This afternoon we headed back out to the Strait of Georgia in hopes of another Humpback encounter. We managed to spot a familiar fluke in the distance close to Texada Island, it was Ocular (BCX1705)!

Ocular has a very easy fluke to identify, as there is a distinct piece missing from the right side of his fluke. A question we often get is how our Humpbacks get their nicknames! With many of these animals, it is determined by who gets a clear catalogue-ID shot (a nice clear view of the underside of their flukes) first. If a new Humpback arrives in our area, the first individual/company to photograph the whale also gets to unofficially suggest a nickname. After that, other suggestions from the whale community are also considered and then determined by a vote. Whenever possible, we will try to find a feature or marking that will help us remember who we are seeing. Ocular received his nickname because the notch in his fluke resembles a spy hole to look through. However, we don’t usually give our whales nicknames until they are around 2 years old. This is due to the high mortality rate of calves in their first few years of life. Until they have official names, we go by their catalogue IDs, or their mothers if they are too young to have one of their own.

Today Ocular was taking long dives and travelling. I think it is safe to assume the long dives were due to feeding since this is an area where the Humpbacks seem to frequent. This is usually an indication the waters are rich with prey. The Humpbacks need to eat anywhere from 3000 to 5000 pounds of food per day! Our waters here are nutrient-rich and are the perfect spot to hang out after their long journey from their breeding grounds thousands of kilometres away, in Hawaii and Mexico. They don’t eat on their journey here, and can lose up to one-third of their weight from fasting for as long as six months!

We know that the whales are able to find this amount of food per day, but something we still do not know is how they are able to locate it. We know they do not have echolocation like dolphins, and the ability to smell underwater is believed to be extremely reduced, if not completely absent, in baleen whales like the humpback. However, there are some interesting theories currently being researched. One research team is testing the hypothesis that a chemical emitted by phytoplankton, which is a primary food source for the Humpbacks, may shed some insight. Dimethyl sulphide, or DMS, is released by phytoplankton when they are eaten by zooplankton, and research has shown that various shorebirds such as shearwaters and albatross may sense an influx in these chemicals, and travel to these dense areas of prey to feed. In an article recently published by Scientific American researchers travelled to Antarctica to see if similar effects can be seen in Humpbacks as seen in seabirds. Although their research is inconclusive, it’s a great example of how old research can be applied to a new hypothesis! In the meantime, we get to enjoy spending time with these animals right here in our own backyard, as they fatten up over the summer to replenish all that lost weight.

Once we finished up with Ocular, we headed to the ODAS Halibut Bank buoy to check out some sleepy Stellar Sea Lions! This buoy records crucial meteorological and wave data that our team frequently checks to determine the conditions for the day. Heading back across the strait, we finished up with a fan favourite, the Gabriola Bluffs, where we saw our Cormorant colony and our active Bald Eagle nest!

All photos were taken by Naturalist Desarae Poier

June 27, 2023, 3:30 - An Afternoon with Ocular

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