When is the peak bloom period for HABs in the Western Lake Erie Basin?

• A. May to June.
• B. August to September.
• C. December to January.
• D. March to April.

Answer: (B)

Peak HABs in the Western Lake Erie Basin happen in late summer. When water is warm, light is abundant, and nutrients are still present, cyanobacteria can multiply rapidly. As the lake reaches its warmest temperatures and often remains stratified, these conditions align most strongly in August and September, producing the heaviest blooms. Outside this window, cooler temperatures, increased mixing, and reduced light limit bloom development, so spring and winter periods are not when blooms peak. This late-summer timing is typical for the Western Basin, reflecting how temperature, stratification, and nutrient availability drive maximum algal growth.