With the fear of the quagga mussel reaching Clear Lake and the invasive plant hydrilla already here, a number of people are wondering what is worse, the mussels or hydrilla.
Whereas hydrilla is already established in the lake, quagga mussels are not (at least there is no evidence that the invasive mussel is here). And make no mistake because hydrilla is a serious threat to our lake. If left unchecked, it could turn Clear Lake into a giant grassy field with no fish and no open water for boating of any kind.
Hydrilla was first discovered in Clear Lake back in 1994 when a small patch of the invasive weed was located north of Lakeport. Within a couple of weeks, that patch had grown to more than 40 acres. While the state has managed to control the plants, every few years there”s another outbreak. California has spent millions of dollars trying to eradicate the plant.
Overall the state has kept hydrilla in check. In fact, not a single hydrilla plant has been found in the lake during some years. In the past few years, only an occasional patch of hydrilla has been found.
But that situation changed last month when state hydrilla crews from the Department of Food and Agriculture (CDFA) found hydrilla once again growing in several locations around the lake. In fact, hydrilla was recently discovered near the boat ramp at Redbud Park in Clearlake.
To eradicate the plants, the hydrilla crew will use a two-prong approach. First, it will spray the plants with the herbicide Komeen, which will knock down the plant. It will then apply the herbicide Sonar to kill the roots.
Komeen is copper-based chemical and has been tested by scientists at U.C. Davis and found to be safe in drinking water. It kills a plant by basically knocking it down. However, it doesn”t kill the roots. The best part about Komeen is that it acts quickly. The herbicide is sprayed on the plants and has a purple color.
Sonar is applied a few days after the Komeen. It is a systemic type of herbicide much like Round Up that”s commonly used on weeds around homes. It disrupts the plant”s ability to photosynthesize. However, it doesn”t always kills the roots and tubers.
Sonar needs more time to be effective. It is applied in clay pellets to the base of the plant and as the pellets dissolve the herbicide goes to work.
Both chemicals are registered and approved for use on aquatic weeds in potable water systems.
Fishermen are concerned that spraying for hydrilla will kill fish and other aquatic creatures, but in an experiment conducted in 1995, the Department of Fish and Game placed bass, catfish, crappie and bluegill in cages, then sank the cages in known hydrilla areas. The hydrilla crew then sprayed the area, including the cages, with both Komeen and Sonar. The fish were monitored for two weeks and the result was that none of the fish died or even got sick. The opinion among biologists is that the herbicides are applied in such low doses they have no effect on fish or other aquatic creatures.
If left unchecked the hydrilla could have a devastating impact on the lake. Hydrilla grows extremely fast and can literally take over a body of water in a short time. Florida is a good example. There are large lakes in Florida that are now completed choked off with hydrilla and the state has given up trying to eradicate the plants. Instead, they cut pathways through the plants so that boats can reach the open water.
California officials also worry that floating hydrilla plants could pass over the Cache Creek Dam and end up in the Delta. Cache Creek empties into the Delta. Experts say if that happens it could cost millions because it would clog up pumps that are used for irrigation and municipal water works.
The bad part about hydrilla is that a plant that has been dormant for years can suddenly sprout and take hold if conditions are right. In one test, a hydrilla plant was placed on a concrete slab and allowed to dry out in the hot sun for three years. The plant was then placed in a pond and within days it sprouted and started growing.
Boats traveling through the plants often spread it throughout the lake. The boat propellers cut off parts of the plants and they become free floating and can drift for miles before taking root. This is what is probably happening at Clear Lake.
Hydrilla and the quagga mussel are two more reasons we have to be careful about what we put into Clear Lake. We need to keep our boats clean and keep them dry.
