[1] The park has a high diversity of plants and animals in its marine, intertidal and near shore habitats.

[5] There were two more islands named Pandayan and Punnaiyadi at 8°46′51″N 78°11′43″E / 8.78075°N 78.19536°E / 8.78075; 78.19536 that were destroyed for construction of the new Tuticorn Port facilities.

The park includes marine components such as coral reefs, seaweed communities, sea grasses, and mangroves.

The flowering herb Pemphis acidula (family Lythraceae) is the only endemic plant species.

[20] A unique endemic species of Balanoglossus – Ptychodera fluva, a living fossil that links invertebrates and vertebrates, has been recorded only at Kurusadai.

Large areas of these reefs are in generally poor condition due to destructive human activities of the 150,000 persons living along the coast.

It appears that the coral reefs of the Gulf of Mannar Marine National Park seem to be healthy and in good condition, despite high rates of sedimentation and other threats.

[24] Stony coral species of families Poritidae and Faviidae constitute the dominant reef builders here.

[25] Along the coast near the park there are about 125 villages which support about 100,000 people who are mainly Marakeyars, a local community principally engaged in fishing.

According to J K Patterson Edward, director of Suganthi Devadasan Marine Research Institute (SDMRI), Tuticorin,"Rampant coral mining by people of the fishing villages along the coast is the main cause of the devastation to the island.