Length-weight relationship, morphometric and meristic controlling elements of three freshwater fish species inhabiting North-Western Himalaya

Length-weight relationship (LWRs) is a propondral index used to understand the general health of the fish through various growth-related indices, besides being helpful to compare different fish populations. In the present study, LWRs, morphometric and meristic elements of three food fish species, including Tor putitora (Chirak), Labeo dero (Karah)and Schizothorax richardsonii (Lass) and inhabiting the Rajouri River of North-Western Himalayan region were investigated. From June 2019 till May 2020,  Specimens of T. putitora, L. dero, and S. richardsonii (45, 40, 40 individual/species, respectively)were collected by using gill and cast nets. Results showed that ‘b’ value for L. dero was 3.187 and for T. putitora was 3.102, indicating a positive allometric growth (b > 3). While, in the case of S. richardsonii, the ‘b’ value was recorded 1.915 with negative allometric growth (b < 3). The regression coefficient (r²) value was noted as 0.95, 0.94, and 0.91 for T. putitora, L. dero, and S. richardsonii, respectively. Moreover, the condition factor of all the three species was near to ‘1’, indicating the suitability of environmental conditions for better growth of these fish species. In addition, a total of 23 morphometric characters and 6 meristic counts were also analyzed, where morphometric characters showed a gradual increase with respect to body length, while the meristic counts remained constant with respect to the increase of body length. Data obtained can give a deep insight into the welfare of fish upon which a proper strategy can be affordable to manage and conserve fish population and their biomass.