Length-Weight Relationships and Growth Patterns of Five Loach Species from the Perennial River Burhi Gandak,India

Abstract

The Burhi Gandak River, a vital tributary of the Ganges, supports a rich diversity of loaches, yet their growth dynamics remain largely unstudied; this research analyses the length-weight relationships (LWRs) of five key species. A total of 2,453 specimens were sampled using gill nets, traps, and cast nets from September 2021 to August 2022. The LWR parameters were derived for total length (TL), standard length (SL), and head length (HL) relative to body weight (Wt). The results revealed distinct growth patterns among the species. Botia dario and Acanthocobitis botia exhibited positive allometric growth (b > 3), whereas Lepidocephalichthys guntea and Botia lohachata showed negative allometric growth (b < 3). Canthophrys gongota displayed a relatively weaker TL-Wt correlation. Total length
was the most robust predictor of body weight for most species, while head length demonstrated limited predictive reliability. This study provides the first comprehensive LWR data for these species in Bihar, providing essential baseline information for their sustainable management and conservation in this understudied riverine ecosystem.