An invasive species of coral colonising the waters off the southern coast of India has been found to be on the decline, lifting the threat to the marine ecology of the region.
Citizen scientists attached to Friends of Marine Life, a local NGO, have reported the declining population of the coral in the near shore waters over the last two years.
In early 2016, scuba divers working for FML had recorded the presence of several colonies of the fast-growing Snowflake Coral ( Carijoa riisei ) amid barnacle clusters on the rocky reef off the Kovalam in Thiruvananthapuram and Enayam, Kanyakumari.
Documentation
The underwater documentation was done as part of a research project harnessing the traditional knowledge of the fishermen community to assess the marine biodiversity of the region. The snowflake coral is known to inhabit reefs and underwater structures such as shipwrecks and piers, attaching itself to metal, concrete and even plastic. It is considered an invasive species because of its capacity to dominate space and crowd out other marine organisms like corals, sponges, algae and ascidians.
Researcher Robert Panipilla who coordinates the project and is part of the diving team said the C.riisei colonies were found to have shrunk in size over the year, with the species almost wiped out at Enayam.
Detrimental factors
Mr. Robert said the deep sea at Kovalam and Enayam and the ocean current at these locations could have affected the survival of the colonies.
“The destruction of the few C.riisei colonies spells good news for the marine ecosystem in the region”, says A. Biju Kumar of the Department of Aquatic Biology and Fisheries, University of Kerala.
Churning of the sea
Dr. Kumar feels that the churning of the sea during cyclone Ockhi late last year could have dislodged the colonies.
A native of the tropical Western Atlantic and the Caribbean, C.riisei was first reported as an invasive species from Hawaii in 1972. Since then, it has spread to Australia, Thailand, Indonesia and the Philippines. In India, it has been reported from the Gulf of Mannar, the Andaman and Nicobar Islands, Gulf of Kutch and Goa.
