NAPLES, Fla. — Florida wildlife officials say a red tide bloom persists along the southwest Florida coast and some fish kills have been reported.

The Florida Fish and Wildlife Conservation Commission says the organism responsible for red tides is a natural part of the ecosystem but it can bloom to high concentrations when conditions favor it. Over the past week, samples were collected offshore in Collier, Lee, Hillsborough, Sarasota, Charlotte and Monroe counties.

A fish kill was reported at Big Pine Key in Monroe County on Feb. 7. Slight respiratory irritation was reported in Sarasota County at Manasota Beach two days earlier.

Fish kills can happen when counts of the organism reach 10,000 cells per liter.