Coral fish diversity in Netrani waters off Murudeshwar Karnataka, south India

Abstract

Fish diversity associated with coral reef patches around Netrani Island, in Karnataka (south India) was investigated by visual census method. Sampling was done in four sites around the Island. A total of 69 species belonging to 39 genera, 19 families and 3 orders were recorded in the transect in four sites. When comparing the abundance, the fishes of Balistidae family dominated in all the four sites (22 %) followed by Pomacentridae (12.5 %), Caesionidae (9.7 %), Labridae (7.8 %), Acanthuridae (7.3 %), Haemulidae (6.7 %) and Scaridae (6.1 %). In line with the abundance and number, Shannon diversity indices (H’) were 2.8 in site 1; 2.6 in site 3; 2.3 in site 4 and 2.2 in site 1. The evenness (J’) of species distribution was more in site 2 (0.9), followed by site 3 (0.8); site 4 (0.7) and site 1 (0.7). The Bray-Curtis similarity was in the range of 69.98 to 79.50. The dendrogram plotted showed that site 2 and 3 form a group with similarity of 79.50, to which site 1 and site 4 got linked. There was no significant difference in the hydrographic parameters of the surface and bottom waters in four sites and also between different sites. The study revealed high coral fish density in the area indicating the need for adopting conservation measures.invertebrates, cnidarians and worms, zooplankton dominated by copepods and nekton dominated by Acetes spp. and clupeid juveniles were the major food items of A. monoceros. The von Bertalanffy growth equation was Lt = 63.53 [1 – e - 0.22 (t + 0.077)]. Natural mortality, fishing mortality and exploitation ratio were 0.53, 0.58 and 0.52 respectively