Distribution and abundance of mysid shrimps (Crustacea: Mysidacea) in the Northern Indian Ocean.

Abstract

The distribution and abundance of mysids were studied based on materials collected from the upper 1000 m of the Northern Indian Ocean (Exclusive Economic Zone (EEZ) of India) during the period 2002–2006. A greater abundance of mysids occurred in the Arabian Sea (48.6% of the total mysid population) compared to the Bay of Bengal (24.8%) and the Andaman Sea (26.6%). Both bathymetry and hydrography are important factors influencing mysid distribution and abundance. In the Arabian Sea, maximum mysid abundance occurred during the inter-monsoon (IM) period, but in the Bay of Bengal and the Andaman Sea abundance was highest during the northeast monsoon (NEM). Twenty-seven species belonging to 21 genera were recorded from the study area. Maximum species richness occurred in the Arabian Sea (18) followed by the Andaman Sea (13) and the Bay of Bengal (9). Pseudanchialina pusilla was the most abundant species found (64.8% of the total mysid population) followed by Siriella gracilis. Out of the 27 species found, 13 are restricted to surface waters. Below 500 m depth only two species, Boreomysis plebeja and Giberythrops acanthura, were found. In the Bay of Bengal and the Andaman Sea, mysid abundance did not show much variation between nearshore and offshore regions.