Shellfish Contamination Closures
Always check for both
PSP
and Sanitary
Contamination Closures if you plan on consuming any shellfish.
Paralytic shellfish poison (PSP, also known as red tide) and
sanitary contamination affect only bivalve molluscs, i.e., shellfish
with two shells. Other shellfish, such as shrimp, prawns, etc.,
and finfish are not affected.
Shellfish and the waters they inhabit are good indicators of
the bacteriological health of the marine environment. Fecal
coliform bacteria in the water indicate the presence of human
or animal wastes and the possible presence of disease-causing
organisms. Shellfish growing waters are considered polluted
when the fecal coliform densities exceed a median of 14/100
mL (based on 15 data points). By comparison the standard for
drinking water is 0 FC/100 mL while swimming water standard
is 200 FC/100mL. The stringent standard for shellfish growing
water is necessary due to the filter feeding mechanism of bivalve
shellfish which can concentrate bacteria.
PSP is caused by a group of related toxins. The best known
of these is saxitoxin (SXT). In all, there are a total of 18
to 24 known toxins comprised of the parent compound, STX and
its derivatives. The relative abundance of each poison varies
with the species and strain of dinoflagellate. While the gonyautoxins
(GTX’s) appear to predominate in the Bay of Fundy, saxitoxin
tends to be higher in the Gaspe Region of Quebec. Saxitoxin
is the dominant toxin in some British Columbia species. Shellfish
and crabs are also tested for domoic acid, which is also a marine
toxin produced by naturally occurring plankton. Ingestion of
sufficient quantities of domoic acid results in amnesic shellfish
poisoning or ASP.
COOKING DOES NOT DESTROY THE
PARALYTIC SHELLFISH TOXIN.
For more information about Shellfish Closures, contact either:
Randy Webb
Fishery Management Co-Ordinator
DFO South Coast Division
457 E. Stanford Avenue
Parksville
V9P 1V7
Phone: (250) 954-2675
Fax: (250) 248-6776
|
Kerry Marcus
Aquaculture/CSSP Co-ordinator
DFO South Coast Division
457 E. Stanford Avenue
Parksville
V9P 1V7
Phone: (250) 954-2676
Fax: (250) 248-6776
|
or visit your local Fishery
Office.
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