The recent fish die-offs around Clear Lake mostly concerned bass, crappie and bluegill. In other words, the majority of the fish impacted by the low oxygen levels were non-native fish. Native species such as hitch, blackfish and sculpin weren’t hit as hard and there is a reason. Bass, crappie and bluegill spend most of their lives in shallow water where the hot weather and low dissolved oxygen (DO) has a much bigger impact than in the deeper water. The native fish spend most of the their lives in the deeper water, which has a higher DO.
Clear Lake has a number of native fish that are rarely seen by fishermen. Take the black fish for example. They spend most of the lives in the deeper water. With the exception of when they are running up the streams to spawn, hitch also spend the majority of their lives in the middle of the lake. Hitch have been in Clear Lake for more than 100,000 years. They were an important native fish for the Pomo Indians who harvested them. The hitch supplied important protein for the tribes that lived along the shore of the lake. The tribes are currently active in protecting the hitch.
Many of these species of non-game fish hover at the bottom of the food chain and without them there would be no bass or catfish, for the simple reason they provide food for game fish.
While hitch, carp and silverside minnows are the most common and easily recognized species of non-game fish, there are others that are an important part of the lake’s ecosystem.
Take the prickly sculpin for example. This distant relative of the ocean lingcod is a native of Clear Lake and dates back to prehistoric times. Few people, including old-time residents, have seen this small fish. They are very common and are an important food fish for the bass and catfish, and yet their habits are so deliberate and their camouflage is so good we rarely seen them.
Sculpin spend most of their time quietly lying on the bottom of the lake. During the day, they hide underneath or in submerged objects such as rocks, logs or other debris. At night they come out to actively forage for food. They feed on invertebrates, mollusks and small fish. In Clear Lake, their primary food is midge lava. Often they lay in wait for a small minnow to swim by and then rush it. They are not fast swimmer, which makes them ideal prey for bass or catfish.
A commercial diver once told me that he had often observed hundreds of small sculpin resting on the bottom. I have also caught bass that spit up sculpin in my livewell. They are an important source of food for the bass. In fact, some of the more experienced bass fishermen use plastic replicas of sculpin as lures and they have been highly successful.
Goldfish are also common in Clear Lake. Contrary to their name, goldfish can be either gold, brown or black in color. The resemble a small carp but do not have the barbels or whiskers. They are also a good food source for the game fish.
Tule perch are also found in good numbers in Clear Lake. This fish superficially resembles a sunfish but is the only freshwater member of the surfperch family, a group that doesn’t lay eggs. The young are developed within the mother’s body.
The Sacramento blackfish is common in Clear Lake but is rarely seen by the average angler. It once was an important commercial fish. It is the largest of the minnow family and can attain weights of up to 10 pounds. It feeds on plankton and spends most of its life in the middle of the lake. Years ago this was the prize fish of the commercial fishermen. The blackfish were transported live to the Asian restaurants and stores in the Bay Area and sold for as much as $5 per pound. They are no longer harvested commercially on Clear Lake.
Why do I bring up the subject of these little known and rarely seen fish that inhabit Clear Lake? We don’t catch them or eat them. The truth is that if we don’t worry about these non-game fish and destroy their habitat, we will in the end also destroy our game fish such as bass, catfish and bluegill. They are tied together by a fragile thread.
Every year there is a cry to clean up the lake and remove the algae, weeds and silt. However, before anything is done to alter the ecosystem in the lake – such as removing the algae, silt or weeds — extensive studies should be conducted on the consequences for these little understood non-game fish. Once any damage is done to the lake it could take a long time before it corrects itself.
