Estimation of relative growth of Minor carp Labeo bata (Cyprinidae) through multi‐linear dimensions

Abstract

AbstractThis study focuses on relative growth through length‐weight relationships (LWRs) and length‐length relationships (LLRs) using a total of 15 linear dimensions of Minor carp Labeo bata (Hamilton, 1822) from the Ganges River, northwestern (NW) Bangladesh. Also, meristic counts covering various fin rays and scales from different body parts (including lateral line scales) of L. bata (Hamilton, 1822) have been studied. A total of 300 individuals of L. bata were sampled occasionally from the Ganges River from July 2013 to June 2014, using various traditional fishing gears (e.g., Cast net, Gill net and Square lift net). Number of fin rays from all fins and scales were counted using magnifying glass. Additionally, a total of 15 different lengths were measured to 0.1 cm and whole body weight (BW) was taken to the nearest 0.1 g for each individual. Fin formula of L. bata is as follows: dorsal, D. 10–12 (i–ii/9‐10); pectoral, P1. 12–16 (iii–iv/9–12); pelvic, P2. 9 (i/8); anal, A. 6–7 (ii/4–5); and caudal, C. 20–24 (iv–vi/16–18), respectively. Minimum and maximum lengths were found as 8.0 to 25.1 cm in total length (TL) and body weight (BW) ranges from 4.8 to 161.0 g. All LWRs were highly significant (p < .001) with r2 values ≥0.960. Based on r2 value, LWR by BW versus TL was the best fitted model among 13 equations. In addition, the LLRs were also significant with r2 values ≥ 0.959. According to r2 value, LLR by TL versus FL was the best fitted model among 15 equations. This study would be very effective for species identification and stock assessment in the Ganges River, NW Bangladesh and surrounding ecosystems.