Studies of the Erythrocyte Antigens of the Skipjack Tuna (Katsuwomus pelamis)

Abstract

The erythrocyte antigens of Katsuwonus pelamis are organized in several blood group systems. The B-system characterized by patterns formed by various combinations of 3 blood factors E, K1, and K2, and their absence, and the C-system by the blood factor C3 and its absence are the most important of these systems. Studies, on approximately 1000 Katsuwonus pelamis, were undertaken in order to find means whereby reproductively isolated stocks Of tuna found in the Central Pacific Ocean could be recognized and described. A study of the relative proportion of phenotypes in the C-system and B-system was carried out. The relative proportions of individuals in the B-system in samples from Hawaii were distinct from those of other areas as were those from the Marguesas. Samples from Tuamotu and the Society Islands were distinct from those from the other areas, but were not distinguishable from each other. It is hypothesized that at least 2 and very probably 3 reproductively isolated populations are represented by the samples collected from these island areas. The relative frequencies of C-system phenotypes did not show significant association with area of capture.