With the arrival of spring, we at the U.S. Fish and Wildlife Service’s Midwest Region and our partners are preparing for our annual lake sturgeon egg takes, one facet of a 40-year-old restoration program that relies on reintroducing fish as its cornerstone. Our efforts in the Great Lakes and Upper Mississippi River basins are at the heart of a broader lake sturgeon restoration program across the waterscape of eastern and central North America where these prehistoric creatures range.

We take pride in sharing our fishery management expertise and resources with Tribal and state partners to restore this iconic and captivating fish. Lake sturgeon are sacred to Tribes and states are working to restore them as part of their native fishery conservation programs and as a valued recreational fishery.

We intervene early as caretakers to give new generations of the species a strong start. What we call egg takes refers to collecting gametes – which is the name for milt and eggs prior to fertilization – from spawning lake sturgeon. In late spring, we also collect young sturgeon in their larval stage for the same reason. These are two main ways our agency begins the annual cycle of restoration activities, which includes rearing more than 120,000 lake sturgeon in nine national fish hatcheries all summer for reintroductions in nearly 40 locations in 11 states in the fall.

The goal is to eventually reach a point where lake sturgeon are re-established in enough places and reproducing sufficiently on their own that reintroductions are no longer necessary. Although dams and degraded habitat may prevent their return in some parts of their historic range, there are other areas where lake sturgeon are demonstrating their resilience.

Providing a spawning assist

Every spring in areas in and around the Great Lakes Basin and upper Mississippi River, we join partners in collecting gametes from spawn-ready lake sturgeon. We carefully capture fish that are sometimes almost the size of their human helpers, gently expel the milt and eggs, and then safely return the fish to the water. We carry out these egg takes so that we can rear young sturgeon in hatcheries during their most vulnerable life stage.

For example, our agency takes part in gamete collections at six sites in four states in and around the Great Lakes Basin and upper Mississippi River:

• Michigan: The St. Clair River, a tributary of Lake Huron, with the largest Great Lakes population at 33,000
• Minnesota: The Rainy River, part of the Hudson Bay drainage
• New York: The St. Lawrence River, the outflow of Lake Ontario and all of the Great Lakes
• Wisconsin: The Sturgeon River, a tributary of Lake Superior; the Wisconsin River, a tributary of the Mississippi River; and the Wolf River, a tributary of Lake Michigan

From these areas, most of the fertilized eggs are transported to Genoa National Fish Hatchery in Wisconsin where they are raised until the fall. By then the lake sturgeon are large enough for the insertion of tags that enable us to monitor them from afar to learn more about their life cycle needs. About 20 of our Fish and Wildlife Conservation Offices take part in ongoing monitoring that helps us measure our progress in reestablishing healthy populations.

Genoa has one of the largest aquaculture operations for lake sturgeon in the United States, including a production building specifically for the species, raising more than 60,000 per year. Those fish support ongoing reintroduction efforts in Michigan, Minnesota, New York, Ohio, South Dakota, Tennessee and Wisconsin waters. Genoa also ships sturgeon eggs and fry to other areas for rearing, research and stocking, as far away as Georgia.

Some of the fertilized eggs are taken to Iron River National Fish Hatchery, in northern Wisconsin, to support reintroductions in Lake Superior tributaries in Michigan and Minnesota. Neosho National Fish Hatchery, in Missouri, joined the rearing effort more recently and is now supporting that state’s lake sturgeon reintroductions in the Mississippi River and tributaries.

Rearing larval fish close to home

In late spring we take part in another similar effort, joining partners in collecting and rearing larval lake sturgeon. In these cases, spawning has already occurred naturally and fertilized eggs have grown into tiny versions of the lake sturgeon’s adult form.

Larval sturgeon are cared for in our partners’ streamside rearing facilities – basically mobile mini hatcheries – so that water from the natal stream can be continuously pumped into holding tanks. The Little River Band of Ottawa Indians pioneered the streamside rearing method to help restore their sacred clan animal they call nmaé. Streamside rearing now takes place in several locations throughout the Great Lakes basin. After a few months, streamside-reared young sturgeon are also implanted with tags prior to their release.

Fishery biologists believe a specific water chemistry helps mature lake sturgeon return to their birthplace when they are ready to spawn. This phenomenon, called imprinting, is what enables fish to return to these specifics geographies even though they migrate far and wide into large lakes and rivers during their growing stage. Our agency takes part in lake sturgeon streamside rearing partnerships at six sites in three states in the Great Lakes Basin, and provides expertise in support of many others:

• Michigan: The Cedar, Kalamazoo and Manistee Rivers, tributaries of Lake Michigan, and the Saginaw River, a tributary of Lake Huron
• Ohio: The Maumee River, a tributary of Lake Erie
• Wisconsin: The Ontonagon River, a tributary of Lake Superior

Adaptive approaches

Why do we sometimes collect gametes and other times larval sturgeon? These methods are chosen for different purposes. When we are trying to give a boost to an existing remnant population, we would be more likely to choose the streamside rearing method, providing the full advantage of imprinting, to help that existing population rebound.

In areas where lake sturgeon have been completely wiped out, unfortunately there is no existing donor population to supplement with reared fish. We must borrow gametes from other populations to reintroduce lake sturgeon into other areas of their historic range where we think they have a good chance of reestablishing. Even though imprinting at the larval stage is not possible, in some areas we have eventually seen reintroduced fish return to their reintroduction sites to spawn.

Progress takes persistence

Because lake sturgeon are slow to mature and do not spawn every year, much of the successful natural spawning and population growth we are now seeing is a result of reintroductions that began decades ago. The long-term reality of these restoration efforts means we must keep our eyes on the prize, building on the progress of our colleagues from the previous generation to make fully restored populations possible during the next.