Wildlife harassment is a nonlethal management technique that encourages animals to move on from an area by increasing a location’s sense of risk and danger. It’s used to manage Canada geese in cities where the birds can clash with people for a number of reasons, from fouling green spaces with their droppings to colliding with aircraft.
The study’s researchers harassed Canada geese by approaching the animals on foot and ATVs and then clacking lumber boards together. They expected that the harassment would be more effective at dispersing geese during the challenging winter season. But surprisingly, the researchers found that harassment was ineffective at significantly changing the behaviour of geese and had diminishing returns over time.
“Birds never fail to amaze,” says Doug Tozer, the director of waterbirds and wetlands at Birds Canada. Tozer, (who was not involved with the study), adds, “Just when you think you know how they operate, they turn around and do something like this. I find it humbling and fascinating.”
For cottage owners (or home owners) who don’t want to share their space with Canada geese, Tozer suggests making your property unattractive to geese in the first place, regardless of the season.
“Geese pretty much eat only grass, and they prefer large open spaces so they can see predators approaching,” says Tozer. “If you don’t want geese around then get rid of your grass, or, at least reduce the amount of grass you have.”
Planting trees and shrubs can also repel geese. This technique is particularly helpful in the summer when geese have a gaggle of young in their care. “Geese with young prefer to be able to run directly from grass to the lake if there’s a threat,” says Tozer. “If you block that path, they won’t come to eat your grass.”
“Birds are really good at what they do,” says Tozer. “They’re smart, they’re adaptive. They often take opportunities when they arise, we therefore shouldn’t get impatient with them when they try their best to survive amongst us.” He adds, “humans are, in theory, smart too. And if true, then we should be able to figure out ways to coexist with birds and other wildlife.”
Want to create a paradise for bees in your garden? Experienced gardeners know to select plants that are attractive to pollinators, emphasizing flowers with enticing colours, shapes, and smells. But gardeners should also ensure they aren’t unwittingly turning bees away from their flower beds.
New research from the University of Bristol shows that applying chemical sprays of fertilizers to plants can discourage bees from visiting flowers. The researchers also found that it’s not the appearance or smell of the chemical fertilizers that’s a turn-off for bees; instead it’s a change in the flower’s electric field that bees are not a fan of.
“It’s basically static electricity,” explains the study’s lead author Ellard Hunting, a research associate for the School of Biological Sciences, University of Bristol. Flowers are typically electrically charged, and slightly more negative than the ground, Hunting says. Bees tend to have a positive charge.
While a flower’s electrical field is not noticeable to humans, it’s a different story for bumblebees. The insects can detect the electrical field thanks to their small body size and fine, sensitive hairs. A flower’s electrical field can provide important information and cues to a visiting bumblebee.
But a communication breakdown occurs when synthetic fertilizers get added to the mix. The researchers found that applying sprayed synthetic fertilizers altered the electric fields of flowers by causing physiological changes in the stressed out plants. Wild bumblebees were less likely to land on the affected flowers.
Hunting compares the altered electric field as sensory overload for bumblebees. “If you look into the sun, it’s too bright, it’s too blinding,” he says. “And I think that’s what’s happening with the bees. The elevation in the electric field and the dynamics are just too much information. They decide this is not nice, and they move on.”
A negative experience at a flower could lead to bigger consequences. “Bees really learn rather quickly,” says Hunting. “If bees arrive at a field, and it was treated with chemical fertilizers, the entire hive might actually decide not to go there anymore,” he adds.
To avoid confusing bumblebees and other pollinators, Hunting suggests choosing fertilizers made from natural sources like manure or seaweed. He also encourages gardeners to apply fertilizers in the evening when no pollinators are around.
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We have a strand of 25 patio lights strung between two trees. The other day, we noticed that 20 of the bulbs and sockets had been removed. We thought someone had snipped them off with pruning shears. But now we’re not so sure. Could a raccoon or a squirrel hang off the cable, bite through the wire, and carry the socket and bulb away?—John Habart, via Facebook
Yes. Our money’s on squirrels. Turns out, they have a reputation for snatching up decorative lights, especially around the holidays. Squirrels steal more Christmas bulbs than the Grinch.
They like chewing on the wires, says Mike Webb, a wildlife expert and the owner of West Coast Problem Wildlife Management on Vancouver Island. A lot of new wiring has soy-based insulation. Tasty! Compared to petroleum-based insulation, soy-based wire insulation is considered better for the environment, and it sure is a win for critters that like to gnaw. Which is not great news for your cottage, your car, your ATV…or anything else with this wiring.
Why take the bulbs? It’s possible the squirrels mistook them for nuts. Or, says Webb, maybe they were simply attracted to the bulbs’ colours and textures.
Of course, without witnessing this behaviour, you’ll never know for sure what happened. “If it was me and I really wanted an answer, I’d put up a motion-activated trail camera,” says Webb. Do it! Then let us know what you see.
Got a question for Cottage Q&A? Send it to answers@cottagelife.com.
This article was originally published in the June/July 2021 issue of Cottage Life.
I noticed last autumn that the Scots pines (Pinus sylvestris) near my cottage were dying off. Any idea what could have been killing them?—Melanie Foord, via email
“It is definitely hard to say without seeing the trees,” says Steve Smith, an arborist with Bartlett Tree Experts in Calgary. “There are a few fungal diseases that can attack pines. The only one I know that seems to favour Scots pine is Lophodermium needle cast.” The needles develop yellow spots, then can turn brown and eventually fall off. Unfortunately, “the fungus is hard to identify on trees because the symptoms are similar to a lot of other tree problems,” says Smith. “We often need to send samples to our lab to confirm.”
Another possible contender is Diplodia pinea, a.k.a. Sphaeropsis sapinea, says Tracy Logan of Logan Tree Experts in Lakefield, Ont. It causes tip blight: you’d see short, stunted brown needles with black specks at their bases. “All two- and three-needle pines are hosts to this disease.”
If a fungus was the culprit, it probably wasn’t entirely to blame. “The first thing I always go towards is environmental conditions,” says Matt Logan, also with Logan Tree Experts. “Too much water; not enough water; too much wind; too cold; poor soil composition…most tree stress is cumulative.” A strong tree may be able to survive an infestation. But not a tree that’s been weakened by multiple environmental factors.
It’s also possible that what you saw was normal seasonal needle drop, says Smith. “The needles on pine trees only last so long, and as the new growth begins to shade out the interior, the tree sheds some of the unproductive needles.” It can be more pronounced in years where the trees have experienced more stress, such as long periods of drought, which we had last year, says Smith.
Don’t cry too hard for these possibly fungus-filled and stressed-out Scots pines. This tree isn’t native to Canada. The Ontario government introduced it in the early 1900s to help deal with soil erosion problems after consulting with European forestry experts. (Because…Canada had no forestry experts in 1925? Seems weird, but okay, government.) As is so often the case with an introduced species, after doing its intended job, Scots pine went rogue, outcompeting native trees and disrupting sensitive ecosystems.
Are we sad when trees die? Goodness, yes. Are we sad when this tree dies? Meh.
Got a question for Cottage Q&A? Send it to answers@cottagelife.com.
This article was originally published in the September/October 2022 issue of Cottage Life.
Last October, I was out on our dock when I noticed three seagulls, one flying and shrieking, and two others harassing two loons in the water. Every time they dove, the seagulls would do a flap-jump type of lift and then settle beside the loons when they emerged. I have never seen this before. Were they fighting over the same food?—Trudy O’Brien, Lake Newboro, Ont.
Bingo! Well, probably bingo. “This sounds like a feeding issue of some sort,” says Kathy Jones, the volunteer manager of the Birds Canada Canadian Lakes Loon Survey. “Both species eat fish.” Beyond that, “I can’t say for sure what was happening,” she says. “Perhaps the loons were on a particularly good raft of fish and the gulls wanted to use it? Perhaps the loons had wandered into the gull’s feeding territory? Perhaps both species were fishing on their own, but loons and gulls just don’t do well in the same space?”
Maybe, except, “I would think gulls fishing on their own are more efficient than them trying to steal food from loons,” says Jones. Loons scarf. A loon could probably easily gobble down a catch before a gull could snatch it away. Then again, gulls are known for stealing food from other gulls, from other birds, even from people. (Try eating French fries on a beach filled with gulls.)
This article was originally published in the September/October 2022 issue of Cottage Life.
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A grainy cellphone video of a leggy black cat sauntering through a residential yard near Whitehorse in August of 2020 was a lucky discovery for a Yukon biologist. The footage clearly reveals the distinctive pompom tail and oversized, cartoon-like hindquarters of a Canada lynx, a relatively common year-round resident of the boreal forest across the Canadian north. Only in this case, the lynx’s coat was soot-coloured, a first according to Yukon government senior wildlife biologist Thomas Jung.
Jung documented the sighting in arecent paper in Mammalia Journal, exploring the significance of variation in coat colour as a positive or negative trait in wildlife. Canada lynx are typically “silver grayish in winter and reddish brown in summer with dark spots,” Jung writes, “[with] black hairs on the tips of their tails and ears.” Paler-coloured individuals are occasionally observed, Jung adds, “suggestive of partial albinism.”
Wider variations in colour occur in other mammals, such as the cream-coloured “Spirit Bear” variation of black bears on the British Columbia coast, with possible benefits such as temperature regulation or being better camouflaged. Jung says black bears in the Yukon are often tan or cinnamon-coloured, to better blend in with the region’s sparse forests. “It comes down to which colour works best in the habitat,” he says.
So-called “melanism” is caused by a genetic mutation causing the individual to produce an excess of melanin, a dark-coloured pigment. Dark-coloured big cats occur in humid tropics, where they may blend in better with the surrounding jungle. Jung’s literature review uncovered accounts of black ground squirrels sighted in burned over patches of boreal forest and similar occurrences in bobcats in New Brunswick, suggesting this melanism enables individuals to be camouflaged with charred timber.
The melanistic lynx spotted near Whitehorse was the first record of such for the species, possibly for good reason. Jung doesn’t expect to see black lynx flourishing in the Canadian subarctic where a dark-coloured feline would be at a distinct disadvantage when stalking hares in the snowy winter. “It doesn’t matter whether you’re in the Yukon or northern Ontario,” he says, “lynx are grayish white because it works. To stalk and ambush their prey they need to be well camouflaged.”
When the sun goes down, the forest doesn’t sleep. There’s a whole night shift of creatures that use the cover of darkness to survive. For both predators and prey, nighttime has advantages and disadvantages. Early mammals, for example, likely evolved for living in the dark because most dinosaurs were active during the day. But, while moving in the darkness may help you escape the notice of a scary diurnal T. rex, you may miss out on a meal that is visually prominent, such as a brightly coloured fruit. These selective pressures likely helped develop an incredible sense of smell that isn’t dependent on light: you don’t see the fruit, but you can still find it with your nose. We as daytime mammals can’t smell our way to our next meal (unless the neighbour is barbecueing again), but nocturnal animals of all shapes and sizes often use smell or hearing or touch as their major sensory organs. This allows the forest to be active 24/7 and means there is a crew change as the daytime team gives way to the night shift one: hawks to owls, red squirrels to flying squirrels, butterflies to moths.
Flying squirrels
Photo by Agnieszka Bacal/Shutterstock
Next of kin
The best way to tell apart our two species of flying squirrel is by size.
Photo by Tony Campbell/Shutterstock
Next of Kin
Southerns are the size of eastern chipmunks and northerns are larger, almost as big as red squirrels.
While many have a love/hate relationship with most squirrels, flying squirrels, with their big, adorable black eyes, seem to create less anger than other squirrel species. If you are lucky enough to find one, the awws at its cuteness will quickly turn to oohs if it decides to glide away.
Flying squirrels can glide more than 20 m from tree trunk to tree trunk using their patagium, a fold of loose skin along their sides that stretches out when they launch into the air. While it’s not true sustained flight like with birds and bats—which flap their wings to attain upward motion—it certainly works for squirrels making a quick getaway from a predator.
It can be hard to see these amazing aeronautic feats at night. Most sightings are quick glances as one glides across an opening and is silhouetted against a darkening sky. Winter bird feeders can help with observations, as these gliders will visit them for a late night snack. If a flying squirrel becomes tolerant of your presence, you might be able to get a good look at its parachute-like skin flaps.
Nocturnal advantage: By foraging at night, our two flying squirrel species (northerns and southerns) avoid direct competition with diurnal eastern gray and red squirrels as well as eastern chipmunks. But, while they do avoid daytime hunters such as northern goshawks, red-tailed hawks, and broad-winged hawks, they are a favourite prey of barred owls.
An owl’s eerie sounds are as part of the cottage at night as ghost stories, s’mores, and campfires. All owls are chock full of adaptations for a nighttime existence: large eyes; soft, silent flight; and, of course, loud, far-carrying sounds for contacting each other. Most importantly, though, who needs lots of light when you have the best hearing of any animal ever tested? Many owl species have asymmetrical ear openings, with one slightly higher than the other, allowing them to hear not only in a horizontal plane (like us) but also in a vertical plane. To understand how this works, think about keeping your head still and facing forward but with your eyes shut. A bee flies by you and you can hear it go from left to right. An owl, though, would be able to tell that the bee was moving slightly upwards as it flew by. They can pinpoint the location of noise-making prey so well that they can catch it without even seeing it.
Probably the most commonly heard cottage owl, the barred owl (above), makes the distinctive and easily imitated Who cooks for you? Who cooks for you all? call to mark their territory and to keep the love alive between a pair. In fact, if two barred owls are feeling especially amorous, their regular call pattern will break into a loud, eclectic series of laughs and hoots that sound like a troop of clowns that have become a bit tipsy at a far-off campsite. They will sometimes call during daylight hours, especially on overcast days.
Nocturnal advantage: Lots of rodents are out after dark, and owls have evolved to take advantage of this buck-toothed smorgasbord. Plus, by hunting at night, owls also avoid competing with faster hawks, eagles, and falcons.
Butterflies get all the attention, but moths are really where it’s at. For one thing, there are way more species of moths in Canada (more than 5,000) than butterflies (around 300). For another, we are used to thinking of moths as drab, and while some are, there are many with a wild side. In the fall, one group to watch for are the underwings. These moths are masters of camouflage when resting on a tree trunk, but when they open their upper wings, they reveal flashes of pinks, yellows, oranges, and reds on their hindwings—which is where they get their name. One theory to explain these bright colours is that they could be used to startle a potential predator. Imagine a bird getting close to finding a camouflaged moth and then the moth flashes its colourful hindwings as it takes flight—this may startle the bird long enough for the moth to escape and hide somewhere else. It could also work the other way around, where a predator notices a flying underwing with its bright colours but when the moth lands it “disappears.” Because the predator is focussed on finding the pink or orange, it misses out on discovering the now-camouflaged insect.
Whatever the reason, having concealed colourful hindwings is a successful strategy—there are more than 100 moth species in this group in North America.
Nocturnal advantage: By being active at night, moths avoid most insect-eating birds, which are usually diurnal. Moths also can collect nectar from flowers at night without competing with many other pollinators. In fact, some flowers only open at night to take advantage of pollinating moths.
Wolves, coyotes, and foxes
Photo by Thea Boyd
The dog-days of summer may be behind us, but are you ready for the three-dog nights of autumn? We have three members of the canine family that you might hear during fall evenings.
Let’s start with the biggest: the wolf. While howling does occur throughout the year, both eastern (or Algonquin) wolves and timber wolves can be quite vocal in fall when it plays a role in their family dynamics. Howling lets pack members know where its members are and also lets one pack proclaim its territory to other wolves. But the howling also appears to be a bonding activity for the pack in the later summer and fall when adults start to leave their pups for the evening and go out to hunt. Pups at this stage are too big to stay in their dens but too little to go along, so they are left at “rendezvous sites,” where they have to wait until the parents return with food. A lot of social interactions happen at these sites, and when the adults make their deep drawn-out howls, you may hear their chorus interspersed with the coyote-like yapping and yipping of the pups. Once they are old enough to hunt with the pack, the rendezvous sites are no longer used and howling is less frequent.
No wolves nearby? There are likely coyotes, which really are just a small species of wolf (and, thus, deserve the same wow-factor). They make lots of noise at night—including yipping that sounds similar to wolf puppies, but can be heard all year. Wolves or coyotes (or both) will often respond to people’s attempts to wolf call. Even other sounds, like the whistle of a train, can get them going; I’ve heard up to three separate coyote packs call back at once from different directions after a train goes by.
Our third cottage canine is the red fox. This little guy is in the dog family, but isn’t closely related to wolves, coyotes, or domestic dogs. Unlike those bigger cousins, red foxes don’t really howl. Their most common sound is a screaming bark. Imagine saying the word “wow” but with a high-pitched, screechy voice. This noise, often repeated a few times, appears to be an identification call that foxes use for distant communication. Like dogs, foxes make the same sounds for different meanings, depending on the situation. As the autumn turns to winter and as we enter the fox’s breeding season, another call may be heard: a drawn-out scream made by females in heat. Heard in the depths of winter, it can certainly put a chill up one’s spine.
Nocturnal advantage: With their keen noses, these canine hunters are able to detect and surprise their prey before being noticed. Also, communicating is easier for packs at night, when the winds tend to die down, and their howls and barks can carry great distances across the dark landscape.
This story was originally published as “Wild Night Out” in the October 2022 issue of Cottage Life. Wolf Lake, Ont., cottager Chris Earley is the interpretive biologist and education coordinator at the Arboretum at the University of Guelph.
Stink bugs. Can’t live with ’em, can’t keep ’em from squeezing into your cottage and stinking up the joint. Well, you can. It just might take a little work.
Why are there so many stink bugs?
Fall is stink bug season. At least, that’s when you’re likely to notice them. As the temperatures drop, stink bugs—North America has more than 250 different species—start to move indoors…sometimes right into your cottage. “Lots of insects overwinter in the adult stage, which means that when the weather starts to get colder, they have to find places to spend the cold weather,” says Bob Anderson, an entomologist at the Canadian Museum of Nature. Great for the stink bug. Not so great for you.
Do stink bugs bite? Are stink bugs harmful?
In general, true stink bugs don’t bite or sting. The most they’ll do is land on your pant leg and freak you out. The invasive brown marmorated stink bug (Halyomorpha halys, pictured), native to Asia, is harmful in the sense that it can destroy entire fruit and vegetable crops, along with a wide variety of plants. (If you think you spot one—look for the two distinctive white bands on the bug’s last two antenna segments—most provinces would like you to report the bug, and have online reporting forms like this one from the B.C. government. To learn more about this invasive, and how to ID it, visit the Invasive Species Centre.
What do stink bugs smell like?
Stink bugs stink either when crushed, or when threatened. They release a strong-smelling substance from their abdomens. Most people liken it to cilantro, but others describe it as freshly cut grass, dirty socks, cat pee, Jolly Rangers, rubber, cinnamon…In short, stink bugs smell like anything.
What attracts stink bugs? How do I repel stink bugs?
In spring, stink bugs are drawn to your property because of native plants or fruit trees. But they’re really only a nuisance when they come inside. Like plenty of other insects, they’re attracted to light, and they’ll find tiny openings to use as doorways into your cottage. There’s unfortunately no sure-fire way to repel them. Your best defense is the same defense that you’d use against any pest insect: inspecting the exterior of the cottage for any cracks and crevices, and sealing them up with caulk. Look around windows and doors, around siding and utility pipes, behind chimneys, and underneath the wood fascia. Look pretty much everywhere. (This will help keep your cottage free from other critters, too.)
As for chemical methods, an all-purpose, exterior spray—the sort that pest control companies use for cluster flies, “would likely do the job,” says Glen Robertson of Robertson’s Wildlife and Pest Control in Coldwater, Ont. The problem? You’d need to get this done early in the fall, before you start to notice them indoors, and a spray could also harm non-target insects. Which means you could end up killing beneficial bugs that you actually want around.
How do I get rid of stink bugs?
“We usually just tell people to vacuum them up,” says Robertson. (Get rid of the vacuum bag right away to avoid any stench.) Happily, the bugs won’t damage your cottage, breed and reproduce, eat your food, or do much of anything while they’re there. If they survive the winter, they’ll leave in the spring.
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BirdLife International recently released its “State of the World’s Birds” report and it doesn’t look good for our feathered friends. Although conservation efforts have been attributed to the rebound of waterfowl and wetland birds like geese and ducks to the tune of about 150 per cent since the 1970s, overall, half of the world’s bird species are in decline, with one in eight facing extinction.
Birds Canada has been contributing vital data to the report, published every four years, and the information could ultimately save our birds.
“People feel like they can’t make a difference… and they can,” says Andrew Couturier, the senior director for landscape science and conservation with Birds Canada.
Canada also publishes our own “State of Canada’s Birds” report, most recently in 2019, which dials down our domestic bird issues, taking into consideration Canada can’t claim exclusive title to many birds, given their migration to other areas to winter or breed. An amazing 66 per cent of the trends concluded in the report came from volunteer citizen scientists, who populated data for breeding bird atlases, the Christmas Bird Count and eBird Canada checklists. In a world where information is power, it’s the monitoring of the numbers that informs the identification of threats, and where action would be most beneficial. Specifically, the establishment of Important Bird and Biodiversity Areas (IBAs), key spots where birds may breed, feed, winter or gather while migrating, are designated with this species and location specific information.
Those IBAs consider the needs of, and risks to, bird species, according to their specific habits. For instance, birds reliant on Canada’s native grasslands have declined a dramatic 87 per cent since 1970. The biggest reason? The increase in crop agriculture. But what volunteer led data showed was that cattle farmers may provide a solution, at least for some species. “Due to the conversion to agriculture in their breeding grounds, there’s hardly any habitat left. But now we have budding relationships with cattle ranchers, whose pastures mimic grassland habitat,” says Couturier. “When ranching is done properly, there’s a high diversity of other creatures as well.”
Hurricane Fiona’s devastation to Nova Scotia, P.E.I., and Newfoundland, whose intensity may be attributed to climate change, could be an example of what Canada’s shorebirds and seabirds are facing. Canada’s bird report states our shorebirds have declined by 40 per cent, but seabirds have been devastated with 55 of 58 species now of conservation concern. Couturier worries that Fiona may have destroyed vital habitat. “Our shorebirds aren’t there now, but when they come back, they may have no beach to breed on.” Monitoring birds that historically bred in these areas will be especially vital in the next few years.
Excepting species like the evening grosbeak that depend on the seeds and fruit of Canada’s mature forests (forest crop specialists have declined by 39 per cent), the rest of the 20 per cent of forest birds that stay in Canada during the winter have increased by 34 per cent. Unfortunately, those that migrate to South America have declined by 31 per cent. One of the actions Couturier recommends for those that migrate is buying bird friendly coffee. “Most coffee is from clear-cuts.” For birds who winter here, Canadians can advocate to save our mature trees and forests, limit pesticide use, and help to establish IBAs and networks of protected areas.
Pesticide use is also a big factor in the world’s reduction of insects, including pollinators. Birds like nighthawks, barn swallows, and bluebirds that feed by catching insects while flying, all once so plentiful their names included the words “common”, have decreased in numbers in Canada by 59 per cent since the 1980s. The signal this depletion sends is as relevant to humans as when coal miners used canaries.
But Couturier still believes that since we’ve turned the tide for endangered birds before, we can again, especially since data informs us now of where best to focus are efforts via the IBA’s. “If we make the case to landowners that have been doing something right or special…we’ll be helping landowners to steward. There are so many people that practice bird feeding, that are clearly interested in birds, but only a small proportion join in the programs.”
The IBAs have been so successful, they inspired KBAs, or Key Biodiversity Areas that encompass all forms of biodiversity. “We always knew that IBAs were bigger than birds,” says Couturier.
It’s hard to argue with the facts. According to the “State of the World’s Birds” report, between 21 and 32 bird species would have gone extinct sometime between 1993 and now, if it hadn’t been for conservation efforts.
The rebound of waterfowl and wetland birds, and the increase of about 110 per cent of birds of prey such as bald eagles and ospreys, are also greatly accredited to data led investment in conservation and cooperative stewardship of their habitats.
Canada’s federal government is among many that has set a goal to protect 30 per cent of land and seas by 2030, and are increasingly using Important Bird and Biodiversity Areas and the newer KBA designation to target the areas that will get the best results. According to Couturier, as of now about 17 per cent of that target has been met.
If we put the same amount of effort into saving our shore, grassland, and aerial insectivore birds, as we did with waterfowl, wetland, and birds of prey, what could we accomplish?
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This past summer, scuba divers in Sudbury discovered an unlikely form of aquatic life in the city’s Ramsey Lake. In late August, diving instructor Jason Fox captured a video of jellyfish, marking the first time the invasive species has been documented in Ontario outside of the Great Lakes. In a video, translucent, dime-sized craspedacusta sowerbii jellyfish pulsate with tentacles suspended in the water column.
“It’s a crazy story and it’s received a lot of attention,” says John Gunn, Canada Research Chair in biology at Sudbury’s Laurentian University and the director of the Vale Living With Lakes Centre. “Jellyfish are usually thought of as marine species. People find it remarkable to learn that we have them here in freshwater.”
Fox told CBC that he “basically stopped counting” jellyfish after three weekend dives in Ramsey Lake, estimating to have seen 50 or more on September 11. His photos and video is the first evidence of jellyfish in Ramsey Lake, but Gunn suspects they’ve been around for perhaps a decade or more. Craspedacusta sowerbii, which is native to China’s Yangtze River, arrived in North America in the 1930s. “It likely came in ships’ ballast water or as part of the aquarium plants trade,” Gunn explains. “It is yet another example of the many species that have joined North American flora and fauna due to human movements.”
The scientific literature suggests the freshwater jellyfish found in Ramsey Lake are innocuous. They eat microscopic phytoplankton in the water column, haven’t been linked to any adverse ecological effects, and swimmers don’t need to worry about the toxic stingers of some marine jellyfish. “They’re elegant and mesmerizing,” adds Gunn. “Divers and swimmers will really enjoy watching them in the water.”
Still, Gunn says the discovery is another cautionary tale of invasive species. “They aren’t like silver carp,” he notes, referencing the oversized exotic fish that have taken over waterways in the southern United States. Gunn hopes jellyfish in Ramsey Lake serve as a reminder of the ways humans have transported plants and animals all around the globe. “When you look at the lake,” he says, “realize that you’re glimpsing into a whole sea of biota that’s made its way here from elsewhere.
“We don’t have any specific concerns with jellyfish, but we do have to worry about others,” Gunn adds. “Stuff gets moved around in bait buckets and on motorboats. Humans are the vectors of countless nuisance species. We have to be extra cautious.”
