Blandin Reservoir is a 449-acre impoundment on the Mississippi River, controlled by a dam at Blandin Paper Company in Grand Rapids, MN. Blandin Reservoir has minimal storage capacity and functions more as a flow-through system, minimizing water level fluctuations. The lake is in ecological lake class 35, which represents moderate size lakes with a high percentage of littoral area and moderately clear and hard water. Other area lakes in this class include Little Cut Foot Sioux and Prairie Lakes.
The northern pike gill-net catch was below the lake class expected range at 1.8/net. Catch rates in past assessments have also been low, varying from 1.6 to 3.8/gill net. As in previous surveys, northern pike size structure was poor. Sampled pike ranged from 11.4 to 24.5 inches, with a mean length of 18.6 inches. Ages 1-5 were represented in the sample. Growth was similar to the statewide average with pike reaching 20.2 inches at age 3.
The yellow perch gill-net catch was near the lake class first quartile at 3.6/net. Catch rates have varied from 1.5 to 10.3/gill net in previous assessments. Size structure was relatively poor with only two fish exceeding 9 inches. Sampled perch ranged from 5.4 to 9.8 inches with a mean length of 6.6 inches. Ages 2-7 were represented in the sample. Growth was similar to the statewide average with fish reaching 6.4 inches at age 4.
The walleye gill-net catch was near the lake class first quartile at 1.1/net. Catch rates in previous assessments have generally been low, varying from 0.6 to 2.9/gill net. Sample size was insufficient to calculate size structure indices. Sampled fish ranged from 8.3 to 18.7 inches with a mean length of 11.8 inches. The length distribution suggests fish over 14 inches may be subject to harvest. Anecdotal reports suggest anglers catch good numbers of walleye in the spring time. Ages 1-4, and 6 were represented in the sample. Age-1 and age-3 fish made up 60% of the sample and correspond to non-stocked years. The preponderance of these small fish in the sample may be because they were too small to be harvested yet. Growth was similar to the statewide average fish reaching 14.8 inches at age 4.
Bluegill were sampled at 1.9/trap net and 1.0/gill net. Net catches in past assessments have generally been low. Size structure was poor. Trap-net sampled bluegill averaged 5.4 inches while those from gill nets average 7.2 inches. Only two bluegill over 8 inches were sampled (both from gill nets). Ages 1, 2, 4 and 5 were represented in the sample. Growth was similar to the lake class average with fish reaching 5.6 inches at age 4.
Pumpkinseed sunfish were captured in slightly higher numbers of 2.2/trap net and 3.6/gill net. Size structure was poor. Mean length of pumpkinseeds was 4.0 inches from trap nets and 5.7 inches from gill nets.
Only two black crappie were sampled for a catch rate of 0.2/gill net. Mid-summer test-netting is typically a poor method for sampling crappie and catch rates are not a true indicator of relative abundance. Angler reports suggest fair numbers of crappie are caught in Blandin Reservoir, particularly in the winter months.
Daytime electrofishing was conducted in attempt to sample largemouth and smallmouth bass. Largemouth bass were captured at 21.3 fish/hour of on-time. This could be considered a moderately high catch rate for daytime sampling, since fish are more likely to spook from the boat and harder to catch than with night-time sampling. Sampled largemouth bass ranged from 2.4 to 17.9 inches with a mean length of 12.5 inches. Ages 2-9 were represented in the sample and growth was similar to the statewide average. Largemouth bass averaged 14.2 inches in 5 years.
In some lakes gill nets provide better catches of smallmouth bass than electrofishing. Only two smallmouth bass were captured with electrofishing, but nine were captured with gill nets for a catch rate of 1.0/net. This catch rate is twice the lake class average and the highest recorded for Blandin Reservoir. Sampled smallmouth ranged from 8.3 to 17.5 inches with a mean length of 14.7 inches. Sample size was too small to calculate meaningful size structure indices or growth rates.
Other species sampled in the survey included bowfin, brown and yellow bullhead, rock bass, hybrid sunfish, shorthead redhorse and white sucker.