North Florida residents report finding carcasses.

A rash of fish kills centered on the St. Johns River - several involving redfish - is puzzling fishermen, outdoorsmen and state scientists looking for a cause.

Six people told a state agency Tuesday they found dead or dying fish in Duval, Clay and St. Johns counties, with death tolls ranging from eight fish to as many as 100.

More accounts continued Wednesday.

Five people said they found dead redfish, a relatively large and hearty fish, although some counted other dead species as well.

"They're just everywhere," said Tom Williams of Orange Park. "We have other fish here on our dock. Little guys, and mullets and some other fish. None of them have died, just the reds."

Williams said he disposed of about 15 redfish carcasses he began finding near his home on River Road during the Memorial Day weekend. All were about 2 feet long or larger, he said.

St. Johns County resident Louann Williams - no relation - said she retrieved a large, obviously ailing redfish south of Julington Creek Wednesday for examination by the Florida Fish and Wildlife Conservation Commission.

"It was as long as my arm. ... I was able to get out of my kayak and walk right behind him and grab him by the tail," she said. The fish lurched away, Williams said, but it stopped a few feet away, so she wrapped a shirt around her hand and grabbed the fish and held it until two state employees came to collect it.

The fish had no obvious cuts or injuries but had mucus in its eyes and was probably nearly dead, she said.

"There's no way a person should ever be able to catch a redfish that size, who is still breathing, with their bare hands and hang on," Williams said.

Fish and water samples from the St. Johns are being sent to a state lab in St. Petersburg, said Catalina Brown, a scientist who coordinates a state hotline on fish kills at the Florida Fish and Wildlife Research Institute.

Water tests can quickly check for some possible causes, such as algae blooms and depleted oxygen levels, she said, but analysis of fish samples could take two weeks.

Oil currently seeping into the Gulf of Mexico is not thought to have played any role in the fish kills.

People along the river began describing fish kills last week, said St. Johns Riverkeeper Neil Armingeon, who asked the people finding those fish to call the state's hot line at (800) 636-0511.

Getting the deaths documented is important, said Armingeon, whose group is helping collect sample fish.

He said the number of kills and the prevalence of a large, resilient species among the dead make the situation more troubling.

"I'm not trying to suggest I know what's going on," Armingeon said, although he said it's important to find out. "Obviously, we're concerned."