Reproductive Biology of Malabar Pufferfish Carinotetraodon travancoricus (Tetraodontidae)

Abstract

Carinotetraodon travancoricus, is endemic to rivers of Western Ghats of India and supports a lucrative export trade of live aquarium fishes from India. Aspects of its reproduction are studied from fishes collected from the Pampa River, South India. Among 966 fishes analyzed females predominated in March and males in May. However, the overall sex ratio was close to 1 : 1. Ripe gonads could be encountered in almost all months, but registered significantly higher preponderances during May to August. A total length of 18.33 mm is observed as the size at first maturity in males and 18.0 mm in females. Highest mean gonadosomatic index was recorded in August (1.4%) in males and in June in females (6.1%). Significant variation in oocyte diameter among different ovary maturity stages has been observed. Primary oocytes at the previtellogenic stages, oocytes with perinulceolar stage as well as with advanced vitellogenic stage were present in ripe ovaries, indicating asynchronous maturation. The absolute fecundity ranges from 139 (21 mm TL) to 480 (29 mm TL). The present results indicate that though fishes with ripe gonads occur throughout the year, the peak spawning period for C. travancoricus inhabiting the Pampa River extends from May to August concurring with South-West monsoon period.