As dead whales continue to wash up on B.C.'s shorelines, experts believe their carcasses are contributing important nutrients back to the food web and environment.
Paul Cottrell, a marine mammal rescue coordinator with Fisheries and Oceans Canada (DFO), admits the death of numerous whales is a sad situation.
“There is some good science and it's important to figure out why they died,” he says.
A dead whale found on Haida Gwaii on Nov. 20 is the fourth to have washed up since Oct. 23, when a female humpback was found dead off Malcolm Island. Nicknamed Spike, she had suffered blunt force trauma. On Nov. 5, a young male was found dead and had signs of blunt force trauma but experts have not been able to positively identify him. Eight days later, another carcass washed up but it hasn’t been identified due to the heavy decay.
Cottrell says there are codes from one to five to rate how much the carcass has decayed. Ideally, they’d like to perform a necropsy as soon as possible on the whales.
“If it's fresh, we can get lots of information, lots of helpful information. [We] can get tissues, internal organs and get lots of detailed information on what may have happened in terms of the cause of death,” he tells Glacier Media.
Decomposition can vary based on temperature and where the whale washes up. Cottrell says some whales still have flesh on them a year after they wash up.
If a whale is bloating, it can be quite dangerous "if you're in the wrong spot at the wrong time," he adds; not only for the public but for scientists conducting the necropsy.
“So we're quite careful about that for sure.”
Whale decay is a source of food for some, not for others
Once a whale dies, its tissue starts to break down. This process can cause bacteria to release gas into the mammal's body cavity.
"That then builds and builds and builds," says Cottrell. "When it releases it, it can be quite a show.”
DFO staff are very aware of the gas build-up when conducting a necropsy, he notes.
“It can be quite... energetic if there's a significant amount of gas in there,” he says. “It can be pretty messy. And I have seen lots of spray and I've been sprayed a few times too. Even with trying to do it properly, it's under a lot of pressure."
The carcasses, meanwhile, provide vital nutrients to other animals.
"It's a great protein source,” says Cottrell, pointing to aquatic and terrestrial food webs.
When they die in the water and sink to the bottom of the ocean floor, the mammals are known as "whale fall."
The result?
"Islands of food," says Cottrell.
"Dead carcasses are really important and could sustain whole ecosystems... Whether it's a blue whale, sei whale, fin whale humpback, these are big animals and they do decompose over long periods of time,” he explains. "There are whole food webs that have evolved around these whale carcasses in deep water.”
On land, many animals feed and eat parts of the whale: bears, wolves, raptors and coyotes, to name a few.
“Especially in the winter, where it's a difficult time of year to find something to forage on,” says Cottrell.
While a dead whale can provide nutrients to other animals, DFO is reminding the public that the meat can be harmful to one's health or one's pet.
“These whale carcasses are really important for terrestrial mammals and aquatic mammals, but they do carry pathogens, and it's not good for humans or dogs,” he says.
Anyone who sees a dead or distressed whale is asked to contact DFO's 24-hour reporting line at 1-800-465-4336.
