City workers scooped up hundreds of dead fish Thursday from the Capaha Park lagoon. A city park official said it is not known what killed the fish.

"It could be that we'll never find out what it was," said Cape Girardeau Park Superintendent Dan Muser, adding that water samples taken from the pond would be analyzed by the Missouri Department of Conservation.

Fish have been found dead in the pond before, but never have as many died at one time, he said. In the past, tests of the water have not positively identified a reason for the massive fish deaths.

On Thursday, city workers used nets to scoop dead fish from the pond. Most of the fish were floating near the sides of the lagoon. Most of the dead fish were small carp and catfish, but workers said several large catfish had also been found floating.

"Most of the fish there are small ones, the `trash fish' that no one really eats," Muser said. "Most of them are what we call bottom-feeder fish."

The pond is a frequent fishing place for children. Fishing derbies are held there annually.

He offered several possible explanations for the deaths. He said the lagoon has had "bacterial" problems in the past, but added that the deaths could also be blamed on a low oxygen content or even unstable weather.

Three aerators were installed in the pond in 1983, when problems with a low oxygen content were first noticed.

"We periodically find dead fish there," he said, "but we usually find them in the summer."

Muser said that also in the summer, people who visit the lagoon complain that the water has an offensive smell. He said dead fish are usually found at those times.

The park superintendent said he doesn't think the water tests will determine an absolute cause for the problem.

"I don't know what it is, but I don't think we're looking at any kind of catastrophe here," Muser said.

Muser said a problem was first detected in the pond on Wednesday, when several fish were seen floating near the edge of the water.

"That was our first indication something was wrong," Muser said. It is also possible that the lagoon water was contaminated somehow, he said.

"The water that is in the lagoon is basically a run off from the area around it. It could be something in the water," he said.