The discovery marked the first record of Asian carps in a Toronto waterway since 2003, when an Asian grass carp was found near the mouth of the Don River.
This time, the two fish were discovered in contained ponds at Tommy Thompson Park near Toronto’s waterfront. The first fish weighed close to 40 pounds and was more than a metre long.
The mouth and gill systems of Asian carps allow them to ingest large amounts of water at all depths and filter food out. They eat phytoplankton, zooplankton and bottom debris.
Experience south of the border has shown it’s almost impossible to keep Asian carps from spreading once they’ve invaded. At some stage in their life, almost all our native fish feed on plankton.
So all fish — up to and including predators like yellow perch and walleye — could see their populations impacted if Asian carps were to multiply in Ontario waters.
“This is significant. They can be quite destructive to the natural environment.”
Rick Portiss, the head of our aquatic monitoring with Toronto and Region Conservation, said the carp discovery was more of a disappointment than a surprise.
“We’ve been on the lookout for this for quite a while,” he said.
“This is significant. They can be quite destructive to the natural environment.” Portiss said this type of carp can chew their way through a lot of vegetation that is key to other natural species. “Once you lose that, you lose the habitat for a log of other key species.”
That threat has led to several U.S.- and Canadian-based agencies and interest groups banding together to address the Asian carp issue. Together, they have warned that the fish species – with their veracious appetites and rapid reproduction rates – pose one of the greatest threats to the biodiversity of the Great Lakes.
The Ontario Federation of Anglers and Hunters (OFAH), home to Ontario’s Invading Species Awareness Program, partnered with several agencies earlier this year to host a series of Asian carp information sessions aimed at informing public about the latest federal and provincial responses to the threat of this invasive species.
“There’s no question Asian carps represent one of the single greatest threats to our Great Lakes fisheries,” said Matt Smith, Aquatic Invasive Species Outreach Liaison with the OFAH.
Earlier this year, the Canadian federal government put in place new aquatic invasive species legislation that provides a national regulatory framework to help prevent intentional and unintentional introductions of aquatic invasive species in Canada.
In July, the U.S. government announced a plan to spend nearly $60 million over the next two years in the battle to prevent invasive Asian carps from reaching the Great Lakes.