Mysis diluviana (mysids) are large, omnivorous zooplankton that play a key role in Great Lakes food webs by coupling benthic and pelagic habitat through diel vertical migrations. Although it is recognized that some of the population remain benthic at night, mysid benthic habitat use remains under-studied as their abundance is assessed primarily with nighttime pelagic net tows. Using Lake Michigan lakewide benthic surveys from 2015 and 2021, we assessed whether benthic grabs with Ponars are useful for quantifying benthic mysid abundance. Mysids were caught in Ponars at 54% of the sites (83 out of 155 stations) in 2015 and 30% of the sites (34 of 114 sites) in 2021. Benthic mysid counts were higher during the day than at night as expected in 2015, but not in 2021. For both years, benthic mysid density increased with bottom depth, and dreissenids had a positive effect. The age structure in pelagic samples was similar between the two years, but night Ponars in 2015 had a larger contribution by juveniles while 2021 night Ponars had a larger contribution of adults than night net tows. Lower overall counts in 2021 mirror the decline observed in net tows, indicating that the perceived decline of mysids is not due to increased benthic habitat use. Long-term monitoring data for 1998-2023 confirmed that the decline we observed between 2015 and 2021 is consistent with a longer-term decline. Nighttime benthic mysid densities calculated from Ponar catches were 8% of the nighttime net tow mysid densities. However, our catchability estimate based on day Ponar catches suggests that Ponars may only catch 10% of the benthic population. Applying this catchability to night Ponar catches resulted in almost 45% of mysids remaining on bottom at night. The proportion of mysids remaining on the bottom at night was higher in shallower areas. In 2015, adjusted for catchability, about 69% remain on bottom at depths 60 m and shallower while 33% remain on bottom at depths 90 m and greater. While Ponar catches were useful indicators of patterns in benthic mysid distributions, our limited understanding of Ponar catchability makes estimates of benthic mysid abundance highly uncertain using this approach. Mysid benthic habitat use remains a major knowledge gap in the Great Lakes.