An abnormal number of humpback whales have been found dead in the waters off Vancouver Island and the B.C. coast, causing some concern with climate change in mind.
Ocean Wise outreach and education lead Aaron Purdy says there have been around four deaths of humpback whales since mid-October, which is unusually high.
“For reference, typically around five to 10 deaths are reported per year. So to have so many in such a short period of time is definitely out of the ordinary,” said Purdy.
He says when humpbacks die, they float to the surface and then sink to the bottom. He adds it is possible that the dead whales have been seen by more boats, or it is a sign that a greater number of animals are dying this time of year.
Two of the deaths were the result of blunt force trauma, according to Purdy, who says the whales were likely struck by ships.
“It’s all too often of an occurrence off of our coast. Humpback whales and other large baleen whales – whales that don’t feed off of other marine mammals or large fish, they’re feeding off of small fish or krill – they migrate up to our coast in the summer months exclusively to feed,” said Purdy.
“Because of that, it means they’re not really focused on anything else and that’s including what threats might be in their immediate vicinity, like a ship.”
Purdy adds small boats might injure the whale, but larger ships like ferries, cruise and container ships can cause a lot more damage.
Humpbacks are a species at risk, after recovering from being an endangered species. Purdy says their population is on the rise, and they are a big source of carbon sinks.
“These are very long-lived animals, they are going to be consuming lots of food over their lifetime and all of that carbon they are consuming is going to be trapped in their bodies,” said Purdy.
“When they die, it’s going to sink back down to the ocean floor. That is going to remove that carbon from the atmosphere and recycle it into our environment in a more natural way.”
He adds a dead whale creates new ecosystems underwater where various animals feed on the whale carcass until it is no longer there.
To limit the number of whales hit by ships, Ocean Wise has made an app for mariners to use since whales are not detectable by radar.
The Whale Report Alert System shows where whales were spotted so boats can slow down, change course or take other measures to try and avoid the creature.
“What that actually needs is for people to report their sightings,” said Purdy. “It’s free to download and you can report any sightings of whales that you have.”
Purdy adds reporting a dead whale if it is spotted is very important as there’s a short window to tracking them down. You can report a sighting at the BC Marine Mammal Response Network at 1-800-465-4336 or use VHF radio.
He also asks boaters to be familiar with the laws surrounding boats and how close they can get to marine life.