St. Louis River Area of Concern Updates: Sturgeon Study

Researchers at Duluth’s EPA lab completed a study that sheds light on what is (or isn’t) behind the slow recovery of Lake Sturgeon in the St. Louis River. Lake Sturgeon are the oldest and largest native species in the Great Lakes.

These huge fish can measure six and a half feet long and weigh around 200 lbs. They can live for over 100 years, and females don’t reproduce until they are in their 20s! After being wiped out in the St. Louis River in the early 1900s, state and tribal resource managers began stocking and monitoring sturgeon in the 1980s.

More than 30 years since the fish were first stocked, the population is not recovering as expected. With a focus on addressing legacy contamination and restoring lost habitat, the St. Louis River Area of Concern (AOC) program initiated a study to determine whether historic pollution held in river sediment is limiting the reproduction of these bottom-dwelling fish.

EPA’s assessment of both eggs and adult sturgeon indicates that while historic pollutants are present in the fish, they are not building up to levels that would affect the survival of eggs or adults. Other factors, such as the species’ extremely long generation time, competition or predation from other species, or habitat limitations may be at work.

For additional information, please contact Melissa Sjolund, St. Louis River AOC Coordinator for the Minnesota DNR at Melissa.sjolund@state.mn.us.

PHOTO: The Minnesota DNR are scanning sturgeon for an embedded tag.