Reproductive Traits in Catfish Sperata seenghala Sykes, 1839 in Gomati River of Tripura, North East India

Abstract

Reproductive information is essential for understanding fish population dynamics and supporting appropriate management measures. This study characterised the sex ratio, gonadal maturity stages, length at first maturity, gonadosomatic index, spawning seasonality, and fecundity of Sperata seenghala in the Gomati River, Tripura, North East India. Specimens were collected from five riverine locations between January and December 2022 using traditional cast nets and drag nets. Sex was determined through external examination and, when required, macroscopic examination of the gonads. Maturity stages were classified using a five-stage scale, while reproductive indices and fecundity were estimated using established procedures. Among 357 fish assessed for sex ratio, females constituted 67.5% and males 32.5%. Mature and ripe individuals occurred mainly from May to September, and the gonadosomatic index reached its highest value in July in both sexes. The length groups at first maturity were 35.0–39.9 cm for males and 40.0–44.9 cm for females. Absolute fecundity, estimated from 50 ripe females, ranged from 20,123 to 47,376 eggs and showed positive relationships with total length, body weight, and ovary weight. The maturity pattern and oocyte-size observations indicated that the species is a single spawner with a prolonged breeding season associated with the monsoon. These findings provide location-specific baseline information on the reproductive biology of S. seenghala that may inform conservation planning, harvest regulation, and future captive-breeding work in Tripura.