Water Quality Improvement

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Jun 01

Alien Invaders Are Lurking

Posted on June 1, 2016 at 7:56 AM by Allan Warren

New Zealand_mudsnailsSummer is here and many of us enjoy spending time outside boating, kayaking, and fishing in local lakes and streams. The downside to these activities is the unintentional spread of aquatic invasive animals and plants. These invaders are an ongoing threat to our environment and are costly to remove once established. Zebra and quagga mussels, New Zealand mudsnails; and aquatic plants such as Brazilian elodea, Eurasian milfoil, and hydrilla are some examples of these aliens. Each of these can be easily and unknowingly transported between lakes and streams on boats, trailers, and fishing gear.

AliensWhy are these invaders so bad? None of these species are native to this area. Many of the aquatic invasive plants Alien Invaders Are Lurking were originally sold as aquarium plants; and the invasive mussels and snails have arrived on boats/equipment. Because they didn’t evolve here, there are no natural checks and balances to keep them under control so their populations explode taking over and outcompeting our native plants and animals.

The most important action we can take to control the spread of these aquatic invaders is to carefully clean our outdoor recreation gear using either the “Clean/Drain/Dry” method or the more thorough decontamination method which is recommended for those waterbodies that are known or suspected of being infested. For more information on how to prevent the spread of these invaders go to the Washington Department of Fish and Wildlife’s aquatic invasive species page (http://wdfw.wa.gov/ais/).

Macroinvertebrate Sampling
Benthic macroinvertebrates (bottom-dwelling organisms including aquatic insects, crayfish, clams, snails, and worms) are often used in studies to determine the quality of waters because of their high numbers, known pollution tolerances, limited mobility, wide range of feeding habits, varied life spans, and dependence on the land environment around the stream. While water quality sampling provides us with a “snapshot” view of the health of the stream; macroinvertebrates give us with a longer view of stream health. The types and numbers of macroinvertebrates present are affected by periodic episodes of poor water quality or by ongoing poor water quality.

Become a Volunteer 
During summer volunteers help us collect samples of these aquatic organisms from selected streams which are sent to a lab to be identified and counted. Pierce County uses the results to determine biological health of the stream. If you are interested in lending a hand with sampling this summer, contact Isabel Ragland at (253) 845-9770 x103 or isabelr@piercecountycd.org.