Musseling In

Hey there, time traveller!
This article was published 27/09/2018 (2548 days ago), so information in it may no longer be current.

Christian Tremblay stepped out from his white Parks Canada pickup truck and walked several paces towards the locked entranceway that stood before us.

As the large metal bar swung open, Tremblay motioned for me to move my car forward before locking the gate behind us and leading me to a grassy clearing up ahead, to the shores of Whirlpool Lake.

Normally open to visitors this time of year, Whirlpool Lake was eerily quiet that mid-August day. Fireplaces lay vacant as wisps of grass poked through the narrow slits of a wooden dock that had been pulled ashore and left to dry.

Near the southwest tip of the lake, a marsh-like patch had emerged where the water had receded, creating a thick mud that swallowed our boots.

With our gear in hand, Tremblay and I set out in a canoe and paddled our way towards a small yellow buoy several yards away.

Lifting it up, Tremblay revealed a series of four plates underneath, ascending in size from largest to smallest.

Mostly empty on the surface, in a few months time those plates, along with 10 other sets around Whirlpool Lake, could reveal what Tremblay – the aquatic invasive species project coordinator for Riding Mountain – and Manitobans alike would rather not want: evidence of zebra mussels in Riding Mountain National Park.

“If something is there, we want to make sure it’s not moved out of the park,” he said.

Named for the striped pattern on their shell, zebra mussels measure only a few centimetres in length and are native to eastern Europe and western Asia.

Zebra mussels were found in Lake Winnipeg in 2013, marking the first confirmed presence of the animal in Manitoba.

The animal was later confirmed in the Red River and Cedar Lake in 2015, but Riding Mountain would prove itself free of them for at least two years after that.

But last December, Parks Canada announced that water samples taken from Whirlpool Lake, located just east of Clear Lake, had come back positive for environmental DNA, or eDNA, which are small genetic traces left behind by aquatic organisms.

As a result, the lake and its campground site were closed as a precautionary measure.

While not definitive proof that zebra mussels are there — along with the fact that no live mussels or larvae, known as veligers, were found either — the results were enough to prompt researchers to continue testing the waters of Whirlpool, and others, for stronger evidence.

If caught early, Tremblay said the situation can still be contained. At worst, the mussels have already begun reproducing — females can produce up to a million eggs a year.

“That’s why eDNA, it’s a very new approach, but at the same time, you never know what that result might mean,” Tremblay said.

Researchers have used three main techniques in their search for zebra mussels.

The first involves the use of PVC plates, also called substrate samplers, like the ones Tremblay showed me at Whirlpool Lake.

Zebra mussels are big fans of PVC plastic and the layered design of the plates allows them to hide underneath.

Whirlpool has the most substrate samplers in the park, but more than a dozen others lie in Clear Lake, Lake Audy, Lake Katherine, Moon Lake, Deep Lake and Bob Hill Lake.

If any adult mussels exist, they’ll likely be found on these plates.

Researchers are also scraping Whirlpool with plankton nets to try and catch any free-floating veligers.

Meanwhile, several lakes are being tested for eDNA using makeshift peristaltic pumps built from electric drills. Water is siphoned through a filter, which will be analyzed later in the lab.

Should zebra mussels establish themselves in Whirlpool Lake, like they have in the Great Lakes area and Lake Winnipeg, the situation will be irreversible.

Not only do the mussels filter lakes of plankton, disrupting local food chains, they have been known to clog water intake systems, cut the feet of swimmers, and be a general eyesore on piers and docks.

“The park is here to preserve the ecological integrity of Clear Lake and the rest of the park,” said Colleen Robertson, a 20-year-old environmental science student who spent her third summer at Riding Mountain helping with the research side of things.

“And if we do introduce zebra mussels or any other invasive species into Clear Lake, or any of the other lakes, you’d see a complete change in the balance of the lake ecosystem.”

But for all the talk on the devastation caused by zebra mussels, prevention remains one of the most important, and perhaps underreported, tools behind controlling their spread.

“People are the threat to it,” said Kathryn Yarchuk, a 21-year-old environmental studies student in her second summer at Riding Mountain.

“And right now, we can do the research on the impacts of it, but by researching it, we’re only having a really small change on what’s happening, versus if you want to make a change you need to be telling people and informing them about why it’s important, and that’s a very important role.”

Veligers are microscopic and have the ability to survive in small amounts of water, while adult mussels can live for up to 30 days outside of it.

As a result, watercraft remain the No. 1 vector for transporting zebra mussels, which can include everything from motorboats, canoes, kayaks and paddle boards. Even inflatable water wings can transport larvae from one area to another.

Both federal and provincial legislation is in place to prevent the spread of aquatic invasive species and Manitoba has six defined control zones where these species are either there already or expected to spread (Central, Nelson River, Whiteshell, Buffalo Bay, Winnipeg River and Saskatchewan River/Cedar Lake).

All watercraft are required to be inspected and decontaminated with hot water if they’ve previously been in a high-risk area, a process commonly referred to as clean, drain, dry and dispose.

But while decontamination is provided free of charge, both federal and provincial officials still manage to catch people who skirt the rules.

Figures provided by Parks Canada show that wardens charged 11 people last year for not getting an inspection. Eight of those resulted in mandatory court appearances, because the vessels were used in infected water bodies or those that were suspected to be.

So far this year, wardens have charged three people and issued several warnings, the majority of which have been for uninspected canoes, kayaks and paddleboards.

Some watercraft have been seized by Parks Canada and the maximum fine for non-compliance is $100,000.

The province, meanwhile, has inspected 9,620 watercraft and performed 1,255 decontaminations at its six inspection sites since May, based on the latest numbers from Aug. 29

But while a number of warnings have been handed out, aquatic invasive species specialist for Manitoba Sustainable Development Candace Parks said the goal isn’t to simply fine people — of which no one has provincially — but to make them aware of the dangers posed by these animals.

“For me, I think that what people need to realize is that with zebra mussels … we’re looking at long-lasting irreversible impacts to a water body,” she said.

Having worked on the file since 2009, Parks has seen first hand the problem of zebra mussels become reality here in Manitoba.

Two falls ago, Parks was walking along Beaconia Beach on the southeast-end of Lake Winnipeg, when she came across a black piece of debris. After checking it further, she realized she was ankle deep in zebra mussels and burst into tears.

“It is absolutely heartbreaking to see it established in your backyard,” she said.

Elsewhere, the province has put Singush Lake in Duck Mountain Provincial Park under quarantine and put in place boating restrictions after a small sample found on a substrate sampler came back positive for zebra mussel eDNA.

Meanwhile, veligers have been found in Lake Winnipeg’s north basin and Poplar River First Nation confirmed they found an adult zebra mussel in one of their gill nets, Parks said.

The Nelson River to the north of Lake Winnipeg will most certainly be invaded by zebra mussels as well, Parks said. The only question is when.

She and others stressed that more lakes and rivers can be protected, as long as the public stays vigilant about decontamination.

But while the focus has largely been on the threat of zebra mussels, Manitoba has nearly 20 aquatic invasive species, among them the spiny waterflea and rusty crayfish. Some species of Asian carp are also of concern to Manitoba.

Asked if she was worried that attention was being taken away from these other species, Parks said the same messaging still applies.

“If I need to use zebra mussels as the conduit to get the information out to the masses, and along the way tell them if you do steps to prevent anything from invading Manitoba, I’ll ride the coattails of zebra mussels as long as I can.”

So far in Whirlpool Lake, the lack of evidence of zebra mussels has been a welcome sign for Tremblay.

But it does beg the question of how that DNA managed to get there in the first place.

“We’ll probably never know,” Tremblay said. “If we don’t find anything else, we can speculate.”