The Lake County quagga mussel prevention program has been in existence for nearly 10 years and to date it has been very successful. No quagga or zebra mussels have been found in the lake thanks to an extensive inspection program whereby all boats entering any of the waterways in the county are screened or inspected.
If the quagga mussel ever becomes established in the county, especially in Clear Lake, the results would be disastrous. Water intakes would become clogged, which would take thousands of dollars to fix. Even outboard motors could sustain damage. This has happened at other lakes across the country.
The good news is the county is taking positive steps to keep the mussel out of Clear Lake and the county. Lake County has one of the most comprehensive mussel inspection and preventative programs in Northern California. Every boat has to be screened or inspected, either monthly for non-residents or yearly for residents. Boats must be issued a quagga mussel sticker before they are allowed on any waters in Lake County. Inspectors are stationed at the public ramps on Clear Lake and they check for a current mussel sticker.
Despite widespread publicity, surprisingly few people know the biology of the quagga mussel, their lifecycle, how they reproduce and their feeding habits. Most people don’t even know where they came from. The mussel is one of seven of the Dreissena species and originally came from the Dnieper River drainage in the Ukraine. The mussel was named after an extinct subspecies of the African zebra because of the stripes on its shell. The mussel has a lifespan of about five years and is a filter feeder, meaning it draws water into its shell cavity by a siphon action and extracts the phytoplankton and zooplankton. An adult mussel is about the size of your thumb nail but it can pump approximately a quart of water through its system in a day. The female mussel is capable of producing up to one million eggs a year.
In parts of the Great Lakes, the mussels number more than 700,000 per square meter. After fertilization, microscopic larva (also called veligers) develop within one or two days. Within a few days they develop bivalve shells. The free-swimming veligers drift with the current up to four weeks until they locate a hard surface. They permanently attach themselves with a strong glue-like substance.
The adult mussels are unable to swim and they also drift with the current. However, once they come into contact with a hard surface they excrete a slime-like substance that is similar to super glue. The mussel will stay attached to the hard surface until it’s either brushed off or removed. This ability to stick to a surface is the reason mussels cause so much damage. They attach themselves to water intakes and clog up the screens on the pumps. They are also known to do the same to outboard motors.
Quagga mussels can tolerate cold water but not hot water. If the water temperature reaches 80 degrees there is a significant mortality of the mussels and at 90 degrees it is 100-percent fatal. Hot water is one method used to decontaminate a boat. The water is heated to 140 degrees and sprayed on the boat. It takes less than five seconds to kill any mussel that comes into contact with the hot water. Once quagga mussels become established they are impossible to eradicate. Scientists are working to create a pesticide that will kill mussels without harming the environment, but to date they haven’t been successful.
Clear Lake has ideal conditions for quagga mussels. The lake has a high calcium content and there is an excellent supply of phytoplankton and other small particles for the mussels to feed on. The mussels would also eat the green algae, which is the good algae in Clear Lake. They will not eat the cyanobacteria, which is the bad algae.
The Lake County Water Resources Department will be doing a public survey and education outreach program on quagga mussels. The survey can be found on its website. For more information about the quagga mussel prevention program call 263-2344. You can also go to http://www.nomussels.com for more information.
