Bathymetric Variation on the Quantitative Diversity in the Deep-sea Fish Assemblage of Southwest India, Arabian Sea

Environmental parameters such as temperature, pressure, and salinity are important parameters that contribute to changes in species assemblages. Changes in environmental parameters along with depth are a common phenomenon in the deepsea floor. In the present study, we collected data during an exploratory trawl survey in deep waters (180-1000 m) in the Arabian Sea southwest of India A total of 84 deep-sea fish species was identified from 22 trawling stations. A multivariate analysis of the species abundance at the various stations showed three distinct groups corresponding to the depth zones of 100-300 m, 300-700 m, and 700-1000 m. The analysis of diversity indices showed that diversity indices are increases when the depth increases. The first 10 most abundant species in the 100-300 m depth region contribute -70% of the diversity also 82%, 50% for 300-700 m and 700-1000 m depth ranges respectively. Therefore, we assume environmental parameters have a significant influence on determining species assemblages in the ocean floor. Moreover, the results of diversity indices will serve as benchmark information for future studies and ecosystem-based modelling of Southwest India.