The humpback whales that we encounter aren’t here year-round. Their behaviours vary seasonally with them spending their summers feeding and their winters mating and calving. Temperate waters have higher nutrient and oxygen content in them, and support more krill and small schooling fish that these whales feed on. The warmer waters have very little food for them, but offer protection from predators including killer whales.
During the summer months in British Columbia, humpback whales spend most of their time feeding on krill, plankton and small fish including herring. They need to build up their fat supply for the winter months, and will eat around 2 tonnes a day, that’s over 4000lbs of food they filter through with their baleen plates. They have a variety of feeding techniques to gather herring and other small fish while feeding including lunge feeding, bubble net feeding, and trap feeding. In their warmer wintering grounds, they consume almost no food and instead live off of their fat reserves for energy during that time.
It is very important for these whales to get enough food during their feeding season as their migration is nearly 5000kms each way, and can take between 4 to 8 weeks depending on how long they stop along the way to feed.
Not long after their calves are born, they migrate back north to feed again. Calves only stay with their mothers for about a year, so they will have one chance to learn the migration routes from summer feeding grounds to winter breeding areas. Individual whales are very likely to migrate to the same areas that they were first taken to by their mothers. This leads to high site fidelity. Most of the humpback whales feeding in northern British Columbia during summer months winter in Hawaii, and the whales in southern BC have been spotted off both Mexico and Hawaii. There are estimated to be 3000-5000 humpbacks in the southeast Alaska and northern British Columbia regions, and 200-400 in the southern BC and Washington regions.
We do see some humpback whales throughout the year. They could be wintering in our surrounding waters to continue feeding, or beginning their journey south much later in the season.
We’re very grateful to be seeing more and more of these whales call these waters home for the 6-8 months that they’re here. It’s especially exciting to start recognizing and encountering the same individuals returning year after year to their same feeding spots, and who they’re spending their time with.