Southern California pilot studies, a two stage randomization procedure was followed. 
As the first stage, wetland systems were randomly selected from a list of systems, and 
then a point sampling location was randomly selected within the selected wetland. 
The area of different estuarine intertidal habitats varied somewhat among the 
three states, although uniformly, either unvegetated sand or mud flats occupied the 
greatest percentage of estuarine area. Shellfish beds (oysters), gravel bottom, and 
intertidal seagrasses were recorded only in Washington and Oregon. San Francisco 
Bay and the rest of California tended to have finer sediments, higher Total Organic 
Carbon, and higher concentrations of sediment nitrogen and phosphorus than estuarine 
intertidal areas in Washington and Oregon. 
For sediment contaminants, there was a pattern of higher average Effects 
Range-Median Quotient (ERM-Q) within San Francisco Bay and the rest of California as 
compared with Washington and Oregon. All values of average ERM-Q for the five 
major areas in the present study were below guideline levels from other studies that 
have determined biotic effects associated with ERM-Q values. Levels of sediment 
contamination across the intertidal of the three western states were generally quite low, 
with only 0.21% of the intertidal area of the West Coast estuaries having exceedances 
of >5 Effects Range Low (ERL) concentrations, and only 0.3% of the intertidal area 
exceeding Effects Range Median (ERM) concentrations. In all cases, the exceedances 
of the ERMs were due to DDT and/or its congener 4,4’ DDE. Some caution in 
interpretation of sediment contaminant results is warranted. While analyses of sediment 
metals met QA requirements in all states, analyses of PAHs, PCBs, and some 
pesticides from Oregon did not generally meet analytical targets. 
Average densities of benthic infauna were highest in Oregon, with California and 
San Francisco having lower but similar abundances, and Washington having the lowest 
value. The benthic community was dominated by polychaetes, oligochaetes and 
amphipods. Surprisingly, the single most abundant polychaete in the West Coast 
intertidal was the nonindigenous Manayunkia aestuarina, introduced from the Northeast 
Atlantic. San Francisco habitats, other than the high marsh, were the most invaded, 
with an average of almost 50% of the classified species per sample consisting of 
nonindigenous species. Puget Sound samples contained about 26% nonindigenous 
species compared to 40% and 44% for coastal Oregon and Washington, respectively. 
Vegetation was present in the quadrats at 150 of the 217 sites successfully 
sampled, and included 28 emergent macrophytes, 2 seagrasses, as well as 
macroalgae. Eighty-two percent of plant taxa occurred at three or fewer sites. The 
most frequently occurring emergent macrophyte taxa were marsh jaumea ( Jaumea 
carnosa) and pickleweed ( Salicornia virginica). The greatest number of emergent 
macrophyte species were observed in California (n = 11), and in San Francisco Bay (n 
= 17) where high marsh was included in the study. Mean cover of nonindigenous, 
emergent macrophyte species was low (8%) throughout the West. Mean cover by 
nonindigenous species was highest in Washington (21%), where both salt marsh 
cordgrass Spartina alterniflora and the introduced seagrass Zostera japonica were 
xv 
