County reports hydrilla finds increase in Clear Lake

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LAKE COUNTY – Officials are reporting a large number of new finds on the lake of the invasive aquatic weed, and are asking for the community's help in preventing the weed's further spread.


The county's Public Works Department reported that on Thursday a large number of floating hydrilla fragments were found along the southern shoreline area of Clear Lake, in a large mass near the entrance to Anderson Marsh.


This find is in addition to other major infestations found in areas around Clear Lake State Park, Lakeside County Park, Soda Bay, Buckingham and Konocti Bay.


With now more than 76 finds of hydrilla on Clear Lake in recent weeks, state and local officials increasingly are concerned and are asking for the public’s help in preventing any further spread of the non-native invasive weed.


First detected in Clear Lake in 1994, hydrilla is an invasive aquatic plant that grows very fast, has no natural enemies in California, provides limited habitat to fish and wildlife, and is capable of crowding out native plants and destroying the lake’s ecosystem.


“Fragmentation of hydrilla – either intentionally by hand-pulling or inadvertently through boating – is a very serious threat, not only to the delicate ecosystem of Clear Lake but to every other water body downstream from Clear Lake, including the Sacramento Delta,” said Dr. Robert Leavitt, Assistant Director of Plant Health and Pest Prevention Services for the California Department of Food and Agriculture (CDFA).


This seriousness, according to Leavitt, is what prompted California to declare hydrilla an invasive species requiring eradication.


It also is the reason why state employees are working diligently on the eradication efforts on Clear Lake. Each of these fragments is capable of starting new plants.


Considered one of the worst invasive aquatic weeds in the world by many aquatic nuisance species specialists, Hydrilla verticillatta is easily spread as it propagates freely from small fragments that are often created by the churning of boat propellers. Those fragments continue to live while floating, and once they come in contact with mud or lake bottom, they begin to root.


If left untreated, hydrilla plants spread rapidly and can interfere with boating, impact water storage and transport mechanisms, and eventually, even harm the ecosystem.


“It’s really important that the public is aware of their role in stopping the spread of hydrilla,” said Pamela Francis, deputy director of Water Resources, a division of the Lake County Department of Public Works. “We need everyone’s help to keep this weed from blanketing Clear Lake.”


As part of its ongoing eradication efforts on Clear Lake, CDFA has placed orange buoys at locations around the lake to mark where hydrilla has been spotted and where treatments occur. Boaters are asked to avoid these areas.


It is illegal to moor to the buoys, and officials also are asking boaters to stay as far away from the buoys as possible to keep out of the treatment areas.


“The boating public should be aware that their cooperation in avoiding these areas is critical to prevent further fragmentation and spread,” said Patrick Akers, CDFA Hydrilla Eradication Program manager.


In addition to avoiding the affected areas, the public is reminded that any removal of any aquatic weeds – whether by hand-pulling or by mechanical or chemical means – requires a permit.


“Some people don’t realize that even the simple removal of one plant by hand can cause fragments to be released,” Francis said.


In addition to fragmentation, hydrilla reproduces with seeds, tubers and turions, which can remain viable for several days out of water or several years in sediment before re-sprouting.


Since 2002, Lake County has implemented an Aquatic Plant Management Program, which allows for the abatement of nuisance aquatic vegetation for the purposes of navigation and recreational use of Clear Lake through a permit process.


This regulatory program is managed by the Lake County Department of Public Works, which serves as a single-point source for obtaining the permit to control weeds to be in compliance with the California Department of Fish and Game, the California Department of Food and Agriculture Hydrilla Eradication Program, the Lake County Agricultural Commissioner, as well as the Regional Water Quality Control Board.


For information, contact the Lake County Department of Public Works, Water Resources Division, at 707-263-2341 or go online to: http://watershed.co.lake.ca.us.


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