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Coastline Protection

Mary Wilcox Silver, UC Santa Cruz Mary Wilcox Silver, professor, Ocean Sciences Department, UC Santa Cruz; adjunct scientist, Monterey Bay Aquarium Research Institute

Increasing incidents of harmful algal blooms along the Pacific Coast have oceanographers stepping up both monitoring and public education efforts.

"It's a problem that's been with us for thousands of years," says Mary Silver, a UC Santa Cruz researcher who is part of a group studying the risk potential. "California has been monitoring this since the late '20s because people died from eating mussels. Some have pretty potent toxins."

In 1927, about a dozen people in Northern California died from eating mussels contaminated with a naturally occurring toxin. That put the state on alert, and monitoring programs along the coast have curtailed human risks.

In recent years, toxins produced by different kinds of microscopic algae, or phytoplankton, have shown up in marine life and birds in West Coast waters. These neurotoxins cause syndromes known as paralytic shellfish poisoning and amnesic shellfish poisoning. Silver has documented the presence of domoic acid neurotoxin in sport fish present near a fishing pier in Santa Cruz. Severe cases of domoic acid poisoning can cause seizures and comas and loss of short-term memory. Commercially sold fish and shellfish are tested for toxins, but recreationally caught seafood can pose a threat, particularly to populations who consume more recreationally caught seafood or whose preparation preferences might make the toxins more dangerous. Cooking a fish whole without gutting it, for example, or frying it increases toxin exposure.

"There are natural shifts in the distributions of these critters," Silver says. "As the currents change certain dangerous toxins will disappear and others flourish."

Using sophisticated remote monitoring equipment, Silver says soon researchers will be able to detect in near real-time the presence of toxic species in the coastal waters rather than waiting for mammal or bird deaths or human illness to alert them. Researchers aren't sure why more incidents of toxins are showing up. Silver isn't yet convinced humans are causing it although in some areas sewage runoff might encourage more algae growth.

"I'm not sure how much of a role humans have played," says Silver. "I'm not willing to say we've screwed up the water."


Click Here to listen to Silver describe her research.


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