Because EMAP's probabilistic sampling design is unbiased, potentially, some of the 
generated sites can fall in locations that are not amenable to sampling (e.g., outside the 
sampling frame, danger or risk to crew, excessive rocky bottom, currents, man-made 
obstructions, etc.). Field teams had a limited degree of onsite flexibility to randomly 
relocate sampling sites when confronted with unexpected obstacles or impediments, but 
the new site was to be no further than 100 m and preferably 40 m from the original 
designated site. Alternative sample sites determined during the initial design process 
were used if a site was found to be unsuitable. 
2.2.2 Site Description - Station Occupation 
Observations were made in the field to document certain attributes or conditions 
to help characterize the overall ecological condition of the site. These included the 
occurrence of macroalgal beds/mats, submerged aquatic vegetation (SAV), or emergent 
vegetation, the presence of burrowing shrimp, the occurrence of marine debris, and 
obvious evidence of disruptive anthropogenic activities (e.g., dredging or landfill 
activity). 
Upon arrival at the sample site, the station number, GPS location, date, time, 
samplers’ initials and agency were recorded. If the station was abandoned, the reason 
for abandonment was also recorded. Observations were made on sea state, weather, 
wind speed and direction, and estimated tidal level as well as air temperature and 
habitat type. Three to five photos and notes were taken to document site characteristics 
and anthropogenic impact such as shoreline construction, dredging or recreational use. 
Habitat was defined by the presence or absence of factors such as dominant plant (e.g., 
Spartina sp., Zostera marina or Z. japonica) or animal (e.g. burrowing shrimp, or 
oysters) species that affect the abundance and number of species in the benthic 
infaunal community. The habitat was also defined by its geological type - rocky, gravel, 
coarse or fine sand, muddy sand, sandy mud or mud. 
2.2.3 Plant Composition/Cover and Burrow Counts 
A 0.25-m 2 quadrat was randomly placed at the GPS-located site and then turned 
over three times to define a 1-m square sampling site. The four adjacent 0.25-m 2 
quadrats were used for: 1) burrow counts; 2) plant cover; 3) sediment chemistry 
samples; and 4) benthic samples. The number of burrow holes of burrowing shrimp 
(Neotrypaea californiensis, Upogebia pugettensis) was counted in one of the 0.25-m 2 
quadrats at each site. If vegetation covered >50% of the quadrat, the vegetation was 
gently pulled back taking care to disturb the sediment surface as little as possible, and 
the density of burrow holes under the vegetation was visually estimated. 
Where rooted plants (e.g. seagrasses, marsh plants, Spartina) or macroalgae 
were present, the plant community was quantified in one of the 0.25-m 2 quadrats. 
Percent plant cover within the 0.25-m 2 quadrat was visually estimated separately for 
green, brown or red macroalgae, Zostera spp., Spartina or other rooted plant genera 
present, and bare (i.e., open, unvegetated) substrate. The maximum total cover 
possible for all species of plants in a quadrat is 100% times the number of species of 
plants in the plot, and thus may be greater than 100% if several species overlapped at 
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