REPORT OF THE STANDING COMMITTEE ON RESEARCH ... - Iccat

ICCAT REPORT 2008-2009 (I)8.4 ALB – ALBACOREAn assessment of stock status for northern and southern Albacore was conducted in 2007 (SCRS/2007/015). Theprevious assessment of the North stock was conducted in 2000 (Anon. 2001a) (using data from 1975-1999) andthat of the Southern stock in 2003 using data up to 2002; no assessment of the Mediterranean stock has ever beencarried out.Complete information on the data preparatory meeting and North and South albacore stocks assessments can befound in the Report of the Ad Hoc Meeting to Prepare Multifan CL-Inputs for the 2007 Albacore Assessment(SCRS/2007/017) and the Report of the 2007 ICCAT Albacore Stock Assessment Session (SCRS/2007/015),respectively.ALB-1. BiologyAlbacore is a temperate tuna widely distributed throughout the Atlantic Ocean and Mediterranean Sea. On thebasis of the biological information available for assessment purposes, the existence of three stocks is assumed:northern and southern Atlantic stocks (separated at 5ºN) and Mediterranean stock (ALB-Figure 1 a) and b)).Nevertheless, there is likely intermingling of Indian Ocean and South Atlantic immature albacore which needsfurther research. Present available knowledge about habitat distribution according to size, spawning areas andmaturity estimates are based on limited studies and old parameter estimates have been presented for the threealbacore stocks considered, with the exception of the new growth equation for the South stock.ALB-2. Description of fisheries or fisheries indicatorsNorth AtlanticThe northern stock is exploited by surface fisheries targeting mainly immature and sub-adult fish (50cm to 90 cmFL) and longline fisheries targeting immature and adult albacore (60-130 cm FL). The main surface fisheries arecarried out by EC fleets (Ireland, France, Portugal and Spain) in the Bay of Biscay, in the adjacent waters of thenortheast Atlantic, and in the vicinity of the Canary and Azores Islands in summer and fall. The main longlinefleet is the Chinese Taipei fleet which operates in the central and western North Atlantic year round. Over time,the relative contribution of different fleets to the total catch of North Atlantic albacore has changed, whichresulted in differential effects on the age structure of the stock.The historical time series of catch was extended back to 1930 for the troll fishery after revision of data for theassessment with Multifan-CL model. Total reported landings for the North Atlantic generally began to declineafter 1986, largely due to a reduction of fishing effort by the traditional surface (trolling and baitboats) andlongline fisheries (ALB-Table 1; ALB-Figure 2a). Some stabilization was observed in the 1990s, mainly due tothe increased effort and catch by new surface fisheries (driftnets and mid-water pair pelagic trawl) with amaximum catch in 1993 at 38,063 t.Total catch in 2007 was 21,549 t representing a decrease compared to the 2006 peak catch of (36,199 t) and thelowest recorded. The surface fisheries accounted for the bulk of the total 2007 catch (87%) (ALB-Table 1). Thereported catch for EC-France in 2007 was 3,179 t, a decrease of 51% from the 2006. EC-Spain troll fleet and baitboat fleets (Cantabrian Sea and Canary Is.) catches in 2007 showed a strong decrease of 40 % from the highcatch registered in 2006. In contrast, EC-Ireland catches have increased by 14 % from 2006. Standardized catchrates of fish age 1 to 3 from the Spanish troll fleet were presented. The estimate of 2007 showed a steep declinefor age 1, and a continued decreasing trend for age 2 since 2005. Age 3, however remained at a similar levelsince 2004. Likewise catch rates of the mid-water pelagic Irish fleet were also presented showing a steep declinein 2007 compared to the higher estimates for 2005 and 2006.The French albacore data for the North eastern Atlantic between 1999 and 2007 have been updated. Catch andeffort data by gear and by 1° square are now available (SCRS/2008/165). Likewise, a historical data series ofFrench Albacore landings from 1886 to 2007 was presented to the group and will be submitted shortly to theICCAT Secretariat (Task I).54