These Animals Can Cause Big Trouble. Why Are States Unleashing Them by the Millions?

When animals that aren’t native to an area harm the environment, we usually label them as invasive and consider them bad. State wildlife agencies spend tens of millions of dollars a year trying to eliminate them.

That makes this fact peculiar: Those same agencies also regularly and purposefully release nonnative fish into the environment that, in many cases, damage local ecosystems.

The reason for this apparent contradiction is that anglers everywhere want something nice to catch. Many US streams, ponds, and lakes no longer support healthy native fish populations, or never did. Without flooding them with brown trout, rainbow trout, largemouth bass, and a whole host of other nonnative species, there wouldn’t be much to fish.

A more complex explanation is money: The very revenue streams that fund state conservation come in part from selling fishing licenses. Stocking nonnative fish helps states sell more of them.