Assessment of benthic habitats of highly threatened oyster reefs of Pulicat Lake, India

The present study was aimed at demarcating the distribution of oyster habitats along the Pulicat Lake, the second largest brackish water lagoon in India, and investigating their benthic faunal assemblages and functional feeding groups. This study delineated three major reefs (6.70 ha, 5.50 ha, and 2.39 ha areas), and two minor beds (1.10 ha and 0.68 ha areas). Four species of oysters, namely, Magallana bilineata, Saccostrea cuccullata, Isognomon ephippium and Pinctada imbricata fucata were found in the oyster habitats, with M. bilineata being a major reef-forming/ecosystem forming species. Macro faunal assemblages in the oyster habitats comprised 71 species representing five major phyla belonging to 66 genera under 48 families. Macrofauna were grouped into five Functional Feeding Groups (FFG) considering oyster habitats as a primary food provider. The FFG analysis revealed that the oyster reef/bed in Pulicat Lake is in moderate Ecological Quality Status (EQS). This study is considered very important to know the current extent of oyster reefs and gain a better understanding of the community interactions within oyster habitats and their ecological value to the dwelling species.