d. Area 4, Immature High Marsh (Netarts Spit) . This marsh, located 

 slightly north of the low sand marsh, has an elevation of about 3.2 meters 

 above MLLW and is bordered by an eroded bank. The dominant vegetation is 

 tufted hairgrass and Pacific silverweed {Potentitla paoifica) . The soil 

 is peaty with an underlayer of fine sand (Table 2) . A large pan (40 by 10 

 meters] retains tidal and runoff water during the winter and spring but 

 dries up by midsummer. 



e. Area 5, High Marsh (South End of Netarts Bay) . A branch of 

 Jackson Creek, which flows directly into the ocean, flows through this 40- 

 hectare marsh. The marsh is dissected by numerous deep tidal creeks with 

 several openings into the bay. These creeks and the northern edge of the 

 marsh have steep eroded banks. The marsh soil is peaty with a sand under- 

 layer. The creek bottom and adjoining tidal flats vary from brown sandy 

 mud to black mud. Marsh vegetation is primarily tufted hairgrass but the 

 composition varies; some areas are dominated by Pacific silverweed, pickle- 

 weed, rush, and other plants. The creeks are often clogged with rotting 

 eelgrass. Several pans are scattered throughout the marsh. Those connected 

 to creeks retain water, while others tend to dry out in midsummer. 



f. Area 6, Netarts Open Bay . This designates the bay channel and 

 tidal flat regions in which otter trawls were used to obtain estuarine 



fish samples. The channels are mostly shallow, many of them having eelgrass 

 beds . 



g. Area 7, Low Sand Marsh Seine Site (Netarts Bay) . This 1 -kilometer 

 section of low sand marsh, located immediately south of area 1, is a 

 narrow 5trip (about 3 to 20 meters wide) that is mostly vegetated by 

 pickleweed. Plant cover is variable, and the shoreline is irregular due 



to erosion. 



h. Area 8, Low Sand Marsh Seine Site (Siletz Bay) . This 0.4-kilometer 

 strip of low marsh, located on the southeast edge of the Siletz spit, has 

 high marsh along eroded banks. 



i. Area 9, Siletz Open Bay . This designates tidal flats and channels 

 which were sampled for estuarine fish using an otter trawl. 



Selection of the study areas was partly based on EPA use of areas 1, 

 3, and 4 for their productivity studies. The intent was to establish site- 

 specific data on the animal communities of marshes where the EPA studies 

 were being conducted. The EPA work focused on determining primary produc- 

 tivity and decomposition rates for selected, nearly monospecific vegetation 

 types (pure stands) and determining the availability of marsh production 

 to detritus-based food chains. The results of this work are currently 

 being compiled (H. Kibby, personal communication, 1979) . Initial conclu- 

 sions are that primary productivity rates range from about 500 to 1,800 

 grams per square meter per year, with Lyngbeye's sedge having the highest 

 productivity. Biomass of this sedge peaks in June-July at about 1,200 

 grams per square meter per year. Seaside arrowgrass apparently decomposes 

 more rapidly than other species studied, and is the only species which 

 showed evidence of grazing (probably by deer) . 



