Thirteen (1.2%) of the 1,108 identified species are nonindigenous, with another 
121 species classified as cryptogenic (of uncertain origin), and 208 species unclassified 
with respect to potential invasiveness. Despite uncertainties of classification, the 
number and densities of nonindigenous species appear to be much lower on the shelf 
than in the estuarine ecosystems of the Pacific Coast. Spionid polychaetes and the 
ampharetid polychaete Anobothrus gracilis were a major component of the 
nonindigenous species collected on the shelf. 
NOAA’s five NMSs along the West Coast of the U.S. appeared to be in good 
ecological condition, based on the measured indicators, with no evidence of major 
anthropogenic impacts or unusual environmental qualities compared to nearby non¬ 
sanctuary waters. Benthic communities in sanctuaries resembled those in 
corresponding non-sanctuary waters, with similarly high levels of species richness and 
diversity and low incidence of nonindigenous species. Most oceanographic features 
were also similar between sanctuary and non-sanctuary locations. Exceptions (e.g., 
higher concentrations of some nutrients in sanctuaries along the CA coast) appeared to 
be attributable to natural upwelling events in the area at the time of sampling. In 
addition, sediments within the sanctuaries were relatively uncontaminated, with none of 
the samples having any measured chemical in excess of ERM values. The ERL value 
for chromium was exceeded in sediments at the OCNMS, but at a much lower 
percentage of stations (four of 30) compared to WA and OR non-sanctuary areas (31 of 
70 stations). ERL values were exceeded for arsenic, cadmium, chromium, 2- 
methylnaphthalene, low molecular weight PAHs, total DDT, and 4,4-DDE at multiple 
sites within the CINMS. However, cases where total DDT, 4,4'-DDE, and chromium 
exceeded the ERL values were notably less prevalent at CINMS than in non-sanctuary 
waters of CA. In contrast, 2-methylnaphthalene above the ERL was much more 
prevalent in sediments at the CINMS compared to non-sanctuary waters off the coast of 
CA. While there are natural background sources of PAHs from oil seeps throughout the 
SCB, this does not explain the higher incidence of 2-methylnaphthalene contamination 
around CINMS. Two stations in CINMS also had levels of TOC (> 5%) potentially 
harmful to benthic fauna, though none of these sites exhibited symptoms of impaired 
benthic condition. 
This study showed no major evidence of extensive biological impacts linked to 
measured stressors. There were only two stations, both in CA, where low numbers of 
benthic species, diversity, or total faunal abundance co-occurred with high sediment 
contamination or low DO in bottom water. Such general lack of concordance suggests 
that these offshore waters are currently in good condition, with the lower-end values of 
the various biological attributes representing parts of a normal reference range 
controlled by natural factors. Results of multiple linear regression, performed using full 
model procedures to test for effects of combined abiotic environmental factors, 
suggested that latitude and depth had significant influences on benthic variables region¬ 
wide. Latitude had a significant inverse influence on all three of the above benthic 
variables, i.e. with values increasing as latitude decreased (p < 0.01), while depth had a 
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