Jim Waymer

FLORIDA TODAY

Dead fish fouled Merritt Island canals this week, adding new casualties to a die-off that's already been claiming hardhead catfish from Satellite Beach to Fort Pierce over the past month.

State wildlife officials received dozens of reports this week about the hundreds of dead fish floating in canals surrounding Sykes Creek, Newfound Harbor and the Banana River.

Species included catfish, flounder, mullet, sailor's choice, pinfish, red drum, sheepshead and trout.

A water test on Merritt Island this week found no evidence of a harmful algae bloom or raw sewage, said Brandon Basino, a spokesman for the Fish and Wildlife Research Institute in St. Petersburg. But that was only one sample, he said, and state biologists continue to monitor the fish kills.

They don't know whether the hardhead catfish die-off and other species of dead fish are linked.

"We're seeing recurring, possibly isolated events within the Indian River Lagoon system," Basino said.

The research institute has been testing the tissues of hardhead catfish but has yet to reach any conclusions about the cause.

"You're talking about a wide span of area," Doug Adams, assistant research scientist with the institute's Melbourne field office, said of the hardhead catfish deaths. "We've seen these hardhead catfish die-offs in the past. We've even seen them Florida-wide."

In 2005, scientists suspected a toxic algae similar to red tide caused thousands of baby hardhead catfish to die in the fall of that year, between Rockledge and Melbourne.

The same algae bloomed in Port St. Lucie the previous year and killed several species of fish before Hurricane Charley broke up the bloom.

During the summer of 1996, thousands of hardheads floated up dead in the lagoon and statewide. Biologists never identified the exact cause, but suspected a virus that killed only hardheads.

Contact Waymer at 321-242-3663 or jwaymer@floridatoday.com Follow him on Twitter @JWayEnviro

To report a fish kill, call Florida's fish-kill hotline: 800-636-0511