Seasonal variation of ichthyofauna in trawling grounds off Mangaluru coast, Southwest coast of India

Mangaluru coast, Southwest coast of India has vast aquatic bio-resources and offers considerable scope for marine fisheries development. The present investigation was carried out to assess the ichthyofaunal diversity off Mangaluru coast, Karnataka, India (Lat.12 degrees 50' 54" N; Long. 74 degrees 50'11" E). The data for the study was collected from 160 multiday trawlers operating from Mangaluru fishing harbour during September, 2012 to April, 2013. A total of 97 species belonging to 72 genera, 50 families and 15 orders were recorded. Order Perciformes was the most diversified group having 56 fish species (57.7 %) followed by Clupeiformes 14 fish species (14.4 %), and Tetraodontiformes and Pleuronectiformes with 4 fish species each (4.1 %). The family Carangidae contributed 13.4 per cent of total number of species, followed by Clupeidae (6.2 %) and Engraulidae (5.2 %). Trichiurus lepturus contributed 15.42 per cent of total landing followed by Sardinella longiceps (12.1 %), Nemipterus japonicus (10.7 %), Decapterus russelli (9.9 %), Rastrelliger kanagurta (9.6 %) and Nemipterus randalli (8.4 %). The overall cluster analysis of the Bray-Curtis similarity (hierarchical clustering) shown that maximum similarity (89.7 %) was between March-2013 and April-2013. The study showed that the samples from adjacent months were having more similarity in species composition and abundance. The stress value, which overlying on the MDS plot (0.06), showed greater extent of ordination in the collected samples.