Fish Population and Algae on Sanford Lake

Sanford Lake is currently undergoing a significant ecological transition following its refill. The reservoir had approximately six years of exposed bottomlands that were recently inundated. During that period, vegetation, debris and other organic materials accumulated on the exposed lakebed. As those materials became submerged following the refill, their decomposition released nutrients into the water. In addition, the summer 2026 season has been abnormally warm and dry. Different plant life existed in the bottomlands before the fill and a population of fish have migrated into the river system that are not well adapted for a lake with these conditions. This has led to increased algae, lower oxygen levels, and higher temperatures that led to an abnormal amount of fish kills.

It is important to recognize that Sanford Lake is re-establishing itself as an aquatic ecosystem. As that process unfolds, the development of aquatic vegetation and filamentous algae will be an important part of the lake's ecological recovery. A healthy and established aquatic plant community will help retain nutrients within the system, and provide habitat for fish and other aquatic organisms.

Regarding Algae:
Unfortunately, some algae are toxic, and no single treatment or "silver bullet" will immediately eliminate a harmful algal bloom once it has developed. Depending on the species involved and prevailing environmental conditions, blooms may dissipate relatively quickly or may persist for several weeks. Guidance from the Michigan Department of Natural Resources states that the most appropriate approach is to allow the bloom to run its course while continuing to monitor conditions. If you'd like to learn more about identifying harmful algal blooms, watch this video by the Michigan Department of Environment, Great Lakes, and Energy.