Area Biologist Evan Armstrong checks a temperature monitoring instrument.

When you’re out on the lake this summer, be on the lookout for red rectangular boxes floating on the water’s surface.  The Ministry of Natural Resources are doing some testing to record lake temperatures in 22 lakes in the region including Dryden, Fort Frances, Red Lake and Thunder Bay districts.

The lakes being tested in the Dryden district include Indian Lake and Little Sandbar Lake, north of Ignace.

The devices are being placed in the water in now, as the ice is alread out, and will be collected again in the fall, before freeze up.  There are small electronic sensors connected to the red floating pieces, while anchored in the deepest parts of the lake.

The purpose of these devices is to measure the lake temperatures every hour, and study how the water temperature fluctuations can affect fish feeding behavior, habitat, productivity and even the survival of the given species.  Some species being tested are walleye, lake trout and brook trout.

Brian Jackson, the area biologist from the Atikokan MNR office, explains that the temperature monitoring program is part of a provincial broadscale program.

“This is a fisheries monitoring program that assesses populations in the lakes on a five year cycle,” states Jackson.

MNR personnel are looking to find out how thick the layers are beneath the surface of the water.  The walleye tend to live in the upper warmer layer, while the trout inhabit the lower, colder areas.

There is a section beneath the two layers called a thermocline.  The goal of the MNR is to find out how the changes in the thermocline’s depth, location, and speed affect the fish populations and the size of the habitats available to them.

“We can see if there’s changes in growth rate or population sizes that might be related to the changes we’re seeing in the temperature”, says Jackson.

Lake sizes being test vary from 65 hectares up to 13,000 hectares and clarity of lakes is ranging from stained (brown murky) lakes to very clear lakes.  This way, the MNR can determine how the physical factors of the lake can affect how temperatures might change the thermocline.

The MNR is advising boaters not to touch or damage the rectangular devices, as they could alter the results in the monitoring.

- Ally Dunham