Concentrations of cadmium in fish tissues exceeded the lower end of EPA’s non¬ 
cancer, human-health-risk range at nine of 50 EMAP/NCA-West and nine of 60 FRAM 
groundfish-survey stations, including a total of seven NMS stations in CA and two in the 
OCNMS. The human-health guidelines for all other contaminants were only exceeded 
for total PCBs at one station located in WA near the mouth of the Columbia River. 
Benthic species richness was relatively high in these offshore assemblages, 
ranging from 19 to 190 taxa per 0.1 -m 2 grab and averaging 79 taxa/grab. The high 
species richness was reflected over large areas of the shelf and was nearly three times 
greater than levels observed in estuarine samples along the West Coast (e.g NCA-West 
estuarine mean of 26 taxa/grab). Mean species richness was highest off CA (94 taxa/ 
grab) and lower in OR and WA (55 and 56 taxa/grab, respectively). Mean species 
richness was very similar between sanctuary vs. non-sanctuary stations for both the CA 
and OR/WA regions. Mean diversity index H' was highest in CA (5.36) and lowest in 
WA (4.27). There were no major differences in mean H' between sanctuary vs. non¬ 
sanctuary stations for both the CA and OR/WA regions. 
A total of 1,482 taxa (1,108 to species) and 99,135 individuals were identified 
region-wide. Polychaetes, crustaceans and molluscs were the dominant taxa, both by 
percent abundance (59%, 17%, 12% respectively) and percent species (44%, 25%, 
17%, respectively). There were no major differences in the percent composition of 
benthic communities among states or between NMSs and corresponding non-sanctuary 
sites. Densities averaged 3,788 m' 2 , about 30% of the average density for West Coast 
estuaries. Mean density of benthic fauna in the present offshore survey, averaged by 
state, was highest in CA (4,351 m' 2 ) and lowest in OR (2,310 m' 2 ). Mean densities were 
slightly higher at NMS stations vs. non-sanctuary stations for both the CA and OR/WA 
regions. 
The 10 most abundant taxa were the polychaetes Mediomastus spp., Magelona 
longicornis, Spiophanes berkeleyorum, Spiophanes bom byx, Spiophanes duplex, and 
Prionospio jubata\ the bivalve Axinopsida serricata, the ophiuroid Amphiodia urtica, the 
decapod Pinnixa occidentalis, and the ostracod Euphilomedes carcharodonta. 
Mediomastus spp. and A. serricata were the two most abundant taxa overall. Although 
many of these taxa have broad geographic distributions throughout the region, the 
same species were not ranked among the 10 most abundant taxa consistently across 
states. The closest similarities among states were between OR and WA. At least half 
of the 10 most abundant taxa in NMSs were also dominant in corresponding non¬ 
sanctuary waters. 
Many of the abundant benthic species have wide latitudinal distributions along 
the West Coast shelf, with some species ranging from southern CA into the Gulf of 
Alaska or even the Aleutians. Of the 39 taxa on the list of 50 most abundant taxa that 
could be identified to species level, 85% have been reported at least once from 
estuaries of CA, OR, or WA exclusive of Puget Sound. Such broad latitudinal and 
estuarine distributions are suggestive of wide habitat tolerances. 
XXII 
