Theories abound about the cause of the recent carp die-off around Clear Lake. They range from herbicide poisoning, a fish virus, and decaying weeds that use up oxygen in the water.
A number of fishermen are concerned that other fish such as bass, crappie and catfish will also die.
The cause of the die-off remains unknown and the number of carp affected is also unknown. Best estimates run from a 1,000-10,000, possibly more. The dead carp have been washing up on beaches all around the lake.
While the die-off has been bad, it”s nothing compared to the massive die-off that occurred in the late 1980s when tens of thousands of carp died. In fact, there were so many dead carp back then that some lakeside residents used tractors with front-end loaders to gather up the dead fish. The cause of that die-off was never discovered.
The Department of Fish and Game (DFG) classify carp as a non-game fish and it”s unlikely that DFG fishery biologists will spend much time trying to figure out why the carp are dying as long as they don”t create a health hazard for humans or other animals.
Carp are a hearty fish and can survive water temperatures that range from freezing to more than 90 degrees. They also have the ability to absorb what is called “atmospheric” oxygen. What that means is that if the oxygen levels are too low in the water, carp can still breathe by sticking their noses above the surface and inhaling oxygen from the air. This dispels the incorrect theory going around that the carp are dying from a lack of dissolved oxygen (DO) in the water.
It”s also unlikely that the spraying of herbicides to kill weeds in Clear Lake has affected the carp. Only a few small areas have been sprayed and the herbicide used is safe for fish.
According to DFG fishery biologist Jay Rowan, the carp could be dying from a virus or a bacterium. He said the overall fish population of all species in Clear Lake is extremely high and the carp could have contracted a bacteria or virus from other fish by being in close proximity. He won”t know until samples of the dead carp are studied in a laboratory.
Regardless of what is killing the carp, there is nothing the DFG can really do to stop it. Clear Lake is just too large to treat. Most likely the carp die-off will run its course the next few weeks.
I took a drive around the lake on Monday and the dead carp are widely scattered. Several bass fishermen said that there even are large numbers of dead carp in the middle of the lake and they have been using care to avoid hitting them because a 15-pound carp can do serious damage to a speeding boat.
A bigger problem is what lakeside residents can do with the hundreds of dead carp washing up on their beaches. They have been told to bury them but several residents are reporting that the ground is too hard to dig a hole. If left on the beach to rot, the stench will drive most people from their homes.
The county plans to place dumpsters at locations around the lake for residents to take the dead carp. These locations will be announced later this week.
Carp aren”t native to the United States. They are native to Europe and Asia. It is thought that they were first introduced in United States in 1830 in New York State as a food fish. They arrived in California in 1872 when five carp were placed in ponds in Sonoma County. From there, they rapidly spread throughout the state and it is believed they arrived in Clear Lake around 1900.
Carp are the most widely eaten fish in the world, with more than 200,000 tons of the fish consumed annually. Carp provide more protein worldwide than cattle. Eastern Europe and Asia are the primary areas where carp are a popular food fish, the reason being they are high in protein and low in fat.
Carp can thrive in just about any type of fresh water. They are omnivores, meaning they will eat both fish and vegetation. Many people don”t know that a carp has large molars in the back of his mouth that he uses to grind up his food. A female will produce approximately 300,000 eggs during a single season. They are also a long-lived fish. The oldest carp on record lived to age 47. Many live to be 20 years old.
Whereas most people think carp are a trash fish, there are individuals who fish for them and consider them excellent fighters. In fact, there are carp tournaments, including several which are held at Clear Lake. There is also the annual bow fishing tournament on Clear Lake where fishermen shoot the carp with their archery equipment.
