Context:

• Coral reefs in the Gulf of Mannar in Tamil Nadu are facing a new threat. Researchers have found that an invasive marine sponge species, Terpioshoshinota, is growing aggressively over live coral colonies in Van Island in the Mannar Bay, which could prove fatal for coral reefs there.

Other Facts:

• The researchers found the sea sponge growth in coral colonies at the depth of a metre during a routine underwater coral monitoring survey in September 2015. Terpioshoshinotawas first reported in Guam in western Pacific ocean, with subsequent reports from Japan, Taiwan, American Samoa, Philippines, Thailand, Australia, Indonesia and Maldives. It has recently also been reported in the Indian reefs from Palk Bay.
• “Invasion of Terpioshoshinota has proved devastating for corals, as this sponge can outcompete and kill coral colonies. The present observation of it in Gulf of Mannar poses a significant new threat to the corals in the area.
• The Gulf of Mannar is known for the high level of diversity and productivity of its reefs.
• A large population of fishermen depends directly on coral reefs for their livelihood and any loss in the productivity of the system would be of huge concern.
• Generally dead coral skeletons host high numbers of sponge species than live corals. However, there are few species of sponge, which can overgrow live corals and eventually kill them.
• Terpios hoshinota is such a sponge species that aggressively overgrows live coral and can undergo outbreaks causing significant declines in live coral cover.

Source:Downtoearth