" A Resident   said. "It was so thick we couldn't walk out."

  "There were blue crabs the size of a dinner plate,"

 A long time Beach Resident  said.

 "You name the species of fish and they were there." 
 

 He said all the species "were swimming amongst each other.

 They weren't attacking each other."

 Beach-goers were grabbing crabs and fish as they swam by, Thursday.

 One observer thought the fish might have been weakened

 by some sort of toxin -- perhaps red tide --

 because they could be scooped up easily by people.

The event lasted until late morning, although the parade had thinned out by 11 a.m. 
 

A few scientists contacted Thursday were surprised

to hear of the unusual fish behavior in Englewood that morning.

It was not typical schooling, they said,

 because many varied species were involved.

Scientists -- usually by nature and always by training -

- are reluctant to speculate

about the causes of natural phenomena

without the benefit of observation and concrete data.

However, they did offer some broad possibilities

 for what they agreed was a highly unusual event,

one they had never encountered before.

It might have been predator avoidance,

said one, but that was unlikely since there were no signs of predators

and the species were varied.  

The Gulf waters have currents

that might have swept many fish along

in an unusual pattern, one speculated.

Or it could have been caused by red tide

 that could not be detected by beach-goers.

Dr. Richard Pierce, director of ectotoxicology at the Mote Marine Laboratory in Sarasota, said he had discussed the occurrence with Dr. Cindy Heil, the director of biotoxin research at the Fish and Wildlife Conservation Commission in St. Petersburg, after a reporter's phone call Thursday.

He said red tide flows in higher or lower concentrations at various levels of the Gulf. It also follows currents, which move at varying levels and speeds.

"Sometimes, we have found it in higher concentration along the bottom. This could be what you're looking at," Pierce said.

Red tide has been lingering in the Gulf for the past couple of months, but it has been detected primarily in an area stretching from northern Sarasota County north to Hernando County.

It's possible, Pierce said, that a stealth red tide could be moving south, flowing with an offshore current along the bottom, "and they're moving ahead of it."  

Key to that theory is that the fish reported Thursday included many bottom feeders. "Sea robins, flounder, grouper are indications that something is moving along the bottom," Pierce said.

"Unfortunately, this might be a phenomenon of red tide creeping in, but we'll have to wait until we get some samples," he said.

Mote recently installed two red tide detectors in Boca Grande, and Pierce said there was some indication Thursday that red tide might have been moving in that direction.

But, he added, it was all simply speculation until tests could be conducted.

"We just don't know what's happening," he said. "That's a lot of maybes and what-ifs. I know the state is working on that and some other reports, so maybe by next week we'll have some answers."