Aquatic Invasive Species

Daphnia lumholtzi, an exotic zooplankton, has invaded freshwater systems throughout the southern and midwestern United States. A study done by Dzialowski et al 2000 conducted regional surveys of eastern Kansas reservoirs to document the range of expansion of D. lumholtzi. It was found in five out of 35 reservoirs sampled in 1994, and 11 out of the 35 reservoirs when re-sampled in 1997. In addition, 40 small ponds inaccessible to recreational boats were sampled, where no D. lumholtzi was found. This suggests that non-human dispersal mechanisms play an insignificant role in the spread of the species.

This study suggests that further experimentation is needed to determine if the absence of D. lumholtzi from these ponds is due to insufficient dispersal mechanisms or the species’ inability to colonize in this environment.

Dzialowski A.R., O’Brien W.J., and Swaffar S.M. 2000. Range expansion and potential dispersal mechanisms of the exotic cladoceran Daphnia lumholtzi. Journal of Plankton Research. Volume 22. Issue 12: 2205-2223.

In the never-ending battle to prevent blood-sucking sea lamprey from wiping out some of the most popular fish species in the Great Lakes, experts are developing a new method of control that uses the invader’s dead body.

The sea lamprey releases some sort of chemical “repellent” when there is mechanical damage done to the skin due to events such as predation. This repellent acts as a warning to other fish in the area to stay away from the potential danger in that direction. Area avoidance as a result of injury-released chemical alarm cues has not been sufficiently studied. Therefore, Xiangyu Wang and his team of scientists are investigating the effects of dead lamprey on migrating lamprey. “It may be possible to counter the lampreys during their mating season by neutralizing the hormones that attract them to their mating grounds by releasing some sort of lamprey repellent at the mouth of particular streams and tributaries,” says Wang.

Wang had done previous work on lamprey larval release of hormones. His interest in sea lampreys came from the fact that they are an ancient species of fish that has been unchanged for millions of years. “This is what makes them so successful,” says Wang. Therefore, he and his team of scientists decided to investigate the species further.

His study will use a Y-shaped water maze with dead lamprey extract continuously injected into one end. The lamprey will have a choice to either swim up the passage in which dead lamprey extract is present or to swim up the passage in which nothing was added. According to Wang, “There is a good chance that the lampreys will respond to the dead fish extract.” If this proves to be true, the team’s next step would be to specifically isolate the chemical that is causing this response and determine an effective method at spreading it. If distributed around spawning grounds, reproduction could be severely reduced and the problems associated with these leech-like creatures would hopefully be alleviated. If lampreys can not find suitable habitats to breed, then their populations will be brought under control.

Complete eradication may not be possible, but the goal is to keep the lamprey numbers low enough to prevent significant harm to the 7 billion dollar Great Lakes fishing industry. Although native to the Atlantic, they can live in fresh water and migrated to the Great Lakes through shipping canals. By the late 1940s, the prolific invaders had decimated trout, whitefish and other sport and commercial species across the lakes. They have dramatically decreased the populations of many  other species of local game fish and hurt the livelihoods of many fishermen.

“They are parasites that feed on the blood and flesh of fish. With their destructive ways they have had a large impact on fish population,” states Wang. This is why research on the sea lamprey has continued to grow; a need for an effective method of control is imminent.

“The results of this study will pave the way for a method to be developed that is effective and has a low impact on the environment,” says Wang. In addition, he expects that his method will improve previous protocols. By using a maze with flowing water instead of a tank, Wang and his team will be able to more accurately model the reaction a lamprey would have in the wild.

The Indo-Pacific lionfish (Pterois volitans) has spread rapidly around the Caribbean basin and is now one of the most abundant predators of its size on invaded Bahamian coral reefs. To fully understand the cumulative impact of lionfish on these newly invaded areas, Stephanie Green from the Simon Fraser University and her colleagues collected data on lionfish density, size distribution, and diet from 13 invaded coral reef sites off the southwest coast of New Province, Bahamas from May though September 2008.

Their analyses revealed that the invasive lionfish populations far exceed sustainable levels on the majority of coral reefs studied. The main tool being considered by managers to control the fish is manual removal by divers.

Green, S. and I. Côte. (2010) Consumption Potential of Invasive Lionfish (Pterois volitans) On Caribbean Coral Reefs. Gulf and Caribbean Fisheries Institute 62:358-367.

Paul Jordan did an outstanding job of analyzing the relationship between religion and popular culture in his Writing 20 paper, using the examples of Borat and Saved!. The introduction grabbed my attention right away, describing a scene from Saturday Night Live. Throughout the paper, Jordan elaborates on satire’s ability to engage the public in broad cultural discussions, specifically surrounding religion. He describes how satire provides a protective “shield” that renders authors able to express their opinions over taboo topics in an “unfiltered” manner. This blatant honesty fosters the reflection of audiences over more serious topics such as religious prejudices.

The points that Jordan made were quite shocking, yet entirely true. A large percentage of the population learns about world affairs, religion, and politics through offensive (yet comical) shows like South Park and SNL. Two years ago I watched that same SNL skit that was described in my introduction; this caused a debate in my Theory of Knowledge class in high school. As ridiculous as it may sound, satire does provoke thought/debate.

Jordan uses two examples to expand upon his thesis: Borat and Saved!. In the movie Borat, Baron Cohen plays a homophobic, racist, misogynistic anti-Semite who comes to America as a reporter from Kazakhstan. As he travels across the United States, he commits a large number of socially crude acts and makes many negative racial and religious comments. The irony in it all is that Baron Cohen is a Jew. Therefore, according to Jordan, Cohen’s use of ironic satire “should be understood not as engendering of racial and religious hatred, but as a condemnation of these prejudices.” In this way, most viewers come away from the film with a sense that the absurd nature of the film ultimately points to something greater.”Exaggerated satire,” used in the movie Saved!, is described as also provoking reflection and evaluation of religious perceptions, biases, and stereotypes. This film takes place in a conservative fundamentalist Christian school, where the characters, who are supposedly “Christian jewels” that have a “holier-than-though” attitude, are hypocrites. While a character named Hillary Faye tries to seem like a “perfect Christian,” she is actually acting snobby and condescending. These images illustrate the inconsistency between fundamentalist beliefs about “loving thy neighbor” and the manner in which they actually interact with society.

Overall, Jordan sculpted an excellent essay, using specific examples, outside sources, and personal opinions. He also adds some of his own humor or “satire, ” to the essay, which makes it easy and very interesting to read. This paper caught my eye at first glance, and I could not put it down until I had read through the whole thing. A major reason that I enjoyed this paper so much was that I had seen Borat and Saved! before, so it was intriguing to look at them from a different perspective. While watching these films I didn’t realize how much I actually “learned” from them, but after reading this paper I agree that, in these cases, comedy provokes serious thought.

This paper was very different from my MWP1, which was written with a more scholarly tone. This topic was also very relatable, whereas my literature review was more directed towards scientists educated in the invasive species field. Science writing is definitely different than descriptive/opinion based writing; I often prefer the latter, however through this writing 20 class I have learned to appreciate scientific writing more as I have become more educated on the topics.

Militaristic language is often used when describing the impacts of invasive species on the environment. Larson (2005) argues that such rhetoric may ultimately be inadequate and lead to an inaccurate perception of these species. He argues that they contribute to social misunderstandings, loss of scientific credibility, and even race-related issues. Rather than use a warlike framework for invasive species, Larson suggests that they be conceptualized as a disease weakening the health of the ecosystem. This metaphor would better adopt a language that focuses on improving “quality of life” rather than emphasizing destruction (Larson 2005).

I have used a combative metaphor to describe an invasive species, the spiny water flea, in my first draft of my citizen science paper. The purpose was to draw the reader in, as well as describe the effect that the species could have on the environment by destroying the food chain (like an army invading in war). “Ballast water surges out of the side of the ship, carrying an army that is unseen by the human eye. Millions of barbed tail spines impel forward as one mass, well armed and seemingly unstoppable” (Naughton 2010). Although I did end up cutting this out of my paper, as it was not appropriate for the scholarly tone of the assignment, I do not think that it overemphasizes the danger of the species, or causes any sort of inaccurate perception.

In his argument, Larson exaggerates the use of militarism in invasion biology. To denote these metaphors as “class and race-based” seems absurd to me. His attempt to connect politics and social patterns with invasive species was quite extreme. I feel that warlike expressions are appropriate to describe the destructive mannerisms of the invasive species, as they can have affects that are detrimental to the environment/ecosystems. The rhetorical power of this language helps to generate action against the species and increase awareness. Using the alternative metaphor of a disease would have the same affect. I do not see much of a difference between the two metaphors, as they both are destructive and can both be “cured” or “solved with an alliance/defeat.” In conclusion, militaristic and combative metaphors within invasion biology seem fitting, as they illustrate species’ harmful affects on the environment, while drawing attention to the issues posed.

Larson, B.M.H. 2005. The war of roses: demilitarizing invasion biology. Frontiers in Ecology and the Environment 3: 495-500

Naughton, H. 2010. Citizen Science Commentary:O.F.A.H. Highlights Citizen Science with Spiny Water Flea Study.Writing 20 Aquatic Invasive Species.

The round goby, or Neogobius Melanostomus, is a small fish that was introduced to the Great Lakes in 1990. Since their arrival, many ecological changes have occurred, including a change in the food chain with their consumption of dreissenid mussels. This is influencing the benthic macroinvertebrate abundance, through predation, and could cause a collapse in the energy flow (food chain). Methods for evaluating the density and size of round gobies are lacking, preventing the true quantification of
the effects of round gobies on invaded ecosystems.  Therefore, in Lake Erie, a team from the Ontario Ministry of Natural Resources evaluated different sampling methods of the round goby, and then applied the best method to estimate the distribution and density of the species. It was found that a combination of angling and bottom trawling were the most effective methods of sampling. With these methods, an estimated 9.9 billion round gobies in Lake Erie in 2002 were found.

T.B. Johnson, M. Allen, L.D. Corkum and V. A. Lee. Comparison of Methods Needed to Estimate Population Size of Round Gobies (Neogobius melanostomus) in Western Lake Erie. Journal of Great Lakes Research. Volume 31, Issue 1. 2005. Pages 78-86.

The jellyfish population in the Mediterranean Sea is of concern to scientists, tourism officials, and beachcombers alike. Invasive jellyfish harm fisheries, by predating on fish eggs and larvae, as well as sting humans and impact tourism. Monitoring these species entails time and money. As a solution, the Mediterranean Commission (CIESM) launched a citizen science initiative, the Jellywatch Program, in the summer of 2009. Since then, new records of a species of jellyfish, Mnemiopsis leidyi, have been discovered along the Italian coast. Geographic coordinates, estimated abundances, and photos were submitted by citizens, allowing Ferdinando Boero and his team of scientists from the University of Salento to monitor their spread from the Black Sea.

The CIESM Jellywatch, furthermore, increased awareness towards gelatinous plankton, leading to the discovery of species that were not even covered by the campaign, such as P. punctata.

Aquatic Invastions (2009) Volume 4, Issue 4: 675-680

Water hyacinth is an invasive plant that was first introduced to Lake Victoria in 1989 ( Wilson et al. 2007). The species spread quickly, infesting about 77 square miles of the lake  by 1998 (NASA Earth Observatory 2007). This has become a huge problem, threatening the biodiversity of the lake, contaminating drinking water, and hampering transportation. In order to remove the aggressive species, biological control agents were released into different parts of the lake in 1995. There was also an El Niño weather pattern during 1997/1998, around the same time water hyacinth populations started to decline. Recently, there has been some debate over the cause of the decline of water hyacinth on Lake Victoria. Some researchers argue that without the presence of weevils, the control agents that eat water hyacinth, the population crash would not have occurred. Others disagree, saying that the wet and cloudy weather of el Niño played a major part by accelerating the decline through direct effects.

In an Aquatic Botany article, Wilson et al. (2007) claims that, although el Niño hastened the destruction of water hyacinth, the presence of weevils was the major contributor to the rapid decrease. Satellite images of water coverage were analyzed and then summarized on a graph, showing the trend of how lake-wide water hyacinth populations changed over time. They agree that increased wind and wave action from El Niño may have been a major stress to plants, but their data shows that the major turning point was in 1999, when the weevils finally became effective.

Williams et. al (2007) combats this opinion in another Aquatic Botany article, stating that el Niño was the major cause of the water hyacinth destruction. Wilson’s article is criticized for condensing the system into an “oversimplification of the spatial complexity”(Williams et. al 2007). They argue that the collapse could not be fully attributed to the weevils because they were introduced 4 years prior to the rapid reduction. There was also a concern of resurgence of the plant because weevils have never become established within the river systems around Lake Victoria. An infestation of weevils must occur before biocontrol can take affect.

Little did they know that in December 2006, satellite images revealed that water hyacinth was back (NASA Earth Observatory 2007). For Wilson, this must have been a hard thing to comprehend. The resurgence of water hyacinth, in my opinion, supports the Williams article. I also agree that Wilson oversimplified years worth of data onto one chart; I was skeptical that the analysis was accurate. Also, their approach was not restricted to dates where the whole lake was clear from cloud cover. Therefore, the Williams article provided the most convincing argument with the data.

In light of the MODIS satellite images that showed images of growing water hyacinth populations, it can be said that biocontrol in general does not always work, and can sometimes turn out for the worse. In this case, the weevils were not acclimated to the size and environment of Lake Victoria, and therefore did not thrive as well. In order for biocontrol to be effective, a large scale infestation must occur; this could take years. The biocontrol must also be regulated frequently; as water hyacinth starts to die off and rot, the weevils also die from rotting plants or lack of food. On broad terms, invasive species pose major threats to our society and environment, and biocontrol should not be taken for granted.

NASA Earth Observatory. 2007. Water Hyacinth Re-invades Lake Victoria.  http://earthobservatory.nasa.gov/IOTD/view.php?i=7426. Viewed 24 Jan 2011
Williams, A. E., R. E. Hecky, and H. C. Duthie. 2007. Water hyacinth decline across     Lake Victoria – Was it caused by climatic perturbation or biological control? A     reply. Aquatic Botany 87: 94-96
Wilson, J. R. U, O. Ajuonu, T. D. Center, M. P. Hill M. H. Julien, F. F. Katagira, P.     Neuenschwander, S. W. Njoka, J. Ogwang, R. H. Reeder, and T. Van. 2007. The     decline of water hyacinth on Lake Victoria was due to biological control by     Neochetina spp. Aquatic Botany 87:90-93

Aliens have invaded planet earth. Caution tape now surrounds the world. Diseases are spreading and the floorboards can no longer be trusted. In the film, Strange Days on Planet Earth, viewers follow Jim Carlton, a marine ecologist, on a “crime scene investigation” in his search for these alien arrivals. Suspenseful music, colorful images, and descriptive examples are used to emphasize the impact that these invasive species have on our world today.

Throughout the film, eerie music is played as if it were a horror movie with CSI undertones. At first, this came off as a bit cheesy, however it definitely got the point across that these “aliens” are dangerous to society and need to be taken care of. Carlton wittily compares the situation to a “russian roulette,” as danger is always eminent. As if on an FBI mission, sound effects and all, the audience learns about different species causing problems to the environment.

The camera stalks a Nile crocodile, buries itself in termites, and gets splashed with sea spray in order to capture some creatures. Vivid, as well as unpleasant images are used to display the relentlessness of the creatures. Scenes of termites eating wood, larvae infesting plants, and weevils crawling on foliage are sped up and flashed across the screen, really illuminating their villainous qualities. In New Orleans, damage from termite infested houses is shown; we later learn that these pests traveled all the way from China after Japan’s surrender in WWII in crates from local wood. They now thrive in the southern climate, and one city block can host around 10 alien nests, sometimes hundreds of feet long. Billions of dollars have been spent on prevention, however the problem still remains. Human interaction plays a large role in the growth, as well as the decline of these invasive species.

The film presents another example of human interaction on the environment, and the varied results it can produce in the context of invasive species. The water hyacinth was brought from Brazil and given to a man’s loved one. Somehow, clumps of the plant traveled downstream, and in 1989 it was found in Lake Victoria in Uganda. Rotting vegetation fouled drinking water, 80% of drains were clogged, and new diseases were erupting. In this case though, humans corrected their mistake by performing biocontrol. The weevil was introduced to the lake, which destroyed much of the plant, in turn alleviating many problems. The film also explained the dangers of biocontrol, and how it can lead to a whole other series of problems. In general though, the use of examples was helpful and necessary to illustrate the negative or positive impact that invasive species can present. Native species are now a 1% minority in the U.S., and 1 or 2 invasions of aliens occur per day. Facts like these really allow the audience to understand the seriousness of the problem.

As portrayed in the film, the invasion of aliens really is a crime that needs justice. With efforts like those of Carlton, the world will soon be on its way to a less-infested sanctuary.

The Burmese python is just one of thousands of non-native animal and plant species that have invaded the United States in the last decades . However this “former pet” has taken a large toll in the Everglades in Florida, killing pets, alligators, and even children. It has become such a problem that, according to the NY Times, Congress is considering a ban on buying nine kinds of giant snakes. Most of the pythons in the park are a product of the international pet trade. National Geographic News stated that over the past 5 years U.S. has imported more than 144,000 Burmese pythons.

Although the pythons have become “celebrities” in Florida, the problems caused by them still remain. The newfound fascination with the snakes seems to have obscured the threat they pose. Attempts to reduce the python population have occurred, such as a six-week hunting season, however the results have not been significant. I think that the best way to control the issue is to ban the buying and selling of the python. Once the cute baby snakes turn into 15-foot-long monsters, some owners try to get rid of their pets by leaving them in the forest. This only escalates the problem. If the U.S. cuts off the booming trade in “exotic pets,” the problem of the killer python would hopefully settle.

It is interesting how the U.S. has allowed this pet trade to occur for so long. I would think that it would be obvious that 15-20 foot Asian pythons would be dangerous as pets. However, now that people have been strangled by these beasts, the officials have no choice but to take action.