Marine Biotoxin Monitoring Program
The
Environmental Management Branch manages the Marine Biotoxin Monitoring Program
for bivalve shellfish in California. Other CDPH agencies
participating in the program are the Food and Drug Branch, Division of
Communicable Disease Control, the Microbial Diseases Laboratory, the Food and
Drug Laboratory, and the Office of Public Affairs.
California
has the longest-standing biotoxin monitoring program in the U.S., beginning in
1927 in response to a massive paralytic shellfish poisoning (PSP) episode. That
event resulted in several deaths and over 100 illnesses that were associated
with mussel consumption. In the fall of 1991, another natural neurotoxin called
domoic acid was discovered in the California marine environment in several
species, including shellfish. Domoic acid poisoning involves a wide range of
symptoms, including severe neurological effects that have been referred to as
amnesic shellfish poisoning (ASP).
Because
PSP and domoic acid toxicity represents a serious ongoing public health threat
that requires year-round attention, the CDPH has implemented a prevention
program that has traditionally been comprised of six basic elements: (1) a
coastal phytoplankton monitoring program for early detection of toxigenic
species that could impact shellfish resources; (2) a coastal
shellfish monitoring program that serves to protect recreational harvesters and
serves as an early warning for harmful algal blooms (HABs) that could be
transported into the bays and estuaries used for commercial shellfish
aquaculture; (3) frequent monitoring of commercial shellfish growing areas; (4)
an annual statewide quarantine on sport-harvested mussels (from May 1 through
October 31); (5) mandatory reporting of disease cases; (6) public information
and education activities.
The
shellfish monitoring component of the Marine Biotoxin Monitoring Program relies
on participation of people from a wide variety of local, state, and federal
agencies, Tribal biologists, educational organizations, researchers, and,
increasingly, citizen volunteers. Program participants collect shellfish
samples, primarily mussels, and ship them to the CDPH laboratory in Richmond,
California where they are tested for the PSP toxins and domoic acid. Commercial
shellfish growers, who account for approximately two-thirds of the total number
of samples, are required to submit shellfish samples at least weekly for toxin
testing as a condition of their certification by CDPH.
CDPH
initiated a volunteer-based phytoplankton monitoring program in 1991 to detect
an initial increase of a toxin-producing species before shellfish and other
seafood resources are impacted. This program draws on a wide range of
participants as detailed for the shellfish sampling program. Phytoplankton
monitoring participants are provided nets for collecting concentrated seawater
samples, which are sent to the CDPH laboratory for examination under a
microscope. This effort allows CDPH to focus additional attention on those
coastal areas experiencing an increase in toxin-producing phytoplankton or an
increase in toxins in shellfish.
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