TRAVERSE CITY — A significant decline in the Lake Michigan alewife population is forcing officials to reduce stocking numbers of fingerling Chinook salmon this spring.
The Department of Natural Resources and the Grand Traverse Area Sport Fishing Association (GTASFA) will release 60,000 fingerlings into net pens in the Boardman River on Thursday. There will not be a stocking in Kids Creek.
Last May, 150,000 fingerlings were released — 75,000 in the Boardman River, 75,000 in Kids Creek.
“Alewives have been on the decline for the past 10 or 15 years,” DNR fisheries biologist Heather Hettinger said. “Lake Michigan is losing a lot of its plankton base to invasive species like the zebra mussel, which in turn takes food resources away from the alewives. Alewives are the predominant food source for Chinook. They also support brown trout, coho salmon, lake trout to some degree, and steelhead. When you’ve got a lake that has a large food base that everybody is feeding off of, any significant decline is huge. We’ve seen this decline over time and it’s gotten to the point where we are very nervous that a major food web collapse similar to what’s happened in Lake Huron could occur in Lake Michigan.”
Officials in states bordering Lake Michigan agreed to cut back stocking by at least 50 percent, she said. That percentage is higher in Michigan, Hettinger added, because “we have more natural reproduction.”
Steve Joslin, media director for the GTASFA, understands the dilemma.
“All the anglers want more fish, more fish, more fish, but you have to have something to feed them,” he said.
Hettinger said the plan is to stay with reduced levels for five years.
“After five years, we have the ability to either continue to decrease stocking, keep it the same or go back to historic levels,” she said.
The GTASFA, which has been working jointly with the DNR since 2007, maintains three nets in the Boardman River. The fish will remain there three to five weeks, depending on growth rate. Joslin said the pens allow the salmon to “implant on the river,” increasing the chances they’ll return to spawn. It also allows the fish to nearly double in size making them less a target of predators, he said.