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Beware of the aquatic monster! Hydrilla - commonly termed as the "world's worst weed" - has been found lurking in the Hoosier state.
Indiana's first hydrilla sighting was confirmed at Lake Manitou in Rochester of Fulton County in August 2006. This means our other lakes and rivers are more susceptible to invasions of this aquatic nuisance if we don't take the necessary precautions.
What is Hydrilla?
Hydrilla verticillata is a submerged aquatic plant with heavily branched stems that grow towards the water's surface. It is characterized by its long, slender stems that can grow as tall as 30 feet and are heavily branched. The leaves are long, whorled, and bear small conical bumps on its underside. The partial evergreen will occasionally produce small white flowers as well. Usually rooted, hydrilla can also be found floating around a body of water in a large mass. Native to
Hydrilla's presence in the United States is one of irritation as we consider it one of the "most unwanted" species in our bodies of water. The reason for our aggravation comes from the fact that hydrilla, like Godzilla terrorizing Tokyo, leaves lakes, rivers and other waterways up heaved and terrorized. The invasive specie forms a dense canopy that forces native species to compete for nutrients and blocks much needed sunlight to aquatic plants below, basically pushing out our native aquatic species out of their home.
Aquatic animals are also affected in heavily infested waters. Fish population imbalances are likely when over abundant amounts of hydrilla is present. The dense mats raise the water's pH, oxygen levels fluctuate and water temperature rises. The fish are left smaller in size and weight; sportfish populations greatly decline.
How Does Hydrilla Affect Us?
Besides adversely affecting the biodiversity and altering the aquatic ecosystem, hydrilla may greatly interfere with recreational water activities and be a strain on local economies.
Management of hydrilla is expensive. Millions of dollars are spent each year in herbicides and mechanical harvesters. Unfortunately, the invasive is practically invisible until its too late; it is only noticeable when it tops off at the surface. The best protection is to prevent hydrilla from reaching our water sources in the first place.
How Hydrilla Has Invaded Our Nation
Hydrilla was introduced to the United States when dumped into a Florida canal in the 1950's. At that time, the invasive was imported and marketed as an aquarium plant. When a buyer wanted to get rid of the plant, he tossed it into a canal behind his farming business. Weeks later he noticed how fast and vast the hydrilla grew and decided to produce and sell it himself.
Problems with the plant choking out aquatic species, destroying natural habitat and interfering with recreational activities began shortly after as the hydrilla grew to overabundant populations. Soon the hydrilla's invasion of U.S. waters would spread outside of Florida to other southern states and way over to California. Twenty-two states including Indiana have reported cases of hydrilla in their waters.
What We Can Do to Prevent Further Spreading
Introduced by dumping aquarium contents into waterways, hydrilla is now listed by the U.S. government as a Federal Noxious Weed. With this designation, it is illegal to import or sell the plant in the United States although sales made through the internet are possible. Today, the plant is mainly transported to new lakes and rivers from plant material on boats, equipment and gear worn in the water. In order to prevent the transportation of hydrilla, please consider these precautions:
The Indiana General Assembly also has passed an "Emergency Rule" regulating Hydrilla verticillata as a pest.
For More Information
The Nature Conservancy's Information on Hydrilla
MIPN - Midwest Invasive Plant Network
DNR / AIS - Hydrilla
Global Invasive Species Database from the World Conservation Union's Invasive Species Specialist Group
Stop Aquatic Hitchhikers! - a "site for recreational users who want to help stop aquatic nuisance species"
Union of Concerned Scientists information on hydrilla
"The Perfect Aquatic Weed" - an article discussing hydrilla's unique biological and physiological characteristics and aggressive growth habit.
Habitattitude - " a site for aquarium hobbyists, backyard pond owners, water gardeners and others who are concerned about aquatic resource conservation"
Educational Resources from the USDA National Invasive Species Information Center
A Science for Kids hydrilla article
Nature picture credits (top to bottom, left to right): Photo © Uni. of Connecticut (hydrilla mass); Photo © Vic Ramey/Uni. of Florida (hydrilla).
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