Quagga mussels grabbed the spotlight again Tuesday during the weekly Lake County Board of Supervisors meeting. A number of concerned citizens showed up for the meeting that lasted until nearly 6 p.m. The meeting shows that Lake County”s citizens are concerned about the welfare of the county”s most prized possession — Clear Lake.
The consensus of opinion is that if the invasive mussel ever gets here it would change the ecology of North America”s oldest lake for thousands of years. Clear Lake”s estimated age is between one and two million years.
Many people have heard about the quagga and zebra mussels but many don”t know how they got into the United States and California and why they are bad for the environment. The quagga and its close cousin, the zebra mussel, are native to the Ukraine. The quagga mussel is a native of the Dneiper River system in the Ukraine, which is near Russia. The mussel is now well established throughout the eastern European countries and actually has natural predators, including a type of diving ducks and a species of fish. It is believed the mussels reached America in 1989 in the ballast of a foreign ship. Ships often pump water into ballast tanks when they are empty to stabilize the ship. When the ship arrives at it destination, the water is pumped out and the ship is loaded with goods. The mussels first appeared in the Lake Erie, which is one of the Great Lakes.
Within a few years the mussels spread throughout the Great Lakes states such as Minnesota, Wisconsin, Illinois and as far east as New York. Trailered boats as well as river currents spread the mussels, which experts said would be stopped east of the Mississippi River. That wasn”t the case as quagga mussels were found in Lake Mead in Nevada in January of 2007. Within just a few months they were discovered in Lake Havasu and in several lakes in San Diego County.
The mussels are filter feeders, meaning they get their food by pumping water through their digestive system. As the water passes through their digestion system the mussel extracts the plankton as food. An adult quagga mussel is only about the size of your fingernail but can pump a quart of water per day through its system. Plankton is a vital food source for most juvenile fish, including largemouth bass. A bass fingerling will feed almost exclusively on plankton for the first week of its life before it switches to insects. If the plankton isn”t available, the young fish could starve. Other species such as crappie, bluegill and catfish as well as the baitfish, such as threadfin shad, need the zoo plankton for food.
The reason Clear Lake is such an excellent bass fishery is because the lake is so fertile in plankton. Of course, the vast number of fish in the lake also attracts thousands of water birds that feed on the fish, such as osprey, grebes and herons. Scientists say that if the mussels get established in the lake this vital food source of plankton would soon disappear and the fish along with it. The birds also would leave once their food source is gone.
Clear Lake”s excellent bass fishery could also be its undoing. The lake”s popularity among fishermen has soared the past few years and the lake now plays host to more than 50 bass tournaments each year. Many of these tournaments draw fishermen who trailer their boats from Southern California, Nevada and Arizona. The fear is that the adult mussels or their larva (called veligers) will hitch a ride on one of the bass boats. Scientists say a mussel or veliger can live for several weeks in the livewell or the boat”s bilge just as long as there is sufficient water.
One of the most effective methods of preventing the mussels from reaching Clear Lake is to conduct boat inspections and boat decontamination. If a boat arrives from out of the area it would have to be decontaminated and that means spraying the entire boat, which includes livewells, bilges and boat trailers, with water that is at least 140 degrees. That temperature will kill the mussels and veligers.
It”s not only bass boats that would have to be checked and decontaminated but pleasure boats as well. Wakeboard boats have large ballast tanks that are filled with water. If a wakeboard boat has recently been to Lake Mead or Lake Havasu there is a good chance it could be infected with the mussels.
Most scientists agree that public education is vital in controlling the spread of the mussels. The bass tournament organizations recognize what the mussels could do to their industry and are educating their fishermen on the importance of checking their boats before launching them. The county is also taking the lead in preventing the mussels from getting here.
