Estimation of growth parameters for tropical Scomberoides lysan (Carangidae)

Abstract

The present study was carried out to understand the growth parameters of the tropical double spotted queen fish, Scomberoides lysan. Growth parameters of S. lysan such as asymptotic length, growth coefficient and age at zero length were estimated based on length frequency data using FiSAT II software. A total number of 1115 samples were collected weekly from the commercial catches in the Northern waters of Sri Lanka during January 2010 to December 2011 and sexes were separated by observing the gonads. The von Bertalanffy growth parameters for male S. lysan were Loo = 87.96 cm, K= 0.41 year'1, to = -0.1582 year'1 and for females, L* = 88.85 cm, K= 0.40 year'1, to= -0.16195 year'1. The growth coefficient (K) of both male and female indicates that this species shows faster growth. The Powell-Wetherall plot gave a Z/K value of 2.174 for males and 1.964 for females, where Z is the total mortality. The estimated growth performance index (0) for male and female were 3.5013 and 3.4993. The inverse von Bertalanffy equation shows that 50 % of males attained maturity at age 2.266 years (55.4 cm total length) and females at 2.712 years (60.7 cm Total length). Estimated longevity (tmax) for S. lysan calculated from Pauly’s equation was 7.317 for males and 7.338 for females. The results give fundamental data for the population dynamics and stock assessment studies of S. lysan.