A Canadian Action Plan to Address the Threat of Aquatic Invasive Species
Canadian Council of Fisheries and Aquaculture Ministers Aquatic Invasive Species Task Group

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Table of Contents


Accidental introduction (unintentional introduction)
Introduction of an aquatic organism, including "fellow travelers," by chance, not by design. For example, the release of an organism transported in ship's ballast water.
Alien species (alien, exotic, foreign or non-indigenous species)
A species occurring in an area outside of its historically known natural range as a result of intentional or accidental dispersal by human activities OR Any species in an ecosystem that enters that ecosystem from outside the historic range of the species.
The controlled cultivation and harvest of aquatic animals and plants.
Aquarium fish
All species of fish and aquatic plants for ornamental use imported or transferred into strict confinement.
Aquatic invasive species
Fish, animal, and plant species that have been introduced into a new aquatic ecosystem and are having harmful consequences for the natural resources in the native aquatic ecosystem and/or the human use of the resource.
Aquatic organisms - This includes all organisms (finfish, molluscs, crustaceans, echinoderms, and other invertebrates and their life stages) defined as "Fish" in the Fisheries Act, as well as marine and fresh water plants.
Live fish (or other aquatic organisms) placed on a hook or in a trap in order to allure fish.
Ballast Water
Any water (with its suspended matter) used to maintain the trim and stability of a vessel.
To completely eliminate a population from a geographic area.
The process of a new species in a new habitat successfully reproducing at a level sufficient to ensure continued survival without infusion of new genetic material from outside the system.
Fellow traveler
Organism which inadvertently accompanies the shipment of the species intended for introduction/transfer.
The Fisheries Act definition of "fish" includes:
  1. parts of fish;
  2. shellfish, crustaceans, marine animals and any parts of shellfish, crustaceans or marine animals; and
  3. the eggs, sperm, spawn, larvae, spat and juvenile stages of fish, shellfish, crustaceans and marine animals.

This document refers to all aquatic species that enter through any pathway (including reptiles and amphibians) and spend most of their life cycle in water.

Indigenous (native) species
Existing and having originated naturally in a particular region or environment
The transfer of an organism to an ecosystem outside the historic range of the species of which the organism is a member.
Intentional introduction
The deliberate release, or holding, of live aquatic organisms in open-water or within a facility with flow-through circulation or effluent access to the open-water environment outside its present range.
Introduced species (exotic species, non-indigenous)
Any species intentionally or accidentally transported and released by humans into an environment or facility with effluent access to open-water or flow-through system outside its present range.
Invasive Species (nuisance or pest species)
A non-indigenous species the introduction of which into an ecosystem may cause harm to the economy, environment, human health, recreation, or public welfare.
Live fish for the food trade
Fish destined strictly for consumption. Imported live fish are held in containment facilities or containment units such as those in restaurants or fish stores.
Marine plant
The Fisheries Act states that "marine plant" includes all benthic and detached algae, marine flowering plants, brown algae, red algae, green algae and phytoplankton
Existing within a historical ecological range, usually within a balanced system of co-evolved organisms.
Naturalized species
Alien species that reproduce consistently and sustain populations over more than one life cycle without direct human intervention (or in spite of human intervention).
Any agent that causes disease in plants or animals; typically referring to microbes such as bacteria, viruses, or protozoan parasites.
One or more routes by which an invasive species is transferred from one ecosystem to another.
An organism that grows, feeds, and is sheltered on or in a different organism while contributing nothing to the survival of its host.
Precautionary approach
Measures to implement the Precautionary Principle. A set of agreed cost-effective measures and actions, including future courses of action, which ensures prudent foresight, reduces or avoids risk to the resources, the environment, and the people, to the extent possible, taking explicitly into account existing uncertainties and the consequences of being wrong.
Range extension
The enlargement of a geographic area that is occupied by a species, usually through intentional human action; the extension is usually incremental, over short distances and contiguous.
The probability of a negative or undesirable event occurring; the likelihood of the occurrence and the magnitude of the consequences of an adverse event; a measure of the probability of harm and the severity of the hazard.
Risk analysis
The process that includes risk identification, risk assessment, risk management and risk communication.
Risk assessment
The process of identifying and describing the risks of introductions or transfers of aquatic organisms having an effect on fisheries resources, habitat or aquaculture in the receiving waters before such introductions or transfers take place; the process of identifying a hazard and estimating the risk presented by the hazard, in either qualitative or quantitative terms.
A group of interbreeding natural populations that are reproductively isolated from other such groups
A population of organisms which, sharing a common gene pool, is sufficiently discrete to warrant consideration as a self-perpetuating system which can be managed
The movement of individuals of a species or population of an aquatic organism from one location to another within their present range
The physical means by which a species is transported from one area to another, usually referring to transport by humans.


  1. International Joint Commission, Alien Invasive Species and Biological Pollution of the Great Lakes System, 2001.
  2. Environment Canada, Toward a National Plan on Invasive Alien Species: A Discussion Document, 2003. Of the 16 species for which information is available, the economic value noted reflects the economic costs associated with 9 species. The effects of the other 7 species are considered negligible.
  3. United States National Invasive Species Council, Meeting the Invasive Species Challenge, 2001
  4. Environment Canada, Toward a National Plan on Invasive Alien Species: A Discussion Document, 2003.
  5. Environment Canada, Canadian Biodiversity Strategy, 1995
  6. Standing Committee on Fisheries and Oceans, Aquatic Invasive Species: Uninvited Guests, 2003.
  7. International Joint Commission, Alien Invasive Species and Biological Pollution of the Great Lakes System, 2001.
  8. International Joint Commission, Alien Invasive Species and Biological Pollution of the Great Lakes System, 2001.
  9. Kristine Maki and Susan Galatowitsch, Movement of invasive aquatic plants into Minnesota (USA) through horticultural trade, Biological Conservation, in press, 2003.
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