Caribou Lake is one of the most heavily developed, and heavily used, lakes in Cook County. It is managed for walleye and northern pike, although it also supports a smallmouth bass fishery. Management goals for walleye in this lake are based on its historic ability to support a dense population of small fish, while goals for northern pike goal are less ambitious.
Caribou Lake supported fair numbers of walleye in 2014, in a range of sizes. Although the walleye gill net catch in 2014 remained within the normal range for a lake of this type, it was well short of our goal for walleye in this lake. This was the third consecutive assessment in which the walleye gill net catch declined, and the 2014 catch was the second lowest ever observed in Caribou Lake. Walleye taken in gill nets in 2014 ranged in length from 6.7 to 24.7 inches. Nine year classes contributed to the gill and trap net catch, with the strongest apparently produced in 2012. Fry stocking in 2004, 2007, and 2009 contributed, at most, four of the 65 fish taken in assessment nets; the rest were produced naturally. Sampling with 0.25-in-mesh trap nets collected some young-of-year (YOY) walleye, indicating another natural year class (of unknown size) was produced in 2014. Walleye growth had been faster than average for this area; fish reached an average length of 14.7 inches by the end of their fourth year, compared to an area mean of 12.6 inches.
Walleye were also sampled by spring electrofishing done by Fond du Lac and the 1854 Treaty Authority in May 2014. A total of 524 walleye 11 inches or longer were marked with orange tags. Recapture of tagged fish during the July 2014 DNR assessment allowed us to estimate that in May 2014 Caribou Lake supported 2,013 walleye 11 inches or longer (plus or minus 1,360 fish). This estimate was lower than estimates obtained in the same way in 2005 and 2008.
The 2014 northern pike gill net catch met management goals for the species in this lake, in terms of numbers and size of fish present. The 2014 gill net catch catch and mean weight for fish taken in gill nets were similar those observed in other assessments done since 2003. Five year classes, none of which appeared to have been exceptionally strong, contributed to the 2014 catch. Growth of young northern pike had been about average for the area; fish reached a mean length of 15.2 inches by the end of their second year, compared to an area average of 14.2 inches.
Smallmouth bass were first observed in Caribou Lake in 1981, and their abundance may have peaked in late 1990s or early 2000s. No smallmouth bass were taken in gill nets in 2014. A few were collected in 0.75-in and 0.25-in-mesh trap nets, and a special assessment targeting smallmouth bass through open-water angling collected seven fish in June 2014. Despite low catches in gill nets and trap nets, Caribou Lake can still provide some good smallmouth bass fishing for anglers looking for bass.
Caribou is one of very few lakes in this area to support a few black crappie. Catches of black crappie have never been high in any assessment, and the 2014 catch, while very low, was typical for this lake. In addition to a few black crappie, the lake seems to support an expanding bluegill population. Bluegill are not abundant, but the 2014 trap net catch was the highest observed to date in this lake. Bluegill were first collected in 0.75-in-mesh trap nets in this lake in 2008, and catches have increased in each subsequent assessment. Bluegill collected in 2014 ranged in length from 1.6 to 9.7 in, with several year classes contributing to the catch. Growth of young bluegill had been average for the area; by the end of their third year fish reached an average length of 5.2 inches, compared to an area mean of 4.9 inches.
Yellow perch are probably the primary forage for walleye and northern pike in this lake, but have rarely been present in sizes large enough to have been of interest to anglers. The 2014 gill net catch, while improved compared to 2011, remained low for this lake historically. Although no yellow perch were aged, lengths of fish taken suggested the catch may have consisted of just one or two year classes.
Caribou Lake has at times been the subject of white sucker removal efforts, due to their perceived effect on walleye when abundant. White sucker were not abundant in 2014. The 2014 white sucker gill net catch was at the low end of the normal range for this type of lake, and was not high for this lake historically.