Sep
03
Filed Under (SW1) by Sean Dickey on 03-09-2010

Native to parts of Eastern Asia, including China, Korea and Russia, the Northern Snakehead, or Channa argus, has recently begun to reap havoc on ecosystems in North America. Initially, the snakehead was brought to the States as a source of food, as it is eaten in its native regions. In my home state of North Carolina, there have been at least two widely reported incidents of northern Snakehead sightings. In August of 2002, a pair of snakeheads were caught in Lake Wylie, NC. In 2007, a large adult Snakehead was caught in the South Fork Catawba River. A major reason why the Northern Snakehead has been so successful in the much of the eastern United States is due to its ability to prey on native species. The snakehead has a nasty reputation from its ugly, menacing to demeanor to the fact that it can grow up to four feet in length. There have even been movie productions like Snakehead Terror about the scary fish.

The most common efforts to remove the fish including the draining or poisoning of the small bodies of water they have infested. A more famous incident of snakehead infestation was in a pond in Crofton, MD. In order to prevent the spread of the fish in the pond, Maryland officials released the pesticide rotenone. Unfortunately, the whole pond was wiped out, but the snakehead went along with them. Six adult fish and one thousand babies were found afterwards.

Although the draining of ponds and the use of pesticides are fool-proof ways to kill of the northern snakehead, it seems quite drastic to destroy a whole ecosystem to save it. In the future, it would be quite helpful if techniques can be developed to isolate the snakehead and kill or limit their growth. Other things to consider are the lasting effects of the pesticide. After it is distributed, does it stay in the ecosystem or does it biodegrade? In the long run, the most effective effort to limit the spread of this invasive fish is prevention. Since 2004, various laws have been passed throughout the United States, especially in greatly affected states such as Maryland, North Carolina and New York, prohibiting the selling, trading or importing of the fish.

Sep
03
Filed Under (SW1) by Josh McGrath on 03-09-2010

The recent economic setback in our country and around the world has had negative effects on almost everyone’s way of life. Abandoning a pet and destroying an ecosystem, however, is no way to solve that problem. Yet people are doing just that. Burmese pythons are large snakes that can strangle and eat prey as large as alligators, and they are being released into the wild by irresponsible pet owners. The snakes can weigh up to 250 pounds and their top slither speeds can reach almost 20 miles per hour.  With such a fast pace, certain pythons have already made it 100 miles towards the opposite coast of the United States. Scientists believe that there are roughly 30,000 nonnative giant snakes living in the wild in the Everglades, and that those snakes could thrive even more if introduced into other states such as California.

The Burmese Python has the potential to kill off numerous other species and establish itself as a dominant force throughout the United States. Its large size and quick movements are reasons it is so abundant in its natural habitat, and could be in the United States. The main enemies of pythons are larger cats such as lions and tigers, but there are really none of those in the US. The only real opposition present for the python is the alligator and even that is an even battle. Beavers, like most animals in the US, do not eat pythons and would simply be tasty treats for the snakes.

With roughly one-third of the United States as a suitable living environment, my question is how long will it take the python to cover that area? The government has already begun to try and kill of the python, but to no avail. The best thing we can hope for now would probably be a really cold winter everywhere in the US.

Picture can be found here.

http://articles.sfgate.com/2008-02-21/news/17141957_1_burmese-python-giant-snakes-alligators

The invasion of the Zebra mussels began in the 1980’s and they were followed by their close relative the Quagga mussel. Zebra mussels tend to inhabit hard substrate while Quagga inhabit both hard and soft substrate. Quagga migrate deeper than Zebra mussels and invade a wider range of aquatic environments. In 2007 Quagga mussels were found in the Colorado River Aqueduct System that serves Southern California. They were also found in the San Vicente Reservoir in San Diego County. In 2008 Zebra mussels were found in San Justo Reservoir. The mussels act as water filters and remove phytoplankton, zooplankton and other small particles that are a source of food for other aquatic animals like zooplankton and small fish, altering the food web. The mussels also collect organic pollutants in their tissues at extreme levels greater than the average concentration in the environment. The waste they produce lowers oxygen levels which lowers the pH to acidic levels and creates toxic byproducts. Quagga and Zebra mussels clog pipelines and screens that take up water and reduces the pumping capacity for power and treatment facilities. For boaters the mussels clog engines and cause overheating and steering problems. It’s almost like the problems caused by the Quagga and Zebra mussel are infinite.

The Zebra and Quagga mussels have the potential to create serious issues in the future, especially for California. The state is already in a water crisis and all reservoirs that get raw water from the Colorado River have been exposed to Quagga mussels. I feel that threats like these should be publicized and given more attention so that everyone can be aware of what can happen. I’ve lived in California my whole life and have never heard of invasive species. Different ways on how people can help with the spread of the mussels should also be advertised. In regards to the environment the food web being altered can starve a lot of the native aquatic species and throw some aquatic environments out of balance. I think this could have a domino effect and cause more problems in society.

I’m still a little unclear about how these mussels are spread and what is the primary pathway by which they are transported to different environments. How do the Zebra and Quagga mussel reproduce? I’m also curious to know what measures are being taken to counter the issues caused by these mussels. I wonder if a species can be introduced into areas where the mussels are a problem and eliminate them without further disrupting aquatic ecosystems. I’m interested to know how these mussels interact with environments in which they are native and can analyzing them in their natural habitat lead to key ways to reducing their effect on habitats they invade.

Quagga and Zebra Mussels in California

Image Link

Sep
02
Filed Under (SW1) by Michael Di Nunzio on 02-09-2010

In 2007 the New York State Department of Environmental Conservation (NYSDEC) announced the first recorded instance of didymo in New York, found in the Batten Kill section of Washington County. The invasive specie tends to spread into new locations via the felt soles of fly fisher’s boots and is currently impossible to eradicate once present in a new area. Resembling degraded cardboard, Didymosphenia geminata covers water beds in heavy mats. Once these mats have overtaken the floor of the water source, fishermen have increased difficulty maneuvering among the infested waters, bottom dwelling organisms are smothered, and the food chain as a whole is disrupted. NYSDEC Commissioner Pete Grannis reasons that a the process of checking, cleaning, and drying gear thoroughly must become a common chore among outdoor water enthusiasts if the spread of didymo is to be hindered. Vermont has taken legal action in an attempt to thwart the aquatic invader, passing a law that will ban felt-soled angling boots by 2012. Still some believe that this will prove ineffectual, and that didymo will continue to spread through the laces and fabric present on the boots.

Didymo clearly constitutes a considerable threat for admirers of the outdoors and the ecosystem alike. I feel that because aquatic invasive species like didymo are becoming such a conspicuous problem, stronger measures should be taken to hamper their dissemination. For instance, before acquiring a fishing license, it should be required that anglers take a brief quiz on the proper methods for checking, cleaning, and drying their gear. Those who argue that the elimination of felt-soled boots is a futile effort have a valid point. Didymo will likely be able to spread through other pieces of equipment or find transportation in other fabrics. Once prevention has failed, the next steps will be control and eradication. Scientists will need to research new ways to impede the propagation of this invasive organism, whether they be chemical or biological.  However, this will give rise to a new set of problems, as the use of chemicals can easily pollute the surrounding environment and the introduction of new species intended to control didymo can have similar destructive consequences.

The situation surrounding didymo, though interesting, leaves several questions unanswered. For instance, scientists have determined with absolute certainty that felt-soled boots can lead to the spread of didymo, but is there any evidence to suggest that the elimination of these boots will lead to a significant decline in the dissemination of this organism? Common sense suggests that the answer is no, as only a single drop of water can transport the organism and didymo will likely find an alternate means of moving about from one water source to the next. This leads to yet another set of questions: is there any effective method of disinfection that can be easily applied to fishing gear? If so, can it be applied to felt-soled boots? If the answers to these questions is yes, then perhaps the ban on these boots is superfluous, and the complaints of fishermen can be mitigated by permitting the continued use of felt-soled boots.

http://www.nytimes.com/2010/08/16/science/earth/16felt.html?_r=1
Sep
02
Filed Under (SW1) by Drew Van Orden on 02-09-2010

Originally from Argentina, many invasive rodents called nutria now call Chesapeake Bay in Maryland home. They are extremely harmful to the wetlands, feeding off of vegetation and destroying the natural ecosystem. Although in South America Nutria are hunted for their fur and meat, they are nothing but harmful in the United States. Because of this, the only way to stop the invasion is to kill them off by setting traps all over nutria feeding areas. This method has killed roughly 15000 nutria but there are still many out there destroying the coastline every day. It is extremely difficult to keep up with their rising population because they mate often and do not have predators hunting them. Right now, estimated damages caused by the nutria exceed $200 million, making it a major issue.

To me there is no question as to what must be done about these invasive creatures. However, complete eradication at this point seems to be nearly impossible, especially with the rate they are reproducing. Although animal rights activists and groups such as PETA may not appreciate it, I think a market for nutria fur and meat must be created in Maryland. This way, commercial nutria hunters will hopefully begin to effectively destroy the population and save the wetlands from being destroyed. I am curious if there are any other options on how to get rid of the rodents, because it seems like such a helpless situation.

image found here

Sep
02
Filed Under (SW1) by Braxton Deaver on 02-09-2010

The Northern snakehead fish has become a major problem. Because the fish is a top level predator it has disrupted ecosystems and caused other populations of fish to dwindle. In lake Wylie, A large lake in North Carolina a Northern snakehead was found and caused a considerable impact on the population of large mouth bass and crappie in the area. By feeding directly on the food  sources like the bass and crappie, it has caused an imbalance in the ecosystems it has invaded and also it has diminished angler’s catches causing a disruption among fisherman. One of the biggest problems with the Snakehead fish is its ability to live for long periods of time out of water. Allowing it to hop itself into other bodies of water spreading its population efficiently. The US department of interior has banned importation of Snakehead fish and its eggs in 16 states.
The Snakehead fish has become more and more of a growing problem. Fish that cause other populations of fish to plummet and are not apart of that natural ecosystem cause a fluctuation in this natural habitat. Being able to eliminate this fish from waters where it causes harm needs to be the common goal. The “Frankenfish” as its been called because of its ability to sustain life for up to three days out of water has dumbfounded scientists. What sort of breathing apparatus has this fish adapted itself to? How has the Snakehead fish been such and apex predator in the locations it has been found? fisherman are doing their part to eradicate this aquatic monster by using poison on parts of the Snakeheads habitat as an effort to ward it off.

Sep
02
Filed Under (SW1) by Lindsay Gaskins on 02-09-2010

Purple Loosestrife Flowers

The purple loosestrife is an aquatic invasive species that has infested almost all of the continental United States, and has become an especially huge problem because it outcompetes native wetland plants, many of which are endangered to begin with.  It arrived in America via ship ballast water, and medicinal purposes.  Without any natural predators, and incredible reproductive abilities, producing up to 2.7 million seeds on a mature plant in just one summer, it can quickly transform an aquatic habitat.  Also, unless it turns out that it is a very localized and isolated case of purple loosestrife, there are presently no effective solutions to get rid of the plant.  The only solutions that currently exist are either highly time consuming, such as removing the plant by hand, or incredibly expensive, like using herbicides.

I think that this invasive species sounds like a huge problem, and considering that it’s spread throughout the United States, I’m surprised that I had only ever heard of it through my environmental science classes and not through the media, because with the current state of wetlands in the country, more should be done about their preservation, given how high the percentage of endangered species are in wetlands.  I was wondering though, is there some sort of way that fungus or blight could be utilized against this species?  They have tried using insects, but it hasn’t completely worked.

Photo from here.

Sep
02
Filed Under (SW1) by Brandon Braxton on 02-09-2010

The Burmese Python has become an increasing problem in the Everglades of Florida. It’s not certain how they arrived but that is beside the point. Their population was rapidly increasing before the second coldest temperatures hit Florida last winter. As a result, about half of the population perished. Still, with the large amount that were present, they still pose a large threat. A Burmese Python is considered an apex creature which means it has no predators. Being at the top of the food chain enables them to prey on many other animals and reproduce at a steady rate. Humans have also had encounters with these giant creatures that average twenty feet in length and humans have sometimes come out on the negative end. With the combined effect on the environment and the scare it is putting on people in the area, more needs to be done to eradicate the pythons in the Everglades.

I think that any invasive species, especially a large apex creature such as the Burmese Python, is going to be hard to deal with. They are not easy to locate and capture and it isn’t right to just hunt to kill an animal. With all the scientific advancements we have we should be able to tamper with their reproduction to decrease their numbers and eventually keep its population at a steady rate. What needs to be done is proactive thinking. There needs to be more laws in place that restrict animal trades from their native lands and they need to be better enforced. The Burmese Python problem can be solved just like anything else but it requires time and effort and it isn’t a particular issue that is at the forefront.

Sep
02
Filed Under (SW1) by Kyle Rand on 02-09-2010

Over the past few years, several articles have addressed the ongoing growth of an aquatic invasive species Didemnum vexillum, or more commonly known as the Sea Squirt.  The United States Department of Agriculture’s database on invasive species says that the first unnatural siting of Sea Squirt was in 1993 in the coastal waters of Maine.  However, recent articles cite that this species truly became a problem in 2003 when it was found in the waters of Georges Bank, just off the coast of New England.  Now, 7 years later, the problem is only getting bigger, as writers from the United Kingdom note that the Japanese species has spread throughout coastal England.

The sea squirt is able to reproduce both sexually and asexually.  Sexual reproduction forms offspring tadpoles that are carried by water currents into new areas, where they are able to attach themselves and reproduce asexually by budding.  New colonies grow very quickly, and instantly cover the hulls of ships and the gravel bottom of large bodies of water.  This poses a problem in that other aquatic species will be unable to feed off of seafloor dwellers such as worms or crayfish because the sea squirts invade their habitat.  This is harmful to both the creatures who would otherwise live and reproduce on the seafloor, and the species that feed on the seafloor.  The sea squirt will slowly damage the entire underwater ecosystem by spreading in mass across the sea bottom.

I find the imposing threat of sea squirts to be worrisome.  They grow so rapidly that one tadpole can reproduce by budding and quickly cover an entire seabed, literally smothering other creatures that would otherwise be living at the bottom of the sea.  Killing off the species that live at the bottom of the seabed could cause a disastrous shift in the marine food chain and ecosystem, and I think it would be well worth the effort to try and find some method of reducing the spread of the sea squirt.  Past experiences with the species in Canada show that it can be very costly to get rid of the colonies, but I think it would be worth the effort to keep researching and find a way to protect the marine ecosystem.  With such rapid growth, wouldn’t the sample size be large enough that research could be done relatively quickly?

Sea Squirt

This image of the invasive species was found at http://www.treehugger.com/files/2010/05/scary-ancient-jelly-like-sea-squirt-found-off-oregon-coast.php

Sep
02
Filed Under (SW1) by Michael Shaughnessy on 02-09-2010

The Zebra Mussel has already caused economic problems in many of the Great Lakes and more recently has been discovered in Laurel Lake in Massachusetts.  They most likely traveled on a boat that came from a body of water that was infested.  Environmental officials worry now about the potential for species being wiped out, intake pipes becoming clogged, and the fouling of drinking water.  Massachusetts was prepared for the invasion and created a rapid response program in 2005.  The program aims to educate local residents, isolate infested areas, and drying and disinfecting boats that are moving to new waterways.  They hope to prevent the possibility of an altogether different ecosystem developing where there is infestation.

I personally had heard of the Zebra Mussel when I was back at home.  I think public education is one of the most important techniques of prevention.  As long as the public is aware of the problem, they can contribute to the process of prevention and if necessary help disinfect the area.  I understand that it travels to new areas on boats, but I didn’t find any information on how to get rid of the Zebra Mussels once they have already infected the area.  It seems like for now Massachusetts only worries about containing the problem rather than fixing it and I wonder if that is enough or is the wrong decision.  I found the article on the Boston Globe website.Zebra mussels have been found in Laurel Lake in Lee and Lenox.

(Picture obtained here.)

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