World's Worst Invasives


More than half a dozen of the 100 of the World's Worst Invasive Species are present in Nova Scotia.

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    Future Threats

    Currently, there is no single “go-to” list of potential invasive alien species that may become established in Nova Scotia in the future. ISANS is working with experts to develop “watch lists” of ecologically important invasive terrestrial and aquatic organisms that are not known to occur in Nova Scotia yet, but are known in similar climates and/or neigbouring regions.

    In the meantime, please click on a species to learn more about these high-profile North American invaders, all of which have the potential to establish in Nova Scotia. Links lead to a variety of resources: some Nova Scotian, some Canadian, some US, and some international.

    Asian longhorned beetle (Anoplophora glabripennis)

    Asian gypsy moth (Lymantria dispar dispar)

    European swallow-wort/dog strangling vine (Cynanchum rossicum/Vincetoxicum rossicum AND C. louiseae/V. nigrum)

    Chinese mitten crab (Eriocheir sinensis)

    Eurasian water-milfoil (Myriophyllum spicatum)

    European frog-bit (Hydrocharis morsus-ranae)

    F. & K. Starr, USGS,

    (Pueraria montana)


    R. Westbrooks, USGS,

    zebra mussels
    (Dreissena polymorpha)


    D. Cappaert, MSU,

    emerald ash borer
    (Agrilus planipennis)



    didymo or rock snot
    (Didymosphenia geminata)

    Watch a youtube video introduction to didymo, produced by New Zealand Fish & Game: