Habitat Selection and Migration

Beluga whales are annual migrators who may move away to a variety of habitats for molting, food acquisition, or other reasons. Climate change, increases in anthropogenic disturbances, and subsistence hunting drive away or reduce population sizes. How have white whales adapted their habitat choices and migration patterns to these environmental stressors?

As an ice-adapted species, climate change has raised the temperatures of many Arctic marine mammal habitats. Moreover, the increases in anthropogenic disturbances (i.e., coastal development, pollution) prevent potential beluga whales from visiting, while subsistence hunting has reduced population sizes, such as the Cook Inlet population that decreased by about 50% over the span of four years (Goetz et al., 2012).

To avoid these potential dangers and find more suitable habitats, belugas have seasonal and daily movement patterns they follow to search for resources and space. As for daily movements, Hobbs et al. (2005) found that amongst the Cook Inlet sightings and tagged whales, individual belugas regularly traveled around 11 to 30 kilometers a day, where longer distances were much more common during the fall and winter (from around August to March) when visiting offshore areas. Ezer et al. (2008) noted that daily beluga movements suggest that water salinity, ice coverage, prey availability, sea level and currents are possible factors for finding areas to eat at or nurse young belugas. These physical measures for daily movements also seem to be similar for migration patterns, in addition to sea-surface temperature (SST) (Goetz et al., 2012).

Here is a video of belugas at a migration ground in Churchill, Canada.

800 belugas traveling together to a migration ground

Amongst the different components that affect a beluga whale's consideration of a habitat, ice coverage seems to be a top priority. Too much or too little ice can make navigating difficult, as this affects the beluga's echolocation capability. Disruptions in echolocation can make finding fellow members difficult and may also make finding their way back home a challenge. These potential safety issues could be possible reasons as to why many of the habitats that belugas choose for any of their activities shows little ice coverage.

Apart from choosing habitats, white whales have interesting behavioral patterns for migration. Notably, belugas seem to strongly exhibit natal philopatry (also known as site fidelity), which is the tendency to stay at, or annually return to, the same site they were born at. As young belugas seem to stay close to the mother for one or two annual migration cycles, the migratory paths and locations seem to be a learned behavior that is maternally taught. When moving to different habitats for breeding or molting, they may travel in large numbers. Echolocation is particularly useful for migration, as it allows for the beluga to navigate itself by using the surrounding water as effective medium for sound transmission and location of objects.

Picture Credits and Licenses: Title Image (scaled to fit into column) - premier.gov.ru, CC BY 4.0, via Wikimedia Commons