A swarm of tiny minnows swirls along the water’s surface in a 6,500-gallon tank as Barry Thoele casts a shadow over the water.
“This is about feeding time for them. So they are waiting for me,” Thoele said as he sprinkled specially formulated dry fish food on the water.
There are about 15,000 minnows in this round tank that is 16 feet wide and 1.5 meters deep. It is one of two partially buried in the ground at Thoele’s farm near Staples, Minn.
The fish in these tanks hatched indoors this spring and some are now two inches long.
In the wild, it takes two years for the minnows, the so-called golden shiners, to grow large enough to use as bait.
Thoele hopes to be able to sell it in November.
“I’m pretty excited about this project because it’s been done really well,” he said. This is my third year working on it. I did the first two years out of my own pocket. This year it has been funded by grants.”
Thoele is participating in a three-year research project through the University of Minnesota’s Duluth Sea Grant Program, supported by an $188,000 grant from the Legislative-Citizen Commission on Minnesota Resources.
Thoele has been in the bait business for 35 years, collecting minnows in natural ponds and lakes to sell to stores. But in the past ten years, natural production has declined and there have been shortages, including last year.
“For the winter market, we were generally short of 8,000-10,000 gallons of shiners,” Thoele said. “If the wildlife isn’t going to support this, we need to find a better way to do it.”
There are a number of possible reasons why natural whitefish production is declining.
“We’ve seen more unstable climatic conditions. We’ve seen more winter deaths, where these fish don’t survive the winter. We’ve seen droughts, we’ve seen really high temperatures. The stability of the system seems to be changing,” said Sea Grant fishing specialist Don Schreiner.
Invasive species such as zebra mussels also disrupt bait collection when contaminated waters are closed for bait harvesting to prevent the spread of the invasive species.
Minnesota restricts imports of minnows from other states because of concerns about the introduction of invasive species or diseases.
Researchers are testing four strategies to increase gold luster production.
Minnows born in a hatchery this spring are raised in outdoor ponds, some with natural food and others with supplemental food.
Others are raised in tanks under more controlled environmental conditions.
The Minnesota Department of Natural Resources is also part of the study, which involves raising minnows in a pond at the state fish farm in New London, Minn.
The collected data provides insight into which methods are most effective and economically feasible.
Although he warns that the research is still in its infancy, Schreiner is pleased with the progress.
“We’ve actually seen that all our save events have been successful so far. So that’s one of the biggest hurdles. Now, of course, they have to get through the rest of the summer,” he said.
“The whole key is getting them to market size in one growing season.”
This research will receive attention outside of Minnesota and will likely involve collaboration with researchers elsewhere as the project progresses.
“This is a good pilot project, not just for Golden Shiner, but a totally different way to raise bait, especially in our northern climates of Minnesota, Wisconsin, Michigan, some of the Great Lakes states,” he said. “So I think there is real potential. And we’re just scratching the surface at the moment.”
This research will be the focus of the annual Minnesota Aquaculture Conference on August 12 and 13.
Mark Tye has been growing shiners indoors for almost 15 years. He owns a small manufacturing company called Tye Fish Solutions in Le Sueur, Minnesota. He took care of the fry, or baby fish, that Barry Thoele raises in tanks on his farm.
In the wild, golden shiners don’t spawn until water temperatures reach about 70 degrees, Tye said, limiting natural reproduction to mostly July and August.
“I was able to manipulate the indoor environmental conditions to simulate summer all year round,” he said. “And so that particular species, the golden sheen, is a continuous spawner. So as long as their environmental conditions are met, and they are well fed, they will continue to reproduce.”
Through trial and error, Tye has also learned to train the minnows to eat specially formulated fish food. That was quite a challenge, but the success means the fish can be spawned and raised in tanks.
“No one has ever produced golden shiners all year round, no one has ever successfully fed them. So it’s pretty groundbreaking,” said Tye, who also works at the University of Minnesota and has published articles about his research.
But the challenge remains to expand what he does now on a small scale and make it profitable.
“To do it within the state where it’s going to make a difference to the demand for gold shiners, we need some producers who are willing to take a risk and experiment and solve some of the problems that will arise.” “Tye said, because at the moment there is no manual on how to do it.”
Barry Thoele wants to help write that manual for the next two years. He has a plan to combine roach buckets with greenhouses where he will grow lettuce or strawberries.
“If we use the same technology that we use to grow products, to farm the fish and then use the waste from the fish to grow products, it’s a win-win situation,” Thoele said.
Thoele believes that minnows will boost the economy of an aquaculture operation because they don’t need to be processed like fish farmed for human consumption, and bait minnows are more valuable.
“If these are three and a half inches, all I have to do is call and I can have a bait dealer here with a truck. I’m loading him out of here. He writes me a check, we both leave happy,” he said.
The minnows can be sold for $10 to $12 a pound. Thoele said there is demand for at least £80,000 extra a year just for the winter fish market. He thinks that as supply increases, demand will be even greater at other times of the year.
“This is actually so promising that if it continues like this, I will be investing a significant amount next year,” said Thoele.
That investment includes a new greenhouse over its existing minnow tanks.
Depending on the type of minnow production, costs for a producer can range from several thousand dollars to hundreds of thousands for indoor production.
When this project is completed in 2024, researchers hope to have learned enough to provide a basic roadmap on how to breed minnows using a variety of methods.
Thoele hopes this research will lead to a future industry, with many small minnow producers scattered across the state.
In the meantime, if all goes according to plan, Thoele will have thousands of minnows ready to sell later this year, just in time for the winter fishing season.