Fish as bio-indicator tool for assessing estuarine health

Fish Health Index and Index of Biotic Integrity directly indicates environmental health and was used in our monitoring at Coleroon, Vellar and Uppanar, estuaries in the southeast coast of India. The use of cast nets revealed 104 species of fish that belongs to 69 genera, 44 families and 10 orders. Assessment using fish health index at Coleroon, Vellar and Uppanar estuaries produced scores of 4.8692, 8.4981 and 1.4042 which means Vellar has better health than Coleroon and Uppanar. In addition, 12 metrics were used to produce the index of biotic integrity where total scores varied from 18 to 51. With Vellar achieving higher scores than Coleroon and Uppanar estuary, a Two-way ANOVA was employed to validate the data with significant achievement (P<0.005). Therefore, we can safely associate Coleroon, Vellar and Uppanar with ‘Fair’, ‘Good’ and ‘Very poor’ grades. Also, visual depiction of Vellar demarcates it as pristine in comparison to Coleroon and Uppanar that are subject to impairments along with dominance of omnivorous fishes. Knowledge from this study eases monitoring of important estuaries particularly for food security so that management sustains community livelihood.