Reproductive biology of a Gobiid fish Oxyurichthys tentacularis (Valenciennes, 1837) inhabiting Ashtamudi Lake, S. India

Reproductive traits of Oxyurichthys tentacularis, a most demanded fish in Ashtamudi Lake, S. India were studied from samples collected using gill net, cast net and dip net during 2013–2015. Sexes were separated by observing the urogenital papilla in males and the gonads. Five maturity stages were identified by examining the gonads. Though advanced maturity stages were encountered throughout the year, higher preponderance of ripe gonads was discernible during August to November and February to April. Gonadosomatic indices indicated same trend in both sexes. The length at first maturity was 86.67 mm in males and 80.17 mm in females. The absolute fecundity ranged from 5,112 (102 mm TL) to 52,431(175 mm TL). Fecundity established linear relationships with total length, body weight and ovary weight. Ova diameter studies revealed that spawning takes place in batches at regular intervals and the species is a multiple spawner. The ratio of males to females was found to be 1:0.7 (χ2 = 10.8; p 0.05) could be observed.