In Western Lake Erie (WLE), Harmful Algal Blooms (HABs) are occurring with increased frequency and duration. Microcystis aeruginosa, the primary HAB- forming cyanobacterium, increases turbidity, disrupts food webs, and produces toxins that can harm humans and animals. While most research focuses on toxin production and bloom formation, less is known about HABs impacts on WLE’s food web and fisheries. This study aimed to determine subsurface Microcystis concentrations and fish community distribution inside and outside of HABs events in WLE using multi-frequency hydroacoustics. Partnering with NOAA-GLERL, data was collected using a Biosonics hydroacoustics system, utilizing 70, 120, 200, and 420 kHz transducers towed along a transect covering HABs and non-HABs areas. Data was collected over two days, during daytime and nighttime cruises, during August of 2022. Fixed station water quality data consisting of Chl-a, Microcystis concentrations, microcystin concentrations, temperature and dissolved oxygen were also collected. Preliminary data indicates Microcystis is distributed throughout the water column, likely from wind-mixing in shallow WLE. Fish in HABs zones appeared constrained between surface blooms and possible toxic bottom conditions. These spatial shifts in fish distributions during HABs events may affect fish abundance indices used in surveys. Improved understanding of these dynamics can help fisheries managers refine regulations and ensure sustainable resources use.