When I started writing about the threat posed by Asian carp years ago, I received an angry letter from a reader. He was 75 years old, he said, and he had seen carp in our waters since he was a child.
In short, he wanted to know why I was trying to scare people about something that “is no big deal.”
What I quickly realized was that he didn’t realize that I was writing about silver and bighead carp, which started spreading through our rivers about 20 years ago. He thought that I was referring to the common carp, which has been around for more than a century.
Now here’s the kicker: The common carp is an introduced exotic species also. But it has become so pervasive in our waterways that most people, including that reader, don’t realize that it’s also an invader.
They don’t know of the damage that it’s done by disrupting ecological balance in our fisheries, notably degrading water quality, crowding out native species, and uprooting beneficial vegetation.
Twenty or 30 years from now, will we also accept the damage done by Asian carp, zebra mussels, and dozens of other invaders as “normal”?
Maybe the following will help us remember:
Lionfish Gobbling Up Native Species
Originally from the Indian and Pacific oceans, lionfish now are spreading throughout the Caribbean, as well as up the Atlantic Coast. Likely they were accidentally introduced into North American waters by the aquarium trade during the 1990s.
Lad Akins of REEF, a marine conservation group says this:
"They are eating almost anything that fits in their mouth. The lionfish can probably consume in excess of half of its own body size. They can take quite large prey.”
"I'm an optimist but potential impacts of lionfish could result in major shifts in the ecology of our Caribbean and West Atlantic reef barriers. It could result in the extinction of some fish species."
Eagle Deaths Linked to Exotic Plant
Bald eagles are dying because of hydrilla, an exotic plant that can provide good fish habitat, but often becomes so dense that it smothers native aquatic species and prevents boating and outdoor recreation.
Most recently, eight eagles were found dead of avian vacuolar myelinopathy at Lake Thurmond on the Georgia/South Carolina border. Eleven died there last year.
The disease is caused by an alga that grows on the hydrilla. Small birds consume the alga and, in turn, are eaten by the eagles.
Invasive Pythons Now Targeting Everglades Birds
Even as they decimate native mammals in the Florida Everglades, Burmese pythons also have begun feeding on birds and their eggs.
Researcher Carla Dove says this:
“This finding is significant because it suggests that the Burmese python is not simply a sit-and-wait predator, but rather is opportunistic enough to find the nests of birds.
"Although the sample size is small, these findings suggest that the snakes have the potential to negatively affect the breeding success of birds.”
Exotic Mussels Choke Off Access
Mounds of zebra mussel shells are creating barriers to boating, as well as blocking fish and fresh water flow in Wisconsin’s Lake Winnebago.
One lakefront property owner says this:
"The channels have become where they won't be able to be used in a couple years. I bought my house because it has great access to the lake. If I can't get access, the property's useless."