Seychelles tuna bulletin: second quarter 1997

Abstract

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 1996 is now 265,658 t. This catch was achieved by an average of 49 vessels licensed per month. The total effort recorded for the purse seine fleet during 1996 was 12,948 fishing days, thus giving a mean catch rate of 20.52 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 Wishing day, The highest annual CPUE on record was obtained in 1992 at 22.27 t/fishing day. The catch within the second quarter of 1997, was 48,222 t. This comprised of 13,691 t (29%) yellow fin (Thunnus albacares) and 28,587 t (59%) skipjack (Katsuwonus pelarnis). The remaining 5,944 t (12%) was mainly big eye (Thunnus obesus) and albacore (Thunnus alalunga). This compares with the catch within the second quarter of 1996 when some 18,288 t (36%) of yellowftn was caught, together with 25,631 t (51%) of skipjack and 6,474 t (13%) of bigeye and albacore. Some 3,460 days were fished in the second quarter of 1997 compared to 3,051 days for the equivalent period of 1996. The effort recorded for the second quarter of 1997 are some 409 days above that recorded for the same period in 1996. Considering that not all logbooks for the period under review have been received at the SFA, this difference between the two years is expected to increase further once all have been collected and processed. 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. The CPUE within the second quarter of 1997 was 13.94 tlfishing day compared to 16.52 t/fishing day in the equivalent quarter 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 1996 was 163,657 t compared to 185,489 t in 1995. The 1996 transhipment figure for Port Victoria has decreased by 512 t from what was reported in the previous Tuna Bulletin. The 512 t has been reallocated to transhipment done at sea. 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. This is reflected in the the total transhipped in Port Victoria as a function of the total transhipped through all ports, whereby 61 % of the total transhipment during 1996 took place in Port Victoria, as has been the case for the last two years. During the second quarter transhipment in Port Victoria totalled 17,964 t. This is an increase of 9% compared to the figures obtained in the second quarter of 1996, when 16,368 t of tuna were transhipped. From Map 2 we can see that the fishing grounds exploited in the second quarter of 1997 were mostly the same as in the second quarter of 1996. However, more fish were caught in and around the Seychelles waters in 1997 than in 1996. Detailed analysis of the Mozambique Channel fishing season indicates that for 1997 the total catch for the area was up by 17% over the previous year's total. The catch rate had also increased from 14.49 tlfishing day in 1996 to 15.91 t/fishing day in 1997. Longliners 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 1996 are related to only 56 logbooks received at the date of publication of this bulletin. 21 logbooks were received from the Japanese, 16 logbooks were received from the Taiwanese, I1 logbooks were received from the French and 8 logbooks were received from the South Koreans. A total of 342 licences were issued in 1996 , compared to 292 licences issued for 1995. For the second semester of 1997, only 13 logbooks have been received to date and 113 licences has been issued_ This underlines the poor and very slow reporting rate of longliners in general. When more data will be available, these statistics will be revised. Analysis of data collected to date show that: A fishing effort of 5147,413 hooks for a total catch of 2240 MT has been reported for 1996. The mean CPUE for the same period was 0.44 t/1000 hooks. The mean CPUE by nationality was: 0.6301000 hooks for the French, 0.53t/1000 hooks for the Japanese 0.31 t/1000 hooks for the South Koreans and 0.21t/1000 hooks for the Taiwanese fleet. For the first semester of 1997, a total fishing effort of 850,141 hooks for a total catch of 511 MT has been reported. The mean CPUE for the same period was 0.60 01000 hooks. The mean CPUE by nationality was 0.67 t/1000 hooks for the French, 0.60 t/1000 hooks for the Japanese, 0.53 1/1000 hooks for the Taiwanese, 0.45 t/1000 hooks for the South Koreans, and 0.40 t/1000 hooks for the Spanish fleet. For this same period, first semester of 1997, according to logbooks received, Yellowfin (Thunnus albacores) comprised 47% of the total catch, Rigeye (Atoms nbesus) comprised 30% and other species (billfishes) comprised 23%. The French and Spanish longliners targeted billfishes (57% and 100 % of their total catch). The principal fishing areas for the second quarter of 1997 were located: at the north, north-west and central part inside the Seychelles EEZ (see map no. 4).