Written by: Megan, Marine Naturalist
On a nice sunny day, the Salish Sea can be perfectly calm. It looks like a mirror and you can see for miles. On these days I love to tell my guests to look for porpoises. We have two types of porpoise in the Salish Sea, Dahls & Harbour. Over recent years Dahls have become fairly uncommon, but Harbour Porpoise sightings are growing.
In majority of coastal waters throughout the Northern hemisphere, Harbour Porpoises can be found. A small animal less than 2m long, they can usually only be seen in a calm sea state. In the 1970’s the population was greatly reduced and rarely seen in the Salish sea but from 2000 onwards we saw a steady incline in numbers and they are now thought to be the most abundant cetacean in the Salish sea.
These animals are fairly boat shy and typically seen in small groups of 1-3 individuals globally. However, in the Salish Sea larger groups of 20+ are commonly seen, whereas this is not seen anywhere else in the Pacific Ocean. A recent study has also observed brand new feeding techniques, mating behaviour and vocalisations with this new found socialness (Anderson et al., 2023).
However, the big question is, is this brand-new behaviour to them. We’ve really only been studying cetaceans for the past 80 or so years and much of that happened when populations were depleted across the world. It’s only now with so much protection and conservation work that we are able to study whales, dolphins and porpoises in greater numbers. Historical records in the 1940’s show a large number of porpoises lived in the Salish sea and it’s possible these new behaviours that we are now seeing would have been happening back then. With the reduced numbers from 1970-2000 it would not have been possible for Harbour porpoises to hang out in large groups. The fantastic thing about science is that there is never a final answer, there is always more to learn.
It’s the same on our boats. You never have exactly the same trip twice! We were very lucky to come across a big group of Harbour porpoises the other day. We stopped the boat and watched them pass. It was amazing, and something I hadn’t had a chance to do all summer.
Fancy trying to spot these guys yourself? Come #ExperienceTheWild on one of our tours this season!
Anderson, D., Shuster, L., Elliser, C.R., MacIver, K., Gless, E.J., Krieger, J. and Hall, A. 2023. Harbor Porpoise Aggregations in the Salish Sea. Oceans. 4(3), pp.269–285.