With a quarter million lakes and countless streams and rivers, Ontario has some of the best fishing anywhere in the world. We have dozens of abundant fish species – but in our waters, 27 kinds of fish are at risk of disappearing from the province. The Gravel Chub and the Paddlefish are no longer found in Ontario waters at all.
Our at-risk fish range from some of the largest in the province, such as the lake sturgeon, to tiny minnows. These fish are threatened by degraded water quality from agricultural and industrial pollutants, and also by damage to habitat such as dams that prevent fish from travelling to spawn.
Thirteen kinds of mussels are also at risk of disappearing from the province's waterways. Mussels, with no ability to move for most of their lifespan, are very vulnerable to threats such as poor water quality, damming, changes to shorelines and wetlands, and agricultural run-off.
The zebra mussel, an invasive species, has caused a dramatic decline in mussel populations across the Great Lakes basin. Zebra mussels attach to the shells of the native mussels, often in such high numbers that they inhibit feeding or breathing. In addition, zebra mussels have negatively affected fish species that mussels rely on as a host during their larval stage.
Fish and mussels are part of Ontario's biodiversity and a major food source for many animals – including people. Mussels also filter and clean the water of lakes and rivers.
Check out the links below to learn more about Ontario's fish and mussels at risk, including how you can help protect them.
The Grass Pickerel is a top predator and hunts by sight, either stalking or ambushing its preferred prey. Young Grass Pickerel usually feed on insects, while adults target other fish, sometimes even eating the young of their own species.
Unlike some other lamprey species, the Northern Brook Lamprey is non-parasitic and does not attach itself to larger host fish. The larvae are filter-feeders, consuming microscopic plant and animal life and decaying matter. Adults have a non-functional intestine and do not feed.
Paddlefish have no teeth and eat by filtering zooplankton out of the water. They swim with their mouths open, filtering the water through gill
arches in the mouth. The gill arches have filaments on them called gill rakers that sieve the zooplankton organisms from the water.
The Shortnose Cisco, also called chub, was once commercially fished in the Great Lakes. In the late 1800s it was the main fish caught by Toronto fishing boats. By the 1930s this species was seldom caught and by the 1980s it had nearly disappeared.
special concern (Great Lakes - Upper St. Lawrence River Population)
Silver lampreys belong to the most ancestral lineage of vertebrates (animals with backbones). From them we may be able to learn about evolutionary pathways, such as the transition from jawless to jawed vertebrates.
The Spotted Gar can breathe air! It uses a special organ called a swim bladder like a lung when the fish comes to the surface for a breath of air. This allows the fish to live in areas with little oxygen in the water. Like most fishes, the Spotted Gar also uses gills to breath underwater.
The Kiyi can be distinguished from the two other deepwater cisco species, Bloater and Shortjaw Cisco, known to exist in the Great Lakes by its unique combination of long paired fins, and eyes so large they make up almost 25 per cent of the head length.
Kidneyshell larvae are clustered into packages called "conglutinates" when released, and somewhat resemble fish fry complete with eye spots, or insect larvae. When a fooled fish bites down on one of these packages, the larvae burst out and attach to the fish gills where they live as parasites and consume nutrients from the fish until they transform into juvenile mussels and drop off.
The Mapleleaf Mussel depends on the channel catfish to survive. By attaching itself to the gills of the catfish, the mussel larvae consume nutrients from the fish until they transform into juvenile mussels and drop off.
A mussel larva must attach to a host fish where it stays until is has consumed enough nutrients to transform into a juvenile mussel. The female Rainbow Mussel goes fishing for host fish by producing a lure that looks just like a crayfish, including an eyespot and wriggling legs. When a fooled fish attacks the lure the mussel ejects its larvae, which have a better chance of attaching to the host fish at such a close distance.
The larvae of most freshwater mussels must attach to a fish host in order to survive. Once attached, the tiny parasitic larvae consume nutrients from the fish until they transform into mussels. The Salamander Mussel is unique in that their larvae use the aquatic Mudpuppy salamander as a host, instead of a fish.
The Snuffbox's main host is the Logperch, which is known to frequently roll over small stones and gravel in search of food. The Snuffbox waits patiently for a Logperch to come along and touch its shell. The Snuffbox then captures the Logperch in its shell and holds the stunned fish long enough to puff out a cloud of mussel larvae that attach to the fish gills, where they live as parasites that consume nutrients from the fish body. The startled fish is then released.
The Wavy-rayed Lampmussel can fish. To attract a fish host that its parasitic larvae can attach to, the female produces a lure that looks like a wriggling minnow. When a fooled fish attacks the lure, the mussel ejects its larvae, which have a better chance of attaching to the host at such a close distance.
In 2011, Lake Ontario Atlantic Salmon, which disappeared from our waters more than a century ago due to habitat loss and over-fishing, were declared "extinct" by the committee that classified species at risk in Ontario. A group of conservation partners, including the Ministry of Natural Resources, is working to restore Atlantic Salmon to Lake Ontario, using strains from Nova Scotia, Maine and Quebec. Learn more