While the Clear Lake hitch has been garnering most of the headlines in Lake County the past few months, the real worry among county officials is the quagga mussel, and it”s easy to see why.
If the quagga mussel ever becomes established in the lake, no one will even think about the hitch. 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 nonresidents or yearly for residents – and issued a quagga mussel sticker before it is allowed on any waters in Lake County.
For example, the county issued 6,447 nonresident stickers and 4,376 resident stickers for a grand total of 10,823 stickers in 2012. The county also has 22 quagga mussel monitoring stations located around the lake and will be adding 50 more within the next few months, using a grant of $2,500 from the Fish and Wildlife Advisory Committee. The new monitoring stations will be given to lakeside dock owners and suspended by a cable from the ends of the docks. The dock owners will be given training and will check the stations weekly and report their findings to Water Resources.
Beginning in the summer the fine for not having a sticker on a boat will be lowered to $100. The infraction will be considered an administrative fine paid to the county instead of to the court.
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 from the water. An adult mussel is about the size of your thumbnail 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 and 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 and permanently attached themselves with a strong glue-like substance. The mortality rate of the veligers can be as high as 99 percent. According to Lake County Invasive Species Program Coordinator Carolyn Ruttan, if a boat infested with the mussels was launched into Clear Lake and only a few of the mussel survived, it would take three or four years for them to become established.
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.
So far only one boat that has entered Lake County has been found infested with the mussel. That boat was quarantined and decontaminated. Keeping the mussel out of the county remains a top priority and everyone”s cooperation is needed to keep it that way.
