Blueberry Lake is in Ecological Lake Class 17,which consists of 99 lakes in northeast Minnesota that are small, shallow, and have turbid and soft (unmineralized) water. Blueberry Lake ranks as eutrophic according to Carlson's Trophic State Index.
Blueberry Lake was not thermally stratified on 06/04/2007, with a temperature of 65 F throughout the water column. Oxygen levels were at saturation to the bottom. Blueberry Lake has been known to winterkill on occasion. Blueberry Lake has three inlets, two of which drain local swamps and one that originates in Canary Lake (22 acres, 4 ft deep) 1/3 mile to the west. Beaver dams in the inlets limit fish movement. The outlet, which has no barriers to fish movement, is to the Bear Island River.
Most of the land surrounding Blueberry Lake is in State or Federal ownership. A small parcel on the northern tip of the lake, west of the outlet, is privately owned and has a house on it. The public access is a gravel boat ramp on the east side of the outlet adjacent to the CSAH 120 bridge.
Fish sampling in the 2007 fisheries lake survey was done with two gillnets, nine standard trapnets, and three small mesh (1/4" bar) trapnets used to sample small fish. Three previous fisheries investigations, dating back to 1965, used 2-3 gillnets and 6-7 standard trapnets. Shoreline seines were used in the 1965 investigation to sample small fish.
Fish populations in 2007 were dominated by northern pike, white sucker, yellow perch, and bluegill sunfish. Black bullhead were captured in the small mesh trapnets in 2007, the first observation of this species in this lake and in this watershed. They are probably survivors of a "bait-bucket" introduction by anglers, and will likely spread to other lakes over time with potentially negative consequences. Largemouth bass have never been captured in DNR investigations on Blueberry Lake, but were reported to be present by a local angler in 2007.
Northern pike numbers in 2007 (10.5/gillnet) were in the fourth quartile for this lake class and were higher than the median catch of 6.8/gillnet in all investigations on this lake. Pike sizes in 2007 averaged 21.4" (2.0 lb), which was in the third quartile for this lake class. The largest pike was 27.0". Most of the pike captured in 2007 were ages 3-6. Pike growth was somewhat slower than normal (in the second quartile) by area standards.
Perch numbers in 2007 (9.5/gillnet) were in the third quartile for this lake class and were similar to the median catch of 11.0/gillnet in all investigations on this lake. Perch sizes in 2007 averaged 8.9" (0.35 lb), which was in the fourth quartile for this lake class. The largest perch was 11.8". Most of the perch captured in 2007 were age 4. Perch growth was faster than normal (in the fourth quartile) by area standards.
Bluegill numbers in 2007 (7.6/trapnet) were higher than in previous investigations on this lake (range: 0.2-1.4/trapnet), perhaps due to the earlier date of trapnetting in 2007. Bluegill sizes in 2007 averaged 7.9" (0.51 lb), which was in the third quartile for this lake class. The largest bluegill was 11.1" (1.4 lb). Most of the bluegill captured in 2007 were age five. Bluegill growth was faster than normal (in the fourth quartile) by area standards.
Black crappie numbers in 2007 (1.2/trapnet) were in the second quartile for this lake class and were similar to the median catch of 1.4/trapnet in all investigations on this lake. Crappie sizes in 2007 averaged 7.6" (0.31 lb), which was in the second quartile for this lake class. The largest crappie was 11.8". Crappie growth was faster than normal (in the fourth quartile) by area standards.
Several large walleye (range: 19.5"-22.3") were captured in 2007. Similar numbers and sizes of walleye were captured in previous investigations on this lake. They were probably migrants from One Pine Lake, as spawning conditions for walleye in Blueberry Lake are very poor.
A few of the game fish examined in 2007 were infected with neascus. One perch was infected with yellow grub. Neascus (black spot) and yellow grub are common parasites that are native to the area. They cannot infect humans, are often removed by filleting fish, and are killed at temperatures used to cook fish.