Regulating ten species and four genera as invasive species under Ontario’s Invasive Species Act, 2015.

ERO number
Notice type
Invasive Species Act, 2015
Posted by
Ministry of Natural Resources and Forestry
Notice stage
Proposal posted
Comment period
August 18, 2023 - October 2, 2023 (45 days) Open
Last updated

This consultation closes at 11:59 p.m. on:
October 2, 2023

Proposal summary

The Ministry of Natural Resources and Forestry is proposing regulatory amendments under the Invasive Species Act, 2015 that would classify 10 species and four genera of species as either prohibited or restricted invasive species.

Proposal details

The Invasive Species Act

The Invasive Species Act, 2015 supports Ontario’s ability to prevent the introduction and spread of invasive species that pose a threat to the natural environment. The Act includes various provisions to enable the establishment of prohibitions and restrictions on invasive species and carriers (pathways) that facilitate the movement of invasive species in Ontario.

Decisions to recommend species for regulation are based on the risk that a species poses to Ontario’s natural environment and socio-economic well-being.

The species listed below have the potential to, or are already, causing negative impacts to Ontario’s natural environment and that regulation under the Invasive Species Act, 2015 would improve Ontario’s ability to prevent their introduction or spread.

Seeking feedback on the proposed species

Prohibited Invasive Species

Prohibited species cannot be brought into Ontario, deposited, released, possessed or transported in Ontario and cannot be propagated, bought, sold or traded in Ontario.

Species and Genera (Genus) proposed to be regulated as prohibited invasive species are:

  • Ide  (Leuciscus idus) / Fish
  • Eastern Mosquitofish (Gambusia holbrook) /  Fish
  • Western Mosquitofish (Gambusia affinis)     / Fish
  • Red Shiner (Cyprinella lutrensis) / Fish
  • Oxygen Weed (Lagarosiphon major) / Aquatic Plant
  • Nutria (Myocastor coypus) / Mammal
  • Watermoss (Genus Salvinia) / Aquatic Plant
  • Crayfish (Genus Procambarus) / Invertebrate
  • Crayfish (Genus Pacifastacus)  /Invertebrate

Proposed exceptions:

  • Ide, Eastern Mosquitofish, Western Mosquitofish, Red Shiner 
    • Exceptions would allow for incidental capture of these species while fishing in Ontario.
  • Red Shiner, Genus Salvinia, Genus Procambarus, Genus Pacifastacus 
    • Transition period for possession to allow for awareness among individuals and businesses who may be in possession of these species. 
  • Genus Procambarus, Genus Pacifastacus 
    • Exceptions would continue to allow the import, possession, transport and sale of Red Swamp Crayfish (Procambarus clarkia), or Signal Crayfish (Pacifastacus leniusculus) that are dead and prepared for human consumption (e.g. cooked).

For additional information on current regulatory exceptions, please see Ontario Regulation 354/16 (General) under the Invasive Species Act, 2015.

Restricted Invasive Species

Restricted species cannot be deposited or released in Ontario and cannot be brought into a provincial park or conservation reserve. In addition, the ministry may prescribe additional prohibitions for certain restricted species through regulation that would reduce the risk of that species being introduced or spread further in Ontario, while also allowing some activities to occur.  

Species/Genus proposed to be regulated as restricted invasive species are:

  • Eurasian Water-milfoil  (Myriophyllum spicatum) / Aquatic plant 
  • Floating Primrose-willow (Ludwigia peploides)  / Aquatic plant
  • Flowering-rush  (Butomus umbellatus) / Aquatic plant
  • Tree-of-heaven (Ailanthus altissima)   / Terrestrial plant
  • Water Ferns (Azolla) / Aquatic Plant

Proposed species-specific rules:

In addition to the general prohibitions in the Invasive Species Act, 2015 that apply to all restricted invasive species (depositing or releasing, brining into provincial parks or conservation reserves), it is proposed the following additional prohibitions would apply to the above-listed plant species: 

  • possess or transport a member of a restricted invasive species in a provincial park or conservation reserve;
  • bring a member of a restricted invasive species into Ontario or causing it to be brought into Ontario;
  • propagate members of a restricted invasive species;
  • buy, sell, lease or trade or offering to buy, sell, lease or trade a member of a restricted invasive species.

Regulatory impact analysis/statement

  • The anticipated environmental consequences of the proposal are positive.

Invasive species are recognized as one of the key threats to Ontario’s natural environment and native species. The ecological effects of invasive species are often irreversible and, once established, they are extremely difficult and costly to control and eradicate.

The regulation of the proposed species enhances efforts and the tools available to prevent the introduction and spread of invasive species in Ontario and will reduce the likelihood that they will impact Ontario’s natural environment in the future.

  • The anticipated social consequences of the proposal are positive.

Invasive species pose a significant risk to Ontario’s natural areas, urban parks, and outdoor recreational activities such as hiking and fishing through the displacement of native species, the clogging of waterways, and reduced aesthetic values.  

By regulating these species, the likelihood of their introduction and spread in Ontario will be reduced, thus preventing any further impacts to these values resulting from these species.

  • The anticipated economic consequences of the proposal are positive.  

In 2019, an economic impacts study undertaken by the Invasive Species Centre, estimated that the potential impacts of invasive species to agricultural, fisheries, forestry, healthcare, tourism, and the recreation industry may be as high as $3.6 billion per year in Ontario.

Preventing the introduction and establishment of invasive species is recognized as the most cost-effective method to manage these species. The regulation of these species will support efforts to achieve this objective.

While limited economic impacts are anticipated as a result of the prohibitions on the import, possession and sale of these species, exceptions and transition periods are being recommended to reduce these consequences.

The anticipated annual administrative costs of this proposal are neutral.

Supporting materials

View materials in person

Some supporting materials may not be available online. If this is the case, you can request to view the materials in person.

Get in touch with the office listed below to find out if materials are available.

MNRF - Biodiversity and Invasive Species Section

300 Water Street, 5th Floor North tower
Peterborough, ON
K9J 3C7


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