Battling 'Red Tide,' Scientists Map Toxic Algae To Prevent Shellfish Poisoning

Play associated audio

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.

It's hard to predict where these blooms will occur because winds and currents move the clouds of algae around. So the scientists target areas where blooms have occurred in the past.

They've found high levels of algal cysts in areas that later had high levels of poisoned shellfish. The toxins don't go away when shellfish are cooked or frozen.

No one has died from paralytic shellfish poisoning in Washington state since the 1940s. But every year the state's Department of Health manually tests thousands of clams, oysters and mussels for toxin levels. And every year some shellfish beds are closed to harvesting.

Mapping the algae at the bottom of Puget Sound won't replace manually testing the shellfish, but the NOAA team wants to make the Department of Health's job easier.

"We want to be able to say when and where there is a really strong chance of a bloom occurring so that the shellfish growers and the health managers are able to put in place some strategies to try and prevent, or reduce and limit, the impacts that these blooms can have," says Stephanie Moore, a NOAA scientist.

Moore says scientists have a lot to learn about what triggers these red tides. One thing's certain though: The algae love warm sunshine-filled water. Researchers say they could see more blooms as water temperatures rise.

Ashley Ahearn is a reporter for NPR member station KUOW in Seattle.

Copyright 2012 National Public Radio. To see more, visit http://www.npr.org/.

NPR

Credibility Concerns Overshadow Release Of Gay Talese's New Book

NPR's Kelly McEvers speaks with Paul Farhi of the Washington Post about Gay Talese's new book, The Voyeur's Hotel. The credibility of the book, which follows a self-proclaimed sex researcher who bought a hotel to spy on his guests through ventilator windows, has been called into question after Farhi uncovered problems with Talese's story.
NPR

Amid Craft Brewery Boom, Some Worry About A Bubble — But Most Just Fear Foam

Fueled by customers' unquenchable thirst for the next great flavor note, the craft beer industry has exploded like a poorly fermented bottle of home brew.
NPR

White House Documents Number Of Civilians Killed In U.S. Drone Strikes

The Obama administration issued a long awaited report Friday, documenting the number on civilians who have been accidentally killed by U.S. drone strikes. Human rights activists welcome the administration's newfound transparency, though some question whether the report goes far enough.
NPR

Tesla 'Autopilot' Crash Raises Concerns About Self-Driving Cars

The National Highway Traffic Safety Administration is investigating a fatal crash involving a Tesla car using the "autopilot" feature. NPR's Robert Siegel talks to Alex Davies of Wired about the crash and what it means for self-driving car technology.

Leave a Comment

Help keep the conversation civil. Please refer to our Terms of Use and Code of Conduct before posting your comments.