Blooming jellies
Diving into glowing smacks of jellyfish in səĺilẁət (Burrard Inlet and Indian Arm), a mystery more than 200 metres deep
AAS BRITISH COLUMBIA’S summer folds itself into fall, the murk of its inlets turns to glass. Shielded by granite, this salt water half an hour from Vancouver’s skyscrapers is where, every October, jellyfish bloom. Tiny fireworks explode around their hair-like tentacles, creating a vortex under their bells that causes bioluminescent plankton to glow.
The photographer and I dive into water thick with mostly Aurelia aurita, or moon jellyfish, whose mild stings we hardly feel. Each year, the jellies return to Metro Vancouver with the currents, and remain in səĺilẁət (pronounced sahlale-wot) — the Hun’qumyi’num name for Burrard Inlet and Indian Arm. The floating sheet-ghosts in
səĺilẁət's midwaters are the shortlived medusa morph. Like all jellyfish, they eat throughout their life cycle and spend most of their lives out of human sight, rooted to rocks and other structures as juvenile polyps. Docks that zipper up səĺilẁət's shoreline offer optimal nurseries.
But in 2022, a much larger bloom seemed to appear. That year, British Columbia experienced record breaking heatwaves that dried upstream creeks used by migrating salmon to return to their spawning grounds.
Locals say səĺilẁət's deep arms, shared by jellies and fish alike, remained full later during these runs. That meant both the moon jellies and the larval salmon were competing for the same precious food source: plankton. “Everything depends on zooplankton,” says jellyfish researcher Jessica Schaub.
Ballooning jellyfish numbers could exacerbate challenges for already-threatened populations of wild salmon.
Musqueam Nation fisheries officer Willard Sparrow fears for the keystone fish that B.C.’S First Nations depend upon. His band’s territory is home to
one of Vancouver’s last wild salmon streams. “Over the past 10 years, we've noticed more jellyfish blooms,” he says of their local waters, concerned about compounding effects like lowering dissolved oxygen levels.
Rising sea temperatures could play a role, too. “When you have an extended summer period, then you would have more productive (bloom) conditions later into the year,” says Brian Hunt, an oceanography professor at the University of British Columbia. Should the short window for jelly breeding widen, it may result in more juveniles, leading, in turn, to larger blooms. In that 2022 bumper-crop year, Port Moody was still sweating through highs of up to 28 C during mid-october.
Since time out of mind, səĺilẁət has been the traditional territory of the “People of the Inlet,” the Tsleil-waututh Nation (səĺilẁətaɬ) — the band is named after this body of water, revered as their first grandmother. The nation continues to steward these waters, and were once guided by the seasons in a complex, cultural cycle of food gathering and spiritual activities.
“Wet, dry and hot: they’re the only seasons we see now,” sighs Sparrow, whose nation’s territories overlap with Tsleil-waututh lands and waters to the south.
The fisheries officer is concerned the beauty of the blooms masks their impact. “They are an indicator of the conditions of the water — acidification, low oxygen, warmer water — and that creates a cycle of bigger, more frequent blooms. This compounds the issue of human impact and climate change.”
For now, səĺilẁət's spawning secrets are obscured by a need to collect more jellyfish data — especially because, in other places, blooms of jellyfish tend to show up when fisheries collapse. In Namibia, for example, when commercial fish stocks collapsed jellyfish populations exploded with the greater availability of food. Around the world, jellyfish have cost fisheries millions.
Yet the appearance of more jellyfish bells may not necessarily be cause for alarm. They’re also an important functioning part of the ocean ecosystem. Juvenile fish and crustaceans shelter in them, and when jellyfish die and slowly sink to the sea floor, they provide nutrients that feed the food web and sequester carbon.
“We need systematic monitoring of jellyfish to find out if changes are actually occurring. Otherwise, we can only speculate,” says Hunt.
For creatures so translucent we can see their organs, there’s still a lot unclear about the jellies of the inlet. We surface from səĺilẁət amid the bubbles from our breath — the bioluminescence illuminating the surrounding moon jellyfish like windows into a nebulous future.
Read an unabridged version of this piece, with more photography by Steve Woods, at: cangeo.ca/jellyfish