also, from a nearby lake in Watsonville, CA
Pinto Lake fish kill probed
WATSONVILLE -- About 200 dead carp have washed up at Pinto Lake in the past week.
The state Department of Fish and Wildlife is examining the fish to determine what caused the deaths, said Robert Ketley, Watsonville water quality specialist. But because of their advanced state of decomposition, it may be difficult to say for sure what happened.
Ketley said it's possible the bottom-feeding carp are victims of the toxic blue algae that plagues the lake. As the algae decays and drifts to the lake bottom, it can cause ammonia levels to increase and oxygen to decrease, he said. Because carp feed in the depths, they are more likely to be affected than other fish.
Cyanobacteria, or blue-green algae, has long infected the 80-acre lake, the center of city and Santa Cruz County parks in rural Pajaro Valley. The problem is pronounced when temperatures rise, and a warm fall produced a late algae bloom.
Exposure to toxins produced by the algae can cause rashes, nausea, diarrhea, liver and kidney damage in humans. The toxins also have been linked to deaths of livestock, dogs and sea otters.
A study of Pinto Lake, released last spring, concluded nitrogen- and phosphorous-laden sediments deposited in the lake 50 to 100 years ago, possibly due to erosion in clear-cut forests, are the main culprits in providing nutrients for algae growth.
No swimming is permitted in the lake, and warnings are posted when toxin levels are too high for safe