WASHINGTON, Aug. 15 (Xinhua) -- An unusual severe, toxic red tide break continues to hurt the coastal environment and the tourism industry in the southeastern U.S. state of Florida, leaving large amounts of dead fish and other sea animals washed up on the state's beautiful white sand beaches along Gulf Coast.

"Since our contractor has been on the island, he started August 1, we collected about 300 tons of fish from the beach," Scott Krawczuk, deputy director of public works for the City of Sanibel in southwest Florida, told Fox News.

The carcasses washed up on the beach range in size from small bait fish to a 26-foot-long whale shark, said local media reports.

Affected beaches have been shut down, and many local businesses have also temporarily closed, according to the reports.

Florida Governor Rick Scott on Monday issued a state of emergency for seven Gulf Coast counties so as to provide more money and resources to address the red tide outbreak.

This year's red tide, stretching 150 miles from Collier to Manatee counties, is one of the worst the state has ever seen, according to local media reports, quoting experts as saying that it began as a patchy bloom in late October and coalesced in late June.

Red tide is a burst of harmful algae growth which can turn ocean water red, brown or green. The microscopic algae release toxins in the water that can kill marine wildlife and negatively affect humans. Some tourists have reported that even breathing air near the shore can be difficult.

Red tide is caused by a combination of conditions, including wind, currents, and the presence of nutrients that allow the algae to grow.

The first red tide outbreak was reported in Florida in 1844.