The Department of Fisheries and Oceans (DFO) had another busy field season in 2024, monitoring for invasive Grass Carp in Ontario’s waters. DFO captured one Grass Carp from Jordan Harbour, making it a total of 33 captures since 2012.
WHAT IS A GRASS CARP?
Grass Carp is one of four invasive carps, alongside Black Carp, Bighead Carp, and Silver Carp, and it can consume up to 40% of its body weight each day in aquatic vegetation. Grass Carp, if it becomes established, would have extreme consequences on our aquatic habitats and our native fish species.
2024 CAPTURE INFORMATION
The Grass Carp was captured by DFO field crews using sustained electrofishing, a newer technique added to their monitoring methodology, including standard electrofishing and gill netting. The Grass Carp was sent to DFO’s lab in Burlington and was determined to be sterile and thus incapable of reproduction. A second Grass Carp was identified based on photographs sent to DFO staff but was never physically recovered.
NEARBY DETECTION
The Province of Québec was also hard at work this year battling invasive Grass Carps, and captured a total of three fish that were later sent to the lab in Burlington for further analysis
MONITORING INFORMATION
In 2024, DFO monitoring crews captured 22,828 fish in 36 different waterbodies. Sampling methods include a mix of different netting techniques, as well as boat electrofishing. A field crew also performed egg and larval sampling in the late spring/early summer when probability of spawning is highest if Grass Carp are present in Ontario’s waters.
REPORT: If you suspect you’ve seen a Grass Carp, note your location, capture a photo, and report it to the Invading Species Hotline (1-800-563-7711) or report online at www.EDDMapS.org.
I.D: For what to do with a Grass Carp if you capture one as well as how to tell the difference between a Grass Carp and native lookalike species, click here.