Thunder Bay

Invasive bloody red shrimp found in Lake Superior

The bloody red shrimp, a potentially harmful invasive species, has been found for the first time in Lake Superior.

A single specimen of the bloody red shrimp was found in a Minnesota harbour in Lake Superior in July

The bloody red shrimp is native to the Caspian region of Eastern Europe, but was found in Lake Superior in July. (Doug Jensen/Minnesota Sea Grant)

An invasive species, with a name right out of a horror movie, has been found for the first time in Lake Superior. 

The bloody red shrimp, which is usually found in the Caspian region of eastern Europe, was found around Twin Ports harbour in Minnesota last July.

If the population grows, the critter could potentially represent a threat to native species that share its diet of zooplankton and algae. 

"How it got here? We're not really sure," said Doug Jensen, an aquatic expert with the University of Minnesota Sea Grant Program, who noted that although only one specimen has been found in Lake Superior, the bloody red shrimp can already be found in other Great Lakes.

There are several ways it could have arrived in Lake Superior, he said. The first is that it could have swam through from other Great Lakes, the second one is that it could have come from a ballast water discharge, and the third one is from a bait bucket introduction.

"The finding really raises more questions than ... answers," Jensen added. 

Early detection important, but the species is elusive

The critter does have natural predators, such as lake trout, in Lake Superior. Otherwise, Jensen said, bloody red shrimp are very difficult to manage. 

"I'm not sure there's any real effective management tool," he said when asked about how authorities could get rid of a bloody red shrimp invasion. Early detection would be one way to manage the issue, he said. Jensen advises boaters to make sure they change filters and clean their boats going from lake to lake in order to avoid contaminating the different bodies of water. 

But he said spotting bloody red shrimp can be difficult. 

The species is photosensitive, so it hides at the bottom of the water during the day and avoids lit environments at night. 

One way to know if the species has established itself in Lake Superior is to look for orange swarms in the water at night. If such orange swarms are seen, Jensen said people should report the sighting to the authorities.