The most common fish in Clear Lake isn”t the largemouth bass, crappie or catfish; it”s the silverside minnow. Presently there are literally millions of these small fish. A good example is Library Park where the small minnows are so thick that you can almost walk on them.
Like many of the fish in the lake the silverside minnow is an introduced species. The fish was first introduced into the lake in 1967 to control the Clear Lake gnat. It does this by eating gnat larva. Prior to the introduction of the silverside minnow the gnat population was controlled by spraying the lake with DDT, which in turn killed many of the fish-eating birds on the lake such as grebes and ospreys.
The introduction of the small minnows did work and within a few years the gnat population was reduced to nearly nothing. Silversides also eat plankton and compete with some of the other plankton-eating fish such as the hitch, blackfish, threadfin shad and even the bass fry and crappie fry. During years when the plankton counts are down the silverside population also goes down. They live two years and spend much of their life in the middle of the lake. The fish is also affected by water temperature and thousands will die during a cold spell. Most of them sink to the bottom and are rarely seen floating in large numbers. The silverside population swings wildly at Clear Lake. One year, such as this year, the silversides are everywhere. During other years few are seen.
The silversides are also an excellent prey fish for juvenile bass. The young bass herd the silversides close to shore before attacking them. For years it was believed that adult bass wouldn”t prey on the small fish because they would have to expend too much energy for a very small meal, however recent studies by fishery biologists have discovered that larger bass will eat the silversides. While not their preferred food source, bass will eat anything they can catch.
One predator that preys heavily on the silverside is the Western Grebe. They are such fast swimmers they have little trouble catching silversides and will gobble them up like popcorn. Another large bird that eats the silverside minnow is the American pelican. I have seen a flock of pelicans herd schools of silversides into shallow water and then scoop up hundreds of the small fish. When you figure that an adult pelican can consume up to 4 pounds of fish a day, that adds up to a lot of silverside minnows.
With the Clear Lake hitch on the verge of being declared an endangered species it will be interesting to see what impact the silverside minnows will play. Both eat the same plankton and, in fact, fishery expert Peter Moyle suggests the silverside minnow could have contributed to the demise of the Clear Lake splittail, which is now extinct. The splittail is a relative of the hitch and was once in the lake by the thousands.
A few anglers will scoop up a net full of silversides and use them for catfish bait. They place five to 10 silversides on a hook. For the most part they are too small and aren”t worth the trouble. The good news is they are excellent prey for smaller fish such as crappie and bluegill.
Part of the reason a large bass hides beneath a large weed mat is because it attracts the silversides, which in turn draws the smaller bass and the larger bass. In other words, one weed mat can supply a complete food chain.
From all indications it appears the silverside minnow population will be part of the Clear Lake ecosystem for many years to come. The lake offers excellent habitat for the small fish and as long as there is plankton and Clear Lake gnats to eat, the small minnow will survive and thrive.
