3 Ways You Can Help Stop the Spread of Grass Carp into the Canadian Great Lakes

Learn how to ID Grass Carp

Grass Carp are one of four species that are categorized as Asian carps. The other three species include Bighead Carp, Silver Carp, and Black Carp; however, Grass Carp pose the most imminent threat to the Canadian Great Lakes. Asian carps pose a significant threat to native species and overall biodiversity in Canadian waters. They will compete with native fishes for food and habitat and can act as carriers for diseases or parasites that could spread to native fishes. They grow very large, and rapidly; native predatory fishes will be unable to control their populations as Asian carps will outgrow them leaving them with no natural predators.

So far in 2024, five Grass Carp have been captured! Three in Lac des Deux Montagnes in the Baie de Vaudreuil, one was found in Rondeau Bay in Lake Erie and the most recent capture was in Jordan Harbour in Lake Ontario. Although there have been individual captures, there has been no evidence of an established population in the Canadian Great Lakes, though spawning has been reported in a few nearby tributaries in the United States. Anglers play a huge role in the early detection of aquatic invasive species. One of the most important things you can do to help prevent the spread of Grass Carp into Canadian waters is by learning how to properly ID and report this species.

The body of a Grass Carp is oblong shaped with a slightly flattened head and moderately small eyes located in the middle of the head on each side. They have large overlapping scales which can vary in colour from blackish to olive-brown with brassy or silvery-white on the sides and belly. The scales will have a cross-hatched or checkered like appearance. Some key features that will help you distinguish Grass Carp from other similar look-a-like species like the Common Carp are that they will have no barbels, the dorsal fin will be narrow, and the eyes are in the middle of the head. There are many other native species that resemble Grass Carp, and it is important that anglers know how to tell the difference! The Grass Carp Identification and Reporting Guide lists key species that may be confused with Grass Carp.

2. Learn how to report invasive species

Now you’ve caught a Grass Carp and you’re confident in your ID skills, what next? The first step will be to report it to the Invading Species Hotline at 1 (800) 563-7711 or email info@invadingspecies.com or report the sighting on the website EDDMapS.org. Once a report has been made, this goes directly to experts in the field, who will review the report and verify the identification. In the case of a positive ID of Grass Carp you will be contacted for more information and pickup of the specimen will be organized. Once you have reported your sighting, take photos and note your exact geographic location (e.g. longitude and latitude). Take photographs of the fish from multiple angles with adequate lighting. A handy tool for noting your geographic location will be using the google maps app on your phone, you can drop a pin, and this will give you a set of coordinates. If you were unable to reach someone directly in the first step (reporting), avoid unintentionally killing native fishes by being certain of your identification before killing a suspected Grass Carp. Ensure you are abiding by all of the laws highlighted in the Ontario Recreational Fishing Regulations Summary. If you are confident in your identification skills, do not release the Grass Crap alive! Kill the fish without damaging the head or eyes. Keep the fish in a cooler, double bagged with the head above the ice while waiting for it to be picked up. The reason the head needs to be kept above the ice is to ensure the eyes do not freeze. Fluid samples from the eye need to be taken to check whether the fish is fertile or sterile and to determine where it came from, frozen eyes prevent an accurate test. Download the Grass Carp Identification and Reporting Guide here: https://www.asiancarp.ca/grass-carp-identification-and-reporting-guide/

3. Learn how to ID Baitfishes

Juvenile Grass Carp closely resemble many of the legal baitfishes found in Ontario and can be quite difficult to tell apart. The Department of Fisheries and Oceans Canada has developed a Baitfish Primer Guide and App which gives recreational anglers a tool to identify their baitfishes, which helps keep invasive species out of our waters and protects endangered aquatic species. If you use live bait while fishing, it is important to know what species you are using and to dispose of your bait properly. In Ontario it is illegal to dump the contents of your bait bucket (including the water) into or within 30 metres of any waterbody. Always purchase your live bait from a trusted local source!

Did you know?

Aquatic invasive species can spread in many ways, through the aquaculture and pet industry, natural dispersal or by hitchhiking a ride in the ballast water of ships, or even on your own watercraft. Recreational watercrafts such as boats, kayaks, canoes, and paddleboards can all serve as vessels in the transport of aquatic invasive species. Additionally, recreational gear used while fishing, or hunting can also be great places for certain species to hitch a ride.

Make sure you take the proper steps to help prevent and reduce the spread of aquatic invasive species. After using your boat, clean any plants, mud, mussels or debris from your watercraft, and equipment. Drain all standing water from your bilge, motor and livewell, and finally, if possible, let your boat dry for 2-7 days or disinfect it with hot pressurized water. Each province has its own rules and regulations regarding cleaning watercraft, and it is important to familiarize yourself if travelling. Learn more about the rules and regulations at this link: https://www.invasivespeciescentre.ca/know-before-you-go/ or for Ontario specific: https://www.ontario.ca/page/invasive-species-action-plans