Abstract
Of the 70 specimens of the lantern shark, Etmopterus unicolor, collected in Suruga Bay and adjacent waters 22.9% were abnormal hermaphrodites, 30.0% normal males, and 47.1% normal females. Fifteen hermaphrodites had female reproductive organs composed of normal ovaries, oviducts, nidamental glands and uteri as well as claspers. The clasper lengths of these hermaphrodites increased rapidly after the sharks reached 510mm TL, the length about equal to the size at maturity for normal females. The ovary and uterus of abnormal females became mature at a total length greater than 500mm, whereas the size at maturity was about 500mm TL for normal females compared to 460mm TL for normal males. In one specimen, the left gonad contained both ovarian and testicular tissues, the bulk of which was testicular.
