At Risk Whales and Porpoises
Porpoises, whales, and dolphins make up a group called cetaceans. Despite looking like fish, these animals are actually mammals. They give birth to live young, produce milk, and have hair, just like us! Unfortunately, the cetaceans in the Salish Sea are facing many threats, and there are a number of species on the at-risk watch list. Four cetaceans at-risk in the Salish Sea include: The Grey Whale (Eschrichtius robustus), the Humpback Whale (Megaptera novaeangliae), the Harbour Porpoise (Phocoena phocoena), and the Killer Whale (Orcinus orca).
Grey Whale (Eschrichtius robustus)
Grey whales are solitary, 11-14 meters long, and have no dorsal fin (only a series of bony vertebrae “knuckles” near the tail). They are baleen whales, meaning they have a filter feeding system composed of a keratinized structure (the proteins that make up our hair and nails), called baleen, in the place of teeth. To feed the whales take a big gulp of water and push it out through the baleen, what is left in their mouths are the small marine organisms they consume as prey. Unlike most baleen whales, grey whales feed on the bottom of the ocean. They strain out small invertebrates from the soft sediment, leaving large, mouth-sized impressions on the ocean floor. They also feed on herring eggs and larvae in eelgrass beds during the spring and summer months.
The grey whale population was severely depleted by commercial whaling in the 20th century, and the current status of the species is population dependent. The Northern Pacific Migratory population, which travels from Mexico to the Bering Sea, Chukchi and Beaufort Seas has recovered well, and is now at 20,000 individuals. The other two populations found in Canada, remain at low levels, and are currently listed as endangered. The Western Pacific population migrates from its winter calving grounds in Mexico, along the British Columbian coast, to its summer feeding grounds in the Sea of Okhotsk, Russia. Its current population is 174 adults. The Pacific Coast Feeding Group population migrates each winter from Mexico to the Pacific Northwest and stay there all summer. Their population is currently 243 individuals strong.
Humpback Whale (Megaptera novaeangliae)
This large, up to 16m long whale is loosely social, travelling in large groups for no longer than a few days at a time. Like grey whales, humpbacks are baleen whales. Their preferred food is krill or small schooling fish, which are gathered in the middle of the water column. Humpbacks migrate from their breeding grounds in low latitude areas in the winter, to their summer feeding grounds in high latitude areas. The whales off the west coast of British Columbia are the North Pacific population. They were severely impacted by whaling in the 20th century, numbers decreased to only 6000 individual whales, but luckily are recovering since then. The current population count is 18,302 whales, and is increasing by ~ 4 % annually. Due to their growing population, humpbacks were down listed from threatened to species in special concern in 2011 by COSEWIC (Committe on the Status of Endangered Wildlife in Canada).
Harbour Porpoise (Phocoena phocoena)
Harbour porpoises are up to 2 m in length, therefore are the smallest Cetacean in British Columbia. Harbour porpoises have teeth, and feed on small, schooling fish such as herring. They travel in groups of 2 to 5 individuals, but can aggregate in larger groups when food is abundant. Although, identification of Harbour Porpoises is easy, their small dorsal fin and their emerging behaviour makes spotting tricky. Harbour Porpoises in British Columbia inhabit shallow waters (<150 m depth). Because of their non-migratory nature, they are constantly exposed to human related threats such as noise, entanglement in fishing gear, collisions with boats and coastal development. Harbour Porpoises are currently listed as species in special concern in Canada by COSEWIC.
Killer Whales (Orcinus orca)
For information of the second most widespread mammal on earth, and on the Galiano Conservancies Cetacean project visit our “Orcas” page click here.
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The threats presented by vessels to cetaceans are multifold and are a considerable reason for population declines. Vessel collisions is the first problem – thirty vessel strikes were reported to the BC Cetacean Sightings Network from 2004 – 2011, with many more going unreported, or unnoticed. Even only the presence of boats nearby is scientifically known as a reason for behavioral change of cetaceans – certain whales spend less time foraging and more time escaping the traffic, others will display more energy intensive behaviors, such as breaching or hitting their fin in presence of boats. Furthermore, boats create acoustic disturbances. Cetaceans rely on echolocation (clicks, whistles, and pulsed sounds) to communicate with one another, locate prey, and navigate. Present noise pollution can inhibit cetaceans perform any of these former mentioned functions. Finally, boats also emit toxins into ocean water. Cetaceans are extremely vulnerable to toxins, since they do not have sinuses to filter out the pollutants, nor sense of smell to avoid them.
Learn more about Orcas and boating here.
As human population on earth is growing, our food industry is too! Human fisheries is targeting Cetaceans’ diet. All Cetaceans are carnivore, but some are only eating one source of food, e.g. Southern Resident Killer Whales are piscivore and their food source is only Salmon. The Cetaceans with a varied of sources in their diet can change the food source when it is scarce, but others, as the SRKW, will perish. ‘Gillnets’ and ‘Seine Nets’ used by fisheries additionally cause Cetaceans to be entangled or caught as bi-catch. Around 86% of the world’s toothed whales are now threatened from the world’s fisheries and 300,000 Cetaceans die annually from entanglement. Half of all humpbacks will be caught in fishing gear at least once in their life.
Persistent organic pollutants (POPs) are the first of the three classes of contaminants threatening Cetaceans. POPs are used for products such as flame retardants, electronics, transfer fluids, and pesticide manufacturing. Important to mention, half of the POPs are used in the clothing industry! In a 2019 study, biologists were testing the bioaccumulation of POPs in Blue Whales (baleen whales) in the Southern Hemisphere and came to the conclusion, that POPs are measurable in high numbers in Blue Whales (higher in males, than females, because they pass toxins down to offspring). This study is one of the first studies on POPs in Cetaceans. In their conclusion, the authors suggest, that baleen whales could be used as sentinel organisms of ocean contamination. Another study on sea lions, relatives of Cetaceans, found that when exposed to POPs, they had lowered immune function, lowered reproduction, and changes in hormone levels. Biological contaminants are the second class of pollutants threatening cetaceans. They include pathogens from human activities, exotic species, from ballast water, and antibiotic-resistant bacterial strains. Their risk on marine life is hard to quantify, but can potentially pose a serious risk. Heavy metals are the third class of contaminants and detectable in very high levels in the oceans – particularly around urban centers.
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