Volunteers needed to take temperature of North Shore trout streams

A bevy of researchers and volunteers will fan out along the North Shore today and in coming weeks to take the temperature of the streams where trout live.

Peder Yurista of the Gitche Gumee Chapter of Trout Unlimited takes temperature readings along Silver Creek in Carlton County. Trout Unlimited and the NRRRI are looking for volunteers to help map cold water spots along North Shore streams, from the Duluth area to the Canadian border, to see which areas will be most resilient to climate change. Photo by John Lenczewski

A bevy of researchers and volunteers will fan out along the North Shore today and in coming weeks to take the temperature of the streams where trout live.

Those trout depend on cold water to survive and it's feared the gradual warming of air temperatures may be warming the water as well, squeezing stream trout into smaller areas.

The goal of the survey is to find out where the coldest pools of water are and document those pockets to be protected and managed to maintain trout - to make sure that any restoration or management efforts are aimed at the right areas on the right streams.

"We have some temperature data at road crossings and a few set locations. But we really don't have data up and down the stream to see where those cold water spots are,'' said Peder Yurista, a board member with the Gitchee Gumee chapter of Trout Unlimited in Duluth.

In short, trout experts and anglers want to get the most bang for their bucks, pouring money into the streams most likely to hold trout in a warmer climate. Streams that get little or no groundwater help are likely lost causes for brook trout and other coldwater species in the warmer decades to come.


The Natural Resources Research Institute of the University of Minnesota Duluth is heading the effort along with Minnesota Trout Unlimited and the Minnesota Department of Natural Resources.

Running into September and then again next summer, the project depends upon pairs of volunteers walking mile-long stretches of stream carrying quick-reacting thermometers and GPS units to map where the coldest waters are - so-called thermal refuges for trout.

It is the first-ever comprehensive effort to map the temperatures of about 100 North Shore streams - from the Nemadji River on the west to the Canadian border on the east.

The groundwater seeps also are an important component of the stream flow, especially during dry summer periods. Without them, some North Shore streams might not have enough water to hold trout.

"The North Shore streams are more vulnerable because they don't have a lot of groundwater infiltration. Most of their water is surface water,'' which warms up rapidly, Yurista noted. "That's why we need to find those spots and put our management efforts there."

The NRRI is providing the training and equipment; Trout Unlimited is coordinating the volunteer effort. Once volunteers are trained, they can do the survey on their assigned streams whenever they have time.

"We want to get as many done this year before it gets too cold. We'll have to come back and finish it next year,'' Yurista said.

Lucinda Johnson, director of the NRRI's Center for Water and the Environment, is heading the $416,000 project funded by the Legislative and Citizens Commission on Minnesota Resources, which allocates the state's lottery profits.


When cold spots are found, NRRI crews will install gauges for long-term monitoring. NRRI researchers also are developing a model for the DNR and other groups to use that will identify the best streams simply by their characteristics plugged into a computer.

"We're trying to get ahead of the curve as these warmer conditions come," said John Lenczewski, executive director of Minnesota Trout Unlimited. "It's not going to take much for many of these streams to get too warm for our coldwater species."

If you go: North Shore stream temperature survey

More volunteers are needed from Saturday into September, and again next summer, to help map water temperatures up and down North Shore trout streams.

Volunteers can meet at 9 a.m. today in the Lester River Park parking lot on Lester River Road, just off Superior Street. Bring waders, appropriate clothes, bug spray and drinking water. Training and equipment are provided.

To get involved, e-mail Peder Yurista, Gitche Gumee Chapter Trout Unlimited board member, at .

John Myers reports on the outdoors, natural resources and the environment for the Duluth News Tribune. You can reach him at
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