Salmon facility key to chinook fishery

Sturgeon Bay — Autumn marched on last Monday along Strawberry Creek.

In places, the seasonal changes were subtle: tamarack needles turned from green to gold, yellow leaves dropped lazily from the crowns of cottonwoods.

But at the head of the tiny waterway southeast of Sturgeon Bay, a traffic jam ensued.

Several hundred chinook salmon crowded in a holding pond. Water exploded and bodies collided as the dark, muscular fish, most about 3 feet long, jockeyed for position.

“We’re ready for the first lift,” said Steve Hogler, a fisheries supervisor for the Wisconsin Department of Natural Resources. “Let ‘er go.”

With that, a crew of DNR personnel herded fish toward a corner of the man-made pool and into a large basket. A crane then hoisted the salmon into the next phase of their human-assisted spawning migration.

For the fish, and the DNR, the frenzy is a rite of fall at the creek since 1969.

The activity took place at the Strawberry Creek Chinook Salmon Facility, a modest collection of buildings and equipment that is the linchpin for the state’s  — and increasingly the region’s — chinook salmon stocking program.

The chinook is not native to the Great Lakes but along with other Pacific Ocean-strain fish was introduced to Lake Michigan in the 1960s to help control nuisance levels of alewife, also a non-native species.

Chinook proved to be the top predator of alewives and grew to be highly valued by anglers for their sport and table value.

The salmon have helped build a Great Lakes fishery that contributes $114.3 million annually to the Wisconsin economy through direct retail expenditures, according to the DNR.

Human boost for salmon

But the species has always needed a heavy assist by humans to reproduce on the Wisconsin side of Lake Michigan. Rivers here generally run too warm and silty and don't offer enough rocky substrate to allow salmon to successfully spawn.

That's where the Strawberry Creek facility comes in. Each fall, DNR crews and volunteers assemble to take eggs and milt from mature salmon to meet state hatchery needs.

The Sturgeon Bay facility is one of three used by the DNR to sustain its Lake Michigan salmon and trout programs, which also include steelhead (rainbow trout), brown trout and coho salmon. The other facilities are on the Kewaunee River in Kewaunee and the Root River in Racine.

But Strawberry Creek has long been the state's primary egg collection site for chinook.

And many years, including 2016, it provides all the chinook eggs needed by the Wisconsin hatchery system and then some.

This year Strawberry Creek yielded 1.8 million chinook eggs for Wisconsin and about 520,000 for Michigan, according to the DNR.

“We meet our state’s needs first,” said Nick Legler, DNR fisheries biologist. “Then, in a year like this, we can assist other states if requested.”

The chinook is also known as "king" salmon.

But for a fish with a royal moniker, the Strawberry Creek site of origin is as modest as it gets.

The stream is a muddy, low volume flow out of a marshy area near Sturgeon Bay.

To draw salmon, beginning in September the DNR uses pumps to hike the creek's volume and velocity. The fish, which were stocked as fingerlings and imprinted on water at the site, heed age-old spawning urges and swim out of Lake Michigan and into the facility.

In the species' native waters along the western coast of North America, chinook swim hundreds and even more than 1,000 miles to spawning grounds.

Here at Strawberry Creek, the migration is about two-tenths of a mile.

The fish gather in a swimming pool-sized area and await their fate.

Over the course of four hours Oct. 17, DNR personnel and volunteers processed 343 chinook, including 100 females that yielded 500,000 eggs.

The fish were calmed in a carbon dioxide bath, then killed with a pneumatic blow to the head.

Next, they were weighed and measured and coded wire tags were cut out of their snouts.

Disease testing

Tissue samples were taken from the fish for disease testing and research purposes. One study, being conducted at Michigan State University, will examine chemical signatures on otoliths from the fish. The work may allow fish caught anywhere in Lake Michigan to be linked to their spawning site.

And central to the facility's purpose, eggs and milt were taken from the fish.

Steve Fajfer, a fish propagation specialist at Wild Rose Fish Hatchery, mixed the white milt with the orange eggs in stainless steel bowls.

Within minutes, the eggs were fertilized, Fajfer said, and the next generation of Wisconsin-reared chinook salmon was on its way.

A DNR van transported the precious cargo to Wild Rose later in the day.

In coming weeks, the DNR will use data taken from the fish and tags to calculate size at age for the fish, a critical measure of fish health that helps guide stocking decisions.

Chinook salmon stocking in the Wisconsin waters of Lake Michigan peaked at 2.89 million fish in 1984.

The numbers were reduced three times since the late 1980s due to disease issues and declines in the forage base.

In its 2015 bottom trawl survey conducted at index sites around Lake Michigan, the U.S. Geological Survey reported an alewife biomass of 0.5 kilotonnes, 70% lower than 2014 and lowest on record.

The 4.0 kilotonnes total prey fish biomass was also an all-time low. The agency has conducted the survey annually since 1973.

Managing the lake's fishery has been made more difficult in recent decades as chinook salmon began naturally reproducing in substantial numbers in Michigan streams.

This year Michigan, Illinois and Indiana decided to cut their chinook stocking. Wisconsin chose to keep the chinook stocking level at about 810,000 fish but cut lake trout and brown trout.

The stocking decisions by state agencies around Lake Michigan have increased the importance of this humble creek southeast of Sturgeon Bay.

Last Thursday, the crews reassembled at Strawberry Creek and collected 520,000 fertilized eggs for the Michigan Department of Natural Resources. Returns of chinook at Michigan weirs have been below average this fall, and the Wisconsin eggs were welcomed by Michigan officials.

It was the last day of operation this fall; the DNR shut off the pumps and closed the gate to the holding pond.

The DNR processed 2,895 chinook this season at Strawberry Creek, an increase from 2015 but below the long-term average, Legler said.

Data from the fish and coded wire tags will be analyzed in the coming weeks, providing critical information on the health of the lake's chinook.

And next spring, the pumps at Strawberry Creek will be turned on again for about a month when juvenile fish from this year's eggs take make a return trip to the facility.

After four to six weeks in the holding pond to allow the fish to imprint, the gate will be opened and the young chinook will swim out into the ever-changing ecosystem of Lake Michigan.