Wednesday, July 29, 2015

Zebra Mussels


Protection of our lakes is vital. Invasive species can have irreversible damage to the indigenous environment. 

Taking precautions to protect our waters is not only the law but our responsibility. Zebra Muscles:

The invasive zebra mussel has quickly taken over much of the Great Lakes waterways of the United States. The immediate goal is to curb the spread of these deleterious invaders. A small mussel, with a maximum shell size from 3.5 - 4 centimeters, the zebra mussel is usually found in large clusters. It is most likely to be confused with Dreissena bugensis, the Quagga mussel, which is also an introduced species to North America. The native false dark mussel, Mytilopsis leucophaeata, is likely the only native mussel that can be confused with the zebra mussel. Zebra mussels have a salient zebra-like striped pattern on their shells, and also lie flat on a smooth surface, unlike many other mussels.
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Ecological Threat: Zebra mussels are known to have caused alarming declines in populations of fish, birds and native mussel species and can disrupt a city's entire water supply system by colonizing the insides of pipelines and restricting the flow of water. Zebra mussels also damage boat hulls, plug water systems used in boat motors, air conditioners and heads and cause navigation buoys to sink. Millions of dollars are spent each year controlling, cleaning and monitoring zebra mussels in other states.

Zebra mussels have a high rate of filtration (especially at high populations) which has led to increased water clarity and sunlight penetration by decreasing the amount of beneficial phytoplankton like diatoms and green algae. Increased sunlight penetration leads to increased water temperature as well as an increased Secchi depths (the depth that light penetrates underwater). This may be deleterious, in that different organisms live within various strata of the water column. Once those strata disappear, so may the organisms. Zebra mussels also feed on zooplankton, and have been associated with their declines as well. Zebra mussels pose a real threat to native mussels by competing for food and attaching to their shells. A zebra mussel colony can eventually smother a native mussel colony.

In addition to their ecological effects, zebra mussels have a negative impact on the economy. Zebra mussels have the ability to adhere to just about any substrate. Due to their sessile nature, once the veliger larvae has bound to its substrate of choice, mussels develop into adults and are permanently secured via anchors known as byssal threads. These byssal threads allow many zebra mussels to cluster together on various types of substrates including pipes, boats, boat trailers, buoys and dinghys. High cost has been associated with removing zebra mussels from intake pipes to power plants, piping associated with air conditioning, fire hoses, and many others as they constrict water flow. The mussels may also sink buoys, destroy fishing equipment, and take over objects left in the water for a long period of time.
Biology: Zebra mussels are capable of invading new ecosystems through adaptive and anthropogenic factors. First, zebra mussels possess a free-floating larval stage called a veliger stage. Zebra mussel veligers may float in the water column for up to a month, allowing for transportation in ballast water, irrigation water, or pipes for local water supply. The veliger stage, in addition to the ability to breed within the first year of life (as well as aggressive feeding rates) allows zebra mussels to multiply and expand their territory rapidly.

Adult zebra mussels are able to attach to a wide range of substrates, including boats, boat trailers, or even algae. This allows for easy invasion of multiple lakes if boaters are neglectful of vigorously checking and cleaning their boats. Many states' Department of Natural Resources have attempted to inform and alert boaters of this issue to avoid further invasions.
History: The Zebra mussel was first observed in North America in 1988 in Lake St. Clair (a body of water that is on the border between Michigan, USA and Ontario, Canada). Since then the zebra mussel has spread to various states located along the Mississippi Waterway, and has been recently reported in Texas, Utah, and California.
U.S. Habitat: Indigenous to lakes, zebra mussels prefer slow-moving water. They are still found in rivers and streams, but their populations are high in lakes. Very turbid water minimizes zebra mussel populations.


Where Zebra Mussels Hide: 

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