Trout, Walleye Thriving In 'Most Polluted' Lake

The discovery of large sport fish by SUNY-ESF researchers could mean Onondaga Lake, Syracuse, N.Y., is on the rebound after decades of pollution.

Thriving populations of large, healthy brown trout and walleye have been found in a lake that was once described by then-U.S. Sen. Daniel Patrick Moynihan (D-NY) as the most polluted body of water in the United States.

Researchers from the SUNY College of Environmental Science and Forestry (ESF), Syracuse, N.Y., discovered the highly prized sport fish earlier in June. They say the presence of the fish could mean Onondaga Lake is rebounding.

"It could reflect the improvement of Onondaga Lake," said Dr. Neil H. Ringler, an ESF fisheries expert who will take over soon as the college's dean of research.

The discovery of fish that require water that is cool or cold and highly oxygenated could be signs that the lake is recovering from decades of industrial and sewage pollution.

"It may be that the quality of the lake has improved over time and is permitting the fish to survive," said Ringler, who has been researching the lake since 1986. "The trout and the walleye are especially of interest because of the cool water. It's clear that there's a fishery there we didn't know about, for the larger fish. This finding suggests that the lake may have far more potential for a cold-water fishery than we anticipated," he said.

Moynihan's widely reported remark about the lake was made during a Senate hearing. In 1990, Moynihan convened the Onondaga Lake Management Conference to oversee research and remediation efforts at the lake. The conference, headed by Dr. Edward Michalenko, has extended a grant to study the movements of fish in and out of the lake.

Ringler said that numeric tags and radio transmitters will be used to track the fish. He is also seeking support from New York Sea Grant, a network of research, education and extension services that promote protection of marine resources.

"Sen. Moynihan described Onondaga Lake in a Senate hearing as the most polluted lake in the United States, and no one argued that point," said Steven W. Effler, director of research at the Upstate Freshwater Institute, which has produced more than 100 peer-reviewed papers about Onondaga. "Certainly, this represents, symbolically at least, a substantial change."

Effler said monitoring efforts have shown gradual improvements in the lake. The trout and walleye are a significant marker of that improvement.

"The questions now are, are they here to stay? Are they reproducing? And that's exactly what Neil Ringer and his team are going to find out," he said.

The fish populations were found by Tony Siniscal, a master's student studying the movement and habitat of fish in Onondaga Lake. He is completing an internship with the state Department of Environmental Conservation, with supported by the Edna Bailey Sussman Foundation.

Siniscal's work involved setting gill nets in an area that has not recently attracted a lot of research interest. He set the nets between 20 and 30 feet below the surface, where experts had believed low levels of dissolved oxygen would hamper aquatic life during summer months.

He was working in sight of the waste beds on the lake's west shore, near a permanent habitat module established in the lake by the Onondaga Lake Management Conference. The module, which resembles a jetty, provides environment for aquatic plants and spawning habitat for fish.

On June 8, when he checked the nets, Siniscal found a brown trout that weighed 10 pounds. In the following days, he routinely found trout of that size and walleye that were more than 24 inches long. The night of June 14, a thunderstorm kept him from returning to the nets until the next morning. On that visit, Siniscal pulled in some 40 large walleye and four brown trout.

"I've fished the area a lot," said Siniscal, who grew up in nearby Liverpool. "I haven't found anybody catching fish of this magnitude. I've checked the records and I've never heard of anybody catching fish like this in Onondaga Lake."

Ringler and Siniscal believe the fish are feasting on the smaller alewives in the lake. They suspect the fish came from Nine Mile Creek, Onondaga Creek or the Seneca River. The researchers believe the fish might leave the lake when the water warms up and becomes less oxygenated later in the summer.

Scientists describe the lake as hypereutrophic. Abundant nutrients, specifically phosphorus and nitrogen, result in significant algae growth, which in turn supply food for bacteria, which consume much of the oxygen deep in the lake.

Essentially, the lake water becomes two layers: Approximately 20 feet on the top that is warmer and oxygenated, and deeper water that is cooler and can be virtually devoid of oxygen. In fall, when temperatures drop, the lake "turns over" and the two levels blend. As a result, reduced oxygen levels in the fall might force fish such as walleye and brown trout to leave the lake. Warm water fish, such as bass and sunfish, can survive all year.

SUNY College of Environmental Science and Forestry:

This article originally appeared in the 07/01/2005 issue of Environmental Protection.

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