Sema

Sema Lake is located within the Boundary Waters Canoe Area Wilderness (BWCAW) within the Superior National Forest and is a non-motorized lake. It is approximately 33 miles northeast of Ely and is accessible by a 15 rod portage off the flowage from Spoon Lake, a 130 rod portage from Knife Lake, and a 0.6 mile winter portage from Kekekabic Lake. This 86 acre lake has a maximum depth of 72 feet and very clear water. Sema Lake was thermally stratified on September 14, 2015 with a surface temperature of 66 F and a bottom temperature of 40 F. Oxygen levels for trout were good to a depth of 34 feet. The most striking feature of this bowl shaped lake is the large sand beach on the lakes east side. There is one campsite on the northeast shore that evidently receives little use and is very grown in. By all accounts, summer and winter angling pressure seems light. The portage from Spoon Lake seemed to have light usage and the portage from Knife Lake seemed to have light to moderate usage. The north shore is primarily covered in birch and balsam fir. The area behind the beach on the east shore is mostly cedar while the rest of the lake is surrounded by a mix of cedar and balsam fir. There is a fair amount of cedar logs down along the shorelines. Sema Lake was stocked with lake trout fingerlings in 1970, 1977, and 1982. Lake trout did exist in the lake prior to 1970 and these stocking events were likely done to try to increase production because of higher fishing pressure on the small system. The 2015 gillnet catch consisted of only two species of fish, lake trout and white sucker. The gillnet catch for lake trout was high at nearly 9 fish/net. This is the highest catch rate on record for Sema Lake and one of the highest for the Tower area. Sizes were somewhat small ranging from 10 to 22 inches with an average of 17 inches. The trout averaged nearly 1.6 pounds which is close to other trout populations from similar lakes. Lake trout ranged in age from 3 to 27 years. Fish generally needed to be over 17 inches or 11 years old to be sexually mature. The fish in Sema Lake grow very slowly compared to other lake trout populations in the Tower area. The trout in Sema Lake are eating mostly aquatic insects but some are also eating crayfish and other minnows. The white sucker gillnet catch was nearly 3 fish/net which is average for this lake but low compared to other similar lakes. The average weight was 1.4 pounds and sizes were from 9 to 19 inches.

Lake trout and white sucker are present in above average numbers. Lake trout reproduction is occurring based on the presence of six fish under 12 largest trout captured was 23 small averaging only 8.9.

Composed of above average populations of lake trout and below average populations of suckers.

Based on Minnesota DNR survey data, anglers target Lake Trout in Sema. See the full species list above for catch rates, size structure, and quality scores.

Minnesota DNR records list public access for Sema. Check the DNR LakeFinder page for the launch type and directions before you go.

Sema has a maximum depth of 72 feet, per Minnesota DNR data.

The most recent Minnesota DNR survey data for the main sport fish in Sema is from 2015. Surveys this old should be treated with some caution — fish populations change over time.

No invasive species are on record for Sema in Minnesota DNR data. Always clean, drain, and dry your equipment to help keep it that way.