Domoic Acid in Seawater off La Push, WA 1998--Surface
Notes:
Slide 10. DOMOIC ACID IN SEAWATER OFF LA PUSH, WA 1998—SURFACE
-Sampling in conjunction w/OCNMS
-Toxin present on dates sampled
-October =October 1 (No data due to bad weather)
-Next sampling Oct 21—Mostly 0’s. Only 2 positives (highest 11 ng/L)
-Appears from data that the bloom went away by Oct 15 in surface waters.
MESSAGE: TOXIN ALSO PRESENT OFFSHORE USUALLY IN HIGHER CONCENTRATIONS
Between August and October, we had the opportunity for an off-shore collaborative sampling effort with the Olympic Coast National Marine Sanctuary (OCNMS) off La Push using their Zodiac to sample 9 stations. We took the same type samples as collected on the beaches. On each of the dates that are plotted, toxin was present in off shore seawater samples. These plots are for surface waters only; however, toxin was detected at depth, but usually in lower concentrations.
In August, the highest concentrations appear to be off shore, about 6500 ng Toxin/L seawater (sta. 6), by September and October the highest concentrations appear closer to shore. The October plot shows data for October 1st. Sampling on Oct. 21st contained virtually no toxin, as confirmed by beach water samples (only 2 positive samples, the highest contained 11 ng/L).