In July, says Donald Boesch, president of the University of Maryland Center for Environmental Research, experts decided that the best way to deal with the fish was to deal death to it. Boesch headed a panel charged with deciding the fish's fate.
The weapon of choice, the insecticide rotenone, has widely been used to kill unwanted fish in other lakes. By the time you read this, eradication efforts may be under way.
Such "fish improvement" schemes have distributed troublesome exotics like northern pike and grass carp.
If the quick attack on the snakehead succeeds, it will offer more evidence for the benefits of responding to invasive species before they can occupy considerable terrain. As a second example will show later in this story, the economic and ecological costs of dealing with a nascent invasion are minuscule compared to the cost of a statewide, let alone nationwide, campaign.
While the chances of success in this instance are good, the intense interest in the snakehead (the "Frankenfish" can supposedly hike overland and live out of the water) may have benefits. Boesch sees the storm of attention as "a teaching moment, a poster child for the problem" of invasives. Indeed, Gale Norton, Secretary of Interior, has proposed to ban importation of snakeheads.
But does that demonstrate that the lesson of the snakehead invasion has been learned? As we'll see in our focus on "least wanted" exotic species, the problem extends far beyond one "Frankenfish" that happened to be dumped in a pond that happens to be near the capital city.
For his part, Boesch wants far wider action against invasive exotics. "There are all sorts of avenues for introduction, and there needs to be a broader approach" to control, he argues.
In other words, why close only the retail drip when the wholesale spigot is gushing?
By the shipload
When we say invaders, we are thinking about lots of organisms:
The key advantage of invaders largely results from transportation. Typically, invaders don't have to face natural controls -- the insects, diseases, competitors and predators that establish the loose "balance of nature" in undisturbed ecosystems. Over centuries in the new location, new controls will evolve, but until then, invader populations can skyrocket, with disastrous results.
Can we sell you an analogy? If the snakeheads were a retail invasion, ballast water invites wholesale invasions. While controls on ballast water now exist in the Great Lakes and elsewhere, they are unevenly enforced.
Bay held at bay by blasted ballast
Many parts of the Bay are dominated by invasives. Andrew Cohen, an environmental scientist at the San Francisco Estuary Institute, a nonprofit research and monitoring group, says, "In many components of the most important habitats, in biomass and in numbers of individuals, 90 to 95 percent" are exotics.
The scale of invasion beggars the imagination. "On almost all of the bay bottom, many tens of thousands of acres, more than 90 percent of the biomass was already exotic a few decades ago," says Cohen. He adds that similar dominance appears among zooplankton -- floating animals that are near the bottom of the food chain. Most species came from Asian hitchhikers carried in ballast water.
The situation is grim, says Cohen. "Could we restore the Bay to something resembling the native species? Probably not. We probably won't find methods to remove the well-established exotics."
However, he points out that slowing the invasions may help some relatively pristine ecosystems by shifting the balance toward natives in places like salt marshes, where plants are subject to mechanical or chemical killing.
That, in turn, would help other components of the ecosystem. "We may have lost the muddy bottom, but we could still save the saltwater fish as a natural community," Cohen concludes. But only if the wholesale invasion of exotics in ballast water is slowed, he adds.
What else invades the ocean?
©2002, University of Wisconsin, Board of Regents.