Bower Lake is a small, bass-panfish lake located in northeast Itasca County in the Mississippi River watershed. The lake has a surface area of 89 acres and a maximum depth of 35 feet. The primary management species are northern pike, largemouth bass, black crappie and bluegill.
The northern pike gill-net catch in 2010 was within the expected range at 3.0/net. This catch rate was similar to previous assessments and near the lake management plan goal of 3.5/net. Northern pike size structure was good. Sampled pike ranged from 25.0 to 30.6 inches, with a mean length of 27.3 inches. Ages 3 through 7 were represented in the sample. Mean length-at-age was above the statewide average for ages 3 through 5, and similar to the statewide average for all other ages. Northern pike reached 26.3 inches in 5 years.
Largemouth bass had been captured in previous test-nettings, but the lake was specifically sampled for bass with night electrofishing for the first time in 2010. This assessment resulted in a catch rate of 36.8 fish/hour of on-time. This was a moderate catch rate compared to other lakes in the area. Sampled largemouth bass had a relatively good size structure, with fish ranging from 5.7 to 19.1 inches and a mean length of 13.3 inches. Ages 2 through 10 were represented in the sample, with age 5 fish (2005 year class) making up 37% of the sample. Mean length-at-age was below the statewide average for ages 1 through 3, and similar to the statewide average for all other ages. Largemouth bass reached 15.1 inches in 6 years.
The gill-net catch for black crappie was within the expected range for this lake class at 3.0/net. The trap-net catch rate for crappie was above the normal range at 7.3/net. This was above the lake management plan goal of 4.0/net. As in previous assessments, black crappie size structure was poor. Only one crappie over 9 inches was captured. Trap-net sampled crappie ranged from 4.1 to 10.1 inches with a mean length of 6.8 inches. Ages 2 and 4 through 9 were represented in the sample, with 60% of fish attributed to the 2005 year class. Mean length-at-age was below the lake class average for all ages. Black crappie took 7 years to reach 8 inches.
The trap-net catch rate for bluegill was within the expected range for this lake class at 27.6/net. This catch rate was above the long-term average for the lake and above the management plan goal of 9.0/net. A similar trend of increasing bluegill abundance has been noted in other area lakes in recent years. Size structure was poor with no bluegill over 8 inches captured. Trap-net sampled bluegill ranged from 3.3 to 7.0 inches with a mean length of 4.7 inches. Ages 4 through 10 were represented, with age 4 and 5 fish making up 60% of the sample. Mean length-at-age was below the lake class average for ages 3 through 6, and similar to the lake class average for all other ages. Bluegill took 8 years to reach 6.1 inches.
The gill-net catch rate for yellow perch was near the lake class median at 5.8/net. This was an increase from the previous assessment when only three were sampled (0.8/net). Size structure of perch was poor with no fish over 7 inches in the sample.
Other species sampled in test nets included pumpkinseed, hybrid sunfish, golden shiner, white sucker and yellow bullhead. Near-shore IBI (Index of Biotic Integrity) sampling with a small-mesh seine and back-pack electrofishing was conducted in 2010 in an attempt to capture smaller fishes not normally encountered with standard sampling gear. Additional species captured in near-shore sampling included blackchin shiner, bluntnose minnow, central mudminnow, Johnny darter and tadpole madtom.