Anglers’ warning: Invasive species found in Bay

Another invasive fish species has found its way to the Bay of Quinte.

Earlier this fall, a commercial fisherman caught a “Tench” near the water treatment plant in Belleville.

Tench, native to Europe and western Asia, were introduced across the United States in the late 19th century for use as a food and sport fish.
Tench were brought to a Quebec fish farm illegally and escaped into the Richelieu River, a tributary of the St. Lawrence River. Until now, they had not been found above the Moses Saunders Dam at Cornwall.

Tench average 20 – 25 centimetres in length, are dark olive to pale golden tan with a white to bronze belly, and a bright reddish-orange eye. They have a single whisker (known as a barbel) hanging for each corner of their mouth. The fins are dark and rounded with no spines and their scales are small and embedded in thick skin.

Sarah Midlane Jones, Communications with the Bay of Quinte Remedial Action Plan, said Tench may affect native species and water quality by competing with native minnows, bullheads, and suckers for food as they eat large quantities of snails and insect larvae.

“By feeding heavily on snails, which graze on algae, they may contribute to algal blooms. Additionally, aggressive feeding by tench stirs up sediments, leading to cloudy water,” she said.

The Bay of Quinte provides great habitat, she notes, as Tench prefer lakes and slow-moving waterways with abundant vegetation and muddy bottoms. They can live in water with low levels of oxygen and in water temperatures from 0 C – 24 C.

Right now, she said, there are more questions than answers.

“One way tench could have been introduced is as live baitfish. They are commonly mistaken for native and introduced species of baitfish.”

Bay of Quinte RAP recommends anglers learn to identify Tench, never buy or use them as bait as it is against the law and don’t put any live fish into Ontario lakes, rivers, and streams.

If you catch or see a Tench, contact the toll-free Invasive Species Hotline at 1-800-563-7711, or visit www.invading species.com. If you catch a Tench do not return it to the water.

As well, if you have any information about the illegal importation, distribution, or sale of Tench report it to the Ministry of Natural Resources and Forestry at 1-800 TIPS-MNR (847-7667) or contact your local MNRF office (ontario.ca/mnroffices)