Mesoscale eddies enhance the productivity in a stratified coastal environment by upwelling. The seas around the Andaman and Nicobar Islands have been found to have frequent mesoscale eddy activity. Commercial fishing grounds coincide with upwelling areas associated with cyclonic and anticyclonic eddies and also with areas between two adjacent eddies. There are different eddy zones supporting different types of fishing gears and fish. The current study aims at identifying the different zones of mesoscale eddies in the Andaman Sea and compares the productivity and fishing activity in each of them. Data collected from 454 commercial fishing trips in the Andaman Sea along with maps of sea level anomaly and Moderate Resolution Imaging Spectroradiometer (MODIS) global level 3 mapped thermal infrared (IR) daytime sea surface temperature (SST) from the Aqua and Terra satellites were used for the study. Known upwelling areas such as the periphery of anticyclonic and the core of cyclonic eddies showed higher catches in longlines, ring seines among the fishing gears, and among all the fish species groups. Downwelling areas such as the periphery of cyclonic and the core of anticyclonic eddies showed lower catches with ring seines and the fish species groups. Areas in between adjacent eddies were explored in this study and the fish captures in such areas were found to be different with types of fishing and the target fish group. The study shows results that link eddy activity with the performance of a fishery.

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Despite extensive studies on mangrove ecosystems of Andaman and Nicobar Islands since the 1870s, knowledge of exact species composition is far from complete, and there is a lack of comprehensive locality data. The present study was designed to review the existing literature and to provide an updated checklist of the true mangrove species of the Islands. Preliminary surveys were carried out in seven regions (four from the Andaman group and three from the Nicobar group), and the specific survey sites for detailed study (n = 51) were selected based on representativeness, importance, and accessibility. During 2009During -2013, all the selected sites were visited, and mangrove species occurrence was recorded. At present, 25 true mangrove species distributed among 10 families and 14 genera were identified vis-à-vis 17 to 36 species reported in earlier studies. The discernible changes in species numbers from earlier studies could mainly be attributed to our exclusion of associated littoral vegetation and of species unlikely to be present among the true mangroves of the Islands. Given their limited geographical area, the low similarity index values between the Andaman and Nicobar Island groups ( ≤ 0.4) indicate a need for periodical surveys, as mangrove biodiversity is usually homogenous in regions where there are no impassable dispersal barriers. Further, regular updating of information on the extent and status of mangroves in the Islands is imperative not only to improve our understanding of phytogeography but also for better management and conservation.

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