EARLY SEX DISTINCTION IN GREATER AMBERJAC K SERIOLA-DUMERILI USING SKIN MUCUS

Vitellogenin (VTG), a female-specific protein, was purified from the p lasma of estrogen-injected greater amberjack, Seriola dumerili, and de tected in the skin mucus of females immunologically, in order to utili ze it for the early sex distinction of this fish. VTG purified with hy droxylapatite and gel filtration (Sephacryl S-300) had an apparent mol ecular weight of 430,000. When enzyme-linked immunosorbent assay was c arried out in the sera and mucus of both sexes using rabbit antibody r aised against VTG, the serum and mucus of the matured females reacted with the antibody but not those of the matured males. The females duri ng the spawning season (May) had much VTG in their mucus but not males . Some fish before the spawning season had VTG in the mucus and serum. These results suggest that VTG occurs in the mucus of the females and can be utilized for the early sex distinction of this fish.