Morphometric relationships between length-weight and length-length and condition factor of four small indigenous fishes from the Payra River, southern Bangladesh

Abstract

The present study describes the length–weight (LWR) relationship, length– length (LLR) relationship, and condition factor (K) of four small indigenous fish species from the Payra River, southern Bangladesh, namely Mastacembelus pancalus, Lepidocephalus guntea, Salmostoma bacaila and Mystus vittatus. A total of 867 specimens, representing 4 species of 4 families used for this study were caught by traditional fishing gear from July to October 2018. Standard length (SL) and total length (TL) for each specimen were measured by digital slide calipers and each body weight (BW) was taken by a digital balance. The allometric coefficient b of the LWR was close to the isometric value (b=3.078 and 3.028) in M. pancalus and L. guntea respectively, although it suggested negative allometric growth in M. vittatus (b < 3.00), whilst positive allometric growth in S. bacaila (b > 3.00). All the LWRs were highly significant (P < 0.05) and most of the coefficients of determination values were ≥ 0.857. The results further indicated that the LLRs were highly correlated (r² ≥ 0.939; P < 0.05). Fulton’s condition factor (K) by month basis ranged from 0.52 (in M. pancalus) through 1.89 (in M. vittatus). The results of this study can be very effective for stock assessment of this four species in Payra River as well as in the surrounding ecosystems.