General Information

Event name: US-05-022
Nature of the harmful event:
Seafood toxins
Event directly affected:
Toxicity detected: Yes (Approximate range: 1-190 ppm)
Associated syndrome: ASP
Unexplained toxicity: No
Species implicated in toxin transmission (transvector): None
Report the outcome of a monitoring programme: Yes (ODA, Shellfish Sanitation Program, and OR Dept of Fish and Wildlife phytoplankton examination)
Event occurred before in this location: Yes (Oregon coastal razor clams have been affected by domoic acid producing algae blooms by four other extended closures in the past ten years.)
Individuals to contact: CANNON, Deborah F.

Location & Date

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Location: Latitude: , Longitude:
General location information: Oregon Coast, Pacific NW, USA
HAB Area code(s): US-22
Additional location information: Shellfish harvest areas on Clatsop and north coast beaches were open at the beginning of the year, the central coast was closed due to toxin residuals from 2004 but opened in March of 2005, and the south coast beaches remained closed from an event that began in the late 2004. The DA event of 2005 began in late April and affected the entire coast by mid-May. Another DA event occurred on the south central and south coast in Oct. 2005.
Bloom event dates (yyyy/mm/dd): Start: 2005-07-01, End: 2005-07-10
Quarantine levels dates (yyyy/mm/dd):
Additional date-related information: Clatsop Beach on north coast of OR began the calendar year of 2005 in open status for all razor clam harvesting; commercial and recreational. Levels of DA were below 10 ppm during Jan - Mar of 2005. Then mussels and razor clams became elevated during the last week of April, rising to 11 ppm in mussels and 24 to 36 ppm in razor clams. The highest level reached for the north coast razor clams was 68 - 04/24/05 and mussels reached 128 ppm on 5/10/05 (the highest seen in Oregon mussels). Mussels dropped to <1 by the end of May. No coast razor clams remained > 20 ppm until mid-July. This area did not see another bloom in the summer or fall of 2005. Domoic Acid levels in razor clams on the central coast beaches of Newport - Walport (rec. only) were still declining from 2004 levels but by March 2005 the area had opened. Then in late April the area was affected by a bloom similar to the impact seen on the North coast only razor clams reached levels of 213 on 05/13/05. This is near the area where Pseudo-nitzchia australis cell counts reached 632,000 cells per liter. Mussels reached the mid-20's. The razor clams were still between 20 and 40 ppm by the end of Dec. 2005. The south coast razor clams began the year in closure but a segment off Coos Bay had opened in April when the same, coast-wide event impacted the area and razor clams and mussels were closed. Razor clams at Coos Bya reached 190 ppm on 05/24/05 and mussels reached 53 on 05/09/06. In Oct. 2005 a separate event occurred in the two southern most counties as indicated by a jump in Pseudo-nitzchia australis cells (67,000 per liter) and mussels elevated from <1 to 12 ppm DA. Toxin levels in razor clams off Gold Beach rose from 18 on 09/17/05 to 36 ppm on 10/16/05. These areas remained closed as 2005 ended. Other species of clams-softshells and butters; were found with detectable levels of DA to as high as 7 ppm during the May event but never over 20 ppm. Detectable levels of DA were not found in oysters, coast-wide during 2005.


Causative organism known: Yes
Causative Species/Genus: Pseudo-nitzschia spp. ( cells/L)
Co-Ocurring Species/Genus:
Chlorophyll concentration, if known: µg/l
Additional bloom information:
Event-related bibliography:

Environmental Conditions

Weather: Turbidity (NTU): Wind direction:
Stratified water: Oxygen content (nL/L): Wind velocity:
Temperature (°C): Oxygen saturation %: Current Direction:
Sechhi disk (m): Salinity: Current Velocity: 0
Nutrient information:
Temperature Range During Event: Max: °C, Min: °C
Salinity Range During Event:
Bloom location in the water column:
Growth Comments
Additional Environmental information:

Toxin Assay Information

Species containing the toxin Toxin type Toxin details Max. concentration Assay type
Razor clams, Mussels, other Bay clams Domoic Acid 213 ppm Other
Kit used: No Type of kit used:
Additional information: HPLC
Economic losses: Closure has unknown but significant impact on commercial razor clam processors and recreational/tourism in the closed areas.
Management decision: Commercial and recreational closure required to comply with FDA and assure public safety. Recreational closure required to assure public safety. Commercial bait harvesting is also closed to prevent any contaminated product from entering commerce.
Additional harmful effect information:
Updated at 03:55 on 26 Jun 2020