More than 30 years ago, a single peach jellyfish ended up in a lake in British Columbia.
Scientists say it’s unclear exactly how the organism got there — it may have shown up in aquarium water — but decades later, thousands of genetic clones of the same organism have been spotted in 34 waterways across the province.
Scientists are now trying to understand the impact of these gelatinous invaders, which are about the size of a quarter.
Yevgeny Pakhomov, a biologist and oceanographer at the University of British Columbia who studies the phenomenon, said in an interview that the exact number of jellyfish is unknown, but the number of their sightings could increase dramatically in the coming years due to global warming.
“This species actually thrives in water temperatures above 27 degrees Celsius. It really likes that warm water,” he said, noting that they can only be observed at temperatures of about 25 degrees Celsius.
Thousands of invasive peach jellyfish are appearing in British Columbia waters, marking their northernmost range in North America.
According to research @UBCScience the number of observations is predicted to increase due to climate change.
Read more: https://t.co/VHFZ7xWl4j pic.twitter.com/Qd742mDvwq
— –@UBC
Pakhomov said there is a risk of a population boom — known as a jellyfish bloom — that could disrupt ecosystems and fisheries, as well as make swimming difficult.
Their spread could pose a threat to native species as they displace competition by eating the plankton that young salmon and trout feed on.
Nick Wong, a science and research manager at the Invasive Species Council of BC and a marine ecologist who was not involved in the study by Pakhomov and his colleagues, said it’s too early to tell what impact the jellyfish will have on British Columbia’s ecosystems.
But he added that the new study is the first significant source of information on how many of the jellyfish have spread across the province.
He added that this study provides a new basis for further research into the interactions of these jellyfish with British Columbia ecosystems.
“With invasive species, before you can determine what’s happening, determine the impacts, determine the risks or establish any kind of management plan, you have to really understand where [the species] are and how they might spread,” Wong said. “So this is pretty important, foundational work.”
Fisheries and Oceans Canada spokeswoman Athina Vazeos said the department does not monitor the spread of peach jellyfish.
“The department recently conducted a screening assessment of several species in British Columbia and this species was not found to be particularly high risk compared to other plants and fish that were included in the analysis,” Vazeos told CBC News in an email.
Spreading around the world
Peach jellyfish are native to rivers and freshwater systems in China, but have been found in other regions for centuries.
Pakhomov said the earliest documented case occurred in France, in the 17th century, during the construction of the Palace of Versailles, when water lilies were brought from China for the palace ponds.
“A few years later, they started seeing jellyfish in these ponds in France, and then it spread all over the world,” he said. “Now they’re on pretty much every continent except Antarctica.”
Pakhomov, who is also a professor in the Department of Earth, Ocean and Atmospheric Sciences at the University of British Columbia, said the phenomenon was largely unexplored in British Columbia until about five years ago when his team decided to start analyzing the creatures.
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Their study, published last month in the Canadian Journal of Zoology, found that peach jellyfish have been recorded in British Columbia since 1990, mostly in the Lower Mainland, on Vancouver Island, around the Sunshine Coast and, more recently, inland around Osoyoos Lake.
As of 2023, there have been 85 reported sightings, meaning the jellyfish were spotted in a different location or in a different year, although each sighting could have involved one or thousands of jellyfish.
After analyzing their genetic material, Pakhomov said his team made an interesting discovery.
“They look like clones, even though we collected them in different places, so it’s obvious that there was a single encounter at some point,” he said.
He added that scientists speculate that the unfortunate introduction of the species was likely due to the aquarium trade with another country, either China or another country to which the species had already been introduced.
Pakhomov hypothesized that the jellyfish spread to different bodies of water via boating or birds. He said that if scientists could figure out how this happens, they could predict when and where they would appear next.
He added that his team’s goal was to accurately map the distribution of jellyfish in British Columbia and better determine their impact on freshwater ecosystems and fish populations.
He stressed the importance of so-called citizen science, in which people collect data and report sightings. If more people knew how to report jellyfish sightings, “we would be able to map species distributions much better.”
The best way to control invasive species is to prevent them from spreading, a spokesperson for British Columbia’s Ministry of Water, Land and Resources told CBC News in an email.
The Ministry appeals to sailors to clean, dry and drain their water equipment, as well as to report any invasive species they notice.
