North and South Atlantic albacore (Thunnus alalunga) stocks assessment ICCAT WG ALB, 26 Sept., 2007 Ex. Report ALB SCI-017 Multifan Inputs for ALB Assessment, March 2007 SCI-030 /2007 Detail Albacore stock assessment, July SCI-036 /2007

ALB- Atlantic Biology Stock structure for assessment: North and South stocks in the Atlantic ocean separated at 5º and Mediterranean stock. Intermingling of Indian and Atlantic oceans needs research. Present knowledge on habitat distribuition by size, spawning areas, maturity based on limited studies mostly from past years. Revised vB growth equation was estimated for South Atlantic stock based on aging dorsal fin ray section Vertical distribution: immature at sub-surface above thermocline in summer. Adult distribution at wider range from surface to ~ 300m depth.

ALB - Spatial distribution based on average catch period

Catch trend Northern stock ALB years BB LL TROL 1975 VPA

Fisheries indicators in North Atlantic BB LL TROL Targeting immature and sub-adults ( cm FL) by surface fisheries in the North Eastern Atlantic from Azores Is. to northern lalitude (SW Ireland) and Bay of Biscay areas, during spring, summer and autumn. Targeting immature and adult albacore ( cm FL) by longline fisheries in Central and Western Atlantic waters all year round. Catch was extended back to 1930 after revision for stock assessment. Trend: declining began in 1986 due to reduction of traditional surface fleets (Troll and Baitboat) and longline fleets. Stabilization observed in the 90´s due to incorporation of new fleets (drifnets & mid-water pair pelagic trawl). Maximun catch of 38,063 t registered in Followed by the lowest on record of 22,685 t in Since then and steady increase until reaching a peak of 36,077 t in Overall description

Surface Fisheries BB LL Longline Fisheries Gears: troll, baitboat, mid-water pair pelagic trawl (MWPT). Main fleets involved: EC (Spain, France Portugal and Ireland) In 2006 the surface fishery represented the 86 % of total catch in North stock EC-France MWPT reported the highest catch of recent years in 2005, but decreased the 30 % in EC-Ireland MWPT catch has decreased since EC-Spain increased the baitboat catch by 49% respecting 2005 catch and the troll catch in 2006 was similar to 2005 level. Longline catches decreased in 2006, due to a decrease of landings by Chinese-Taipei fleet of 60% compared to 2005 caused by decline in fishing effort.

Catch trend Southern stock ALB years BB LL BB LL

Fisheries indicators in South Atlantic BB LL TROL Targeting immature and sub-adults ( cm FL) by surface fisheries in the South Eastern Atlantic in coastal waters of Namibia and South Africa from October to May. Targeting adult albacore (> 90 cm FL) by longline fisheries in Northeast coast off Brazil (5ºS-20º S) and over the South Atlantic area by longline fleet from Chinese-Taipei Central all year round. Trend: total reported catch in 2006 was 24,375 t, an increase of about 5,000 t respect The Chinese –Taipei catch increased in 2006 to 12,293 t. As for Brazilian catches, the Chinese –Taipei vessels (incluidng Belize and St. Vincent flagged boats ) stopped fishing for Brazil in 2003, then albacore was only caugth as by-catch in the SWO and Trop target longline fisheries, reaching 267 t. The decreased of albacore in 2006 in inshore waters of South Africa and unfavorable foreign currency has caused a reduction in number of active baitboat vessels. Overall description

Catch trend Mediterranean stock ALB years BB LL BB LL Reported catches in 2006 were 5,874 t, an increased with respect to Longline Other Surf Main Fleets

Assessing the State of Atlantic stocks BB LL BB LL Background Thorough revision of North and South Atlantic stock data: Task I and Task II, was done and more robust method was implemented to analyse Catch-at- Size (CAS) information. Historical Catch for North Atlantic stock was recovered and incorporate to the analyses up to Catch rates analyses were reviwed and new model applied for some longline fleets resulting in better fit to data. Substantial work was undertaken to implement new methods which do not assume that CAA is known whitout error, to assess the albacore stocks. This new implemented method provided the opportunity to evaluate a range of hypothesis: - how the fisheries operated over time and their impact in the population ?

ALB- North stock. Total Catch-At-Age (CAA) 1 to 8+ age group Bubble size proportional to number of fish

ALB- North stock. Catch-At-Age (CAA) by Fishery 1 to 8+ age group Bubble size proportional to number of fish on each fleet LONGLINE FLEETS By-catch By-catch USA SURFACE FLEETS Target BB ESPTarget TR ESPTarget OTHER By-catch JPN Target Ch-TAI

ALB- North CPUE time series Surface TR fleet Longline Taiwan LL target

ALB-N- Recruitment and Spawning stock Age 1- recruit MFCL model 2005 high but uncertain MFCL model SSB ~ ¼ Max in 40´s

ALB- N- Relative F, SSB and status stock relative to MSY

ALB- North State of stock SSB has decreased to one fourth of the SSB in the highest level in the 40´s Recruit decreased from the 60´s until In 2005 the estimated recruitment is high ~ 60´s, but magnitude is uncertain. The stock rebuild to levels near B MSY (SSB 20% below MSY) vs 2000 assessment when SSB 50% below MSY Current F is 50% above F msy Estimates of MSY varied over time as a combination of surface and longline fisheries with changing selectivity pattern over time period. MSY for 3 recent years ~ t, but over time ranged from t to t.

ALB- North Atlantic Fishing trajectory and 2005 status evolution of relative biomass and fishing mortality estimated trajectory relative to MSY status in 2005

ALB- North Atlantic Uncertainty of 2005 status determination 2005 status F/Fmsy =1.5 B/Bmsy = 0.81

ALB- N- Projections VPA relative SSB (SSB/SSBMSY) for scenarios of cte catch TAC of t 2006 CATCH of t t Projected Current catch for 2006 & 2007

ALB- N- VPA Projections scenarios assuming strong year class relative SSB (SSB/SSBMSY) for scenarios of cte catch Projected Current catch for 2006 & t TAC t TAC

ALB- South stock. Total Catch-At-Age (CAA) 1 to 8+ age group Bubble size proportional to number of fish

ALB- South stock. Catch-At-Age (CAA) by Fishery 1 to 8+ age group Bubble size proportional to number of fish on each fleet LONGLINE FLEETS By-catch JPN Target and By-catch BRATarget Ch-TAI SURFACE FLEETS Target BB SATarget BB NAMTarget OTHER

ALB – South CPUE time series Longline Taiwan Target Surface Baitboat

ALB- South Atlantic Fishing trajectory and 2005 status

ALB- South Atlantic Uncertainty of 2005 status determination 2005 status F/Fmsy =0.63 B/Bmsy = 0.9

ALB- South State of stock Last assesmment was done in 2003 Longline CPUE ´show a declining trend at the begining of time series, less marked in the recent period. Thos indices traget adult albacore. Surface CPUE´s (Baitboat) target mostly immature albacore and no trend is seen. Current SSB has declined 25% from unfished SSB. Accordingly it is likely that in 2005 SSB is about 90% of Bmsy and F is 40% below F msy Estimates of current MSY is around t and Replacement yield is around t, current catch t is below.

ALB- S- Projections B MSY 10 years projections SSB over time trend and 80% confidence bounds Projected cte catch = t

ALB- N MANAGEMENT Rec. ALB- S MANAGEMENT Rec. Current TAC is t 2005 and 2006 catches have been above Projections indicate that stock will not recover from overfished state if catch level remain > t If strong year class enters the fishery the stock would recovered faster Current TAC is t 2Recent catches have been below Projections indicate that catches at 2006 level will recover the stock from overfished state Current management scheme is sufficient for recovery of South stock

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