DEFINITION: (source -
https://www.nationalgeographic.org/encyclopedia/invasive-species/)
An invasive species is an organism that is
not indigenous, or native, to a particular area. Invasive species can cause great economic and environmental harm to the new area.
Not all non-native species are invasive. For example, most of the food crops grown in the United States, including popular varieties of wheat, tomatoes, and rice, are not native to the region.
To be invasive, a species must adapt to the new area easily. It must reproduce quickly. It must harm property, the economy, or the native plants and animals of the region.
Many invasive species are introduced into a new region accidentally. Zebra mussels are native to the Black Sea and the Caspian Sea in Central Asia. Zebra mussels arrived in the Great Lakes of North America accidentally, stuck to large ships that traveled between the two regions. There are now so many zebra mussels in the Great Lakes that they have threatened native species.
Introduced Species
Some species are brought to a new area on purpose. Often, these species are introduced as a form of pest control. Other times, introduced species are brought in as pets or decorative displays. People and businesses that import these species do not anticipate the consequences. Even scientists are not always sure how a species will adapt to a new environment.
Introduced species multiply too quickly and become invasive.
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My thoughts...
So, brown trout are introduces then outcompete native brook trout. It's situational. Brook trout are invasive out west.
Here's the rub: Just because a fish we revere (smallmouth bass, brown trout, etc.) is invasive, it does not automatically follow that we should ignore the potential damage that can be causes by snakeheads. That's a little bit like saying "I got fat by eating too many burgers. What harm could ice cream do?"
Or, to be more simple and direct: two wrongs don't make it right.
Using already established invasive species as a rational for promoting a new invasive is wrongheaded.