MEXICO CITY - Researchers in Mexico say they have discovered five previously unknown coral reefs off the country’s Gulf coast.

The federal Education Department says the reefs collectively cover an area of more than 2,700 underwater acres (1,100 hectares).

It says in a statement that they lie both inside and outside a marine protected area, and scientists are asking for them to be legally protected against oil extraction and development projects.

The department says the discovery includes a 3-mile-long (5-kilometre-long), 2,300-foot-wide (700-meter-wide) reef off the Tamiahua Lagoon, near the city of Tampico, the longest and northernmost reported in the area to date.

Saturday’s statement said the reefs are a fundamental part of the marine food chain and an important refuge for species fleeing rising water temperatures.