unable to detect a measurable decline in the collform levels at any 
location In the two bays. Because the cleanup effort was Intended to be 
a model for nonpoint source control efforts In Puget Sound, the lack of 
Improvement Is of great concern. Additional sampling will be carried out 
through the winter and summer of 1987. 
Closures of commercial shellfish beds prohibit the sale of oysters, 
clams and others bivalve crops from those areas. However, the producer 
may be able to "relay" or "depurate" his harvest. Relaying—the transfer 
of contaminated shellfish to certified waters—Is practiced by at least 
one oyster farmer In Puget Sound. Depuration—the on-site clearance of 
bacteria In a closed purified sea water system—Is presently not allowed 
In the state; however. It Is a common practice In several East Coast 
states. Relaying Is feasible only If the producers have access to 
certified grounds. It Is an expensive process, not entirely acceptable 
In today's fastidious market where product quality Is a foremost 
consideration. Therefore, resolution of bacterial contamination sources, 
rather than relying on product treatment, offers the greatest level of 
product quality, consumer acceptance, and economic return. 
Paralytic shellfish poisoning (PSP) 
For many years. It was known that humans could suffer poisoning (and 
In some cases die) when they had eaten clams, mussels and other bivalve 
shellfish. It was not until the late 1920's that what Is now termed 
"paralytic shellfish poisoning" was determined to be caused by large, 
seasonal concentrations of a toxic, free-swimming, marine d1noflagel1 ate 
called Gonyaulax catenella , which when Ingested by filter-feeding 
molluscs, resulted In accumulation of toxins In the body of the shellfish. 
Until 1978 PSP contamination was confined largely to sporadic 
outbreaks In the Strait of Juan de Fuca, and although Gonyaulax catenella 
was present In Puget Sound, It did not often occur In numbers sufficient 
to produce toxicity from shellfish consumption. However, In 1978 there 
was a major outbreak of PSP affecting shellfish as far south as central 
Puget Sound. Blue mussels and butter clams ( Saxidomus qlqanteus ) were 
the most severely affected, and most Intertidal commercial and sport clam 
digging was banned for several months. Since 1978, annual outbreaks 
("blooms") of varying severity of Gonyaulax have resulted In restrictions 
on the harvest of clams, mussels, and other shellfish at numerous 
locations In north and central Puget Sound. Although these restrictions 
have not had a major Impact on the commercial harvests, there Is concern 
that PSP could spread to the numerous commercial growing areas of south 
Puget Sound. The cause of the outbreaks Is unknown, and there Is no 
evidence, as yet, to link them to any man-induced factor. 
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