Climate Change May Supersize Lamprey

The life-sucking sea lamprey may grow bigger in size and numbers in Lake Superior because of global warming.

The temperature of the water in Lake Superior has climbed about four degrees in the past 30 years. James Kitchell is a retired professor working with UW Sea Grant. He says it is the fastest warming lake in the world. Combine that with a growing lake trout population and it makes a near perfect habitat for sea lamprey.

UW Sea Grant has a project to help figure out what effects these changes could have on Lake Superior and its fish population. Kitchell says they will try to model what the lake’s rising temperature and its effects on the sea lamprey population could have. “The result of the warming is that ice off goes earlier in the spring and ice on happens later in the fall and into the winter. And that’s a longer growing period with higher temperature for lampreys, and they become bigger.”

Kitchell says he is worried that the growing lampreys could make controlling the eel-like fish predator more difficult. “Bigger lampreys are going to kill more fish and lay more eggs. And the result is going to be an effective increase in lamprey population that is caused by climate warming effects.”

Kitchell says lampreys currently are only at 10 percent of what they were at their peak population 60 years ago. “When they were at their maximum abundance they were causing substantial declines in many of the fish populations that were important to many of commercial and recreational fisheries. And in each of the lower lakes, Ontario, Erie, Michigan and Huron, Lake Trout the most important commercial fisheries disappeared, absolutely disappeared.”

It is estimated that there are 75,000 adult sea lampreys in Lake Superior.