Ichthyofaunal biodiversity of trawling grounds off Mangalore coast

The present investigation was taken up with objective to assess the status of ichthyofaunal diversity off Mangalore coast. A total 97 species belonging to 72 genera, 50 families and 15 orders were recorded during the study period. The value of Shannon-Wienner index (H') was recorded ranged from 1.404 to 1.648. There is less variability among H'. Diversity and evenness are highly correlated (0.90) and showed variation with each other. Average value of Simpson index was found to be 0.038 and the value of Simpson index increased with decrease in diversity. Cumulative curve (K-dominance curve) plot showed that density of fish species is high in the month of Oct. 2012 and proved the number of species (richness) more in the month of October 2012 compared to other months. From the overall cluster analysis [Bray-Curtis similarity (hierarchical clustering)], it was founded that the maximum similarity (89.65%) was observed between the month March 2013 and April 2013. During the study period, there were good landings immediately after the ban period (monsoon). It is evident that seasonal trawl ban, in the present form, has helped long-term recovery of the stock.