First Fertile Female Lake Sturgeon Found in Red River System as Stocking Program Nears End
Like all good things, fisheries management plans take time, especially when they involve a species that can live for a century and grow to more than six feet in length. Started in 2002, with the goal of bringing back a viable, reproducing lake sturgeon population to the Red River which forms the border between North Dakota and Minnesota, the Minnesota Department of Natural Resources’ (DNR) Lake Sturgeon Restoration Plan looked ahead after reviewing the past in order to restore what once was. With the
discovery of the first sexually mature male fish in 2017, and now a ripe female in this spring’s survey, agents of the DNR, with the help of a North Dakota fish hatchery will wrap up the 20-year program in the coming season, and look forward to a future where self-sustaining sturgeon can roam hundreds of river miles up and down the border water.
With populations becoming well-established due to the DNR’s reintroduction efforts in the Pelican River chain of lakes around Detroit Lakes, Minn. and within the Ottertail River drainage, fish as large as 65 inches have been recorded by agency personnel. Incidental catches by anglers also show a viable population of larger fish established in a variety of lakes and flows in the areas which have been repopulated through the program. Lake sturgeon recently observed in the Red River well downstream from the stocking locations also show noteworthy movement of these re-colonists throughout the fish’s historic range. As the sturgeon have matured and found their spaces in the system and its tributaries, agents have been waiting for the program to pay off in the form of those individual specimens that are ready to breed, and following the surveying of a number of male sturgeon which were producing milt and ready to spawn over the past two springs, DNR staff confirmed that an egg-producing female was recently found under the Big Pine Lake Dam.
“I’m happy to report we were out last week [the week of June 3] and we got a female that was ripe,” said Nathan Olson of this spring’s long-awaited survey result, “in the grand scheme of it, we looked at 80 fish, and only one was for sure a female ready to spawn, but seeing that one female was huge,” he stated, adding the first documented reproductive-ready female lake sturgeon in the Red River system was approximately 54 inches in length, right around the mark where the species becomes sexually mature.
According to Olson, the female sturgeon was most likely a fingerling stocking from the area more than 15 years ago, and not one of the larger fish stocked in the late 1990s. She was captured and released via electric surveying methods along with approximately 40 other fish that day, which most likely included other females which were either not ready to reproduce, or may have been, but were not discharging eggs at the time of the survey. Olson pointed to this spring’s fickle weather as a possible cover for other females in the group, as sturgeon are highly dependent on both photoperiod and water temperature to start the spawning process, which will be a key focus of the agency once the stocking program wraps.
“We will continue to monitor to see if we can find natural reproduction,” said Olson in regard to what happens after 2022 and the end of the stocking program, “that’s the next big step: to figure out if they are self-sustaining,” he continued, adding that the removal of lowhead dams and the restoration of natural rapids and spawning areas that will congregate these fish will continue after 2022 in partnership with local government units.
Ancient & Recent History
Prior to 1900, the lake sturgeon, a fish with its roots in prehistory and evolving little since its first appearance in the fossil record around 70 million years ago, were commonplace and grew quite large in the unobstructed flows of the Red River and its tributaries, which provided ample spawning areas to sustain the species. However, like other populations around North America at the turn of the century, the lake sturgeon in the Red River fell victim to over harvest and exploitation, as the value of their meat and roe for caviar spiked. This precipitous drop in population was further confounded by the construction of lowhead dams which prevented the remaining fish from reaching their historical spawning sites in the tributaries of the Red River. According to DNR records, by the mid-1900s, the fish was extirpated from its historic range in the border water, with only an occasional, unconfirmed catch suggesting any had survived and certainly not enough samples remained to sustain a population.
Following studies and assessments of the potential to restore sturgeon populations in the Red River, a program led by the DNR in conjunction with agencies in North Dakota, South Dakota, Manitoba, along with tribal groups known as the Red River Fisheries Steering Committee, began reintroduction of lake sturgeon to the Red River basin in 1997, with 75 fish stocked into Big Detroit Lake and 303 fish placed in the Otter Tail River by the DNR.
From there, the DNR’s 20-year Lake Sturgeon Restoration Plan came to be in 2002, with 3,600 yearling fish stocked into the waters of Detroit Lake in Becker County, Minn., Otter Tail Lake and River in Otter Tail County, Minn., and the Buffalo River in Clay County, Minn. Since that time additional stockings of fingerlings and fry on tributaries such as the Roseau River and Red Lake River have taken place, along with placement in tribal waters, such as White Earth Lake and Round Lake near Mahnomen, Minn., with
the hopes of establishing a number of reproducing populations throughout the fish’s historic range.
While all of the rivers and lakes stocked by the DNR fall on the Minnesota side of the Red River, the National Fish Hatchery near Valley City, N.D. has taken on the sole supplier status for the repopulation efforts, according to Janae Fernholz, Biological Fisheries Technician at the facility located along the Sheyenne River. Between 2012 and 2018, the supply of lake sturgeon – reared from milt and eggs collected by the Rainy River First Nations tribe members from fish spawned each spring along the Rainy River on the Minnesota-Canada border – was split between the Valley City hatchery and the National Fish Hatchery in Genoa, WI.
Upon receipt by the fish hatchery and after a disinfecting process, the eggs are placed and rolled in jars to simulate the natural movement of water. Once the tiny sturgeon hatch in the containers into a state referred to as sac fry and they absorb their yolk sac, they are fed brine shrimp and then a formulated dry diet to help them grow quickly. As they do, they are moved through a series of tanks and separated periodically to give each fish enough room to maximize their size as they develop throughout the summer.
“We can only keep them at so many fish per tank to keep their growth up,” said Aaron Von Eschen, Hatchery Manager, “our target number is 7,500 eight-inch fingerlings by September, and once they convert onto the dry food, they grow pretty quick,” he concluded.
“We’ve noticed that once we’ve feed-trained all of our lake sturgeon, they can put on a half-inch of growth a week, and that will peak in late June, then after late June or early July, that’ll slow down, but we’ll have them at eight inches of length by the end of Summer,” added Fernholz. Prior to relocating to Valley City to manage the hatchery, Von Eschen worked at the Genoa, WI facility, and brought his familiarity with lake sturgeon to the ongoing efforts to produce fish that will be healthy and viable for the DNR stockings in the fall of each year. Currently, the sturgeon are raised intensively within a rearing building near Baldhill Dam near Lake Ashtabula, as a building located at the fish hatchery is being rehabilitated to help house half of the sturgeon that will be raised in future seasons.
Looking ahead, with the prospective end of the restoration plan in Minnesota three years away, the program is not likely to be discontinued at the Valley City hatchery. “I think the program will continue to exist here, I know there has been a petition to list the lake sturgeon as a threatened species in some areas, so I don’t see the program going away,” Von Eschen said, continuing “in Wisconsin we raised fish over there for anywhere from New York to Michigan to Wisconsin to Tennessee to Georgia, so I think there are states out there that are looking for these fish; I imagine we’ll have fish available for another state if they wanted them,” he concluded.
While the stocking may stop in 2022, important work remains to assist in the final phases of the lake sturgeon reintroduction plan and with expansion of their range throughout the Red River drainage. While many lowhead dams between lakes and on rivers have been removed to allow sturgeon and other fish to access more river miles, better habitat and traditional spawning areas, a few remain which prohibit fish movement. With help from Minnesota’s Legacy Amendment dollars, the DNR is partnering with local governments to remove dams, restore natural rapids and provide those ideal spawning areas and expanded flows for sturgeon to use as many of the stocked fish from the beginning of the program begin to reach spawning age.
“We’re hoping that there’s still some big rapids in spots where they can do something to reproduce,” Olson said in regard to removing lowhead dams and restoring the original runs in places like Pelican Rapids, Minn., where lake sturgeon can spawn in stretches to those similar to ones found on the Rainy River which have helped that population rebound, “it’s sort of uncharted territory for us, at least down here where we’re trying to do our sturgeon work,” he concluded.
As the barriers fall and their populations rise – with these recently-found reproducing lake sturgeon serving as the mothers and fathers of a new generation – in the coming years it is likely that more anglers will encounter these ancient fish as they reestablish themselves in the Red River and connected waters. It is also likely, that somewhere down the line, a viable catch-and-release sport fishery of lake sturgeon will exist throughout their original range in the river between Minnesota and North Dakota thanks to a twenty-year vision, an a helping hand from fisheries staff and hatchery personnel in the region.
By: Nick Simonson