Gonadosomatic Index as a Determinant of Spawning Season in the Milieu of Ovarian Dynamics of Indian Freshwater Spiny Eel Mastacembelus armatus (Lacepede)

Abstract

Gonadosomatic index is a less expensive and alternative method than histological observation for the determination of spawning season in fish species. Mastacembelus armatus, an indigenous fish species of southern Asia, also resides in Indian subcontinent. This fish species is facing an alarming declining in their number in the last decade. Due to its moderate cost, It is mainly taken by the lower income group of people of the society. Reproductive care, by artificial breeding, has been taken for those fish species having a high cost in the market or becoming less in number in nature for business purposes or preserving the biodiversity, respectively. The present study was undertaken to understand the spawning season of the fish Mastacembelus armatus by calculating the gonadosomatic index, so in recent future artificial breeding can be done in this fish species. The mean GSI value for testes is 0.95 ± 0.06, 1.42 ± 0.22, 2.10 ± 0.38 and 0.72 ± 0.08 in growth, maturation, spawning and resting phase respectively. The mean GSI value for ovary is 1.38 ± 0.4, 2.86 ± 0.84, 12.50 ± 1.70 and 1.80 ± 0.15 in growth, maturation, spawning and resting phase respectively. In this study it was found that spawning season include one peak in a year and mainly it falls in the months of June to August in both the sexes.