and spiders. They also consumed various dipterous larvae and pupae, 

 especially psychodids, found in marsh habitats. In the chum salmon's 

 stomach, insect foods often formed a surface layer over a ball of 

 flatfish larvae, indicating that the salmon fed subtidally and then 

 fed along the shoreline. The most abundant food organism in the 

 salmon was Hemileuoon, which comprised 39 percent of the stomach 

 content. Harpacticoids were abundant in the stomachs of staghorn 

 sculpin and stickleback but not in the chum salmon. Starry flounder 

 mostly ate decapod larvae, adult Callianassa, and amphipods. Surf 

 smelt mostly consumed Hemileuoon. 



In marsh pans, staghorn sculpin consumed mostly amphipods, 

 aquatic isopods, and small fish, while threespine stickleback ate 

 a large variety of animals, including calanoid and harpacticoid 

 copepods, and ceratopogonid larvae (Fig. 20). Very little of the 

 diet of the two fish could be considered terrestrial, although 

 some of the dipterous larvae live in marsh litter or soils. 



Staghorn sculpin and threespine stickleback captured in tidal 

 creeks had diets very similar to fish captured in pans (Fig. 21). 

 Sculpins concentrated on amphipods and isopods; the stickleback 

 diet included a total of 40 prey types dominated by harpacticoids 

 and ceratopogonid larvae. 



Several species of fish captured in the slough near the sedge 

 marsh consumed large quantities of amphipods (Fig. 22). Shiner 

 surfperch supplemented this food with the gastropod Alderia and 

 polychaetes. Ampharetid polychaetes (probably Hobsoni-a florida) 

 were eaten by both the perch and the starry flounder. 



Young staghorn sculpin and English sole captured in the tidal 

 flat below the low sand marsh ate tanaids, amphipods, harpacticoids, 

 and polychaetes (Fig. 23). These invertebrates are characteristic 

 forms of tidal flat substrates. There is little indication of use 

 of marsh foods by the sculpin or sole. 



Among the dozen fish species examined which were captured in 

 bay channels, the dominant foods were decapods (especially Crangon) , 

 polychaetes, and a variety of amphipods, fish, and other aquatic 

 animals (Fig. 24). Terrestrial foods were of minor occurrence. 



V. DISCUSSION 



Marsh studies, especially those of vegetation, have concentrated 

 on level marsh habitats due to their prevalence and importance as pro- 

 ducers of organic detritus. However, nutrient transfer to aquatic 

 food chains involves both bay detritus transport and secondary 

 production by marsh invertebrates in pans, tidal creeks, and adjoining 

 tidal flats. This study determined community composition, trophic 

 structure, and food-chain relations for fauna in both level marsh 

 and aquatic habitats in two Oregon estuaries. 



