Today was a humpback day! We didn’t have to go far out of the harbour when we saw KEY0034 Sherwina blow in the distance! The blow of a humpback is very distinct, and you can tell the whale species from the shape of the blow. A humpback has a large column-shaped blow that gets bushy as it goes into the air. When the conditions are right, this blow can be seen from a couple of miles away!

Today Sherwina was doing what the humpbacks mainly come to our waters to do, feeding! When humpbacks are feeding most of the time it happens beneath the surface. They will dive anywhere between 2-10 minutes on a typical foraging dive, although sometimes it can be much longer, up to 45 minutes. Whales have many adaptations for staying beneath the water for so long, some of which all mammals have! The mammalian diving reflex helps those animals which still require breathing air while also spending time under the water. When they enter the water their heart rate will slow and the blood will be restricted from their extremities and any non-vital organs so they aren’t using the dissolved oxygen for processes that aren’t a priority. Digestion will also be slowed during the dives. Whales can also absorb a huge percentage of the oxygen from each of their breaths, nearly 90% absorbed compared to humans who only absorb about 5% with each breath. They also have a larger volume of blood proportionally to their body than other mammals and higher levels of hemoglobin present, allowing more oxygen-binding abilities.

All these adaptations allow whales to continue to power their muscles using oxygen even after long periods under the water. As a last resort, whales can switch to anaerobic respiration where they use glucose instead of oxygen for their energy cycle. The downside of this method is that lactic acid is produced in the muscles and can cause fatigue in the animals. Luckily Sherwina wasn’t doing very long dives so she likely didn’t have to worry about pushing to the extremes of what the whales can do.

We continued to watch Sherwina as she fed in our waters before our time with her was eventually up and we had to leave her behind. We went to find other animals such as harbour seals and cormorants before returning to the Nanaimo Harbour.

Sherwina is a beautiful whale, so please enjoy the photos of her and the other wildlife taken by our naturalists Carmen and Cheyenne.