Trophodynamics and reproductive biology of Otolithoides biauritus (Cantor) landed by trawlers at Vanakbara, Diu along the west coast of India

Abstract

The trophodynamics and reproductive biology of koth Otolithoides biauritus caught by trawlers at Vanakbara, Diu was
studied for the period from September 2005 to May 2008. The length-weight relationship showed that growth was allometric
and there was no significant difference between the sexes. The overall sex ratio was 1:1.09 with mature females occurring
throughout the year. The peak breeding season was in the monsoon season from May to August as evidenced by maturity
stages, gonado-somatic index and the size progression of yolked ova. The length at first maturity of the female was
110.15 cm. The absolute fecundity ranged from 1,82,020 to 1,941,400. The mature ovaries of O. biauritus contained two
batches of mature ova measuring from 0.75 to 0.79 mm and 0.65 to 0.69 mm in diameter. O. biauritus was found to feed more
intensely during the post-monsoon months. The most important food item was Acetes spp. followed by finfishes. Fishes
possessing empty stomachs were frequently encountered in the commercial catch. Young ones of O. biauritus fed more
abundantly than adults with penaeid prawns dominating the gut contents while adults preferred finfishes as their diet.