THE OCCURRENCE OF DOMOIC ACID IN RAZOR CLAMS (SILIQUA-PATULA), DUNGENESS CRAB (CANCER-MAGISTER), AND ANCHOVIES (ENGRAULIS-MORDAX)

In September 1991, water fowl died in Monterey Bay, CA, after eating a nchovies (Engraulis mordax) contaminated with domoic acid. Analysis re vealed that the anchovies contained up to 485 ppm domoic acid in their viscera. This was the first reported incidence of domoic acid-related mortality of any organism in the United States. After this reported o utbreak we obtained frozen samples of anchovies that were harvested ne ar Newport, CA, in April 1991 and found they contained 270 ppm domoic acid in their viscera. By May, average domoic acid levels in frozen an chovy samples from this same area were less than 1 ppm. In October 199 1, domoic acid was detected in razor clams (Siliqua patula) from Orego n and Washington and appeared to peak (an average of 106 ppm for all W ashington State beaches) in the first week of December 1991. The avera ges then declined to less than 20 ppm without 6 months. However, domoi c acid was still present at low levels (averages <5 ppm) in razor clam s from Washington state beaches in December 1993. Dungeness crab (Canc er magister) in Washington and Oregon were also found to contain domoi c acid, but only in their viscera. Domoic acid concentrations in the r aw viscera of individual crabs from Washington state in December 1991 averaged 13 ppm and ranged from 0.8 to 90 ppm. The highest average lev els of domoic acid in Washington state crabs were in the Grays Harbor and Willapa Bay samples, 32 and 31 ppm, respectively. By 1992 domoic a cid level averages were <5 ppm in preseason samples of Dungeness crab taken along the Oregon and Washington coasts, ranging from 0 to 71 ppm . The highest levels of domoic acid in 1992 (36-71 ppm) were recorded in samples taken early in that year (January through April).