Visitors to Clear Lake will see some profound changes this summer. The water is exceptionally clear and the aquatic weeds are everywhere just beneath the surface. There is also a lack of grebes and other fish-eating birds.
By July the weeds will be the No. 1 concern among those who live either on the shores of the lake or those who boat on the lake. For example, the shoreline in the Lakeport area is full of weeds that are presently just beneath the surface. These weeds will be sprouting to the surface within the next few weeks and will block access to the lake for many of the lakeside residents. Their only solution is to spend thousands of dollars treating the area with a herbicide and during these hard economic times many of the homeowners simply don”t have the money.
The excessive amount of weeds and a full lake will also have an impact on the fishing. The weeds offer excellent hiding areas for the bass, crappie and other fish. Clearer-than-normal water also makes the fish spooky and harder to catch.
Many county residents are also concerned that the grebes haven”t returned to the lake in any significant numbers. The grebe population numbered in the thousands only a few years ago. This year there are probably fewer than 1,000 of these birds on the lake and to date I haven”t seen a single grebe nest. On Tuesday I checked out on the primary grebe nesting areas near Long Tule Point and saw very few grebes and no nests. The reason for the lack of grebes is because there are no threadfin shad, very few silverside minnows, small bluegill and other small baitfish. Since the food source for the grebes is very limited, nature prevents them from nesting because there isn”t enough of a food source for the young. The past three years has seen very limited nesting of the Western and Clark grebes. In 2008 there wasn”t a single documented grebe nest on the lake and last year there were only a few.
The lack of shad and silverside minnows also has resulted in very few eared grebes visiting the lake. Even the cormorant population is down. Threadfin shad and silverside minnows consume various species of plankton and with the clear water there is little or no plankton. Recent plankton surveys done by Lake County Vector Control show a decrease in the amount of one of the primary plankton ? the Daphnia. They are actually very small plankton crustaceans and one of the primary food sources for all the juvenile species of fish in the lake, including bass. When the plankton population is down the small fish that rely on them also suffer and the birds that feed on the small fish have to migrate to other lakes to find food. Threadfin shad are a perfect example. When the shad were numerous in the lake, the plankton counts were very high and the grebe population and the populations of other fish-eating birds peaked. The shad population crashed two years ago and the bird population has declined considerably.
Clear Lake is a good example of a complex ecosystem where each species depends on the other to survive. If one link in the food chain is broken it impacts the entire chain. This year the lake is clearer than it has been in at least 15 years. Whereas the swimmers and some of the boaters like the gin clear water, the creatures that live in the lake prefer cloudy water rich in nutrients. A clear lake also means an explosion of weeds and that”s what is occurring this year.
Actually, there is little man can do or should do to change this 2-million-year-old lake. Clear Lake was here long before humans and will be here long after we are all gone.
