Point 18: Resist Exotics

[Tim Smith]

18. We support measures designed to prevent, contain, mitigate or eradicate exotic species that threaten smallmouth bass or the systems they inhabit. We do not support control measures that represent a significant threat to the continued survival of native species.

[Tim Smith]

Exotic species have the potential to make vast and unanticipated changes in the systems where they are introduced.

 

This dynamic has played out enough times to become a basic ecological principle. If you're from North America you've seen the effects of zebra mussels, european starlings, autumn olive, Japanese honeysuckle, purple loosestrife, kudzu, asian carp and rusty crayfish. You should have an intuitive idea about how profoundly exotic species can affect the landscape. They can decimate a fishery and drive other species extinct.

 

What exactly is an exotic species? It's a species that's a newcomer to an ecosystem. It has no long-term evolutionary history in an ecosystem. It's a species to which other native species are not adapted.

 

Notice a few things here:

 

1. The critical point here is that evolution and adaptation are what make an animal "exotic".

 

2. Being an exotic speices has nothing to do with whether or not that species was spawned in that setting. An animal is not "native" simply because it was born in a particular setting. Nor does having a few dozen or even a few hundred years of existence in an ecosystem make a species native. Evolution takes a long time.

 

I realize there are still a few people around who's skin crawls at that word "evolution". If that word is causing you to reject this idea...please hear me out. Even the Young Earth Creationists acknowledge the existence and importance of natural selection. The environment favors some traits and eliminates some others. That's evolution. That's what we're talking about here. Natural resource management has wasted enough time accomodating our accumulated societal stupidity on this point.

 

3. Some of you with a broad knowledge of the effects of sportfish introductions will find it a bit ironic that conservation principles for smallmouth bass would inveigh against exotics since smallmouth bass themselves have often been that exotic species negatively affecting local species.

 

True. Sport fish can be exotics just like everything else. Movement of sport fish outside their native range to "improve" fisheries is an exercise for the simple minded. Don't do it. If you do, you're taking unecessary risks with systems millions of years old. A lot of bad names could be applied to people who do that. Just assume here I've called those people those names and save me the trouble of actually doing it.

 

Smallmouth bass and other sport species have a native range too. Introduced species like spotted bass and Eurasian milfoil and rusty crayfish and various diseases have had demonstrably negative effects on smallmouth bass fisheries inside their native range. The hope of these philosophies is that they foster an ethic that keeps sport species inside their native ranges and out of habitats where they would not normally occur without human intervention. Reverse bigotry against a species in its' native range merely because it is a warm-water top predator sport fish predator is tiresome in the extreme. Smallmouth bass are potent exotics outside their native ranges. That doesn't invalidate their role as a native species inside their range.

 

4. Not every exotic species will cause havoc. Some will. The tools available to make predictions in ecosystems are weak. Assume species transfers outside their native range will cause problems. Resist their spread. If economical means become available to contain them, employ those.

 

5. Modern fisheries may have a positive role to play. In a few limited cases it might be possible to target and reduce exotic species with catch and kill tactics. Anglers can reduce the average size and sometimes the density of fish populations in the right context. This may be an especially viable approach in low production areas where a high total fishing pressure can be brought to bear on the system.

 

6. Always keep in mind that a "naturalized" population of exotics is still doing damage. Problems from exotics don't go away in a generation or two. It generally takes a long, long time for local ecosystems to adapt to new and influentital species. In most cases the damage is irreversible. Superfund projects spend hundreds of millions of dollars to remove radioactive toxins from the environment. Genes and species have vastly longer half-lives than that.