by Brandon Peoples
The media likes to make a big deal about invasive species. We’ve seen plenty videos of jumping carp, documentaries about Red Lionfish, and photos of pipes choked by zebra muzzels. But what about the other aquatic invaders, the ones that sometimes sneak past the headlines…the species that may even be threatened in their native range? Today, I highlight a few of those–some of my favorites from the USGS Nonindigenous Aquatic Species database. Browse the database for yourself–you’re liable to find something surprising!
American shad have experienced massive population declines on the East Coast due to dams, habitat degradation, and overfishing. In fact, harvest of any American shad is illegal in many East Coast states. However, American shad have become established in several major Pacific tributaries, where they were stocked heavily the 1800s. High densities of American shad can compete directly with commercially important populations of salmon, sometimes drastically reducing food sources.
Smallmouth bass are one of the most popular sport fishes in the US, and are personally one of my favorite fishes. Smallmouth are native throughout the Mississippi River basin, and are carefully protected by fishing regulations in their native range. But popularity comes at a cost. These voracious predators have been introduced around the world, and have affected native fish communities from Japan, to South Africa, to Arizona.
Brook trout are heralded by angling purists as the gem of Appalachian streams. Brook trout are highly sensitive to temperature changes and sedimentation from deforestation. They are imperiled in several parts of their native range, and millions of dollars and work-hours have been devoted to restoring this charismatic clear-water beauty. But brookies are an unwelcome member of Rocky Mountain stream fish communities, often replacing and/or displacing native species of Cutthroat trout. Biologists in the East are fighting to keep Brook trout around, and biologists in the West are trying to get rid of them!
Pumpkinseed is a colorful and welcome addition to many a pond fishing experience. But these are one of the nastiest invaders in European waters, wiping out invertebrate food sources and out-competing native species.
Goldfish seem completely harmless in your home aquarium. But when you can’t take care of them anymore and release them into a nearby waterbody, these east-Asian natives can establish considerable populations. In some waterbodies of the American West, goldfish can grow to massive sizes and can have detrimental effects on native species.