Grass Lake is categorized as a lake class 14 lake, is 24 acres with a maximum depth of nine feet; Secchi disc was 5.1 feet in brown stained water. The initial water sample taken found that pH was 7.1, conductivity 82 and total alkalinity 44.3. The lake is located 8 miles west and 7 miles north of Isabella down the Bandana Lake Road (FS 383). The access is a 0.15 mile trail off FS 383 then a 75 foot carry-in trail down a small hill to the lake. There is a small turn around area and user made campsite. The carry-in trail is wide enough to push a small trailer to the lake and is suitable for canoes and small boats.
Northern Pike were found in above average numbers and size in 2013 for this type of lake. The average fish was about 19 inches and 2.3 pounds, with one larger fish of 39 inches and 12.2 pounds. Historically, the pike catch in Grass Lake is average for this lake type in both numbers and size. The most abundant size of northern pike weighs at about 2 pounds. In each of the past five assessments since 1991 at least one fish around 30 inches or larger has been sampled. Reproduction appears to be consistent and growth is faster than average for the Finland Area. Grass Lake is known by local anglers to be a pretty good pike fishing lake. The fish are a bit on the small side, but the action is good and you have a good chance at fish 30 inches and larger.
Yellow Perch in 2013 were sampled in above average numbers and smaller than average size with an average length of 6 inches weight of 0.09 pounds. This was the highest catch on record, with the smallest average size. The largest fish sampled was 7.1 inches which presently will not interest most fishermen, however; perch are a valuable forage species for the pike population.
White Sucker in 2013 were sampled in above average numbers and smaller than average size with an average length of 12.4 inches and weight of 1 pound. The historical catch ranged from 22.5/lift in 1996 to 5/lift in 2007, weight ranged from 1.94 pounds in 1996 to 1 pound in 2013. White Suckers are also a valuable forage species for the pike.
Two Largemouth Bass and four Bluegill were sampled in trap nets. All fish were small and two years old. Largemouth Bass were first sampled in 1996 and Bluegill in 2007. It appears that their numbers at this time are limited and they provide for a poor fishery.
In 1988, 600 fingerling and 72 adult Black Crappies were stocked. This was the first assessment since 1991 that no crappies were sampled. Since the initial stocking, their numbers and average size has fluctuated widely. Their absence in the catch in 2013 is a bit puzzling given the fact that both Bluegill and Largemouth Bass were captured, indicating that winterkill is not a likely cause. It appears that all three of these species maintain small populations in Grass Lake with occasional year classes in an optimal growing year.