Some population parameters of Rastrelliger spp. from palaw and adjacent coastal waters, Taninthayi region in Myanmar

Abstract

An investigation of the population parameters of Rastrelliger brachysoma and R. kanagurta in Palaw and adjacent coastal waters, Taninthayi Region was carried out from April 2017 to March 2018. Asymptotic length (L∞), growth coefficient (K), age at zero length (t0) and growth performance index (ϕ') were estimated 25.20 cm, 1.50 year1, -0.109 year and 2.979 for the former species and 28.88 cm, 0.55 year-1, -0.299 year and 2.662 for the second species. Total mortality (Z), natural mortality (M) and fishing mortality (F) were calculated 2.55 year-1, 2.49 year-1 and 0.06 year-1 for R. brachysoma and 2.03 year-1, 1.25 year-1 and 0.78 year-1 for R. kanagurta. Exploitation level (E) of R. brachysoma was found to be 0.02 and 0.38 for R. kanagurta. The length at first capture Lc was 14.39 cm with an age (tc) of 0.4 year for R. brachysoma and 21.78 cm with an age (tc) of 2.25 year for R. kanagurta. The length-weight relationship of R. brachysoma was observed as W=0.0274 L2.7921, r=0.93, r2=0.8671, a=-1.563, b=2.7921 for male and W=0.0553 L2.5585, r=0.88, r2=0.7718, a=-1.2575, b=2.5585 for female. The length-weight relationship of R. kanagurta was observed as W=0.0283 L2.7738, r=0.92, r2=0.8424, a=-1.5484, b=2.7738 for male and W=0.0912 L2.3954, r=0.94, r2=0.8927, a=-1.0399, b=2.3954 for female. Result showed that R. brachysoma and R. kanagurta had shown negative allometric growth because b values was less than 3 (b