The National Park Service defines a invasive species as a non-native organism whose introduction causes or is likely to cause economic or environmental harm, or harm to human, animal, or plant health.
It is often thought that the terms 'invasive' and 'non-native' can be used interchangeably, but this is not always true. For a plant or animal to be invasive, it must do harm. Simply being non-native is not cause for concern. The National Park Service actively manages those non-native species that do harm.
Understanding the difference between invasive and non-native species and when a species is managed is crucial.
...and when a species is non-native
Non-native species are those that have occurred outside of their natural range. That natural range could be as far as another country or as near as a different region of the same country.
Unlike invasive species, non-native species may not hinder or prevent the survival of others within the ecosystem. They simply exist where they have not naturally occurred. Other terms used for non-native species include 'exotic' or 'alien' species, but these are often discouraged terms, as they may imply another meaning.
You might even recognize some non-native species of plants in your own backyard or on your dinner table. Non-native species such as petunias and tomatoes, present no threat to native plants and have been cultivated by humans for centuries.
Link to source: https://www.nps.gov/subjects/invasive/learn.htm
I don't blame the State conservation agencies for being cautious about the invasion of snakeheads. Remember, the Hudson, Delaware and Chesapeake Bays are key spawning areas and nursery waters for the Atlantic striper population.
No one knows what the long-term effects will be in the bays or in any other waters now populated with snakeheads since their native range is Asia.
