A grab-sample study of the benthic invertebrates of the Columbia River Estuary

The report provides benthic invertebrate densities and sediment texture data for 48 stations in the Columbia River estuary (Columbia River mile 0-28) sampled by grab sampler between 31 August 1975 and 22 January 1976

Biological baseline data, Youngs Bay, Oregon, 1974

This report presents biological baseline information gathered during the research project, "Physical, Chemical and Biological Studies on Youngs Bay." Youngs Bay is a shallow embayment located on the south shore of the Columbia River, near Astoria, Oregon. Nearby portions of the Youngs River, Lewis and Clark River, Columbia River, and Skipanon Waterway were also included in the study

Analysis of benthic infauna communities and sedimentation patterns of a proposed fill site and nearby regions in the Columbia River Estuary

The Port of Astoria has proposed to fill a 32.4 hectare inter- and subtidal area at the mouth of Youngs Bay, Columbia River, Oregon. The possible effects of this fill on the biota and sedimentation patterns of this area were studied from 31 August 1975 to 29 February 1976. Part I, the biological studies, analyzed the quantity of benthic life at the fill site in comparison to that in the lower 28 miles of the Columbia River estuary. The sediment textures of benthos samples were analyzed to determine sediment-fauna relations; salinity-temperature measurements were made at selected sites. Fish life at the fill site was also sampled to determine species composition and the relation of fish stomach contents to benthic life. Studies on sedimentation patterns (based on dredging records, photographs, and sediment samples taken in Slip 2 of the port docks) aimed at identifying undesirable sediment deposits which might occur because of the fill. The dominant benthic taxa at most stations were amphipods and polychaetes, although oligochaetes were abundant at some muddy stations. Amphipod densities in the lower river varied from about 200/m2 in deep areas to between 5,000 and 50,000/m2 in shallow, fine sediment areas such as Youngs Bay and extensive shoaling areas. These areas of high density, which include the fill site, were dominated by the tube-building amphipod Corophium. Twenty-five species of fish have been captured in this and previous work in Youngs Bay. Food habit studies have shown Corophium to be eaten in large quantities by many of these species. Using density estimates and river bathymetry as guides, it was very roughly estimated that 0.8 percent of the amphipod standing crop in the study area (CRM 0-28) occurred at the fill site, which represents 0.09 percent of this area. Net sediment transport seems to be from the Columbia River into Youngs Bay, but transport out of Youngs Bay does occur and may contribute greatly to sediment deposition in Slips 1 and 2. Sediment samples from Slip 2 were mud, but this changed abruptly to coarse sand at the slip mouth. This shows that slip sediments arise from suspended fine mud and not from coarser-grained bed-load sediments. There is little that can be done to prevent such deposition. The proposed extension would probably not affect this problem, but might alter the flow of water around the port. More extensive investigations of circulation and suspended sediment content should be made

A Study of the Invertebrates and Fishes of Salt Marshes in Two Oregon Estuaries

Source: https://erdc-library.erdc.dren.mil/jspui/Partial This study, examines the invertebrate and fish life in the estuarine tidal marshes of Siletz ond Netarts Bays, Oregon. Sweep nets, corers, enclosures, and clip-quadrat samplers were used to collect both quantitative and nonquantitative samples of invertebrates in level marsh, pan, tidal creek, and tidal flat habitats located in seven study areas representing various types of marsh. Fish in these habitats, as well as in slough and bay channels, were sampled by seine and otter trawls. Community taxonomic composition and trophic structure along with fish stomach contents, are presented as relative frequency histograms and pie charts