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Toxic algae bloom seen last summer in bay returns to Belvedere Cove

A toxic red tide spotted in Belvedere Cove last week is caused by the same microorganism that killed thousands of fish and marine life in the bay last summer.

According to the San Francisco Bay Regional Water Quality Control Board, the algae species Heterosigma akashiwo isn’t known to cause human illness, but officials still recommend people and pets stay out of the water.

“We’re carefully monitoring and tracking the bloom because we know the horrible effects that last year’s algae bloom had on marine life,” the board’s executive officer, Eileen White, said on a July 31 media call.

So far, they haven’t seen significant harm to marine life. A website set up by the California Department of Fish and Wildlife had registered 39 reports of dead organisms at The Ark’s press deadline Aug. 7, with the lone local report in the Pickleweed Inlet of Richardson Bay in Mill Valley.

The reddish-brown tide was spotted in Belvedere Cove, in Richardson Bay and off Muir Beach. Other reports have come in from Seaplane Lagoon off Alameda, the Berkeley Marina, near San Francisco Airport and San Pablo Bay.

“We don’t yet know what the trajectory will be of this bloom,” said David Senn, senior scientist at San Francisco Estuary Institute. “We’re hoping it doesn’t turn into what it turned into last year.”

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