Testing the efficiency of temperate benthic biotic indices in assessing the ecological status of a tropical ecosystem

• Assess the ecological status of Indian coast using temperate benthic indices
• Examine the effect of seasonality on the performance of benthic indices
• 21 indices with different ecological principles and paradigms were applied.
• Effect of seasonality on the indices observed in the estuaries and inner shelf
• Non-monsoon period is a suitable time for effective use of benthic indices.

The objectives of the present study were to evaluate the ecological status of tropical coastal waters using the temperate benthic indices and examine the effect of seasonal variability on the performance of benthic indices. Macrobenthic samples were collected from northwest to southeast coast of India during 2003–2012 and we tested different univariate indices, ecological strategies, indicator species and multimetric indices. AMBI and multimetric indices performed satisfactorily in evaluating the ecological status. Seasonal variability on the biotic indices was observed during the southwest monsoon and fall intermonsoon period due to recruitment. Therefore, we recommended the non-monsoon period (January–May) as a suitable time of the year to use the indices for effective assessment of the Indian coastal waters. Results show that, the temperate benthic indices are efficient in assessing the tropical environmental status. However, complementary use of different indices is suggested for accurate assessment of the environmental status.