Welcome to the State of California 

Toxic Phytoplankton Distribution

volunteer Monitoring Program data 

The CDPH Marine Biotoxin Monitoring Program coordinates a volunteer-based monitoring program for toxic phytoplankton along the entire California coastline. A small number of the hundreds of phytoplankton species present in our coastal waters produce toxins that can be fatal to humans and other mammals when concentrated by bivalve shellfish such as mussels, oysters, clams, and scallops. This volunteer-based effort is one of several elements of CDPH’s effort to protect the public from these neurotoxins.

The map on this page provides a summary of observations for two of our toxin-producers: Alexandrium, a dinoflagellate responsible for the paralytic shellfish poisoning (PSP) toxins, and Pseudo-nitzschia, a diatom responsible for domoic acid, which can cause amnesic shellfish poisoning (ASP).

 Disclaimer: the data provided here are informational and qualitative and are not intended to provide guidance to those wishing to sportharvest shellfish. Sport collectors should always contact the CDPH Biotoxin Information Line at 800-553-4133 for information on current shellfish quarantines and health advisories.

Acknowledgement: map layers were created using GPS VisualizerLink will leave the CDPH site and open in a new window..

 Phytoplankton Map Viewer

Last modified on: 6/15/2010 2:17 PM