Biology and Growth Parameters of Spotted Seerfish - Scomberomorus guttatus (Bloch & Schneider, 1801) from North East Coast of India

Abstract

Seerfish is one of the most commercially important food fish in India. The production figure of seerfish shows an increasing trend in the last five decades in the Indian coasts. Among the five species of seerfishes the species Scomberomorus commerson and S. guttatus commonly occur in Indian waters. The seerfish production in India during 2011 stands at 48954 t and that of spotted seerfish was 17535t (35.8%). The exploratory survey results of Fishery Survey of India (FSI) by deploying demersal and pelagic trawl indicated the dominance of S. guttatus (62.2%) in the seerfish catch during the period 2006-10 in the northeast coast of India. The biological as well as growth and population parameters of a particular species are absolutely needed to manage the fishery to a sustainable level. Hence in this paper an attempt has been made to analyze the exploratory survey data collected onboard FSI vessels to study the biology and growth parameters of spotted seerfish S. guttatus in the northeast coast of India. The study indicated that the size range of the species ranged between 16.1-63.5cm fork lengths with 39.1-42cm length group dominated the population. The male to female ratio was 1:1.6. The length weight relationship was Log W = -1.1283 + 2.4627 Log L (r = 0.91). There were six stages of maturity and the spawning season was between January and June. The growth parameters such as L∞, K and t 0 were 64.6cm, 0.97 and -0.1532 respectively. The natural mortality was 1.43 and fishing mortality was 1.28. The longevity of the species was estimated as 2 years. The virtual population analysis (VPA) indicated that the mortality due to natural causes alone was up to 28cm length suggesting exploitation of smaller specimens. The food and feeding study shows that the species are piscivorous in nature.