SARASOTA (AP) — A large red tide bloom that’s about 12 miles long and six miles wide is lingering off the Charlotte-Sarasota County coastline and killing fish.

The Herald-Tribune reports that September and October are the most common months for red tide blooms which are caused by toxic algae.

Area hotel owners and tourism officials are hopeful that the problem won’t worsen or spread.

The red tide effects are limited to southern Sarasota and Charlotte counties. No dead fish or bad air quality were reported on beaches north of Venice.

Red tide naturally occurs in the Gulf of Mexico. The bloom is deadly for fish, marine mammals, sea turtles and other sea life.

The toxins also can become airborne and cause breathing problems for people with asthma or other respiratory diseases.