At a Glance

More than 40 California lakes and waterways have been impacted by toxic algae blooms, the most in state history.Water agencies say they've been caught off guard by the blooms, and there's no quick fix for the problem.

For the first time in its history, California has reported toxic algae in more than 40 lakes and waterways from Los Angeles to northern parts of the state.

The rapid growth of the algae has led to health warnings, as well as , according to the East Bay Times. The situation, which has led to a reduction in park visitors and revenues, caught water agencies off guard.

"The algae caught everyone by surprise, and it was difficult to get clear guidance and protocols on what to do about it," said Carolyn Jones, an East Bay Regional Park District spokeswoman. "We went more than 80 years before we had a closure for this toxic substance in the drought."

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The cyanobacterium, which occurs naturally, can cause gastrointestinal problems and allergic reactions in people and sickness and death among pets and wildlife. The cyanobacterium has blossomed during the state's drought.

The microbes are causing more trouble because nutrients that built up during the drought were washed off hills during this year's rains.

Reporting of algae blooms has been spotty and inconsistent among the many different lake operators and owners. But there are many signs the algae is getting worse in California, said Beverley Anderson-Abbs, an environmental scientist with the state Water Resources Control Board.

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Among the waterways affected are Del Valle Reservoir near Livermore, Pyramid Lake near Los Angeles and Lake Elsinore in San Bernardino County, which have closed at times. San Jose closed its Cunningham Lake to boating and fishing for the first time earlier this month, and Contra Costa County health officials posted warning signs this year in some waters in Discovery Bay, a boater-oriented community.

Some lake managers are testing herbicides to reduce algae blooms, but experts say there is no quick solution.

"There is no silver bullet," Anderson-Abbs said. "Generally, the best thing to do is to stay out of the water until the bloom is over."

MORE ON WEATHER.COM: California's Long-Term Drought

The images in this slideshow give us a look at a historically low Folsom Lake, located northeast of Sacramento, California, on Sept. 17, 2015. (MARK RALSTON/AFP/Getty Images)