Seasonal dynamics of fish assemblages in an intertidal mudflat of Indian Sundarbans

Sumit Homechaudhuri,Atreyee Chaudhuri,Sudeshna Mukherjee

doi:10.3989/scimar.03766.15a

Abstract

In the present study, the seasonal and inter-annual fish assemblage structure of intertidal mudflats of Indian Sundarbans was analysed during tidal cycles. A total of 31 fish species belonging to 22 families and 9 orders were collected during high tide, whereas only 12 were recorded during low tide. Fish assemblage descriptions were based on several community descriptors, namely diversity (H′), species richness (S), species dominance (D), and species evenness (J) and on an ecological guild classification. A canonical correspondence analysis (CCA) was performed to evaluate the relationship between estuarine habitat and fish assemblages in the mudflat habitat during inundated and exposed conditions. All the diversity indices showed marked seasonal and inter-annual variations. Temporal variations were also found in fish assemblage structure in both tidal conditions. Estuarine species were the most important ecological guild of the mudflats during both high and low tides. Of all the abiotic variables examined, CCA showed that salinity, pH and nutrients were the most important influencing fish assemblage during high tide. Total dissolved solids, water temperature and salinity were significant during low tide. Considering the importance of mudflats in supporting fish diversity, the present study emphasizes the increased efforts for conservation of this habitat in the Indian Sundarbans.

Highlights

Estuaries and coastal lagoons show high levels of habitat heterogeneity and support a large fish production (Elliott and Hemingway 2002)
Table 1. – Water and soil parameters of studied mudflats of the Indian Sundarbans
Table 2. – Percentage abundance of the species caught in each season in mudflat habitat during high tide and low tide in three different seasons in three respective years (Y1, Y2, Y3)

Summary

Introduction

Estuaries and coastal lagoons show high levels of habitat heterogeneity and support a large fish production (Elliott and Hemingway 2002). Mudflats are a dominant habitat in many estuaries, often covering a considerable part of the total estuarine area. This particular type of habitat has been recognized to be of key importance for the estuarine food web due to its high productivity when compared with subtidal areas (Elliott and Dewailly 1995). Mudflats are structurally less complex than mangroves, but they contain great abundance and diversity of invertebrates and are periodically immersed and emerged in each tidal cycle. They are only available to nekton during tidal

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