A case of hermaphroditism and some other gonadal abnormalities in the skipjack Katsuwonus pelamis (Linnaeus).

Abstract

IN the course of the examination of more than 2300 gonads of Katsuwonus pelamis (Linnaeus) for the study of the spawning habits of this fish, from the Laccadive Sea at Minicoy, I came across three abnormal gonads including a hermaphrodite one. As this is the first record of abnormal gonads of tuna from Indian waters it has been described in this present note. The normal gonads of the skipjack (Fig. 1) are paired and elongate organs with the left lobe usually being shghtly larger than the right and both are suspended from the dorsal wall of the body cavity by a fold of the peritoneum. They are free distally but proximally they unite to form a common duct opening into the cloaca. In the female the posterior part of the ovary itself functions as the duct whereas in the male there is a slender duct running along the entire length of the mid-ventral side of each testis.