Biological features of the schilbid catfish Pachypterus atherinoides from the Payra River, Southern Bangladesh

Abstract

Some biological features including sex ratio, length-frequency distributions (LFDs), size at sexual
maturity, spawning season, length-weight relationships (LWRs) and condition factor of Pachypterus
atherinoides were studied. Samples were collected seasonally during March 2018 to January 2019 from a
tributary of the Payra River. The overall sex ratiowas significantly different from the expected value of 1:1
(p<0.001) in favor of female specimens. Females were significantly largerin size than males. Size at sexual
maturity was estimated at6.4 cm total length. Seasonal variations in the gonadosomatic index (GSI) indicate
that the main spawning season is fromsummer to autumn. The LWRs showed positive allometric growth in
males and isometric growth in females; however, with clear seasonal variation. Fulton’s condition factor
varied in both sexes and was attributed to the variations in GSI with maturity.The findings of this study will
be helpful to formulatemanagement and conservation strategies of P. atherinoides population.
Keywords: Pachypterus atherinoides, Spawning season, Length-weight relationship