The pattern of changes in the macrobenthic community was studied along the south-east coast of India from the estuary to continental slope. A transect perpendicular to the coast was selected for sampling in estuary, inshore region, continental shelf and continental slope. Sampling was done in 16 stations in the depth range of 1.7–1000 m. The community structure was characterized in terms of species composition, abundance, diversity and feeding type. Four taxa were encountered in the study area comprising 181 species of polychaetes, 65 species of molluscs, 47 species of crustaceans and six species of ‘others’ (four echinoderms and two cnidarians). Polychaetes were found to be dominant at all the depths constituting 53.89% of the total abundance and 60.54% of the total number of species. Number of species and Shannon diversity of macrobenthos increased from estuary to shelf region and then decreased. The abundance was found to be maximum in the estuary and minimum in the slope. Carnivorous species were found to be dominant in the estuarine and inshore regions and surface deposit feeders in the shelf and slope regions. Dissolved oxygen decreased gradually from 30 m depth and beyond 150 m the decrease was pronounced due to the presence of the oxygen minimum zone. The distance based linear model (DISTLM) showed the environmental variables to explain about 76.45% of the total variability in macrofaunal distribution. Among the various environmental parameters, total organic carbon, depth and salinity explained more variability than others. Gradual change in community structure was quite evident with increase in depth.

A checklist of free-living marine nematode species recorded from the continental shelf region of southeast coast of India is presented (10°34.03’ to 15°14.48’ N and from 79°52.13’ to 80°53.87’E). The checklist comprise 191 species belonging to 97 genera in 32 families currently know from the area. We provided a synthesis of the taxonomical and ecological work carried out until now that could guide to future research.

Marine sediments in continental shelf ecosystems harbor a rich biodiversity of benthic communities. In this study, the spatial and temporal diversity and community assemblages of free-living marine nematodes were studied by sampling at six depths and over 3 years from the southwest continental shelf off Bay of Bengal, one of the least explored tropical shelf ecosystems. The dominant marine nematode species were related with abiotic variables as part of this study. The effects of sediment granulometry generally decreased with increasing depth and the highest nematode density and species diversity were recorded on coarse sand (shallower depths). Multivariate analysis of the nematode community data showed that community structure differed significantly among depths as well as among years. Statistical analyses showed significant correlations between the nematode community and abiotic variables. Sediment texture, organic matter, water pressure and depth profile were crucial factors for determining diversity, vertical profile and feeding types of the nematode community. Other environmental factors, including anthropogenic pressure, did not have an effect on nematode diversity except for the presence of some tolerant species (Metachromadora spp., Sabatieria spp. and Siplophorella sp.). This study represents a baseline of knowledge of free-living marine nematode communities that can be used in the future to compare nematode assemblages from temperate shelf ecosystems.

A checklist for commercially important food fishes from Parangipettai, Southeast coast of India is presented (lat. 11̊ 30' N, long. 79̊ 46' E). This comprises 93 species belonging to 57 genera and 42 families currently known from the area, which are all of commercially valuable. We provided a synthesis of the taxonomical work carried out until now that could guide to future research..

The Indian Ocean tsunami of December 26, 2004 devastated the southeast and southwest coasts of India. The impact of this tsunami on the macrobenthic communities of the continental slope off the southeast coast of India was assessed using samples collected prior to the tsunami (May–June, 2004), 6 months after the tsunami (June–July, 2005), and 18 months post‐tsunami (May–June, 2006). Samples from three different transects (Chennai, Cuddalore, and Karaikkal) and at three different depths (200 m, 500 m, and 1000 m) revealed the impact very clearly. Sediment granulometry, numerical abundance of macrofauna, number of species, diversity (Shannon–Wiener index and Total taxonomic distinctness index), species richness, species assemblages, and feeding types of macrobenthos showed the impact of the tsunami and the slow recovery thereafter. Our data showed that the macrobenthic community had not returned to the pre‐tsunami state after one and one‐half years.