Aquatic Invasive Species

The United States of America has often been called the “melting pot” of the world, as it accepted people from all parts of the globe. However, an undesirable byproduct of such mixing was the introduction of many different species. While some people intentional bring exotic animals and plants to this country, an exponentially larger number are transported unknowingly. The current world is incredibly connected; even the landlocked ports of the Great Lakes can be associated with ports in Egypt, Australia, and Argentina. In fact, Dr. David Lodge demonstrated how the laurentian Great Lakes are connected to such ports by a maximum of four degrees of separation. Along their journeys, the ships have a tendency to pick up hitchhikers and other unwanted passengers. Even though most of these species aren’t able to survive due to differences in salinity and temperature, those that do survive are incredibly resilient. Their effects have already proven costly, such as the Zebra Mussel infestation in the Great Lakes. Additionally, San Francisco Bay has become the ultimate melting pot for different species, as noted in Dr. Lodge’s lecture.

How can we control this problem? Federal regulation seems to be the best starting point, but enforcement is the largest issue. Treatment or replacement of ballast water proves promising, as the removal of species offshore could help preserve the ecosystems of our port cities. However, until these systems become cost effective, many shipping companies would either forget or simply refuse to implement them. The Coast Guard in conjunction with Port Authorities would be the general enforcing agents. Legislation regarding which species may be brought in is much more clear cut and straightforward than which species are barred from our borders. The Lacey Act is a prime example of the ultimate failure to protect our natural habitats from invaders (other than ourselves). While this would be time-consuming, it would prove very cost-effective and allow researchers to model the effects of different species introduction. These are just a few of the many ways to protect our borders. Above all, the greatest asset to limiting foreign species invasions is clearly the enforcement of current laws, and the formation of stricter ones to preserve our native species.

-Evan Schwartz

Many attempts have been made to try and control the spread of aquatic invasive species and not went as well as intended, one of which being legislative doctrines such as the Lacey Act. These doctrines, the Lacey Act in particular, have proved to be quite ineffective. This is not only because the Lacey Act lists a mere nineteen species, but also because most of the species listed were already established in North America at the time when they were included in the Act. Congress apparently takes much too long a time when passing new amendments to the Lacey Act to make it an effective doctrine. This is why targeting the invasive species problem on the trade regulation level is a more effective path.

Stricter food and drug trade regulation laws with other countries seem to be one of the best methods to go about solving the aquatic invasive species problem. Many people oppose the inspection of each ship that comes into North American ports because it is relatively costly. However, it seems to be the safest route, since according to Lodge’s lecture nearly every port in the world is connected to a body as small as the Great Lakes by only four degrees of separation. This means that, due to the incredible connectedness of the world’s shipping industry, any single port can feasibly receive goods from nearly any other port on the planet Earth! For this reason, it does not seem as if one could possibly classify any water body as a “danger zone” since the world’s ports are apparently so connected. Therefore, it appears that, although costly, more rigid trade inspection and regulation laws are necessary, even if it means the inspection of every ship that comes into North American ports.

According to Dr. David M. Lodge’s lecture about science on the front lines of invasive species management and policy on March 16, 2009, at Duke University, the United States’ current system for invasive species control is not adequate and needs reform. One of the principles of Lodge’s argument involves taking a new perspective and looking at invasion potentials in probabilistic terms. Lodge claims that the invasion process can be broken up into successive steps that include, in order, the introduction of the species into a pathway, the transport and release a living specimen, the establishment of the invading population, that population’s spread, and finally concluding with ecological, human health, and economic impacts. Lodge’s new suggestion to controlling invasive species involves attention to and analysis of each individual pathway individually. He claims that the probability of a successful invasion is the combination of the probabilities of each step in the invasion process. Thus, in order to more effectively target invading species, the focus should be on the step with the highest probability, followed by combating the steps with the next highest probabilities. This way, only the most beneficial approaches will be focused on first. According to Lodge, recent scientific advances allow accuracy in specific species risk assessment up to eighty and ninety percent, so the future for this method of controlling invasive species is very promising.

To this point, the United States has had some success in invasion control using geographic modeling and environmental matching techniques. Lodge and colleagues have performed a great deal of research analyzing the temperature and salinity conditions of ports throughout the world. The results of their studies have been effective in determining the risk of invasion of aquatic species, including the zebra mussel, at various locations throughout the U.S. However, this is one of the few bright spots in U.S. control of invasive species because there are many more problems than effective solutions. First of all, there are few importations restrictions in the United States, and because of the rapid growth of globalization, there is a huge issue over control of shipping. The Lacey Act has failed to accomplish its main purpose, as it is ineffective at preventing the importation of invasive species. The few restrictions on importations that do exist are primarily motivated by the desire to protect humans (primarily from disease); also, animals are easily transported because they are considered innocent on charges of invasion ability unless already proven guilty. Furthermore, Lodge notes that policy to control both national and international trade is a long time coming. The better solutions to these outlined problems are early detection and rapid response. One technique that has been proposed by Lodge to fight the high Asian carp density in the U.S., which might be higher than its native population density, is the use of eDNA sampling. This would be an example of early detection because if the presence of an invasive species can be determined before its full-fledged invasion, the species can be more easily controlled. Rapid response is also key to eliminate the threat before it becomes too widespread.