Red Tide - considerations

Almost every Mainer is familiar with the phenomenon of red tide or harmful algae blooms (HAB). We also trust that our local fishmongers will only serve us safe food. But what about when you are harvesting your own?

The algae we're concerned with are dinoflagellates, some of which are responsible for bioluminescence. In Maine the phytoplankton culprit is called Alexandrium tamarense who, when the conditions are right, produce toxins. Conditions necessary for HAB are the presence of the algae in the water and nutrients like potassium and nitrogen, which are supplied from upwellings from deeper areas in the Gulf of Maine. Other sources of nutrients are from pollutants, including fish farms and aquaculture. A storm after a series of calm, sunny days and warm water is a common scenario in which a bloom takes place.

The shellfish themselves are not harmed by the algae, but they are filter-feeders and the toxins remain with the shellfish. According to NOAA, over 50 percent of unusual marine mammal mortality events are due to harmful algae blooms.

The most significant hazard is that if people eat shellfish that have processed the algae they may get paralytic shellfish poisoning (PSP).

The first symptom many report is a numbness or tingling around the mouth also reported is tingling of the face and neck areas, headaches, nausea, and muscle weakness. In extreme cases, the symptoms can lead to respiratory failure and death.. If any of you or your party experience symptoms like this it's time to mobilize quickly!

The last case of PSP in Maine occurred in August of 2007 when a downeast family ate mussels found on a drifting barrel. Symptoms took only minutes to manifest themselves and hospitalization was necessary. So use caution and remember how long it can take to get to a hospital from Jewell island or where ever you are paddling.

It's a good idea to keep the shellfish hotline in your phone list. 1-800-232-4733 or 207-633-9571.


There's more information on the state site - including beach closures

More info is available at these sites:

http://oceanservice.noaa.gov/redtide/

http://www.whoi.edu/sbl/liteSite.do?litesiteid=3230

http://www.whoi.edu/redtide/