A team of international researchers, who published their study Monday, said their report was the first to "show the long-term impact of sea temperature rise on reef coral and fish communities".

"Large sections of coral reefs and much of the marine life they support may be wiped out for good," the researchers warned.

The team, led by the University of Newcastle upon Tyne in northern England, surveyed 21 sites and over 50,000 square meters (538,000 square feet) of coral reefs in the inner islands of the Seychelles in 1994 and 2005.

They said their work is the first to show the long-term impact of the 1998 event where global warming caused Indian Ocean surface temperatures to increase to record and sustained levels, killing off over 90 percent of the inner Seychelles coral.

Many of the reefs collapsed into "rubble which became covered by unsightly algae" and would be unable to reseed and recover.

The researchers said the reefs are possibly unable to recover because of their "relative isolation" and a lack of nearby reefs to provide new larvae, which could help such reefs to regenerate.

The destruction of the reefs has also removed food and shelter from predators for a large and diverse amount of marine life, and "in 2005 average coral cover in the area surveyed was just 7.5 percent".

The study claims that four fish species -- a type of butterfly fish, two types of wrasses and a type of damsel fish -- "are possible already locally extinct, and six species are at critically low levels".

It cited the six species as a type of file fish, three types of butterfly fish and two damsel fish.

The researchers also said that species diversity of the fish community had decreased by 50 percent in the worst-affected areas.

The study was published in the Proceedings of the National Academy of Sciences.

All rights reserved. copyright 2018 Agence France-Presse. Sections of the information displayed on this page (dispatches, photographs, logos) are protected by intellectual property rights owned by Agence France-Presse. As a consequence, you may not copy, reproduce, modify, transmit, publish, display or in any way commercially exploit any of the content of this section without the prior written consent of Agence France-Presse.