Grunwald Lake

Largemouth Bass

Good

Largemouth Bass were captured at a rate of 183 fish per hour. We typically like to see Largemouth Bass abundance around 60 fish per hour. When abundance get as high as triple the management goal, we start to worry about the population getting stunted. We caught 122 Largemouth Bass ranging in size from 3.7” to 19.9” with the largest fish weighing 4.25 pounds. The average length Largemouth Bass was 10.1 inches. 23% of the stock (bass over 8 inches) was longer than the “quality” size of 12 inches. We sampled Largemouth Bass over 15 and 18 inches and 6% of the stock were longer than 15 inches and 3% were longer than 18. These numbers are higher than the two previous surveys, when no fish over 15 inches were sampled. The best estimate of recruitment is the fact that this lake has not been stocked with Largemouth Bass in the last ten years and there are several year classes of Bass – indicating natural reproduction is sustaining the population. Based on this sample, the bass population is over-abundant. Size structure was better than in previous surveys but could be skewed by the timing of the sample as well as the morphology of this deep clear lake. This Bass population could use some harvest of smaller individuals (less than 14 inches), in accordance with the current regulation (three Largemouth Bass under 14 inches).

Channel Catfish

Improving

Fishing for Channel Catfish should be better in the future as this lake will be entered into IDNR’s Channel Catfish stocking program. Anglers should not be surprised if they hook into one.

Black Crappie

Fair

Deeper water in this lake make crappie difficult to detect with electrofishing. Black Crappies tend to be very cyclical in their population numbers. We typically don’t manage for or stock Crappies in small ponds as they can become over-abundant and compete with young of year Largemouth Bass. The IDNR strongly discourages illegal stocking of Crappie for this reason.

Bluegill

Very Good

The Bluegill catch rate of 165 fish per hour is higher than the management goal, but not high enough to cause concern. Bluegill abundance was lower in 2014 and 2018 when catch rates were 82 and 70 fish per hour. Size structure looked better in the 2014 and 2018 samples with over 60% of the stock measuring longer than 6 inches. Size structure has decreased in quality in our 2023 sample. Bluegill ranged in length from 1.3 to 6.9 inches, with an average length of 3.9 inches. Of all the Bluegill in the sample of stock length or greater (4 inches), 6% were greater than 6 inches. The Bluegill are healthy and most likely ready to spawn (some were seen on beds). We may have sampled this lake a little too early this time around, missing the largest Bluegills when they are in the shallows spawning. We don’t have creel data to know what harvest is like, but a 10 fish limit should prevent over-harvest of Bluegill.