Marine ecosystems are facing disruptions due to changes in ocean conditions, such as temperature, salinity, and sea ice levels. These shifts are causing increased fluctuations in the abundance and species composition, which in turn affects how these ecosystems function. Marine species, which are found across a wide range of latitudes, are being impacted to different extents. In response to rising ocean temperatures, species in warmer waters tend to move toward cooler, northern areas more quickly than species in colder regions. In this way, dispersal north to new areas may help animals buffer against lost feeding opportunities on historical foraging grounds.

For instance, small herbivorous zooplankton, like Calanus finmarchicus, have been observed shifting northward in the North Atlantic, and zooplankton populations in places like the Davis Strait are becoming more typical of southern waters. These changes in zooplankton could have ripple effects throughout the food web, especially for species that rely on these organisms for food, such as baleen whales. Since zooplankton play a crucial role in maintaining the stability of marine food webs, shifts in their abundance and composition could affect the feeding opportunities for zooplanktivorous and piscivorous whales.

However, we don’t yet fully understand how these shifts in prey distribution might influence whale populations or whether an increase in low-quality prey could offset the effects of having less nutritious food. Will whales be able to buffer against climate-induced shifts in prey by shifting north to new areas or by altering their behaviour and spending more time feeding each day? To find out, we need to conduct long-term studies where we document spatio-temporal shifts in whale habitat-use patterns and simultaneously record their behaviour and prey field characteristics. By collecting aerial images of whales and measuring their body area index (relative measure of how fat or skinny an individual is) over time, we can track changes in whale body condition to infer whether whales can mitigate climate impacts.