was concentrated west of the 70° meridian, in and around the Seychelles EEZ and in the Mozambique Channel where fishing is usually good in the second quarter of the year. By contrast, fishing in the first semester of 1998 was very poor in and around the Seychelles waters. Most vessels had started off fishing as far as the Eastern Indian Ocean and gradually moved westward in the first quarter. By the second quarter most vessels were fishing in the Mozambique Channel were most of the fish caught during that quarter was fished. Longliner activity PRINCIPAL POINTS Readers should be aware that these statistics only represent a small sample of longliner activity in the WIO because: Not all longliners fishing in the WIO have a licence to fish in the Seychelles EEZ and therefore are under no obligation to report to SFA. Not all those with a Seychelles licence provide daily log sheets especially the Taiwanese and the Koreans. Some Distant Water Fishing Nations (DWFN) provide SFA with log sheets covering their activity in the whole Indian Ocean while others confine their reports to the Seychelles EEZ.The statistics published for 1997 are related to 69 logbooks received at the date of publication or this bulletin and a total of 357 licences were issued. For the first semester of 1998, 26 logbooks have been received to date and 62 licences have been issued. Analysis of data collected to date shows that: For the first semester of 1998, longliner activity was concentrated in January, February and March. This is the usual pattern observed in the past years. A fishing effort of 3.5 million hooks for a total catch of 1610 MT has been reported for the first semester of 1998. The mean CPUE for the same period was 0.47 t/1000 hooks. The mean CPUE by nationality was; 0.521/1000 hooks for the French,54t/1000 hooks for the Japanese 0.60t/1000 hooks for the Indonesians (considered as the "other nationalities" in the tables, and 0.18t/1000 hooks for the Taiwanese fleet.For this same period, YeNowlin (Thunnus albacores) comprised 42% of the total catch, Bigeye (Thunnus obesus) comprised 33% and other species (billfishes) comprised 25%. The French and Indonesian longliners targeted billfishes (76% of their total catch). The principal fishing areas for the first semester of 1998 were located: Between the equator and latitude of 10°S, and between longitudes 50°E and 60°E inside and outside the Seychelles EEZ.
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