Restoring Lake Sturgeon in the Maumee River

A juvenile lake sturgeon (Credit: U.S. Fish and Wildlife Service Southeast Region, Public Domain)

In the 1800s, lake sturgeon were so plentiful in Lake Erie that they were seen as a nuisance. Despite being a prized catch nowadays, lake sturgeon used to be known for their destruction of fishing equipment. According to Sturgeon for Tomorrow, the fish were targeted by culling attempts early in the 1800s until they were later recognized as sport fish. The species then fell victim to the effects of an overfished commercial fishery. Even further, the sturgeon’s eggs were highly sought after for caviar and inhibited proper population management.

It’s no surprise that sturgeon populations continued to decline until eventually being designated as a threatened species in Michigan in 1994, according to The National Wildlife Federation. Climate change and invasive species have made rehabilitation more difficult as sturgeon are out-competed in the ecosystem, and varying water levels impact habitat suitability and spawning. Lake sturgeon already face delayed maturation and periodically interrupted spawning cycles, but pollution and other climate variables affect the quantity and quality of spawning habitats.

Lake Sturgeon in Ohio

Lake sturgeon aren’t doing much better in other parts of the Midwest. Lake sturgeon are also considered endangered in Ohio, likely due to a lack of nearby rivers suited for lake sturgeon spawning. The closest suitable habitats for sturgeon are the Niagara River and St. Clair – Detroit River. For that reason, in 2018. The Toledo Zoo, USFWS, USGS, Ohio DNR, Michigan DNR, University of Toledo and Ontario Ministry of Natural Resources and Forestry all worked together in a multi-agency effort to stock the Maumee River with sturgeon.

The 25-year stocking plan requires the work of groups like the Genoa National Fish Hatchery, who have spent the past several years rearing sturgeon until they reach 6-8 inches, wherein they are tagged with a PIT tag and released. The release is planned concurrently with the Toledo Zoo’s sturgeon stocking event. The PIT tag allows for future monitoring—growth, survival, and adult returns for spawning can all be concluded through these devices.

Friends of the Upper Mississippi reports that both locations also tagged a few dozen fish with “acoustic transmitters to track juvenile lake sturgeon movement, habitat use, and survival in the Maumee River and migration into Lake Erie.” The plan is scheduled to follow similar trends for the next 20 years to stabilize lake sturgeon populations so they can be sustained naturally, without the need for intervention.

Lake sturgeon spend most of their lives in lake environments but move to rivers during spawning seasons. Half of the fish in this project are reared in Maumee River water, while the other half may have been born elsewhere but are reared in a stream-side facility, thus familiarizing the fish with the Maumee River. This process allows researchers to further test the viability of stocking hatchery-reared fish that may have been born in different waters.

Conclusion

The method appears to have been effective as anglers have begun to catch sturgeon reared by the Toledo Zoo and the Genoa National Fish Hatchery in the Maumee. According to the Toledo Zoo, the zoo relies on an established lake sturgeon habitat (like the St. Clair River) to take newborn fish for rearing and eventual release in the Maumee.

While part of this restoration plan originated from a desire for recreational fishing, several environmental factors have all of the agencies involved in this project worked up. The Toledo Zoo shares that “Lake sturgeon serve as an indicator of biodiversity and Great Lakes health because they are sensitive to habitat destruction and pollution. Their presence in a system indicates a relatively healthy and stable environment that likely benefi­ts many other species.” Even without their status, sturgeon are a part of the ecosystem, therefore crucial to preserving the native environment and strengthening the resilience of the Maumee River.

Juvenile lake sturgeon. (Credit: U.S. Fish and Wildlife Service)

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