Aquatic Invasion Background

    Aquatic Invasion Background

    Invasive species are organisms that did not originally inhabit an ecosystem (sometimes called non-native) whose introduction causes, or is likely to cause, harm to the economy, the environment, or human health. Not all non-native species are considered invasive, since many non-native species are not able to spread or reproduce once introduced to a new habitat and do not cause harm. Additionally, some non-native species provide economic benefits, like crops, and are not considered invasive.

    Invasive species may prey upon, displace or otherwise harm native species. They may also alter ecosystem processes, transport disease, or cause illnesses in animals and humans.  Invasives can affect the commercial, agricultural, aquacultural, and recreational activities dependent on such waters, resulting in severe economic impacts. Control of invasives can be extremely difficult once they are established. 
    Many natural barriers exist which help isolate species and prevent their introduction into new regions. Invasive species must overcome barriers in the environment that would otherwise prevent their spread. 

    These barriers are:

    Geographic barriers such as a mountain range, ocean or river that prevents easy movement from one area to another and  separates different habitats.

    Survival and establishment barriers are environmental features that prevent an introduced species from thriving. These might include soil moisture and pH for plant species, water temperature, pH, or salinity for aquatic species.

    Human activities are often the culprit in introducing and perpetuating the spread of invasive species. Here are some examples of human activities which have served as pathways for spreading invasive species:

    Illegal fish stocking: Illegally introducing a non-native fish into a water body.

    Legal stocking: Legally introducing a non-native fish into a water body, usually for recreational fishing, or for population controls on other fish.

    Ships and boats: To stabilize ships, water is often taken into a ballast tank.  Aquatic organisms can be taken in and transported in this ballast water.  Organisms can also be transported by attaching to the outside of the ship itself, this is called hull fouling.

    Ornamental plants: Some ornamental plants can spread into the wild and become invasive.

    Pet trade: Intentionally or accidentally releasing pets into their non-native habitat.

    Wood: Insects can get into wood, shipping palettes, and crates that are shipped around the world.

    Agriculture: Invasive pests and diseases can be transported across US borders through the commercial or personal transport of agricultural items, such as fruit, vegetables, and plants.

    Improperly cleaned equipment: Fieldwork and recreational activities can unintentionally spread invasive species on the equipment that is used.

    Dispersal and spread barriers are natural or constructed blockades such as a wall of vegetation on land or a barrier of electricity in water. These are made to prevent rapid dispersal and spread from the site of establishment.

    For more information on aquatic invasive species please call the Division of Wildlife Resources at (801) 538-4700 or see:

    Invasive Mussels: Threats and prevention efforts in Utah (Utah Division of Wildlife Resources)

    Invasive Species Fact Sheet (The Ecological Society of America)


    When retiring classroom animals be sure to:
    o Give the animal to another responsible teacher 
    o Return it to the place where it was purchased (perhaps make prior arrangements to do so)
    o Keep it as a classroom pet 
    o Donate it to your local natural history museum, zoo, or aquarium (check before you acquire the animal)
    o Humane euthanasia (contact your local veterinarian for advice)