Diversity of reef associated fishes in hook and line fishery at Mandapam, Gulf of Mannar, south-east coast of India

Abstract

Reef associated fishes landed by hooks and lines at Mandapam landing centre in Ramanathapuram District, Tamil Nadu for a period of four years from October 2008 to May 2012 were studied based on fortnightly samplings. The hook and line fishing is seasonal in Gulf of Mannar and lasts for six months annually from October - November to April - May, as this area remains rough during the rest of the year. The average annual landing of fish during the study period was 171 t with a peak of 295 t in 2008-09 and showed a decline since then. A total of 32 species of reef associated fishes belonging to 14 families were landed. Among them, Sphyraena barracuda contributed the maximum with a share of 42% followed by Caranx heberi (15%). Family-wise landings indicated the dominance of Sphyraenidae (46%). The diversity index (H’) was the highest during 2008-09 and the evenness of distribution of individuals among different species did not show significant variation in different years. Funnel plots of average taxonomic distinctness (∆+ ) and variation in taxonomic distinctness (λ+ ) indicated that the values in most of the years are within the normal limits.