Estimation of morphometric relationships for flathead sillago, Sillaginopsis panijus (Hamilton, 1822) in the Bay of Bengal (Bangladesh) using multi-linear dimensions

Abstract

This study on flathead sillago, <em>Sillaginopsis panijus</em> (Hamilton 1822) estimates the first morphometric relationships from the marine ecosystem, Bay of Bengal, Bangladesh using multi-linear dimensions. Additionally, meristic counts for different fin-rays were done. Alltogether, 204 specimens were captured during July 2018 to June 2019 by several gears including seine net and long lines. Morphometric measurements as well as body weight (BW) were recorded for each individual. The LWRs (length-weight relationships) were assessed as: <em>W = a × L^b</em>. Lateral line scales and fin rays were observed by magnifying glass. The LWRs and LLRs (length-length relationships) were found significant (<em>p </em>< 0.0001), with the <em>r²</em>values being ≥ 0.913 and ≥ 0.952, respectively. Based on <em>r²</em> values, LWRs by BW <em>vs.</em> SL and for LLRs, TL <em>vs. </em>FL were found as the best model. Fin formula observed for <em>S. panijus </em>is D₁ IX; D₂ I/24-28; P_.17-20; P_v.1/5; A I-II/24-27; C 2/16-18. Scales on lateral line were ~82-86. This investigation should be helpful for resource management in the marine ecosystems of Bangladesh and other subtropical countries.