Over the past two decades, humpback whale activity has been increasing in B.C. waters, according to researchers.
The increase in activity has been 100 years coming, UBC’s Marine Mammal Research Unit director Andrew Trites said.
“Humpback whales were hunted mercilessly for their oil (and) were all removed by whaling at the turn of the last century,” Trites told Global News. “Once they were protected from whaling, the numbers began to increase. And as the populations increased, they began to show up more and more in B.C.”
A study was conducted by UBC researchers, the first of its kind, which looked into humpback whale entanglements at B.C. aquaculture facilities.
It found that eight entanglements occurred from 2008 to 2021, at seven fish farms. Five of the entangled whales were able to be freed but three were killed.
The eight entanglements accounted for less than six per cent of all entanglements in B.C. over that time period.
Most entanglements happen in the containment net that separates the fish inside the farms and the ocean, researchers found.
“This work gives us hope we have strategies and protocols in place to respond to entanglements,” said first author Rhea Storlund, a doctoral student in UBC’s Institute for the Oceans and Fisheries.
All eight of the whales that got caught up in nets were relatively young.
“This could be due to naivety and inexperience, as well as developing new feeding methods compared with adults,” said co-author Stephen Raverty, an adjunct professor.
Another factor about the entanglements was facility design at the fish farms.
Overall, the study found that the number of humpback whales impacted by fish farms was relatively small compared to the numbers that returned to B.C. (7,000 whales).
“Fish farms are not an intrinsic problem for humpback whales,” Trites said.
However, researchers said industries, including fishing which is responsible for 94 per cent of all entanglements, need to “step up to minimize the harms caused to whales.”
The study was published with PLOS One, a peer-reviewed open-access journal published by the Public Library of Science.