Journal of Aquaculture Research & Development

Abstract

The Sex-Ratio, Developmental Stages and Cycle of Gonad Maturation of Neolissochilus hexagonolepis in the Mid-Reaches of the River Tamor

Suren Subba, Vinod Kumar Mahaseth, Bharatraj Subba and Shyam Narayan Labh*

A population of Neolissochilus hexagonolepis captured from the mid-reaches of the river Tamor, eastern Nepal were investigated between December, 2014 and November, 2016. Fish samples were collected in the second half of every month and were evaluated for the Gonado-Somatic Index (GSI), developmental stages and cycle of gonad maturation. The population structure showed asymmetric sexual pattern with females dominating the number of males for most part of the study period. Monthly mean GSI varied from 0.17 ± 0.05% to 3.27 ± 1.68% and from 0.13± 0.07% to 10.57 ± 4.56% for male and female fish, respectively. The gonads were observed to pass through six stages of maturation viz. immature, maturing virgin and recovering spent, ripening, mature, spawning and spent. The maturation cycle showed an extended breeding season of the fish from May to November with peak breeding activity in July. The information gathered during the present study could be incorporated in management plans for making sustainable conservational efforts for the near-threatened N. hexagonolepis population in the river Tamor.

Published Date: 2024-07-29; Received Date: 2019-11-15