Brule Lake has long been known as one of the best BWCAW walleye lakes in Cook County. The 2009 catch was about average for the lake, historically, as was the size of the fish taken. The walleye population was entirely self-sustained, since the lake had not been stocked since 1985. Growth of young walleye had been slow, most likely because of low numbers of yellow perch in this lake. Larger walleye would have been able to feed on the abundant northern cisco present.
Northern pike were relatively abundant in 2009, but fish taken in the assessment were below average in size. Brule Lake provides the cool water and cisco forage base needed to produce large northern pike, and it is likely that larger fish were present. Most of the northern pike taken in 2009 were two-year-old fish from a strong 2007 year class. Growth rates for young northern pike had been somewhat faster than average.
The 2009 assessment yielded one of the higher smallmouth bass catches seen in this lake historically, although the catch was below the median for the lake class. Smallmouth bass collected tended to be large, and growth had been fast. Five-year-old fish reached an average length of 13.9 inches at the end of their fifth year, compared to an average of 11.5 inches for other lakes in Cook County.
Brule Lake does not support any panfish. Northern cisco were abundant and large in 2009, and would provide some angling opportunity for those with the right gear. Brule Lake is also open to netting for cisco for a period each fall. All anglers (and netters) on Brule Lake must abide by BWCAW regulations at all times; the lake is entirely non-motorized.