Northwest Fisheries Science Center

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Document Type: Contract Report
Center: NWFSC
Document ID: 6180
Title: Benthic invertebrates and sediments in vegetated and nonvegetated habitats at three intertidal areas of the Columbia River estuary, 1992
Author/Editor: George T. McCabe, Susan A. Hinton
Publication Year: 1993
Publisher: National Marine Fisheries Service
Contracting Agency: U.S. Army Corps of Engineers. Portland, Oregon
Contract Number: E9592012
Pages: 37
Date: 1993

Benthic samples were collected at Miller Sands, Jim Crow Sands, and the remnant intertidal marsh in Grays Bay in July and September 1992.  At each area, two stations in intertidal vegetated habitats and two stations in adjacent nonvegetated habitats were sampled.  Benthic invertebrate data were analyzed by sampling station to determine species composition and density (both total and by species).  Benthic invertebrate densities were compared between vegetated and nonvegetated habitats, between months, and between areas.

At all three wetlands, benthic invertebrate densities at individual stations were high, with all values exceeding 15,000 organisms/m2.  In September, benthic invertebrate densities exceeded 100,000 organisms/m2 at three stations (GS, Jll, and J12), and total benthic invertebrate densities were significantly higher in September than in July (ANOVA, P < 0.05); however, there were no significant differences between the three wetlands or between vegetated and nonvegetated habitats (P > 0.05).  Densities of C. salmonis were significantly higher in September than in July and significantly higher in nonvegetated than in vegetated habitats.  In addition, C. salmonis densities were significantly higher in the Grays Bay wetland than in either the Miller Sands or Jim Crow Sands wetlands (ANOVA, FPLSD: P < 0.05).

Notes: Report to U.S. Army Corps of Engineers, Contract E9592012, 37 p.