Where it flows under a gravel road east of the city of Sturgeon Bay, Strawberry Creek

doesn't look like much. But this little tributary to the bay of Sturgeon Bay is where chinook salmon were first stocked in Wisconsin waters back in 1969.

Follow the creek upstream a few hundred yards and you'll come to a concrete holding pond and a few outbuildings that make up Wisconsin's primary chinook egg-collection facility. Each fall, eggs are gathered here to produce the chinooks that will be stocked into Lake Michigan and Lake Superior the following year.

Chinooks were introduced here to help control alewives, an exotic species whose population had exploded in Lake Michigan in the absence of natural predators. These predators, primarily lake trout, had practically disappeared by the 1950s, thanks in large part to another exotic, the sea lamprey. Both alewives and lampreys got into the Upper Great Lakes via the Welland Canal, which allowed them to swim around Niagara Falls.

"By 1967, alewives made up an estimated 85 percent of the Lake Michigan fish biomass," said DNR fisheries biologist Paul Peeters. "Alewives are 'pelagic' fish, meaning they swim high in the water column. Some forward-thinking biologists thought we needed a pelagic predator."

Both the chinook and coho  salmon fit that niche. Once these Pacific salmon took hold, sport fishing caught on quickly. Today, chinooks and cohos help control alewives and provide a booming sport fishery. Lake Michigan is a perfect habitat for salmon to grow to maturity, but neither species reproduces successfully in Wisconsin's Lake Michigan tributaries, which are slow, silty and warm in summer. And so the state stocks several million salmon in Lake Michigan each year.

Salmon imprint on their home waters as fingerlings, then swim out into the ocean or lake, where they grow to maturity. At the age of four, most salmon return to their natal streams to spawn and die. Since Wisconsin's salmon are produced in hatcheries, they imprint on the streams where they are stocked as fingerlings and return to these streams when they mature.

Salmon returning to Strawberry Creek swim up into the holding pond, where they remain until their eggs and milt are ripe. Then, a DNR fisheries crew gathers and fertilizes the eggs and transports them to hatcheries in Wild Rose, Westfield and Bayfield.

This operation produces several by-products as well. Excess eggs or eggs not suitable for the hatcheries because they are too ripe, unripe or diseased are sold to a bait company in Fort Atkinson, which turns them into fish bait. Chinooks under 30 inches are iced and taken to Paul's Pantry in Green Bay, where they are distributed to needy families. Chinooks over 30 inches are picked up by a company in Algoma that makes them into a liquid fertilizer, which saves the DNR the expense of disposing of the carcasses.

Every salmon processed at Strawberry Creek is measured, weighed and sexed. The facility also helps with a number of studies conducted by DNR staffers. Salmon in these studies are marked as fingerlings with a tiny coded tag made of stainless steel wire implanted in the fish's snout and an adipose fin clip. Each adult salmon with an adipose clip that returns to the facility is scanned with a metal detector. The head of a fish bearing a coded-wire tag receives a numbered plastic tag keyed to the data sheet. Its head is cut off and sent to a laboratory, where the coded-wire tag is removed and data on the fish recorded.

"The code on the wire tells us this salmon is part of a certain group of fish exposed to certain conditions," said Peeters.

Studies have looked at rearing, disease-handling and marking techniques, age at maturity and other factors.

"All of our salmon studies are done in conjunction with facilities like Strawberry Creek," said Peeters. "Because the fish come right back to us."

In recent years, low water levels in Lake Michigan made it difficult for chinooks to swim up Strawberry Creek. Peeters devised a diversion system that pumps water via a plastic pipe from the Sturgeon Bay Ship Canal a quarter mile away and dumps it into the creek just above the facility at a rate of 1200 to 1500 cubic feet per second. This increased flow draws salmon upstream. Together  with an aeration system, it supplies oxygen to the fish in the holding pond and helps flush waste out of the pond, keeping up to 1,000 mature salmon healthy until they can be processed.

"At the peak of the run, we sometimes get several hundred to 1,000 salmon in one night, so we may process fish three or four days in a row," Peeters said.

A day at the facility is a bit like a cattle drive. Using a movable screen, technicians crowd the salmon to one end of the pond, where a hydraulic  basket lifts them up to a table. There, the fish are put into a tank of water pumped full of carbon dioxide, which knocks them out. The fish are then slid one at a time down a chute to the processing table, where they are measured, sexed and examined for ripeness. They are then passed on to the hatchery or bait-company crews or sorted into the food-pantry or fertilizer bins.

"We process an average of 5 or 6,000 chinooks per year," Peeters said. "We gather in excess of 3 million eggs, which are turned into 1.5 to 2 million fingerlings for stocking in Lake Michigan each year. In 2002, we handled over 11,000 salmon here, and that was a record. That year, we sold 14 tons of surplus eggs for bait."

The chinook salmon program is funded by Great Lakes trout and salmon stamp sales, so it will continue as long as anglers buy the stamps. DNR budget cuts may indirectly affect the program, however. The Wild Rose hatchery is in need of repair, for instance, and fisheries positions have been cut.

"If we want to have salmon for sport fishing and to control alewives, we need to continue to stock them," Peeters said. "That's what this program is all  about."

Wisconsin's chinook salmon program has come a long way from its humble beginnings in 1969, but the little creek in Door County where it all started is still the the pipeline that keeps it going.

Strawberry Creek: Wisonsin's chinook salmon pipeline 
September  2004