Florida’s southwest coast has experienced a flare-up of the toxic “red tide” algae causing warnings against swimming, dead fish to wash up on beaches, and the cancellation of a beachside festival. And there are concerns that it that the bloom, which started in October, could stick around for awhile.

The annual BeachFest in Indian Rocks Beach was cancelled after it determined, with help from the city and the Pinellas County Health Department, that red tide likely would continue through the middle of next month when the festival was scheduled.

“Red Tide is currently present on the beach and is forecasted to remain in the area in the weeks to come,” the Indian Rocks Beach Homeowners Association said in a letter to the public. “It is unfortunate that it had to be cancelled but it is the best decision in the interest of public health.”

Nearly two tons of debris, mainly dead fish, were cleared from Pinellas County beaches and brought to the landfill, county spokesperson Tony Fabrizio told the Tampa Bay Times. About 454 kg. of fish have been cleared from beaches in St. Pete Beach since the start of the month, Mandy Edmunds, a parks supervisor with the city, told the newspaper.

Red tide, a toxic algae bloom that occurs naturally in the Gulf of Mexico, is worsened by the presence of nutrients such as nitrogen in the water. The Florida Fish and Wildlife Conservation Commission warns people to not swim in or around red tide waters over the possibility of skin irritation, rashes and burning and sore eyes. People with asthma or lung disease should avoid beaches affected by the toxic algae.

The Florida Fish and Wildlife Conservation Commission reported that it had found red tide in 157 samples along Florida’s Gulf Coast, with the strongest concentrations along Pinellas and Sarasota counties.