10 new non-native species added to Ontario's invasive species list

Ontario is prohibiting 10 new non-native species under the Invasive Species Act to help prevent and reduce their spread.

“Invasive species damage our ecosystems, impact our ability to enjoy outdoor activities, and harm our economy by threatening the forestry and agriculture sectors,” said Graydon Smith, Minister of Natural Resources and Forestry. 

Examples of new species that will now be prohibited include certain fish, aquatic plants and invertebrates. Restrictions will also be placed on groups of new aquatic and terrestrial plants.

The full list of the new prohibited and restricted invasive species can be found here.

In addition, the government has initiated consultation to renew the Ontario Invasives Species Strategic Plan to address the evolving and increasing threat of invasive species in Ontario.

Ontario spent more than $5 million in 2023-24 to support ongoing research, monitoring, and management of invasive species through programs and education across the province.

See: Phrag-Fighters get locals up to speed on invasive plant species

The Invasive Species Act, 2015 currently lists 42 species, four groups, one family and two carriers. The Act provides legislative tools to prohibit and restrict certain invasive species, as well as carriers that facilitate the movement of invasive species.

Ontario has the highest number of invasive species in Canada. Once established, invasive species can harm the natural environment and are extremely difficult and costly to control or eradicate.

For prohibited species, it is illegal to import, possess, deposit, release, transport, propagate (breed/grow), buy, sell, lease or trade these invasive species.

For restricted species, it is illegal to deposit or release restricted invasive species in Ontario and cannot be brought into a provincial park or conservation reserve.

The following species and groups will be prohibited in Ontario effective January 1, 2024:

Ide (fish)

• Potential impacts: introduce parasites, virus and disease transmission, and compete with native fishes.

Eastern and Western Mosquito Fishes (fish)

• Potential impacts: outcompete native fish species for food and habitat through aggressive feeding of zooplankton, eggs and larvae, leading to the loss of biodiversity and potential loss of some native species in Ontario.

Red Shiner (fish)

• Potential impacts: reduce native fish populations through predation on eggs and larvae, genetic impacts through hybridization, and introduction of parasites.

Oxygen Weed (aquatic plant)

• Potential impacts: dense colonies outcompete native vegetation, adversely affect water quality and impede recreational activities such as boating and swimming.

Nutria (mammal)

• Potential impacts: burrowing and foraging behaviour impacts agricultural areas and increases flooding risks, spread parasites and disease to humans, pets and livestock, and can destroy coastal wetlands.

Genus Salvinia (Watermoss – aquatic plant)

• Potential impacts: dense colonies outcompete native vegetation, adversely affect water quality and impede recreational activities such as boating and swimming.

Genus Procambarus and Genus Pacifastacus (Crayfish)

• Potential impacts: compete with native crayfish and fish species for food and shelter.

The following species and group will now be restricted effective January 1, 2024:

Eurasian Water-milfoil (aquatic plant)

• Potential impacts: outcompete native vegetation, adversely affect water quality, impede recreational activities and create habitat for mosquitoes.

Floating Primrose-willow (aquatic plant)

• Potential impacts: dense colonies outcompete native vegetation, adversely affect water quality, and impedes recreational activities such as boating and swimming.

Flowering-rush (aquatic plant)

• Potential impacts: can displace native riparian vegetation, forms dense stands which impact industrial and recreational uses of shallow waters, and reduces habitat of native fish and increases habitat for invasive fish.

Tree-of-heaven (terrestrial plant)

• Potential impacts: changes chemical and microbial activity in soils, reduces soil nutrients, displace native plant species, associated with several fungal pathogens and the preferred host to the spotted lanternfly (Lycorma delicatula).

Genus Azolla (Water Ferns – aquatic plant)

• Potential impacts: dense colonies outcompete native vegetation, adversely affect water quality, impedes recreational activities such as boating and swimming, and negatively affect wild rice populations.