Serum Esterase Groups of Pacific and Atlantic Tunas

Abstract

Starch-gel electrophoretic analysis of serum specimens of 8201 skip-jack tuna (Katsuwonus pelamis), 187 ablacore (Thunnus alalunga), 107 bigeye tuna (T. obesus), and 65 yellowfin tuna (T. albacares) taken from the Pacific and Atlantic oceans demonstrated individual genetic variations inthe serum esterase component within each sp. The esterase system proved to be independent of any known blood systems, of sex, and of size of fish in each sp. In shipjack tuna extensive data allowed an application of the system to the problem of identifying subpopulations, or isolated breeding populations. Heterogeneity tests for the gene frequencies of the esterase system showed a population in the equatorial Atlantic is different from any populations recognized in the Pacific; eastern Pacific (Baja California) specimens were indistinguishable from those of Hawaiian waters; and the Western Pacific (Japan and Palau) has at least 1 subpopuiation different from the population in Hawaiian waters.