A STUDY OF THE INVERTEBRATES AND FISHES OF SALT 

 MARSHES IN TWO OREGON ESTUARIES 



by 

 Duane L. Higley and Robert L. Holton 



1 . INTRODUCTION 



North American salt marsh ecosystems have been intensively studied 

 because of their high productivity and relatively simple structure. 

 However this attention has been mainly directed to the Atlantic coast 

 marshes. Prior studies have investigated community structure and popula- 

 tion energy flow (Odum and Smalley, 1959; Teal, 1962; Nixon and Oviatt, 

 1973), nutrient pathways using radionuclide tracers (Marples, 1966), and 

 faunal distribution (Barnes, 1953; Davis and Gray, 1966). Studies centered 

 in the Chesapeake Bay region, the Carolina coast, Sapelo Island (Georgia), 

 and Barataria Bay (Louisiana) have produced the following information on 

 salt marsh characteristics: (a) Primary productivity is high (about 445 

 to 2,883 grams dry weight per square meter per year), comparable to the 

 most fertile natural and agricultural systems; (b) little of the marsh 

 production is grazed (<10 percent), most ending up in detritus food webs 

 of the estuary; and c) the nutritional content of detrital particles 

 consumed is enhanced by adhering decomposer organisms (summarized by de la 

 Cruz, 1973). Because of the major importance of detritus food chains in 

 marsh and other estuarine habitats, recent work has emphasized determining 

 the rates and outputs of marsh detritus (Reimold, et al., 1975), and the 

 structure of the dependent heterotrophic food chains (Odum and Heald, 

 1975). 



Floral composition and zonation of salt marshes on the Pacific coast 

 have been documented (MacDonald, 1977). The major study of Oregon salt 

 marsh vegetation is by Jefferson (1974) , who characterized and mapped 

 essentially all Oregon's coastal marshes except those in the Columbia 

 River. Her descriptions of species composition and community structure, 

 succession, and distribution apply to Washington marshes (MacDonald, 

 1977) . Further description of marsh composition and zonation is provided 

 by Frenkel, Boss, and Schuller (1978). They studied the transition zone 

 between intertidal marshes and contiguous upland vegetation in Oregon and 

 Washington. 



Eilers (1979) conducted an intensive study of the salt marshes of 

 Nehalem Bay, Oregon. He determined plant associations and zonation 

 relations, and measured primary production and detrital output. Net 

 primary production varied between 518 and 1,936 grams per square meter per 

 year. An excess of 90 percent of the intertidal net production was trans- 

 ported into the estuary as detritus. 



The Environmental Protection Agency (EPA) is currently studying salt 

 marsh plant productivity in Siletz and Netarts Bays, Oregon. The EPA 

 study is part of a larger program concerned with defining wetland bounda- 

 ries, the reactions of wetlands to perturbation, and the effects of wet- 

 lands on water quality (H. Kibby, Corvallis Environmental Research Labora- 

 tory, EPA, Corvallis, Oregon, personal communication, 1979). 



