The fish community in Kushog Lake is a mix of species with cold to warm water affinities, including lake trout, brook trout, burbot, walleye, northern pike, largemouth and smallmouth bass, rainbow smelt, rock bass, yellow perch, pumpkinseed, brown bullhead and a variety of minnow species.
Kushog Lake was stocked beginning in the 1920s with lake trout and smallmouth bass and as early as the late 1800s with lake trout fry, and in the 1950s with brook trout. Rainbow smelt, rock bass and rainbow trout were “accidentally” introduced to the lake in the 1960s. Ministry of the Environment data suggest that lake whitefish, lake herring (cisco) and muskellunge are also present in the fish community.
The major change in the last 50 years has been the introduction of northern pike into Kushog Lake likely when a beaver dam broke. Historically, northern pike have not been found in the Haliburton Highlands and the Kawartha Lakes of central Ontario.
Kushog Lake is currently managed as a naturally-reproducing lake trout lake.
In a post-stocking assessment conducted in 1987 stocked lake trout represented 35% of the catch; however, volunteer creel results from 1986 to 1996 showed that 65% of the lake trout caught were wild. This suggested that natural reproduction was occurring though at an undetermined level. Natural reproduction appeared to originate primarily from the north basin.
Deep-water lake trout habitats are excellent in North Kushog Lake, including Ox Narrows, but are limited in the South basin.
At Ox Narrows most lake trout spawning activity was found to occur at water depths of less than 1 m. SCUBA divers found that the spawning bed consisted of only a thin rock layer with many large boulders, providing eggs with little protection. It was therefore decided to construct an artificial bed in 1977 on this site to improve the substrate quality, and to extend the bed into deeper water, with the aim of reducing predation and minimizing the effects of winter drawdowns. This spawning bed was further enhanced in 1984.
In 1978, another artificial spawning shoal was created in the south basin; however, subsequent MNR notes indicated that the bed was too shallow (2-4’ deep) and had become contaminated with silt, making it sub-optimal habitat.
From as early as 1952, local MNR personnel had voiced concern over the effects of fall and winter drawdown on lake trout reproduction. Now Kushog Lake winter water levels are scheduled to be lowered by mid-September prior to lake trout spawning to prevent eggs from being exposed.
Kushog Lake, unlike some other lakes in the area (e.g., Halls Lake) does not contain the Haliburton Gold sub-species of lake trout.