"Public health officials have their hands full keeping your clam chowder and raw oysters safe. That's due, in part, to red tides."

"Red tides happen nearly every year as coastal waters warm, killing fish and poisoning shellfish along U.S. coasts. They're not actually tides; they're huge blooms of naturally occurring toxic algae.

If people eat shellfish infected with these algae they can become sick with what's called paralytic shellfish poisoning.

But scientists with the National Oceanic and Atmospheric Administration are working to prevent outbreaks by tracking when and where red tides will happen next.

The toxic algae sleep nestled in the muck at the bottom of Puget Sound. A team of NOAA scientists based in Seattle was recently out looking for the algae so they can predict where and how big the red tides might be in the spring and summer — when the algae wake up and start to infect shellfish."

Ashley Ahearn reports for KUOW in Seattle on NPR's All Things Considered March 28, 2012. [2]