Dead fish floating in Florida Bay may have died from heat

The Miami Herald reports: Thousands of fish popped up dead this week in Florida Bay -- possible victims of what might be described as a marine version of heat stroke.

The fish kill was unusually large for the waters of Everglades National Park, with floating redfish, snook and other species covering nearly 20 acres in between Buoy Key and the coast, said Dave Hallac, the park's chief of biological resources.

"These things happen," Hallac said. "It's just the size of it that was concerning."

Some fish kills happen almost every year in Florida Bay. Because much of the bay is shallow, with vast flats only a few feet deep, water conditions can change rapidly with the weather.

Cold snaps can kill temperature-sensitive fish such as snook. Extended hot, dry spells can raise salinity and kill sea grass, with a sometimes fatal effect on other life as the decaying plants suck oxygen from the water.

While low oxygen is suspected, Hallac said, levels must have dropped quickly. He fished the area over the weekend and caught sea trout.

There was no visible evidence of the green algae blooms that have plagued the waters of Florida Bay and the Keys in past summers.Hallac said the park collected water samples and is working with the Florida Fish and Wildlife Conservation Commission to pinpoint the problem.

Until results are in, the cause will remain officially unresolved.