Diel vertical migration (DVM) is a common behavior in zooplankton populations world-wide. Every day, zooplankton leave the productive surface ocean and migrate to much deeper and darker waters to avoid visual predators and return to the surface at night to feed. While this behavior is primarily for predator avoidance, it may also help retain migrating zooplankton in biologically productive regions. Compared to fast surface currents, deep ocean currents are sluggish, and can recirculate. We test the hypothesis that DVM into these recirculating currents increases local retention of migrating zooplankton in a biological hotspot along the Western Antarctic Peninsula. A subsurface, recirculating eddy has recently been described in Palmer Deep Canyon, a submarine canyon adjacent to a biological hotspot. Previous simulations have shown that residence times of particles increase with depth within this feature. Here, we use in-situ observations to illustrate the presence of vertical migration behavior in local zooplankton populations. We then use model simulations to demonstrate that vertically migrating particles have residence times on the order of 30 days, which is significantly greater than residence times of non-migrating particles. The presence of this seasonal, retentive feature, and the resulting retention of critical zooplankton populations may serve as an important resource for local predator populations. The interaction of DVM with this subsurface feature may be important to the establishment of the biological hotspot within Palmer Deep Canyon. Similar interactions between DVM behavior and subsurface circulation features, modulated by mixed layer depth and day length, may also increase residence times of local zooplankton populations elsewhere.