Macrobenthos at marine hotspots along the northwest Indian inner shelf: Patterns and drivers

Abstract

Marine hotspots are areas prioritized for conservation and monitoring, based on their sensitivity or vulnerability. Understanding the natural variability of resident organisms in such critical areas is integral for deciphering human-induced perturbations to formulate appropriate management strategies. Five marine hotspots along northwest India, comprising three active harbours and two marine protected areas, were surveyed seasonally to understand the macrofaunal distribution patterns and functional traits. Among the 33 macrobenthic taxa, Polychaeta constituted the dominant taxon. Spatial variability was prominent due to differences in terms of polychaete species types, relative abundances and functional trait matrices. Monsoonal hypoxia altered the macrobenthic species and functional composition. CCA revealed a combination of natural (texture, DO, salinity) and anthropogenic (PHc, SS, ammonia) hydro-sedimentological variables as key drivers for the polychaete distribution patterns. The results are expected to improve the understanding of the variability and functioning of polychaete taxocommunity within the ecologically and economically significant "marine hotspots".

Keywords: Abiotic factors; Benthos; Hypoxia; Marine hotspots; Northwest Indian shelf; Polychaetes.