A 50-year-old photo shows jellyfish blooms in Kwakshua Channel are not a new phenomenon.
Even after five decades, Doug Colton remembers the jellyfish. He spent his teenage years in the early 1960s in the then-bustling mill town of Ocean Falls, 35 kilometers northeast of Bella Bella. In the summers, Colton and his family visited nearby spots, including Calvert Island. He has vivid memories of the island. Their family hiked along the muddy, overgrown trail to West Beach and checked in on the people who maintained the BC Telephone Company transmitter. Oh, and the swarms of jellyfish.
“[Kwakshua] Channel, where we took our rowboat ashore at times, was full of millions of jellyfish,” says Colton.
Snapshots and local knowledge like this are critical since we rarely have baselines to determine if blooms are new, more frequent, or unchanged.
“The idea that jellyfish are taking over the world—a jellygeddon—is a fairly contentious one,” says Brian Hunt, a Hakai professor of oceanography at the University of British Columbia. “There’s definitely good evidence that jellyfish are increasing in some places, but in others it’s probably more a case that jellyfish are in the public eye. So people are more aware of them, which is giving this false impression of increase.”
Around Calvert Island in recent years, Hakai scientists have documented massive blooms of moon jellyfish (Aurelia aurita), including the same spot where Colton’s father photographed a bloom. Scientists still don’t fully understand what triggers jellyfish blooms. Rising ocean temperatures and overfishing are two potential factors. Human infrastructure could play another role. Hard surfaces, like docks and other human-built structures, provide an ideal spot where tiny, anemone-like jelly polyps can attach during a jellyfish’s juvenile phase.
Once they grow into adults, it can be difficult to determine how many jellyfish are in an area. Along with conventional studies that use nets, Hakai scientists have turned to the skies.
“An aerial approach [to estimate the number of jellyfish] with drones had never been done before,” says Hunt. “What we are trying to do on Calvert [Island] is really advance the state of the science.”
Scientists have yet to figure out for sure if jellyfish blooms are increasing in frequency or size in this part of coastal British Columbia, but they are sure of one thing. Jellyfish have a certain magnetism usually reserved for animals with a backbone.
“Jellyfish are that animal with no brain. They’re this very basic animal, but they’ve really captured the public imagination,” says Hunt. “And I think there’s a lot more to jellyfish than meets the eye.”
Doug Colton agrees. “There was never anyone else around,” he says. Except for the jellyfish.
Schaub J, Hunt BPV, Pakhomov EA, Holmes K, Lu Y, and Quayle L (2018) Using unmanned aerial vehicles (UAVs) to measure jellyfish aggregations. Mar Ecol Prog Ser 591:29-36. https://doi.org/10.3354/meps12414