One of the most asked questions by guests on our tours when we encounter marine mammals is: what does this animal eat? The Salish Sea is one of the most biodiverse inland seas in the world, and so the answer varies species by species! Here are some of the most common species we see, and what they’re likely eating for dinner.
Bigg’s Killer Whales
These apex predators are at the top of the food chain. Bigg’s killer whales, also known as the mammal-eating ecotype, eat a diverse diet of harbour seals, sea lions, porpoises, dolphins, and sometimes large baleen whales, too! When we find Bigg’s killer whales hunting, it’s usually a harbour seal, since harbour seals make up 60% of their diet in this area. These whales need to eat about 4% of their body weight every day, which equates to roughly 100 to 400 pounds of food depending on their age and size.
Humpback whales
Humpback whales in the Salish Sea almost always eat the same thing for dinner: krill! Krill makes up close to 90% of their diet, with small forage fish such as anchovies and herring comprising the rest. It’s remarkable that one of the largest animals in the world mostly eats the smallest animals in the world! To sustain themselves, it’s estimated humpback whales need to eat anywhere from 2,000 to 4,000 pounds of food a day.
Sea lions
We have two species of sea lions in BC—Steller sea lions and California sea lions—and they have very similar, over-lapping diets because they are generalist predators. Any fish they can catch will be on the dinner menu. Schooling fish like herring, hake, salmon, and eulachon are some of their favourites. Both species can be found sharing haul out sites and congregating near the mouth of the Fraser River. Steller sea lions are known to do most of their hunting at night!
Harbour seals
Like their larger sea lion cousins, harbour seals are generalist predators, known to consume up to 60 different prey items. A type of fish called hake is one of their favourites to eat for dinner, but they also enjoy herring, cod, squid, octopus, shrimp, and mollusks. A harbour seal’s diet can vary depending on where they spend time in the Salish Sea. For example, harbour seals near the mouth of the Fraser River consume more juvenile salmon than harbour seals in Puget Sound. These cute pinnipeds need to eat about 5-6% of their total body weight every day.
