The Crystal Springs trout hatchery near Altura in southeastern Minnesota will temporarily close on Dec. 18 so the facility can be depopulated and disinfected to remove a pathogen that causes furunculosis, a disease that forms boils and lesions on fish and eventually kills them.
“Killing the hatchery’s fish is unfortunate and a choice we’d prefer not to make, but immediate and aggressive action is necessary to eliminate this pathogen,” said Paula Phelps, coldwater fish production supervisor for the Department of Natural Resources.
Crystal Springs produces brook and lake trout that are stocked in Minnesota rivers and lakes, primarily in southeastern and northeastern Minnesota. Phelps said temporarily closing the hatchery will mean that some waters will get fewer stocked trout.
However, the DNR plans to mitigate those impacts on trout populations and anglers as much as possible. This will be done by partially replacing the Crystal Springs brook trout production with brook trout from Wisconsin hatcheries. Also, the DNR’s Lanesboro fish hatchery can provide brown and rainbow trout to help make up for the temporary lack of Crystal Springs trout.
Brook trout from outside sources will not be stocked in waters that contain native trout. That will conserve and protect Minnesota’s native brook trout strains, particularly in southeastern Minnesota.
“The amount of brook trout from external partner agencies will not fulfill our regular stocking needs,” Phelps said. “The DNR will develop a plan to determine where the most effective and efficient locations will be to stock these fish to best meet recreational demand.”
“The fact that fewer native brook trout strain will be available for stocking during the next three years will be a key consideration as the DNR develops its brook trout stocking strategy,” Phelps said.
Lake trout from Crystal Springs are stocked only in Lake Superior, a practice now being reviewed as part of the revision to the 10-year Lake Superior fisheries management plan. If the decision is to keep stocking Lake Superior, lake trout from Ontario could replace some of the fish now provided by Crystal Springs.
Flood waters from the Whitewater River likely carried the pathogen, a bacterium called Aeromonas salmonicida, into the hatchery. The pathogen occurs naturally and can cause fish kills in the wild when conditions are right, but is more likely to infect and kill fish kept in confined areas.
The DNR’s pathology lab first detected the pathogen in July 2014. Treatments – three in 2014 and two in 2015 – did not eliminate the disease agent, which is contained in water the hatchery releases into a holding pond that drains into the river.
Once depopulation and disinfection of the hatchery is complete, the hatchery will resume operation using uncontaminated brook trout brood stock and be regularly tested for any reoccurrence of the pathogen.
However, a hatchery must be disease-free for three years before fish produced there can be stocked in Minnesota waters. Brook trout brood stock takes three years to produce, meaning eggs can be available in 2018 and fish for stocking in 2019. The Lake Superior fisheries planning process will determine whether lake trout production will resume at Crystal Springs.