Sao Paulo, Sep 25 (IANS/EFE): The coral reefs of northeastern Brazil have been reduced in size by some 80 percent over the past 50 years due to abusive extraction and pollution from urban and industrial sources, a new report says.

Researchers working on the study, which was prepared by the Federal University of Pernambuco and the environment ministry, started gathering data in 2002 and finished their work last year under Beatrice Padovani, a professor.

The report, which will be presented at an environmental conference Monday, found the presence of coral along about 2,000 km of coast in northeastern Brazil, the Globo Web site reported, citing excerpts from the study.

Extractive activities, pollution, excessive fishing and rising water temperatures led to an 80 percent decline in coral reefs, the report said.

"Until the 1980s, there was much extraction to make lime in the country," Padovani said, adding that pollution and sediment also harmed the coral reefs.

The researchers also noted that rising ocean temperatures due to climate change and more frequent weather phenomena, such as the "El Nino" effect, had affected reefs.

"In 2012, it is likely that there will be a new 'El Nino'. The reefs that will suffer most are the ones in the worst environmental condition," Padovani said.