Invasive Species, the Pests Who Come to Dine
By Senator Lisa Murkowski
Most Alaskans - understandably - consider themselves fortunate to live here.
We are blessed to be a part of the largest, wildest, most beautiful and most exciting State in the Union.
And among our many blessings has been freedom from the worst kinds of exotic invasive species, such as the zebra mussels that plague other regions of the country, for which we can thank the influences of distance, climate and foresight.
Unfortunately, we cannot be completely free of invaders that can threaten our own indigenous plants and creatures, nor are we free of the responsibility to prevent dangerous organisms from gaining a foothold. Among the most dangerous are aquatic invasive species, because their colonies may go unnoticed until they are well-established and harder to eradicate.
Alaska has strong laws to prevent exotic species from becoming permanent residents. It's too bad such laws only work to deter species carried by humans that are paying attention.
Some species may find humans willing to help them out. The Northern pike now infesting Southcentral Alaska drainages come to mind, along with the yellow perch that someone either maliciously or ignorantly dropped into a lake on the Kenai. Luckily, the latter was discovered and eradicated - we think. Both species are capable of decimating native fish, including salmon.
Plants can be threats, too. Aquatic species such as Japanese knotweed, Reed Canarygrass and Foxtail barley are colonizing in some parts of Alaska. Where they thrive, they can overwhelm Alaskan species. They don't care that they were supposed to be ornamental additions to someone's garden; once they reach the wild, they are on their own.
But the worst threat may be from species that are only too happy to find their own transportation to Alaska, can't read the laws, and are adept at hitchhiking to new places.
A number of aquatic invasive species - and I might add, at least one non-aquatic species of significant concern - have found their way to Alaska already. Others are near our border, and still more appear to be working their way in our direction.
Atlantic salmon - escapees from salmon farms in British Columbia or Washington Stateare yet another threat. They have been found in streams from Southeast Alaska to Prince William Sound, and in ocean waters as far north as the Bering Sea. Natural reproduction of escaped Atlantic salmon has been observed in British Columbia streams, and it is possible this species could someday find a foothold in Alaska that would be disastrous for any Pacific salmon stocks that shared the same streams.
Several other species have not yet been observed in Alaska, but are considered imminent threats, and Prince William Sound may be where they will show up first.
The European green crab is an example; it became established in California and has already moved as far north as Vancouver Island. Although small, it is highly aggressive, and preys on juveniles of other crab species, as well as on clams, mussels, urchins, other fish and plants. In Alaska, all the major crab species - king, Dungeness and Tanner - could be at risk if it becomes established here.
Another is the Chinese mitten crab, which is now at home in the San Francisco area and may be moving northward. One specimen has been found near the mouth of the Columbia River. Because this creature comes into fresh water to spawn, potentially moving hundreds of miles up rivers, it is a serious threat.
Larvae of both crab species could travel in ballast water entering Alaska from Outside. Valdez Harbor is especially vulnerable, as it receives the third-largest volume of ballast water of any U.S. port, due to the regular arrival of tankers filling up on Alaska North Slope crude, many of which arrive from ports already infested with invasive species. This is a significant and continuing threat, although to date only a small number of problems have been detected.
I strongly support continuing efforts to develop technologies and practices that will meet this challenge. Among the promising ideas is a new method of introducing ozone into ballast water both when it is pumped aboard and when it is discharged, which has so far shown excellent results in removing small biological hitchhikers. I want to note this is research that has been funded by the oil and gas industry - British Petroleum to be precise. The industry's willingness to step forward on this issue should be recognized and applauded.
Another technology under development was originally intended to limit the quantity of oil that would spill from a holed tanker hull by establishing a negative pressure gradient in the hold, but is now being investigated as a means of eradicating invasive species as well. The spill control application involves both reducing air pressure in the tank, and layering inert gas over the oil to control fumes. In a hold used for ballast water, the pressure reduction, combined with the introduction of inert gas via "bubbler" pipes near the bottom, creates an oxygen-poor environment that may effectively kill a variety of unwanted species, including some too large and hardy for ozone treatment.
Each of these technologies, and others currently being developed, have a long way to go before they can be considered adequate solutions. But the fact that they are being developed is positive. The problem of aquatic invasive species is not being ignored, and the government's obligation to address it will not be overlooked.