Invasive species, climate change attributed to birds and fish mortality


“These types of botulism-related death events may become more frequent as we move into the uncertain world of climate change,” says environmentalist NVCA

Experts have confirmed that the recent bird and fish deaths that brought hundreds of carcasses to the shores of Wasaga Beach and the area is likely botulism, and it likely has a lot to do with invasive species.

Last month, several residents and visitors to Wasaga Beach Provincial Park began reporting the discovery of dead birds along the shore.

Park superintendent John Fisher confirmed in late October that there had been a death of birds and fish.

Brian Stevens, a wildlife pathologist at the Canadian Wildlife Health Cooperative, said his organization was first notified of the death on October 18.

“We received reports of around 200 birds from Wasaga Beach on Oct. 18,” Stevens said in an email. “Since that time, other reports have slowly poured in.”

While the University of Guelph-based Canadian Wildlife Health Cooperative intends to examine the organs of dead birds found on local shores, evidence so far points to botulism.

“The birds we examined are in good body condition and there is no evidence of underlying disease at autopsy,” Stevens said. “The bird species affected – fish / mollusc-eating waterfowl such as persimmon ducks, red-necked grebes and ring-billed gulls – and the general good condition in which these birds are found strongly suggests type E botulism. epidemic.”

David Featherstone, senior ecologist at the Nottawasaga Valley Conservation Authority (NVCA), said this most recent death is not an isolated event. This has been happening on the shores of Georgian Bay since the 2010s.

Along Lake Huron, there have been bird and fish deaths since the late 1990s. Although there are many factors affecting the health and mortality of birds and fish in the lake Huron, those deaths may be linked to invasive species and even climate change, according to Featherstone and other experts with their eyes on the lake.

Mortality conditions over the past 10 years share some commonalities: warm waters, filamentous algae that grow and die on rocks, and two invasive mussels.

“There is a very interesting connection between the food chain and these bird deaths,” said Featherstone. “Botulinum and bacteria thrive in decaying algae, and are taken up in the food chain by filter feeders such as invasive zebra and quagga mussels and some native invertebrates. “

According to NVCA, zebra and quagga mussels are invasive species that have become common in Lake Huron, including Georgian Bay. They add filtration to the excess water, due to their numbers, and bring sunlight deeper into the water, allowing more algae to grow.

Invasive mussels are eaten by some forms of waterfowl and another invasive species, the round goby. These gobies are eaten by the endangered lake sturgeons which currently have a stronghold in the Nottawasaga River, which they use for spawning.

Eventually, as birds and fish eat the bottom feeders that have ingested the decaying algae, the bioaccumulation of botulinum toxin causes botulism disease in birds and fish, and they will become paralyzed and die – sometimes by drowning. .

“Zebra and quagga mussels appear to be a real vector,” Featherstone said. “And I think climate change could play a role. There is a link between extreme storms, more nutrients entering coastal areas and more algae produced. ”

In the last major storm in October, the Collingwood sewage treatment plant was overwhelmed and untreated sewage was sent to Georgian Bay.

Events like this, Featherstone said, can lead to additional algae growth and dieback due to nutrients pouring into the coastal area.

“It is potentially an additional source of development of botulism,” said Featherstone. “These types of botulism-related death events may become more common as we move into the uncertain world of climate change.”

Gary Wheeler, spokesperson for the Ontario Ministry of Environment, Conservation and Parks, said the latest bird kills appear to affect fewer birds than the big event of 2011, which left about 8,000 to 9,000 dead and stranded birds and fish. on the shore of Wasaga Beach Provincial Park.

In the latest death, Wheeler said parks staff found carcasses of white-winged scooters, long-tailed ducks, common golden eyes, as well as sturgeon, salmon and carp.

David Sweetnam, executive director of Georgian Bay Forever, reported hundreds of dead birds stranded on Wasaga Beach, Midland, Collingwood and Tiny Township last month.

He said the deaths are not necessarily caused by climate change in the first place, but are “exacerbated” by climate change.

“Climate change adds stress and allows invasive species to take hold,” Sweetnam said during a water levels webinar that was part of a series hosted by the Georgian Bay Association and Georgian Bay Forever.

Bird and fish mortality illustrates the importance of working to prevent invasive species from entering local lakes, Featherstone said.

Zebra and quagga mussels first arrived in the Great Lakes in the 1980s from ballast water discharged by large ships from Europe.

“Unfortunately, the invasive species that are present already are,” he said. “All the efforts that municipalities, businesses and private citizens can do to prevent invasive species from entering and spreading… to stop this introduction of new species is always a good thing. ”

One of the important ways to prevent the spread of invasive species is a thorough cleaning of marine equipment and construction equipment used along shorelines, experts say.

Ontario’s Invasive Species Awareness Program encourages boaters to drain all water from the engine, livewell, bilge and transom when on shore, and to clean all recreational equipment with a high pressure wash, hot water or leave it to dry in the sun for at least five days.

You can learn more about invasive species and how to prevent their introduction on the Invasive Species Center website here and on the Nottawasaga Valley Conservation Authority website here.

The Department of Northern Development, Mines, Natural Resources and Forests reminds people to keep pets away from dead birds or fish and to report dead or dying waterfowl to the Canadian Cooperative Health Center de la fauna at 1-866-673-4781.

To report fish deaths, contact the Department of Northern Development, Mines, Natural Resources and Forestry at 1-800-667-1940.


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