Howarth Park boat rentals closed due to blue-green algae bloom

Recreation and Parks officials warned people and pets to stay out of the waters, restricting even boat rentals.|

A blue-green algae bloom near the Howarth Park boathouse at Lake Ralphine kept boat rentals docked July 6 and will likely remain that way for several days, according to Santa Rosa Recreation & Parks.

Signs have been posted near the water advising parkgoers to avoid touching or ingesting the algae and to keep children and pets away.

“Both animals and humans can be affected by blue-green algae,” said Ray Ho, managing director and toxicologist at the San Francisco branch of California Poison Control. “If you’re in a body of water with blue-green algae, or if you ingest it, you can develop symptoms such as rashes, vomiting or diarrhea.”

Kristi Buffo, communications coordinator for the city of Santa Rosa, said while most algae is harmless, some species of blue-green algae, also known as cyanobacteria, produce toxins.

“To determine whether an algae bloom is toxic and the level of toxicity requires laboratory testing,” she said, “and the cost and timeframe to conduct these tests each time blue-green algae is observed at Lake Ralphine is prohibitive.”

When rentals are not interrupted by algae blooms, the Lake Ralphine boathouse rents out approximately 25-35 boats per weekend, and also provides boats for use by summer campers with Camp Wa Tam and Doyle Adventure Camp.

Dogs are at the most risk for developing symptoms of cyanobacteria toxicosis, caused by the poisonous algae, because of their tendency to play in the water.

Algae blooms frequently appear in stagnant water during warm weather spells, and may appear as blue-green or red-brown blooms, mats or scum on the water, according to the Cornell University Canine Health Center. Symptoms of cyanobacteria toxicosis may develop rapidly or over several hours, and should be treated as a veterinarian or medical emergency.

The Santa Rosa Recreation & Parks Department on May 14 advised people to stay out of Lake Ralphine because of the blue-green algae.

Visitors to freshwater parks can learn more about keeping their animals and themselves safe at

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