Greenstone Lake is located 10 miles east of Ely. There are four accesses that are all remote carry-ins. There is no ramp on this lake. Accesses consist of a 3/4 mile portage from Madden Lake, a 1/2 mile portage from the North Kawishiwi River, a winter snowmobile route to Pickerel Lake, and the trail system off the Madden Creek Rd. This 332 acre lake contains three inlets, all on the east side (small creeks from the north and from the east drain wetlands, and the Conchu Lake Outlet) and one major outlet, the Greenstone Lake Outlet which flows to Pickerel Lake. Greenstone Lake has a maximum depth of 72 feet and the water color at the time of this survey was light brown. On August 11, 2014 Greenstone was thermally stratified with a surface temperature of 74F and a bottom temperature of 43F. Oxygen levels were adequate to a depth of 62 feet. Lake bottom substrates along the shoreline of Greenstone Lake are mostly boulder and rubble. Aquatic plants are sparse and only grow in some of the shallow bays. There are a handful of water access only cabins on the lake, overall it is quite undeveloped. The overall gillnet catch rate for all fish combined was 10.9 fish/net which is average compared to historic surveys. Total yield was 14.5 lbs/net which is slightly below average. Fish species sampled in gill nets were walleye, northern pike, yellow perch, bluegill, white sucker, and rock bass. Walleye have been stocked as fry in Greenstone Lake dating back to 1942. Most recently, around 350,000 fry have been stocked every three years. In the 2014 survey twenty-nine walleye were sampled in gill nets for a catch rate of 3.2 fish/gill net, which is above average compared to other similar lakes. Fish captured in gill nets ranged in size from 8 to 24 inches with an average of 16 inches. Average weight per fish was 1.7 pounds which is good compared to other similar lakes. Growth based off of otolith ages appears to be somewhat slow compared to other walleye populations from lakes in the Tower Management Area. Ages ranged from 1 to 12 with only two missing year classes (2003 and 2005). When comparing stocked vs. non-stocked year class strength the stocked classes seem to be outperforming by a fairly wide margin. Interestingly the oldest year class observed (2002) was tied with two much younger year classes (2011 and 2012) for the strongest representation by a year class in the catch. The northern pike gillnet catch was 1.8 fish/net which is above average compared to other similar lakes but slightly below the lake assessment average. Average weight was 3.3 lbs/fish which is slightly better than other similar lakes. Lengths ranged from 20 to 32 inches with an average of 24 inches which is better than the historic average of 23 inches. Although bluegill are normally not assessed with gill nets, they have been captured on a fairly regular basis in Greenstone. The 2014 catch was 1.6 fish/net which is above the historic average. Sizes were small with an average of 4.5 inches although this isn't a lot different than the average historic length which is 5 inches. Fourteen yellow perch were sampled in gill nets for a catch rate of 1.6 fish/net which is above average compared to other similar lakes and past assessments. Lengths ranged from 6 to 7 inches with an average of 6.5 inches. These sizes are on par with fish from previous surveys. Cisco were sampled in only one survey (1976) but the thermal habitat of the lake appears quite suitable. We set 3 experimental gill nets deep and 3 deep water small mesh gill nets specifically targeting cisco habitat. No fish were captured in the small mesh nets and only one northern pike and one white sucker were sampled in the deep experimental sets. In addition to these nets, walleye and pike stomachs were checked for cisco remains, none were found.