Hill River Lake has undergone three documented periods of severe winterkill. The first was during the drought in the 1930's. A dam was constructed at the outlet in 1935 and reconstructed in 1950 in an unsuccessful attempt to prevent winterkill by raising water levels. More recently, the dam was reconstructed during road reconstruction. The second recorded period of winterkill, during winters of 1969 through 1971, was attributed to runoff from a large poultry farm. The third period, during the mid 1990's, decimated populations of Northern Pike, Largemouth Bass, Bluegills, and Black Crappies. Although the lake has a 60 foot maximum depth, much of the lake is considerably shallower. The lake is also relatively fertile and experiences heavy blue-green algal blooms annually.
Eighteen years after the most recent severe winterkill, however, fisheries for pike, bass, and panfish have substantially recovered while bullhead populations have declined dramatically. Modest populations of Northern Pike and Largemouth Bass were sampled in 2014 while net catches of Bluegill and Black Crappie were very strong. Bluegills and crappies were relatively young and relatively small averaging 5.8 and 6.1 inches in length, respectively. The abundance of young panfish in 2014 may bode well for panfish angling opportunities in the near future, barring a winterkill.