Be Weir Aware
Published: Friday, August 7, 2020
By: Dan Armitage
Sharing shorelines with four of the five Great Lakes, fisheries-wise what happens in Michigan definitely doesn’t stay in Michigan. The Wolverine State has developed a fantastic Great Lakes sport fishery, which includes native lake trout, brown trout, steelhead, and several salmon species that have been introduced to our inland seas since the 1960s. And, as salmonids are wont to do, they roam and set up shop anywhere the conditions are right. Fish hatched in Michigan thrive in all five Great Lakes, and it all starts with a rather primate fish collecting process that dates back centuries.
The Michigan Department of Natural Resources (MDNR) relies on stocking fish and using eggs taken from spawning fish. Fisheries for coho and king salmon, as well as lake-run rainbow trout, or steelhead, were spawned using stocked fish from California and the Pacific Northwest, where the fish are born in freshwater lakes and streams and migrate to the Pacific Ocean to mature and grow before returning to their native streams to spawn.
The trout and salmon that were introduced to the Great Lakes state followed those instincts, migrating downstream from where they were planted to reach the open waters of the Great Lakes to feed, grow, and mature before continuing the cycle.
Getting eggs from these far-ranging salmonids to use in stocking efforts is a challenge, and begins with catching mature, pre-spawn fish. In Michigan, they use an ages-old fishing technique that features a weir.
Described as a “removable dam,” by Aaron Switzer, the manager of the MDNR’s Platte River State Fish Hatchery, the weir coordinator explained that his agency uses two types of weirs: those that allow water to completely pass through but don’t allow fish to pass upstream and those that not only stop fish passage but impound water as well.
“Our lower weir on the Platte River allows water to pass through but doesn’t allow fish to pass,” said Switzer. “It goes in August 15 every year. What that does is it allows us to control the number of coho [salmon] that we let up from the lower weir.”
MDNR allows 20,000 coho salmon through the weir as part of a consent agreement, after which the remaining salmon are harvested and the eggs stripped. In a typical season, the eggs are harvested around the second week of October after waiting for the fish to reach the spawning stage.
The MDNR operates five weirs—on the Platte River in Benzie County, Little Manistee River in Manistee County, the Boardman River in downtown Traverse City in Grand Traverse County, the Swan River (on Lake Huron) in Presque Isle County, and Medusa Creek near Charlevoix in Charlevoix County.
The Platte River facility is the DNR’s source of coho salmon eggs. The Little Manistee River weir is the prime source for collecting king salmon eggs and the state’s only source for steelhead eggs. Any fall steelhead, brown trout or other fish that wind up in the Little Manistee River during Chinook egg take are allowed to pass upstream, according to the MDNR.
The Swan River facility has been considered a back-up facility, but is used to procure Chinook eggs when the Manistee weir under-produces. The weir at the Boardman River isn’t used for collecting eggs, but rather to keep the fish from going upstream from Grand Traverse Bay and going belly-up in downtown Traverse City—and to serve as an educational facility to teach the public the role of weirs and stocking practices.
There is no public access to the weir at Swan River, which is on private property, and the weir at Medusa Creek is strictly a harvest facility, where water is diverted from the creek into a holding pond where the fish collect until they are ready to spawn.
The Platte River’s upper weir consists of steel panels that fit in the channels in the concrete lining the walls. It is installed in stages to keep from suddenly disrupting the downstream flow. That weir goes in during early September and remains in place until mid-July to block steelhead and sea lamprey from ascending and spawning in the river. The invasive lamprey prey on native lake trout and, similar to salmonids, spawn in tributary streams before descending on the Inland Seas where they can ravage a lake’s fishery.
Without weirs, MDNR staffers would have to rely on nets or electro-fishing gear to collect fish, a process that would be longer, more expensive, and not nearly as effective. So the next time you boat a laker, steelhead or salmon from one of our Great Lakes, thank a weir!
To learn more about how the MDNR manages Michigan’s fisheries and those that benefit the entire Great Lakes, visit michigan.gov/fishing.
About the Author
Dan Armitage is a popular Great Lakes-based outdoor writer and host of the Buckeye Sportsman show (buckeyesportsman.net), syndicated weekly on 30 radio stations across Ohio. Dan is a certified Passport to Fishing instructor and leads kids fishing programs at Midwest boat and sport shows, and is a licensed Captain with a Master rating from the US Coast Guard.
This article first appeared in the Summer Issue (Jul/Aug) 2020 of Great Lakes Scuttlebutt magazine.
tags: Dept of Natural Resources, Environmental Impact, Fishing
