As a result of 5 years of sampling the following results were reached: (1) so far as growth was concerned 3 size groups were recognised during June-July. The `classic' type measuring similar to 52-62 cm, a group ranging from 54-55 cm and a 3rd group measuring 64-65cm. By marking the fish and by studying the degree of distribution of the stomach parasite, H.fusca it was noted that the albacore entering the north east Atlantic during summer constitute a heterogenous population migrate along the same route upto the north west boundary of Cape Finisterre. Thereafter they diverge, one group forming a semi-circle along the Bay of Biscay, another moving northwards and on reaching the south of Ireland bends westward.