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Additional location information:
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This event was evident along the entire coast line, north to south, but mainly on the Clatsop beaches where razor clam habitat is abundant. Shellfish sampled from coastal bays did not reach toxic levels during this event.
The entire coast of Oregon began the calendar year of 2003 closed for razor clam harvesting due to domoic acid levels in these highly prized clams. In October 2002, domoic acid levels increased from <3 to 117 ppm by Dec 2002, on the most popular razor clamming beach on the northern Oregon coast called Clatsop Beach. Beaches on the central and southern coast were also affected starting in late Oct 2002 with levels rising to 61 ppm by November 2002.Domoic acid levels in the north coast or Clatsop Beach razor clams declined from the 90’s to 40’s ppm ranges during Jan to May, 2003. In June and July levels ranged widely from the 40 – 20 ppm range. On July 15th Clatsop Beach went into a juvenile protection closure. August and Sept saw all sites on Clatsop Beach less than 20 ppm except one site at 21 ppm; re-sampling for this site was 14 ppm. After Oct 1 Clatsop Beach was opened for all harvest. There was still one sample of 29 ppm but a resample 3 days later had 3 sample sets from the same site with all less than 10 ppm. Bimonthly testing on Clatsop Beach since Oct 2003 has continued trending downward in 2003 to less than 10 ppm at all sites with several less than 5 ppm for domoic acid.Other species of clams- softshells and butters; mussels and oysters (Pacifics), on the north coast showed no detectable levels of domoic acid all year round.There was apparently a significant domoic acid bloom on the central and southern coast of Oregon during 2003 which prevented razor clams on these beaches from purging the domoic acid levels they had retained from the 2002 event. Domoic acid levels in razor clams ranged widely from 85 – 40 ppm domoic acid on these beaches during the months of Jan – April, 2003. Then, during May and June of 2003, domoic acid levels appeared to jump to a higher range of 86 – 287 ppm. During this same period mussels, other types of clams and oysters, which had previously been below detection for domoic acid, were found with 1.6 to 15 ppm domoic acid.The non-razor clams and mussels quickly dropped to less than 1 ppm domoic by July. But the central and south coast razor clams stayed in the 100 – 40 ppm range until late fall when sampling became difficult due to high surf and big swells. These areas (from Seaside, OR to California border) have been closed to razor clamming since Nov 2002 and remain closed at the time of writing this 2003 summary, March 2004.
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