abstract:Albacore, Thunnus alalunga, caught in the south Atlantic Ocean was examined based upon historical size and catch data collected from longline fishery between 1981 and 1997. There were no apparent changes in size composition in the southern stock between 1981 and 1993. Dominant size of albacore ranged from 70 to 120 cm in most years except for 1994-1997 period when large amount of small albacore (i.e., < 70 cm) were evident. Adjusted catch-per-unit-effort (ACPUE) was higher while mean size of fish caught was smaller in ICCAT statistical area 34 than in 33 in all years. ACPUE decreased continuously from 1981 to 1996 in area 33, but was high in area 34 during 1981-1986 period, decreased to low values in 1987-1993, and increased again after 1993. Increases in catch of small albacore were also seen in areas within and outside Japanese Southern Bluefin Tuna fishing ground. Shift in modes of length frequency distribution for small albacore from 1995 to 1997 coincides with mean growth rate of ages 1 to 3 fish in the southern stock. This observation might suggest an increase in abundance of southern stock in recent years especially in area 34. Implications of such an observation in relation to the management of southern stock were also discussed.