Invasive_Mussels_in_the_Great_Lakes

Invasive Mussels in The Great Lakes By: Hannah Lake Michigan is the second largest of the Great Lakes and is known for supplying fish for both commercial and recreational fishing. The Great Lakes contain 20% of the world’s fresh water – a finite resource (Audubon). In 1980 the Great Lakes took in a species that would unknowingly damage the ecosystem, as they knew it. As ballast ships came to the Great Lakes proceeding from the Caspian and Black Seas, they carried many invasive species like the zebra and quagga mussels. Zebra and quagga mussels are no larger then a quarter in size, but are capable enough to destroy an ecosystem from the bottom up. These mussels have had a dramatic impact on the ecosystem and have made it very difficult for other aquatic life to survive. The zebra and quagga mussels are freshwater bivalve mollusk that are originally native to southeast Russia but have now been introduced to parts of Europe and the United States. These mussels have a high plasticity meaning they are easily adaptable to changing environment and also an extremely prolific species that can cause widespread damage on property as well as on an ecosystem. The quagga and zebra mussels may be the reason for Diporea, a small shrimp-like species that serves as a food source for larger fish, is no longer abundant. The whitefish that feed on Diporea are growing to less than half of their expected size (Science Daily). As well as the severe effect on other smaller fish that normally feeds on plankton that are unable to find food as easily to sustain them, which is having a relentless impact on their survival rate. These mussels are suspension feeders; which means they filter the algae out of the water to obtain their food. Both types of mussels use inhalant and exhalant siphons that protrude from there shells to extract their food. The pseudofeces that is produced from filtering the water accumulates and creates a foul environment. Pseudofeces is the way that filter-feeding bivalve mollusks get rid of suspended particles, which have been rejected as unsuitable for food. The rejected particles are wrapped in mucus, and are expelled without passing through the digestive tract. Although they may closely resemble the mollusk's real feces they are not actually feces, hence the name pseudofeces, meaning false feces. Each individual mussel can filter up to a liter per day. (USGS) Within the first few years after introduction to the Great Lakes they could be found on beaches, shallow waters, and water intake pipes in layers up to eight inches think. The mussels can attach to any surface with their byssus threads; which are string like strands of protein. Their life span can be anywhere from four to five years reaching sexual maturity within two years. Once sexual maturity is reached they can release up to one million eggs per year with a survival rate between 98 to 100 percent. Reproduction occurs when female mussels expels their eggs and are then fertilized outside the body by the males (USGS). Once fertilized, larvae will begin to appear within three to five days and are free-swimming for about a month. When they reach the juvenile stage they will settle on the bottom of the lake and start searching for their desired substratum. Quagga mussels prefer deeper, cooler waters as well as softer substrates, including sand and mud (USGS). Because these mussels live in sand and other soft substrates they have caused problems on the beaches. Washing up on shore and burrowing into the sand causes many people cut their feet when stepping on them. The shape of the quagga mussels’ shell has a rounded angle and is very light in color. These mussels now cover almost the entire bottom of Lake Michigan, to depths up to 520ft with their maximum density around 150ft. Although the quagga mussel was introduced into the Great Lakes until the mid 1990’s they have quickly become the dominant of the two species. The zebra mussels live in warmer waters and prefer but are not limited to attaching to harder surfaces including; rocks, glass, buoys, intake pipes and even each other. They are able to produce twice as many byssus threads as quagga, which allows for them to live not only in still water but also faster moving waters. They received their name from their light and dark stripes on their shell, and have a flattened underside, which allows them to attach to things more efficiently. Zebra mussels are notorious for their bio-fouling capabilities by colonizing water supply pipes of hydroelectric and nuclear power plants, public water supply plants, and industrial facilities. They colonize pipes constricting flow, therefore reducing the intake in heat exchangers, condensers, firefighting equipment, and air conditioning and cooling systems. (USGS) These colonize are also causing water and electric bills to rise due to the high preventative costs companies are incurring. Before the introduction of these mussels the Great Lakes were cloudy and filled with millions of tiny microorganisms. Today the lakes are mostly clear which allows light to penetrate to deeper levels and promote growth of some “blue-green algae” which is a common name for several types of algae. (Muskegon Health) This alga is a natural part of waterways and are not all harmful, but some do produce toxins that can be noxious. The recent rapid growth of these algae has resulted in the death of hundreds of diving birds. This deep penetrating light is not only a bad thing, but can also have some positive effects as well. One positive result is that it allows for some plants to grow bigger giving smaller fish shelter from larger predators. Researchers with the New York Education are conducting a three-year study to evaluate a Pseudomonas fluorescens strain of bacterium that is not only toxic to zebra and quagga mussels, but also benign to non-target organisms such as bluegill sunfish, minnows, and brown trout. (NETL) This bacterium is showing great promise for the removal of these invasive mussels. Officials say that the bio-pesticide achieved a 98 percent kill rate of zebra and quagga mussels. (UPI) Recent discoveries have been made in identifying parasite and infectious microbes that can kill these mussels. This parasite attacks the mussels digestive glad leading to their imminent death. In small trials this parasite has eliminated the mussels in pipes at a hydropower facility with a 95 percent kill rate. (Science Daily) They are now working to identify and purify these toxins. Although these test show great promise, they are unable to determine how effective either will be in open waters like the Great Lakes or how long till they could be ready for commercial use. These invasive mussels have had a devastating impact over the last twenty years and no one knows for sure what will happen in the future. Research will continue and hopefully a solution will be found before any more irreversible damage can be done. Preventative measures are being taken to limit the spread of these and other invasive species. The most beneficial way for you to help is to follow these simple steps: 1. Inspect, 2. Remove, 3. Drain. It’s everyone’s job to use these steps whether you are a boater, paddler, seaplane pilot, pond owner or angler you have a very important role in keeping unhabituated lakes free of aquatic invasive species. These steps were put into place to stop any further spread of not only these invasive mussels but also other aquatic hitchhikers. We are now the only preventative measure that can help to stop this spread. Bibliography * http://nas.er.usgs.gov/queries/factsheet.aspx'speciesid=5 * http://policy.audubon.org/threats-great-lakes * http://www.sciencedaily.com/releases/2009/02/090219081038.htm * http://www.lapa-west.org/Assets/PDF/Marrone2010.pdf * http://www.lakescientist.com/2011/quagga-and-zebra-mussels-unsettle-great-lakes-ecosystem-126 * http://www.netl.doe.gov/publications/factsheets/project/Proj291.pdf * http://www.muskegonhealth.net/publications/fact_sheets/algae.pdf Personal Reflection Although I grew up on the Great Lakes my entire life I never knew that there was an invasive species that was damaging the ecosystem. Before this paper I never understood why cleaning off your boat was so important, but now I see that by doing that prevents the spread of these invasive species. My dad and I always go fishing on Lake Michigan and now I can see the effect they have had on it. The fish don’t get a big as they used to and is getting harder to find them. The main reason why I wrote this paper was because of my dad. He told me little about them and what they were doing but he didn’t know a lot of details. So I decided that this would be the perfect idea for my paper as well as being able to give it to him so he is able to learn more about them.