Since the early 2000s, Pacific white-sided dolphins have been the "big story" in Howe Sound, but in 2013 humpbacks whales stole the show. Tessa Danelesko, a marine biologist with the B.C. Cetacean Sightings Network, told a group gathered for the Bowen Island Nature Club AGM that the population of these 15-metre-long mammals who spend time in the North Pacific is estimated to be close to 6,000, with approximately 200 to 400 of those whales spending time in the Salish Sea. Danelesko also taught the group about the visible differences between cetacean species, so that when they catch a glimpse, they know what they're looking at.
If you're looking right into their mouths, you will see that one difference between porpoises and dolphins is the shape of their teeth, but most of us will have a better chance of identifying what we're seeing by noting the difference in head shape: porpoises have much more rounded heads than dolphins with their long, pointy noses. Dall's porpoises can be distinguished from harbour porpoises (which are more solidly coloured and typically light to dark grey) by the striking black-and-white contrasts on their bodies. Danelesko told her audience that scientists have recently discovered that a surprising number of local porpoises are a hybrid between these two species, even though they may strongly resemble one or the other.
On the topic of "the stars of Howe Sound," Danelesko explained teeth found in First Nations middens (domestic trash heaps) show that Pacific white-sided dolphins made their home in this region thousands of years ago, and then, they mysteriously disappeared. In 1984, when researchers listening for killer whales heard calls that were more chatty and at a higher pitch. These "killer whales on helium" proved to be Pacific white-sided dolphins, and this was the first sighting of them in the area. Scientists still do not know exactly why they've returned, but think it may have something to do with the recovering stocks of small fish in the area.
Danelesko explained that scientists divide killer whales into three groups: residents, Bigg's (transients) and offshore. These are all the same species, although there is no evidence of mating between the groups in hundreds of thousands of years.
The killer whales we see in Howe Sound are mostly Bigg's (transients), named in honor of Dr. Michael Bigg, a pioneering killer whale researcher. They travel in fairly fluid, changing groups, unlike residents, who stick with their mothers for life. While the residents, who don't often come to Howe Sound but are more often seen near Point Grey or farther out in the Georgia Strait, eat almost entirely salmon, Bigg's (transients) eat other marine mammals. If someone spots a killer whale, they can identify the females and juveniles by their more curved dorsal fins. In adult males, the dorsal fins stand straight up, and following puberty they can stand as tall as 6 feet.
Danelesko said very little is known about offshore killer whales, as they live so far out in the Pacific. However, she did say that these whales sometimes travel in groups of 100 or more, and have been known to eat not only fish, but also sharks and possibly seabirds.
Humpbacks, along with minke and grey whales, are baleen whales.
Danelesko offered the group a look at several artifacts particular to baleen whales: baleen, whale lice and barnacles. Baleen is the filter inside the mouths of these animals, made of the same substance as human hair, keratin. The whale opens its mouth underwater, and the baleen strains the food (such as krill or herring) from the water. Danelesko brought in actual baleen for her audience to touch and explore, as well as a barnacle off of a grey whale. Greys, she says, host a large number of parasites including barnacles, possibly because they are slow moving. These occur on humpbacks as well but in less visible quantities. What is more remarkable about humpbacks, says Danelesko, is the amazing recovery they've made. When commercial whaling was banned in the North Pacific in 1966, their numbers had been reduced to 1,400. Now, that population is estimated to be close to 6,000.
Danelesko urged people to contact the B.C. Cetacean Sightings Network if they see any kind of whale, porpoise, dolphin or sea turtle. Information collected through the network is used to understand the status of cetacean species (threatened, at risk, not at risk, etc.) and also to understand what areas act as critical habitats.
To report sightings of whales, dolphins, porpoises or sea turtles: Use the online sightings form at www.wildwhales.org.
Phone toll-free: 1-866-I-SAW-ONE (472-9663)
Email: [email protected]
