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Abstract. This paper is the first contribution to the knowledge of pteropods in surficial sediments of the entire western continental shelf of India. Both qualitative and quantitative analyses of pteropod assemblages were carried out on 50 coarse fractions (>125 μm) of topmost portions of grab samples recovered along 12 transects covering the inner shelf to the upper slope (30–200 m water depths). The distribution of eight significant species was mapped. The resultant maps were correlated with the bathymetric, hydrographic and aragonite preservation conditions in the investigated area. This study reveals a bathymetric control over the distribution of Limacina inflata, Creseis acicula and Creseis chierchiae across the shelf. Furthermore, a marked difference in vertical salinity gradient from south to north along the shelf appears to have a profound influence on the abundance of these species. The pteropod shells in sediments of the northern offshore region with anoxic bottom conditions are generally well preserved, unlike the southern region, where oxygen concentration of the bottom water is relatively high enough to cause dissolution or even elimination of many shells of the most susceptible pteropods like C. acicula and C. chierchiae. The variation in the intensity of the oxygen minimum zone along the western continental shelf of India has significant influence upon the distribution pattern of Clio convexa.

Because of the increasing oil industry development in the Arabian Gulf, hundreds of oil and gas facilities have been installed in both offshore and inshore areas during the last few decades. However, no studies have been conducted till now on the influence of these platforms on the structure and composition of marine faunal assemblages. The present work addresses this issue to propose environmental management measures connected to the utilization of fishery resources. Offshore and inshore surveys were carried out along the Saudi Gulf waters using trawl and beach-seine nets, respectively. Data relative to only fish (offshore) and fish and invertebrates (inshore) were collected concurrently with several factors: density of oil and gas facilities (offshore), distance to the nearest coastal platform (inshore), oceanographic variables, and habitat characteristics. Results of offshore surveys indicated higher fish density—both total and of fishery resources—in locations with a higher number of oil and gas facilities within a 5 km radius, whereas biomass density was not significantly different. Hence, oil and gas facilities seem to serve as nursery areas for small fish. For inshore communities, more species and diversity were found in stations closer to coastal oil and gas facilities. In addition, among the five coastal embayments sampled, those with more oil and gas facilities had more species. The findings of the present work support the hypothesis of a positive net ecological role of oil and gas platforms of the Saudi Arabian Gulf, with the implication that this effect could be extended to improve the sustainability of important fishery resources.