Seasonal variations in habitat selection and catch trends of Sciaenids (Family: Sciaenidae) from the tropical waters off Goa, west coast of India

Abstract

Seasonal variations in species composition, habitat selection and catch trends of sciaenids off Goa, west coast of India were investigated for twelve seasons from 2006-2011, with the exceptions of June-September (monsoon). Present observations based on 248 hours fishing effort (186 trawl operations) revealed 14 species of the family Sciaenidae. Sciaenid abundance (alpha=0.05, P=0.03071) and weight (alpha= 0.05, P=0.1426) was significantly higher during pre-monsoon than the post-monsoon season with an exception of post-monsoon 2009. Analysis of spatial variation revealed that sciaenid abundance varied significantly (alpha=0.05, P=0.0593) between sandy and rocky habitats with dominance of juveniles and adults respectively. Dominance of juvenile population along sandy regions irrespective of the season indicates perennial recruitment and emphasizes the importance of the near shore sandy regions as potential nursery grounds. An assessment of sciaenid landings of Goa (1969-2004) revealed significant increase (R=0.709) during the initial phase of post-mechanization (1969-1986) due to increase in fishing effort and expansion of the demersal fishery to deeper waters. In contrast, marginal decrease during 1986-2004, despite the elevated fishing effort, suggested reduced resilience of the sciaenid populations in the region towards seasonal hypoxia and sustained fishing pressure, with a slow recovery rate.