Along with fishermen, boaters and other recreational users, summer means aquatic weed growth in Clear Lake. Every year it seems the lake has more of a weed problem. This year, with a full lake, the weeds will be growing more profusely than ever.
Clear Lake is host to approximately 35 different species of aquatic weeds. Some are native to the lake but most have been introduced and are considered either invasive, noxious or both.
An invasive weed is normally classified as one that is not native to this country or was introduced into an environment where it did not evolve. For example, hydrilla is considered an invasive weed. Most invasive weeds have no natural enemies.
A noxious weed is any plant designated by a federal, state or county government as injurious to public health, agriculture, recreation, wildlife or property. It can be native or non-native.
Years ago, when the lake was covered with algae, there was very little weed growth because sunshine couldn”t penetrate to the bottom of the lake to stimulate the weed growth. That all changed about 10 years ago when the water clarity improved.
The other factor centers around the number of new species of weeds that keep showing up in the lake each year. Most of the unwanted weeds are introduced into Clear Lake through people who dump their aquariums into the water or from boat trailers and boats.
One weed that”s rapidly becoming a problem is water primrose. Many of the channels and bays are becoming completely choked off because of primrose”s presence. A good example are the Clearlake Oaks Keys. The Keys Homeowners Association has been battling primrose for several years.
The question is how will the county deal with the invasive weeds? There is an aquatic weed plan and a number of licensed weed control companies around the lake, but the big question is who will pay for it? Weed control doesn”t come cheap and in just about all cases the homeowner is expected to foot the bill for the removal of weeds from around their docks and harbors.
Many homeowners don”t think they should have to pay because the lake is considered public land and anyone can use it.
Aquatic weeds aren”t always bad. Weed growth supplies rich oxygen to the lake, which in turn helps the fisheries. In addition to providing cover for the juvenile fish, the weeds attract plankton and other microscopic creatures that are on the bottom of the food chain. For example, a small aquatic species called daphnia now exists in the lake by the billions. Daphnia provide a valuable food source for young bass, crappie and bluegill.
Daphnia also feed on blue-green algae, which has plagued the lake in the past.
Weeds also use up the nutrients that algae needs to thrive. In fact, the lake has been pretty much free of large concentrations of the hated blue-green algae since the weed explosion.
Of course, too much weed growth chokes off entrances to the docks and harbors, making boating nearly impossible. During the the past few summers many of the lakeside residents haven”t been able to use their boats for a good part of the summer because of the weeds.
Lakeside residents are allowed to spray the water around their docks with an approved herbicide to control the weeds. However, there are certain conditions they must follow. They must first obtain a permit from the Lake County Department of Public Works and they must also hire a state-licensed herbicide applicator.
Spraying weeds isn”t cheap. Typically it will cost in the neighborhood of $1,000 to apply a single application of herbicide around the average dock.
The other method of getting rid of the weeds around the docks is by mechanical harvesting. However, the problem is that many of the weed areas also contain hydrilla, a noxious weed that the state has spent millions of dollars to control. If a stalk of hydrilla is cut and then drifts off, the chances are good that it will re-root itself in another area of the lake.
The county also must give permission to do any mechanical harvesting and a permit is only given if no hydrilla has been found within a quarter-mile of the site for which the harvesting is to take place.
The one thing you can count on is that the weeds won”t disappear soon. It will take years of research and a lot of money to control the weeds in a lake as large as Clear Lake.
