The recent fish die-off in the Lakeport area is a reminder of what can happen if we don”t take care of the county”s most precious resource — Clear Lake.
Approximately 2,000 dead fish were found just north of Lakeport on July 31. More than half of the fish were carp, but at least 500 were largemouth bass, crappie and catfish. The area where the fish died stretched from Rumsey Bay to the Pit Stop. A check of the area on July 31 revealed dead fish in isolated pockets around docks and lakeside homes.
The fish die-off drew widespread media attention, including television coverage from a Sacramento TV station.
The official explanation for the fish die-off was the hot weather and a lack of oxygen in the water. While this is probably true, the primary reason for the low oxygen levels was because of the commercial spraying of herbicides just five days prior to the die-off. The herbicide killed the weeds, which in turn used up the oxygen as they decomposed.
The fish die-off occurred on either Saturday night, July 29, or Sunday morning, July 30. The area where the fish die-off occurred was the same area that was sprayed with an herbicide July 24-25 to control aquatic weed growth.
During this period, the daytime temperatures averaged more than 105 degrees. I took a water temperature reading at Library Park in Lakeport on July 25 and it was a scorching 91.5 degrees.
The hot weather combined with the dying vegetation completely depleted the oxygen in the areas that were sprayed. That in turn killed the fish. Fish aren”t the smartest critters in the world and most won”t move to a new area when the dissolved oxygen (DO) levels drop.
The county issued six permits for herbicide spraying of weeds for north Lakeport during that week. The total area to be sprayed covered approximately 2 1/4 acres divided up into small plots.
According to the county”s Clear Lake Integrated Aquatic Plant Management Plan, the licensed applicator is supposed to visit the area where the spraying is to take place immediately prior to applying the herbicide. The applicator is supposed to check DO levels, water temperature, wind and several other factors. If the conditions are not right and there is the possibility of harm to the lake, the spraying is to be delayed and rescheduled.
With more than a week of record high temperatures, there is no way the county should have approved the spraying.
What the plan doesn”t address is who is monitoring the commercial applicators. In other words, the county doesn”t have a monitoring plan in place to record water temperatures and other adverse weather conditions. The county relies on the contractor to do this.
What should be in place is a plan requiring the applicator to check in with the county the day the spraying is to take place. The county should check the weather conditions and approve or disapprove the spraying.
In short, the county should be required to sign off on each day there is spraying to be done.
A check of the local fishing guides and other fishermen who were on the lake during the week of July 24-31 revealed that no other areas suffered any significant fish die-off. There were reports of a threadfin shad die-off in the Nice-Lucerne area, but these are normal and occur every year. Shad are fragile fish and any change in water temperature normally results in a die-off, sometimes massive.
It”s not only the county that”s to blame for the fish kill. The Department of Fish and Game (DFG) also has to share in the blame. Clear Lake is the largest natural lake in California, yet the DFG has no fishery biologist assigned to it (there is no biologist doing any monitoring of Clear Lake whatsoever).
Worse yet, DFG doesn”t even have a fishery biologist for Lake County. Instead, the DFG has basically turned over the fish management of the lake to the county and the county doesn”t have a biologist or fish expert.
There are two game wardens assigned to the county but they spend much of their time doing work on the Mendocino Coast. It all adds up to a disaster just waiting to happen.
Fortunately only 2 1/4 acres were sprayed late last month. If it had been double or triple that amount, the fish kill could have easily reached 10,000.
So what”s the solution?
The Lake County Fish and Wildlife Advisory Committee has been recommending for several years that the county hire its own fishery biologist. Clear Lake is rated the No. 2 bass fishing lake in the world and draws thousands of tourists from around the country. Since the DFG can”t manage the fishery in the lake, it behooves the county to step in and do the job. If a fishery biologist had been on board last month it is doubtful that the recent fish kill would have occurred.
