Fish you were (NOT) here

There’s something fishy going on… and thankfully a few concerned citizens “caught” it!

On July 10^th 2019, the Aquatic Invasive Species (AIS) Hotline received a report of numerous dead fish in the Elbow River, just outside of Bragg Creek. Fish biologists confirmed on July 11^th that the fish were tilapia. This warm-water species is native to Africa and the Middle East, and pose immense risks to native fish species by creating turbid waters and outcompeting them for food and space.

Photo credit: Travis Shield

Unfortunately for the tilapia, their warm-water loving trait likely lead to their demise – depending on the species, they can die from temperatures ranging from 7 to 17°C. Although, the Elbow River was 11.7°C on July 11^th, the thermal shock from their tank environment to the Elbow River was enough to o-fish-ally end this scare. Tilapia’s intolerance for low water temperatures makes their establishment in the Elbow River highly unlikely, as temperatures between 0°C to 4°C are common in winter months. Even though the tilapia did not survive, any parasites or diseases that they may or may not have been carrying have the potential to affect native and stocked fish populations.

So how did these fish get into the Elbow River? Even if they end up on your dinner plate, they certainly do not belong in our rivers and streams! Tilapia have been introduced around the world as a food source, as they are easy to grow and are mild-flavored. There are several licensed aquaculture facilities in the Calgary area, where the fish could have been deliberately dumped from. Facilities have been contacted regarding this fish introduction, as the release of fish into Alberta waters is illegal and prohibited under the Fisheries (Alberta) Act.

Photo credit: Paul Christensen

Environment and Parks staff will continue to scale the Elbow and Bow Rivers to ensure the tilapia aren’t lured into any warm spots, where wastewater treatment plants discharge their water. You too can help us by keeping your eyes peeled while you’re fishing, floating or hiking in the area!

How can you help?

1. Don’t let it loose! Never release unwanted aquarium species – it’s illegal, unfair to the fish and harmful to the environment.
2. Report what you see! Call the AIS hotline at 1-855-336-BOAT (2628) or use the EDDMaps Alberta app.
3. Learn to identify Alberta’s 52 prohibited aquatic invasive species using our pocket guide.

4. Fill out Fisheries and Oceans Canada survey on live seafood to help them gain a better understanding of the use and movement of commercially available live seafood.