A resurvey was conducted at Dunns Lake in 2008 to evaluate the lake's physical, chemical, biological characteristics. A total of 12 different species of fish were sampled, plus hybrid sunfish. The Dunns Lake Aquatic Management Area, on the southeast side of the lake, offers fishing opportunities for shore anglers and wader fishermen. Dunns Lake has a history of partial winterkills with the latest recorded event occurring during the 1992-1993 winter.
Dunn's lakeshed (5,584 acres) was dominated by row crop agriculture. The lakeshed to lake ratio was 39:1. Roughly 1/2 of the shoreline remained undeveloped, with forest being the dominant cover type. Aquatic vegetation was sparse and there was little diversity (5 varieties). The only submergent species found, in early July, was filamentous algae. Sand was the only shoalwater substrate classified as abundant. Dissolved oxygen dropped below 2 mg/l at 12 foot on 6/24/08. Water clarity was poor, with a secchi disk reading of 1.5 feet in late June. Water chemistry results further indicated a degraded lake.
Gill nets sampled 0 walleye for a catch rate of 0.0/net, which was below the normal range for this type of lake. The 2003 catch rate was also 0.0/net. A total of 1 walleye was trap netted, with that fish measuring 11.7 in length. The fish was from the 2006 year-class. The latest stocking regime (1 pound of fingerlings every-other-year) was initiated in 2004. Thus far, the stocking efforts do not appear to have been highly successful. Possible explanations for the poor population were inadequate forage and predation from northern pike and largemouth bass. Gill netting in 2013 will be used to further evaluate fingerling walleye stocking efforts at Dunns Lake.
Gill nets sampled 18 northern pike for a catch rate of 3.0/net, which was within the normal range for this type of lake. The 2008 catch rate tied the all-time high catch rate from 1980 (3.0/net). The 2003 catch rate was 2.8/net. Northern pike were 15.5 to 31.8 inches long averaging 26.1 inches. Northern pike were 1 to 5 years old with 4 year-classes present. Dunns has a history of producing low numbers of larger sized northern pike and this was again the case in 2008.
Gill nets sampled 10 yellow perch for a catch rate of 1.6/net, which was within the normal range for lakes of this type. The 2003 catch rate was 33.7/net. Yellow perch were 5.3 to 6.1 inches long averaging 5.7 inches. Yellow perch were 2 to 4 years old with 3 year-classes present.
Spring night-time electrofishing sampled 14 largemouth bass for a catch rate of 10.4/hr of electrofisher on-time. The 2006 catch rate was 13.9/hr. Catch rates (n=5) from 1991 to 2008 ranged from 1.0 to 47.2/hr, averaging 21.8/hr. Largemouth bass were 8.5 to 18.3 inches long averaging 11.8 inches. Largemouth bass were 2 to 6 years old with 5 year-classes present. Age 2 fish accounted for 57% of the electrofishing sample. The mean length at third annulus formation was 11.8 inches. The low number of fish captured indicated a fair largemouth bass population. A lack of aquatic vegetation is likely limiting largemouth bass recruitment at Dunns Lake.
Gill nets sampled 26 carp for a catch rate of 4.3/net, which was above the normal range for this type of lake. The 2003 catch rate was 10.8/net. Carp were 18.0 to 22.5 inches long with a mean of 19.8. The trap net catch rate was 0.9/net.
Gill nets sampled 20 black bullhead for a catch rate of 3.3/net, which was below the normal range for this type of lake. A total of 6 black bullhead were trap netted for a catch rate of 0.7/net. Trap nets sampled 3 yellow bullhead for a catch rate of 0.3/net.
Trap nets sampled 782 black crappie for a catch rate of 86.9/net, which was above the normal range for this type of lake. The 2008 trap net catch rate was the highest ever measured at Dunns Lake. The 2003 catch rate was 6.6/net. Black crappie were 6.2 to 8.7 inches long averaging 7.1 inches. Gill nets sampled 298 black crappie for a catch rate of 49.7/net, with fish lengths ranging from 4.1 to 8.2 inches. Black crappie were 1 to 4 years old with 4 year-classes present. Most of the black crappie appeared to be from the 2005 year-class. Growth was slow. Black crappie, being so abundant, should provide plenty of action for anglers fishing Dunns Lake.
Trap nets sampled 1,308 white crappie for a catch rate of 145.3/net, which was above the normal range for lakes of this type. The 2008 trap net catch rate was the second highest ever measured at Dunns Lake. The 2003 catch rate was 5.6/net. White crappie were 6.1 to 11.0 inches long averaging 7.7 inches. Gill nets sampled 28 white crappie for a catch rate of 4.7/net, with fish lengths ranging from 6.3 to 9.3 inches. White crappie were 2 to 4 years old with 3 year-classes present. Approximately 83% of the trap netted fish were from the 2006 (age 2) year-class. On average, white crappie grew faster than black crappie did for every year-class (ages1-4). White crappie should provide anglers good action in the near future.
Trap nets sampled 95 bluegill for a catch rate of 10.6/net, which was within the normal range for this type of lake. The 2003 catch rate was 4.7/net. Bluegill were 4.1 to 7.95 inches long averaging 6.3 inches. Bluegill were 2 to 6 years old with 5 year-classes present. Growth was fairly fast.
Shoreline seining sampled young-of-the-year: bluegill (2), largemouth bass (16), northern pike (3), and yellow perch (5). Johnny darter (8) and bluntnose minnow (175) were also seined.