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Aquatic invasive species (AIS) (also referred to a aquatic nuisance species or ANS) are aquatic animals and plants that have been introduced into waterways in which they do not live naturally. They have harmful effects on the natural resources in these ecosystems and the human uses of these resources.

Introduction to AIS - PA Sea Grant video

In addition to the banned species below, some of the least-wanted AIS in Pennsylvania are: New Zealand Mudsnail, Sea Lamprey, Hydrilla, Spiny Water Flea, Eurasian Watermilfoil, Asian Clam, and Red-eared Slider (turtle). In 2004, northern snakehead (ID poster) were first found in Pennsylvania waters.

It's not always "foreign invaders" that are the problem. White perch and flathead catfish are other examples of species that have turned up where they don't belong. While native to some PA watersheds, they have been introduced to other areas where they are not wanted.

Aquatic species banned in Pennsylvania (sale, barter, possession or transportation)

    • Bighead carp (Hypophtalmichtys nobilis)
    • Black carp (Mylopharyngodon piceus)
    • Crayfish (all species) except when they are either transported:
      (i) As bait on, in or about the water from which taken.
      (ii) For testing and scientific purposes or restaurant consumption, adequate measures have been taken to prevent their escape and they are accompanied by documentation stating the point of origin and the destination to which they are to be delivered.
    • European rudd (Scardinius erythropthalmus)
    • Quagga mussel (Dreissena bugensis)
    • Round goby (Neogobius melanostomus)
    • Ruffe (Gymnocephalus cernuus)
    • Silver carp (Hypophtalmichtys molitrix)
    • Snakehead (all species) (ID poster)
    • Tubenose goby (Proterothinus marmoratus)
    • Zebra mussel (Dreissena polymorpha)


    • Biodiversity -- The variety of species, their genetic makeup, and the natural communities in which they occur.
    • Introduced species -- A species living outside of its natural geographic range. Can be deliberately or accidentally introduced or brought into the new ecosystem. Also called exoticnon-nativenuisance or invasive species.
    • Invasive -- Spreading or taking over. Invasive species often take over or dominate a habitat.
    • Native -- An animal or plant originating in a region or geographic range. For example, brook trout are native to Pennsylvania.

STOP the spread of AIS

    • When retrieving your boat for the day, check the boat, motor and trailer for weeds and other things "tagging along."
    • Wash your boat's hull with hot water or with a high-pressure spray.
    • Drain livewells, bilges and other compartments.
    • Drain all standing water from your boat.
    • Don't dump leftover bait into the water you're fishing, unless you collected the bait there.

For more on cleaning boats and gear, visit our Clean Your Gear page.



Rusty Crayfish
Photo credit: USGS



Quagga Mussell
Photo credit: Wikimedia Commons



Round Goby
Round Goby