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Dams block walleyes' spawning grounds
Group studies way around barriers for reproducing sport fish
By Jeff Kart
Bay City Times
10/14/03

Walleyes can't jump.

That's created a spawning problem for the prized sport fish in the Saginaw River Watershed, which has more than 300 dams along its 6,000 miles of tributaries.

Walleyes, unlike salmon and other species, can't jump past the barriers to reach the upper river system, which is lined with gravel and cobble, the perfect habitat for laying their sticky eggs.

So the walleyes are left with the spawning areas below the dams, which are scarce.

As a result, only 20 percent of the walleyes in the bay watershed reproduce naturally, according to the Michigan Department of Natural Resources.

The rest are stocked by the agency, which put in more than 1.8 million walleye fingerlings this year, breaking a 9-year-old record.

Experts say the situation would be much different if just a handful of the dams in the river system were removed or made passable with "fishways," detours that walleyes could swim through. Other fish also would benefit.

A first-ever analysis of dams in the river system is now under way, with $75,000 in funding from the Saginaw Bay Watershed Initiative Network, the U.S. Fish and Wildlife Service and the city of Frankenmuth.

Researchers plan to create an inventory of the dams, propose ones that could be removed or changed to open up spawning areas, and look at how other states have dealt with the problem.

"Saginaw Bay currently has what many people consider to be a world-class walleye fishery," said Michael T. Kelly of Auburn, project coordinator for The Conservation Fund, which administers the Saginaw Bay Watershed Initiative Network.


"People mention Saginaw Bay in the same breath as Lake Erie ... and some of the lakes in Minnesota and Wisconsin.

"It truly is world-class, but this is an attempt to take Saginaw Bay to the next level and develop a natural population of walleye in the Saginaw Bay."

Striking a balance

The issue is more complicated than simply getting fish past the dams.

A balance has to be struck between dams that are abandoned, dams in use and dams on public and private property. Then there's the sea lamprey, an invasive species which attaches itself to fish and sucks their blood and other bodily fluids.

In many cases, dams serve as barriers to sea lampreys, and opening them up could make the problem worse.

But the potential positives outweigh the negatives, Kelly said.

A large, naturally reproducing walleye population would have recreational and economic impacts.

"People right now come from all over the United States to fish the Saginaw Bay," said Kelly, who puts a pole in about twice a week.

The situation isn't unique to the Saginaw Bay and river. There are an estimated 2,400 dams in Michigan, and more throughout the Great Lakes.

But the Saginaw Bay, unlike Lake Erie to the south, doesn't have many places for walleyes to spawn, Kelly said.

Erosion from tributaries that empty in the bay has smothered most of the reefs with sand and silt. Sampling by the Michigan DNR has shown there are few reef-spawning walleyes left and virtually no successful reproduction in the bay.

Short of controlling erosion and installing new reefs - a monumental task - getting walleyes past the dams is the best solution to returning the bay and river to their heyday in the 1940s, Kelly said.

"If the Saginaw Bay is ever going to move beyond a stocked walleye population, then we need to begin doing some work in a number of areas, and No. 1, that includes getting fish to these traditional, high-quality spawning areas," Kelly said.

Thousands of walleyes are already swimming up to the bay from Lake Erie, passing up the Detroit River, through Lake St. Clair, and around the Thumb.

"The natural reproduction of walleye in Lake Erie is so good, that fish are beginning to essentially migrate to find new areas where they may in turn begin building new populations," Kelly said.

From the bay, the fish are heading into the tributaries that make up the Saginaw River Watershed.

Most of the flow of the 22-mile Saginaw River originates from four major tributaries: The Cass, Flint, Shiawassee and Tittabawassee. Altogether, the river watershed takes in 22 counties with a population of 1.4 million, according to the Great Lakes Commission.

Three big dams

Public Sector Consultants of Lansing is heading up the inventory project. The study got under way last month, and is expected to be finished by September 2004.

Mark A. Coscarelli, senior consultant with the company, said the work will focus on the river watershed, as opposed to the bay.

The study will look at three dams in particular: the Dow Chemical Co. dam on the Tittabawassee River, the Chesaning dam on the Shiawassee River and the Frankenmuth dam on the Cass River.

"These have really been identified by fisheries managers as three that would really open up a lot of the upper reaches," Coscarelli said.

The city of Frankenmuth is contributing $15,000 to the project.

"They are at a point where the structure is aging and they've got to make an investment in that structure," Coscarelli said.

He said many communities are being forced to come to terms with their old dams for safety reasons, because they're getting old and there are ongoing costs with maintaining and licensing the barriers.

Coscarelli stressed that removing dams isn't the focus of the study. The intent it to create ways for fish to get around the dams.

In some cases, that can be done with fishways. In other cases, removing a dam is the best solution. There are some dams on state property, and others on private property, and the report will offer recommendations.

A majority of the dams in the Saginaw River Watershed are low-head barrier dams, less than 10 feet tall, Kelly said.

Some were built to control flooding, others were built by small power companies to generate electricity, but were abandoned after the companies went out of business, Kelly said. Consumers Energy still operates some hydroelectric dams on the Au Sable and Rifle rivers, he said.

The welfare of walleyes won't be enough to get dams removed. Many communities, like Frankenmuth, were built around dams, Coscarelli said.

Older residents can remember jumping off a dam and swimming in the mill pond. County fairs are held around dams. People take boat rides in the areas.

"I think a lot of these people who have been in these communities for a long time kind of view it as heresy, removing a dam," he said. "It's sort of akin to saying were going to come in and demolish the old courthouse."

Coscarelli said the cost of removing a low-head dam can range from $200,000 to $1 million, depending on the circumstances.

It's not as simple as pulling the barriers out, in many cases, because there are issues with sediment that builds up behind a dam wall over the years.

Simply removing an old dam could wash out a stream, cover spawning beds, releasing contaminants and killing fish.

"It's not either-or. If it looks like removal is not possible, that doesn't mean there aren't ways to enhance fish migration," Coscarelli said.

Other dams, like the one at Dow Chemical in Midland, still are in use.

Dow's dam is used to allow the company to take in water for service uses and backup fire protection, said Neil C. Hawkins, environment, health and safety leader for Dow Michigan Operations.

It's a long concrete wall under the water, lined with trees and boulders.

Walleyes can't get past it, said James P. Baker, district fisheries biologist for the DNR in Bay City. There is about 200 yards of halfway decent spawning ground below the dam, Baker said.

"From there on, it's a river of sand," he said.

Hundreds of thousands of walleyes come to the dam every spring to spawn. The Tittabawassee River has the largest spawning run of all the tributaries in the Saginaw River Watershed, according the DNR.

But there are so many walleyes that spawn below the Dow dam, and so little room, that the fish end up laying eggs on top of eggs.

The eggs that are double-stacked don't survive.

"They have to breathe," Baker said.

A fishway on the Dow dam doesn't work for walleyes, Baker said. It was built about 30 years ago, when not much was known about building the passages, Baker said.

Hawkins says the fishway does work, and Dow shuts it down four to six weeks a year to prevent sea lampreys from getting through. But he said Dow is supportive of the study and always willing to cooperate with the DNR.

"We're open to any suggestions they might have," Hawkins said.

Baker said some major barriers are removed, it might still take decades for the walleye population to rebound.

"It should be happening naturally," Baker said. "I foresee we will be in a stocking program for the foreseeable future ... but maybe sometime down the road, the fish will be able to take care of themselves."

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