French Lake (816.0 acres; class 24) is located in Rice County near the Town of Faribault. Residential development has disturbed and altered the majority of French Lake's shoreline. In areas with residential development, lawns are typically maintained to the water's edge and shorelines being altered with rock riprap or sand blankets, thereby disrupting the natural riparian buffer. A DNR owned access is located on the southeast corner of the lake, but can be difficult to use when water levels are low due to the shallowness of the area. The sport fish community consists of black crappie and bluegill, which are the primary management species, and walleye, muskellunge, and largemouth bass, which are the secondary management species. Walleye and muskellunge populations are maintained through stocking. Walleye fingerlings are stocked at a rate of 1 lb/littoral acre in 2 out of 3 years (2003, 2004, 2006, 2007, 2009, 2010, and 2012). Muskellunge are stocked annually at a rate of 600 fingerlings per year. A population assessment was conducted on 8-6-2012 to monitor the sport fish populations in French Lake using 8 gill nets and 12 trap nets.
A dissolved oxygen profile was taken on 8-6-2012 and ranged from 6.2 ppm at the surface to 0.6 ppm at 25.0 ft deep. Thermal stratification of the water column occurred between 16.0 and 18.0 ft of depth as indicated by a drop in temperature.
French Lake has historically produced quality black crappies. Since 1984, black crappie catch rates have varied from 6.7/trap net in 1987 to 38.6/trap net in 1998. The 2012 catch rate (30.9/trap net) fell within this range and was high when compared to similar lakes. Black crappies were also sampled very effectively with gill nets, and were captured at a rate of 55.1/gill net, which is also very high when compared to similar lakes. Seven year classes of black crappie were present in the French Lake sample (2005-2011). Age-2 (2010 year class) black crappies were the most abundant, accounting for 46% of black crappies sampled. Age-4 (2008 year class) black crappies were the second most abundant, accounting for 21% of black crappies sampled. The oldest black crappies sampled were age-7 (2005 year class). Black crappie size structure was good as lengths ranged from 4.2 to 12.7 inches and averaged 8.2 inches for trap netted crappies. Gill nets captured smaller black crappies as they ranged in length from 4.3 to 11.3 inches and averaged 6.9 inches. Data from the survey indicated good growth of black crappies in French lake as lengths averaged 5.0 inches at age-1, 6.8 inches at age-2, 8.4 inches at age-3, 9.5 inches at age-4, 10.4 inches at age-5, 11.4 inches at age-6, and 11.8 inches at age-7.
The bluegill population has been variable in French Lake ranging from 2.6/trap net in 1979 to 75.0/trap net in 2003. The 2012 catch rate was 30.8/trap net, which is slightly above average when compared to similar lakes. Although bluegill catch rates have decreased since 2003 (75/trap net) and 2007 (45.4/trap net), the size structure of trap netted bluegills appears to have increased. In 2007, bluegills ranged from 2.9 to 7.9 inches in length and averaged 4.9 inches, and in 2012, bluegills ranged from 0.7 to 8.3 inches in length and averaged 5.9 inches. Six year classes of bluegills were sampled (2006-2011) with age-5 bluegills being the most abundant (38% of the sample). Growth of bluegills in French Lake appears to be good, as bluegills averaged 3.7 inches at age-1, 4.8 inches at age-2, 5.6 inches at age-3, 6.7 inches at age-4, 7.4 inches at age-5, and 8.1 inches at age-6.
The walleye catch rate slightly decreased from the 2007 survey, dropping from 4.9/gill net in 2007 to 3.3/gill net in 2012, but still was within the long term range of catch rates (0.6 and 6.0/gill net in 1979 and 1984, respectively). The 2012 catch rate of 3.3 walleye per gill net is good when compared to similar lakes. Three year classes of walleye were present and corresponded to 3 stocking events in 2006, 2009, and 2010. Although sample size was small, walleye size structure was good, with lengths ranging from 12.3 to 22.5 inches and averaging 15.7 inches in gill nets. Walleye grow fast in French Lake as they averaged 13.2 inches at age-2 and 15.8 inches at age-3.
Largemouth bass and muskellunge are secondary management species on French Lake; however their populations were not assessed because they are not effectively captured by the gears used in this survey. The muskellunge population will be assessed during early spring of 2013. Two muskellunge were sampled during this survey and they had lengths of 39.4 and 44.3 inches. One largemouth bass was sampled measuring 6.6 inches.
The 2012 yellow perch catch rate (23.0/gill net) decreased from the 2007 catch rate (30.6/gill net) but still was good when compared to similar lakes. Five year classes (2004, 2007-2010) were sampled, with age-3 fish representing 60% of yellow perch. Yellow perch exhibited small size structure, with no fish exceeding 10.0 inches. They ranged in length from 3.9 to 9.9 inches and averaged 7.4 inches.
Northern pike have historically been scarce in French Lake and the trend continued in 2012 with a catch rate of 0.4/gill net, which is low when compared to similar lakes. Trap netted and gill netted northern pike ranged from 21.7 to 34.7 inches in length.
Freshwater drum continued to be abundant in French Lake with the 2012 trap net catch rate (5.6/trap net). The 2012 catch rate is similar to the 2007 catch rate and is consistent with historical catch rates of freshwater drum in French Lake. Freshwater drum were relatively large, ranging in length from 17.1 to 23.4 inches and averaging 20.3 inches.
Common carp, pumpkinseed, white crappie, golden shiner, white bass, and white sucker were also present in the 8-6-2012 assessment, but occurred in low numbers.
Anglers can help maintain or improve the quality of fishing by practicing selective harvest. Selective harvest allows for the harvest of smaller fish for table fare, but encourages release of medium- to large-sized fish. Releasing these fish can help maintain balance in the fish community and provide anglers the opportunity to catch more and larger fish in the future.
Shoreline areas on the land and into the shallow water provide essential habitat for fish and wildlife that live in or near Minnesota's lakes. Overdeveloped shorelines cannot support the fish, wildlife, and clean water that are associated with natural undeveloped lakes. Shoreline habitat consists of aquatic plants, woody plants, and natural lake bottom soils.
Plants in the water and at the water's edge provide habitat, prevent erosion, and absorb excess nutrients. Shrubs, trees, and woody debris such as fallen trees or limbs provide good habitat both above and below the water and should be left in place. By leaving a buffer strip of natural vegetation along the shoreline, property owners can reduce erosion, help maintain water quality, and provide habitat and travel corridors for wildlife.
- Eurasian Watermilfoil
Recreational activities such as recreational boating, angling, waterfowl hunting, and diving may spread aquatic invasive species. Some aquatic invasive species can attach to boats, while others can become tangled on propellers, anchor lines, or boat trailers. Many species can survive in bilge water, ballast tanks, and motors or may hide in dirt or sand that clings to nets, buckets, anchors, and waders. Fortunately, completing simple steps can prevent the transport of aquatic invasive species.