Decades ago, a single jellyfish arrived in BC, leading to the widespread spread of thousands of clones in 34 waterways.

Over 30 years ago, a single Chinese peach blossom jellyfish found its way into a lake in British Columbia.

The exact manner of its arrival remains unclear, with researchers speculating it may have been in aquarium water. However, now, decades later, thousands of genetic clones of the same organism have been observed in 34 waterways across the province.

Scientists are currently investigating the effects of these gelatinous invaders, each about the size of a quarter.

Evgeny Pakhomov, a biological oceanographer at the University of British Columbia studying this phenomenon, mentioned that the actual numbers of jellyfish are unknown. He warned that sightings could increase rapidly in the future due to a warming climate.

Pakhomov explained, “This species thrives in water that is over 27 degrees Celsius. It particularly enjoys warm water, becoming observable around 25 degrees Celsius.”

He highlighted the risk of a significant increase in their population—referred to as a jelly bloom—that could disrupt ecosystems, fisheries, and even make swimming unpleasant.

Their spread poses a threat to indigenous species by potentially outcompeting them, consuming vital plankton for juvenile salmon or trout.

Peach blossom jellyfish have historically inhabited rivers and freshwater systems in China but have been observed in various regions for centuries. The first documented case took place in France during the construction of the Palace of Versailles in the 17th century when water lilies were imported from China for the palace ponds.

Pakhomov revealed, “A few years later, they began noticing jellyfish in those French ponds, and from there, it spread worldwide. It can now be found on every continent except Antarctica.”

Pakhomov, also a professor in the Department of Earth, Ocean, and Atmospheric Sciences at the University of British Columbia, shared that the phenomenon remained largely unexplored in British Columbia until about five years ago when his team initiated investigations.

Their research, recently published in the Canadian Journal of Zoology, indicates that sightings of peach blossom jellyfish in B.C. date back to 1990, mainly in the Lower Mainland, on Vancouver Island, around the Sunshine Coast, and more recently, as far inland as Osoyoos Lake.

By 2023, there had been 85 sightings, each representing a separate location or year, potentially ranging from a single jellyfish to thousands.

Upon analyzing their genetic composition, Pakhomov’s team made an intriguing discovery.

“Although collected from different locations, they appear to be clones, indicating a single introduction,” he explained.

Researchers suspect that this initial entry was likely due to the aquarium trade with another nation, possibly China or a country where the species was already present.

There are two methods through which the jellyfish can reproduce: asexually and sexually. The genetic analysis revealed that all studied jellyfish are male clones, suggesting asexual reproduction.

Pakhomov pointed out, “The absence of females prevents complete sexual reproduction.”

He speculated, “It remains uncertain whether females are not developing under certain conditions or if only male polyps are being introduced into the systems, indicating a potential limitation to one sex based on water temperatures.”

Pakhomov hypothesized that boating practices or bird activities could transport jellyfish to different water bodies. By understanding these mechanisms, researchers may predict future appearances.

He emphasized their goal to map the distribution of jellyfish in B.C. accurately and assess their impact on freshwater ecosystems and fish populations.

Pakhomov stressed the importance of citizen science, urging people to report jellyfish sightings to enhance species distribution mapping.