After spreading throughout Europe, Japan, and Australia, it is no secret that the New Zealand mud snails are invasive species. In North America, they have become particularly present in most major Western waterways, with the exception of the Great Lakes. Edward P. Levri and his team from Penn State collected samples at several different depths in Lake Erie to further explore the minute presence of the snails in the Great Lakes. He and his colleagues found three separate areas in Lake Erie where the mud snails had invaded. Overall, however, the findings were relatively modest. The scarcity of the mud snails in the lake can be attributed to depth they were found; it is very unlikely that they have been or will be transportated through recreational activities such as boating. Levri and his team stress that although further invasion is improbable, there is still the possibility that they can spread by dredging, the digging up of sediments, or even more introductions from Europe.
Journal of Great Lakes Research 3, 335-340 (2007)
Journal of Wildlife Management, Volume 73, 1414-1419 (2009).
In recent years, a need for effective ways to exterminate Nutria from regions such as Luisiana marshes has arisen. The most simple method of killing them is through the use of traps. To improve the effectiveness of traps, Susan Jojola, Gary Witmer, and Patrick Burke researched how the use of attractants improved the chances of capturing a nutria. After a controlled study of 14 different possible lures in both a lab setting and in nature, the researchers concluded that a synthetic nutria fur and anal-gland extract was the best formula to attract the animals. The final chemical developed increased the chance of capture by around two and a half times. The use of attractants like the one created was suggested to be used as a cost-effective method to reduce nutria damage.
Environ Biol Fish (2009) 86:389–398
The lionfish (Pterois volitans) is a beautiful saltwater fish native to the Indian Ocean. In the past decade they have been sighted all around the Gulf of Mexico and the Northern Atlantic. James Morris and John Akins of the National Oceanic and Atmospheric Administration (NOAA) decided to collect samples of lionfish and, by examining their stomach contents, identify their diet and any species under threat from this new invader. Samples were collected from a variety of locations, from reefs and canals to mangrove habitats. They focused on two primary statistics. Morris and Akins recorded the frequency and percent volume of a species in the stomach. The diet of the lionfish is about 78% teleosts (a variety of fish) and 14% crustaceans. Another statistic recorded is that lionfish had much larger volumes of food in their stomach between the hours of 8:00-11:00 AM. Based off this data, the teleost variety of fish is most under threat from this aquatic invader.
Eriocheir sinensis, better known as the Chinese Mitten Crab, has become a topic of wide concern in the last few decades. It has spread from the seas of China, through the Thames River and along the coast of England, and into the Pacific coastline of the United States. An ongoing search to find a solution to the spread of this invasive specie has led a team of scientists from the Department of Zoology of the Natural History Museum of London to investigate the possibility of using these crabs as a food source for humans. The team researched the effects of their consumption on human health by measuring levels of Dioxin and PCBs in their meat. The levels of toxins, when compared to guidelines for European Tolerable Daily Intakes, showed that adult men and post-menopausal women would be able to consume meals a few times per week. However, the potential health risk is too great, and another solution must be found.
Environ. Sci. Technol. doi:10.1021/es802935a (2009)
Journal of Great Lakes Research 36(3): 540-547 (2010)
With the help of modern human transportation, invasive species can reach habitats that they never could before. The ballast water of ships carries multitudes of microorganisms that, when discharged into a new ecosystem, can disrupt the natural balance in that area. Experiments done in the Laurentian Great Lakes concluded that assemblage, staining, and observation was the most efficient way to evaluate the freshwater organism content in ballast discharge while other methods proved ineffective and unclear.
Euan D. Revie and his research team from the University of Minnesota Duluth tested multiple ballast water treatments, such as: enzyme digestion, flow cytometry, and multiple stains. A reliable process to test the densities of phytoplankton cells in the 10-50 micrometer range has yet to be found, and reliability was based on several factors. The methods were tested for precision of the organisms’ conditions at ballast water discharge, consistency of results in a given area, and practicality as well as speed of method during on-site projects.
Diversity and Distributions doi: 10.1111/j.1472-4642.2007.00434.x (2007)
In recent years, the Laurentian Great Lakes have been a destination for many invasive species. One of the most recent aliens to enter is the bloody red shrimp (Hemimysis anomala), which is native to the Black Sea. Many scientists wonder how these shrimp got to the United States.
Asta Audzijonyte, from the University of Helsinki, with a team from Finland and Austria, tracked the shrimp using mitochondrial DNA, the gene sequences found the the mitochondria of a cell. The shrimp found in the Great Lakes had most likely come from the Danube delta. The team were able to track the crustacean from the Danube delta, to the Danube River, through the Main-Danube canal, finally to the Rhine delta where the the shrimp could travel to the United States via the ballast water of Trans-Oceanic ships. With this method of tracking, the authors were able to figure out where the bloody red shrimp originated from.
Starting in 1959, the American Bullfrog has been introdouced into most provinces in China, and because of its size and predatory nature, has been able to thrive off consuming the native species. The bullfrog has been known to eat a number of the native anurans, but to what extent has been hard to determine for scientists. Yanping Wang and his team from The Society for the Study of Amphibians and Reptiles, decided to try and determine which prey the bullfrogs preferred to determine the overall effect the bullfrog has. First, they tested which bullfrogs, larger or smaller and male or female, consumed most on a daily basis. Then they determined which of the four main sources of food the bullfrogs preferred and which size. The results of the experiment showed that the though the bullfrogs preferred the smaller species such as the Rana limnocharis but only because of the species generally smaller size compared to the other prey.
Journal of Herpetology. Volume 41, p. 514-520.(2007)
The snakehead fish did not belong in the Potomac River in Washington D.C. This invasive creature is native to eastern Asia that has been introduced to portions of Japan and central Asia and is sporadically made its way through Europe to the eastern seaboard of the United States. Scientifically known as Chana Argus, this aliens ability to migrate over land with its adaptive air breathing gills to other bodies of water poses a serious threat in the spread of its own invasion.
Authors John Odenkirk and Steven Owens used The primary Virginia Department of Game and Inland Fisheries (VDGIF) as a major resource in their findings. the VDGIF Documented a population of northern snakeheads within a 23-km reach of the main-stem tidal freshwater Potomac River and associated tributaries in 2008. methods such as poision and bounty hunting have been effective ways to combat the snakehead. Scientists understand the threat and that the introduction of exotic fishes like the snakehead can adversely affect native species through increased predation and competition for food and space.
Transactions of the American Fisheries Society 134:1605–1609, 2005
North American Journal of Fisheries Management dio: 10.1577/M05-074.1 (2006)
In an attempt to eradicate the invasive Northern Snakehead from Maryland waters, state and local government agencies have been adding the toxin rotenone to the invaded waters. This practice is outline in Andrew Lazur’s study, titled Acute Toxicity f 5% Rotenone to Nothern Snakeheads. After adding rotenone into local ponds to levels at low as .075mg per liter of water, there was a 100% mortality rate among the Northern Snakehead within 1 hour. Ultimately, 8 adult and 834 juvenile dead Snakheads were collected from the lake. However, this effective solution has a severe downside: nearly 500 kg of native fish were also collected. This study concluded that the use of the toxic rotenone is an extremely effective solution to ending the ecological threat that the Northern Snakehead presents.
Journal of Applied Ecology Vol. 47, no. 2, pp. 273-280. Apr 2010.
As a biocontrol introduction into Australia to control insect pests, Cane Toads quickly became the bigger problem. Cane Toads, Bufo marinus, defense mechanism is the release of a poison. Consequently, the predators in this region are extremely susceptible to death by consumption of the toad due to their lack of natural encounters with this animal.
Although many efforts have been made to control the Cane Toad they haven’t been successful. Little attention has been brought up concerning the use of meat ants but have proven to be an effective method in attacking Cane Toad metamorphs. In research conducted by Georgia Ward-Fear,Gregory P. Brown, and Richard Shine, even in brief (2 min) trials, 98% of metamorph toads encountered at least one ant in trials at high ant density, and 87% at low ant density. Most of these toadlets were killed (overall, of animals attacked, 82·5% were killed at high ant densities, 51% at low ant densities: Ward-Fear et al. 2009, 2010).