September 27th - T18's in the Strait of Georgia

On September 27th our open boat Cascadia headed South in search of whales. The T18’s are a very easy pod to ID, due to Galiano (T19B) and Spouter (T19C)’s very unique dorsals. Galiano’s dorsal has a distinct lean to the left as well as a large notch out of the middle of it, and Spouter has a very large triangular dorsal that appears ‘wiggly’ when viewed from the front or back.

Orca dorsal fins are made out of a fibrous tissue known as collagen, the most abundant protein in the human body, with absolutely no bones within them. Male orca dorsal fins can reach an astonishing 6 ft. (1.8 metres) in height, so this is a lot of fin to support solely with collagen! While collapsed dorsals are extremely common in captive orca, it is almost unheard of to observe a fully collapsed dorsal in wild orca. It is possible to see partial collapses, as Galiano demonstrates. There are many different reasons why this may be observed. Dehydration, illness, and stress are thought to play major roles in dorsal fin collapsing, but something as simple as gravity acting on such a large fin may cause collapsing as well. When the whales come to the surface to breathe, the large dorsals break the surface of the water and are no longer being suspended by the water. Standing freely in the air, the gravity of the earth will slowly start bringing the fin back down. This is a very gradual process for wild individuals because they typically do not spend extended times on the surface. For captive whales however that often are doing tricks above water and leading to increased surface time, gravity will be acting on this fin much faster.

The dorsals of whales are also kept straight by the momentum of travelling at speed through the water. Think about when you are travelling in your car and you roll down your windows. Your hair will blow straight back. This is essentially the same thing that is happening to dorsal fins as whales travel. This constant forward motion keeps the fins nice and strong!

Besides the T18’s, we also spotted california sealions,stellar sealions, a great blue heron, harbour seals, multiple cormorants.

Check out these awesome photos Naturalist Ryan caught of the trip!

Family photo! From left to right: Nootka, Esperanza (back left), Spouter (back right), Galiano.

Galiano (T19B) with his very distinct dorsal fin.

Left to right: Spouter (T19C), Galiano (T19B)

Harbour seals on the rocks!

Stellar sealions fighting for the best sleeping spots