{"Bibliographic":{"Title":"Benthic infauna and sediment characteristics offshore from the Columbia river, July 1993","Authors":"","Publication date":"1995","Publisher":""},"Administrative":{"Date created":"08-16-2023","Language":"English","Rights":"CC 0","Size":"0000053307"},"Pages":["SH153.2\n.H591\nBenthic infauna and\n1993\nsediment characteristics\noffshore from the\nColumbia River,\nCZES\nJuly 1993\nCoastal Zone and\nby Robert L. Emmett and Susan A. Hinton\nEstuarine Studies\nDivision\nOctober 1995\nNorthwest Fisheries\nScience Center\nNational Marine\nFisheries Service\nSeattle, Washington\nLibrary\nNorthwest Fisheries Science Center\n2725 Montlake Boulevard E.\nSeattle, WA 98112","NWFSC10-7\nSH\n153.2\nH591\nBENTHIC INFAUNA AND SEDIMENT CHARACTERISTICS\n1993\nOFFSHORE FROM THE COLUMBIA RIVER,\nJULY 1993\nBy\nRobert L. Emmett\nand\nSusan A. Hinton\nFunded by\nU.S. Army Corps of Engineers\nPortland District\nP.O. Box 2946\nPortland, Oregon 97208\n(Contract E96930048)\nand\nCoastal Zone and Estuarine Studies Division\nNorthwest Fisheries Science Center\nNational Marine Fisheries Service\nNational Oceanic and Atmospheric Administration\n2725 Montlake Boulevard East\nSeattle, Washington 98112-2097\nOctober 1995","CONTENTS\nPage\n1\nINTRODUCTION\n3\nMETHODS\n3\nSampling\n3\nBenthic Invertebrates\n4\nSediments\n4\nData Analyses\n4\nBenthic Invertebrates\n5\nSediments\n5\nStatistical Analyses\n6\nRESULTS\n6\nBenthic Invertebrates\n16\nSediments\n16\nPhysical Analyses\n16\nSediment and Invertebrate Relationships\n22\nAnnual Fluctuation\n28\nDISCUSSION\n34\nCONCLUSIONS\n35\nACKNOWLEDGMENTS\n36\nREFERENCES\n41\nAPPENDIX FIGURE\n42\nAPPENDIX TABLES","INTRODUCTION\nThe U.S. Army Corps of Engineers (COE), Portland District, is authorized to maintain\nnavigational channels in the Columbia River and its estuary and entrance. Four Ocean\nDredged-Material Disposal Sites (ODMDSs) off the mouth of the Columbia River have been\ndesignated by the Environmental Protection Agency to receive dredged material (Fig. 1).\nThese sites are identified as ODMDSs A, B, E, and F and are used for disposal of materials\ndredged primarily from shoals at the mouth of the Columbia River, but may also receive\ndredged material from other areas in the lower estuary. Average annual dredged material\nquantities in the mouth of the Columbia River estuary range from 3 to 9 million cubic yards,\nwith an average of 5 million cubic yards (1980-1994), with most of the material historically\ndisposed at Sites A and B. Site F has been used little, except for disposal of material dredged\nduring the 1989 Tongue Point Monitoring Program (Siipola et al. 1993). In 1994, ODMDSs\nA, B, and F were expanded to accept additional material because material disposed at the\nprimary ocean disposal site (ODMDS B) had not dispersed, but accumulated into a mound,\nwhich came to within 48 ft of the MLLW.\nThis temporary (5-year) spatial expansions of Sites A, B, and F were initiated by the\nCOE, Portland District, in 1992 while searching for a long-term solution for dredged material\ndisposal. In 1993 material dredged from the mouth of the Columbia River was deposited at\nexpanded ODMDSs B and F.","2\nN\n.12\n15\nW\nE\nPacific Ocean\n30\n31\nDOMOS\n32\n33\nColumbia River\n36\n39\n3\nSouth\n53\n52\n.54\nD1 . F2\nE3\nB2\nD4\n42\n*\nODMDS F\nC5\nA4\nB6 . D7\n55\n* A7\n57\n56 & 59\n58\n60\nE\nBenthic invertebrate and\nFeet\nsediment station\n2,000\n2,000\n4,000\n0\n45\nSediment station only\nOcean Dredged-Material\n1,200\n600\n0\n600\nDisposal Site (ODMDS)\nMeters\nFigure 1. Locations of benthic invertebrate and sediment stations offshore from the Columbia River\nsampled during July 1993. Stations 56 and 59 were in the same location.","3\nTo minimize negative biological effects, ODMDSs should be located in areas with no\nunique biological characteristics and relatively low standing crops of benthic and epibenthic\ninvertebrates and fishes. Also, candidate ODMDSs must be carefully evaluated from the\nstandpoint of technical feasibility and economics.\nA widespread benthic invertebrate survey offshore from the Columbia River was\nconducted during the mid 1970s under the COE's Dredged Materials Research Program\n(Richardson et al. 1977). A relatively recent site-specific survey of ODMDS F and its\nvicinity was conducted by the COE, Portland District, from 1989 to 1992 (Siipola et al.\n1993).\nThe primary goal of the present study was to assess benthic invertebrate communities\nat 28 stations and sediment characteristics at 30 stations in an area offshore from the\nColumbia River during July 1993. Eight of the benthic invertebrate stations were previously\nsampled during an intensive benthic survey at ODMDS F (Siipola et al. 1993) and 11 stations\npreviously sampled during a reconnaissance-level benthic invertebrate survey (Siipola 1994).\nMETHODS\nSampling\nBenthic Invertebrates\nThe sampling stations were located offshore from the Columbia River, extending about\n16 km north, 17 km south, and 16 km west of the river mouth (Fig. 1). Twenty eight stations\nwere sampled for both benthic invertebrates and sediments; two additional stations were\nsampled for sediments only. Station depths ranged from 12.2 to 65.8 m (Appendix Table 1).","4\nThe Global Positioning System (GPS) was used to identify station geographic coordinates and\nlocate previously sampled stations.\nA 0.1-m2 modified Gray-O'Hara box corer (Pequegnat et al. 1981) was used to collect\nbottom samples (Appendix Fig. 1). Five benthic invertebrate samples were taken at each\nstation. Benthic invertebrate samples were preserved in 18.9-liter buckets with a buffered 4%\nformaldehyde solution containing rose bengal (a protein stain). Within 2 weeks, the samples\nwere individually sieved through a 0.5-mm mesh screen, and the residue, containing the\nmacroinvertebrates, preserved in a 70% ethanol solution. Benthic organisms were sorted from\nthe preserved samples, identified to the lowest practical taxonomic level (usually species), and\ncounted. All specimens were placed in vials containing 70% ethanol and stored at the NMFS\nPoint Adams Biological Field Station, Hammond, Oregon.\nSediments\nSediment samples for physical analyses were collected at all 30 stations. These\nsamples were collected from the box corer using a stainless steel spoon, placed in labeled\nplastic bags, and refrigerated until delivered to the COE North Pacific Division Materials\nTesting Laboratory at Troutdale, Oregon.\nData Analyses\nBenthic Invertebrates\nAt each station where benthic invertebrates were collected, the total number of\norganisms was determined and the number of organisms/m² calculated. Each sample\ncollected at a station was treated as a replicate, allowing calculation of a mean number of\norganisms/m² and standard deviation for each species and for each station. Two community","5\nstructure indices were also calculated for each station. The first was diversity (H), which was\ndetermined using the Shannon-Wiener function (Krebs 1978):\nwhere p, = n/N (n is the number of individuals of the ith taxon in the sample, and N is the\ntotal number of individuals in the sample) and s = number of taxa. The second community\nstructure index was equitability (E), which measures proportional abundances among the\nvarious taxa in a sample (Krebs 1978):\nE = H/log2s\nwhere H = Shannon-Wiener function and S = number of taxa. E has a possible range of 0.00\nto 1.00, with 1.00 indicating that all taxa in the sample are numerically equal.\nCluster analysis, using the Bray-Curtis dissimilarity index with a group averaging\nfusion strategy (Clifford and Stephenson 1975), was used to identify stations that had similar\nspecies and densities in July 1993. A 0.5 dissimilarity value was considered a significant\ndifference between groups. The mean number of organisms/m² for each species per station\nwas used in the analysis. Species that had densities less than 20 organisms/m² were excluded\nfrom the analysis to reduce the effect of uncommon species.\nSediments\nPhysical analyses of sediments included determination of grain size and volatile solids.\nMedian grain size and percent sand and percent silt/clay were calculated for each sample.\nStatistical Analyses\nLinear and polynomial regression were used to identify significant relationships\nbetween various sediment characteristics (median grain size, percent silt/clay, and percent","6\nvolatile solids) and benthic invertebrate community metrics (density, number of taxa, H, and\nE). We used analysis of variance (ANOVA) to identify significant differences between\ninvertebrate densities, number of taxa, H, and E between different years. Densities were\nlog10(x) transformed to normalize the data before performing statistical tests.\nRESULTS\nBenthic Invertebrates\nDuring the July 1993 benthic invertebrate survey, 361 different taxa were identified\n(Appendix Table 2). However, specimens from 25 taxa were not considered benthic\norganisms and were eliminated from the analysis. The number of benthic invertebrate taxa\nper station averaged 107 and ranged from 65 (Station 42) to 145 (Station 52) (Table 1,\nAppendix Table 3). Overall densities averaged 8,768 invertebrates/m², ranging from 1,392\norganisms/m² (Station 42) to 14,728 organisms/m² (Station 52). Stations with high densities\ngenerally had higher number of taxa (Fig. 2) (regression, r2 = 0.51, P < 0.001).\nThe three most abundant taxa within each major taxonomic group found throughout\nthe study area included the polychaetes Prionospio lighti, Spiochaetopterus costarum, and\nMagelona spp.; the molluscs Nitidella gouldi, Tellina spp., and Axinopsida serricata; and the\ncrustaceans, Euphilomedes carcharodonta, Diastylopsis tenuis, and Diastylopsis spp. (Table 2).\nPolychaetes were the most abundant taxa, averaging 4,777/m² and molluscs the least\nabundant, averaging 1,018/m².\nDiversity (H) was generally high at most stations and ranged from 2.60 to 5.13, with\nmost values greater than 3.50 (Table 1, Appendix Table 3). Equitability (E) was moderate,","7\nTable 1 . Summary of benthic invertebrates collections, by station, offshore from the\nColumbia River, July 1993.\nEb\nNumber/m²\nSD\nH\nStation\nDate\nNumber of\ntaxa\n3.79\n0.56\nA4\n21 Jul 93\n112\n9,278\n3,659\n4.80\n0.70\nB2\n20 Jul 93\n115\n8,807\n1,640\n4.79\n0.71\nB6\n21 Jul 93\n111\n5,783\n806\n4.97\n0.79\nC5\n20 Jul 93\n80\n1,542\n525\n4.72\n0.71\nD1\n20 Jul 93\n103\n6,124\n3,971\n3.53\n0.51\nD7\n21 Jul 93\n118\n12,381\n4,855\n3.38\n0.52\nE3\n20 Jul 93\n89\n5,156\n3,065\n1,843\n4.42\n0.68\nF2\n20 Jul 93\n92\n3,101\n7,645\n2.70\n0.42\n12\n19 Jul 93\n89\n13,171\n942\n4.80\n0.76\n15\n19 Jul 93\n80\n3,239\n3,342\n4.78\n0.67\n30\n19 Jul 93\n141\n12,329\n3,099\n4.53\n0.66\n31\n19 Jul 93\n115\n9,353\n1,950\n4.17\n0.62\n32\n19 Jul 93\n107\n7,613\n1,406\n4.71\n0.75\n33\n19 Jul 93\n79\n5,145\n2,524\n4.49\n0.63\n36\n19 Jul 93\n135\n13,375\n3,653\n590\n5.13\n0.76\n37\n19 Jul 93\n107\n5,937\n1,214\n4.14\n0.65\n39\n19 Jul 93\n81\n1,392\n318\n4.74\n0.79\n42\n21 Jul 93\n65\n9,801\n1,649\n4.27\n0.62\n45\n21 Jul 93\n114\n52\n20 Jul 93\n145\n14,728\n2,275\n3.85\n0.54\n3.66\n0.58\n9,639\n1,824\n53\n20 Jul 93\n79\n7,138\n2,357\n4.58\n0.67\n54\n20 Jul 93\n115\n0.56\n13,663\n3,416\n3.94\n55\n21 Jul 93\n127\n889\n4.31\n0.62\n56\n21 Jul 93\n123\n11,664\n0.39\n57\n21 Jul 93\n98\n13,006\n9,890\n2.60\n1,237\n4.10\n0.57\n58\n21 Jul 93\n140\n12,204\n848\n4.31\n0.62\n59\n21 Jul 93\n127\n12,646\n5,061\n3.14\n0.46\n60\n21 Jul 93\n110\n13,627\n8,768\n4.19\n0.63\nMean\n107\n0.11\nSD\n21\n4,104\n0.66\n\"Diversity (Shannon-Wiener function)\nb\nEquitability","8\n160\n140\n120\n100\n80\nr 2 = 0.51\n60\n40\n20\n0\n5.00\n4.00\n3.00\n2.00\n1.00\n0.00\nInvertebrate density (log10 (mean number/m²)\nFigure 2. Regression relationship between benthic invertebrate density and number of taxa\nat 28 stations offshore from the Columbia River, July 1993.","9\nTable 2. Dominant benthic invertebrates found at 28 stations offshore from the Columbia River,\nJuly 1993 (all stations combined).\nMean number/m²\nTaxon\nPolychaeta\n1,323\nPrionospio lighti\n847\nSpiochaetopterus costarum\n360\nMagelona spp.\n327\nPhyllodoce hartmanae\n318\nChaetozone setosa\n174\nMediomastus californiensis\n160\nNephtys caecoides\n157\nPholoe minuta\n118\nLeitoscoloplos pugettensis\n100\nGlycinde spp.\n893\nMiscellaneous\n4,777\nTotal\nMollusca\n175\nNitidella gouldi\n128\nTellina spp.\n127\nAxinopsida serricata\n120\nOlivella pycna\n120\nOlivella spp.\n98\nAcila castrensis\n53\nOlivella baetica\n34\nMacoma spp.\n29\nCylichna attonsa\n21\nMytilidae\n113\nMiscellaneous\n1,018\nTotal\nCrustacea\n327\nEuphilomedes carcharodonta\n142\nDiastylopsis tenuis\n131\nDiastylopsis spp.\n91\nOrchomene pinquis\n86\nRhepoxynius spp.\n51\nDiastylopsis dawsoni\n43\nCallianassa californiensis\n40\nLeucon spp.\n38\nRhepoxynius vigitegus\n34\nRhepoxynius abronius\n356\nMiscellaneous\n1,339\nTotal\nMiscellaneous\n1,367\nDendraster excentricus\n161\nNemertea\n63\nEchiurida\n27\nAmphiodia spp.\n17\nMiscellaneous\n1,635\nTotal\n8,769\nTotal","10\nranging from 0.39 to 0.79 with most values between 0.50 and 0.79. There was an inverse\nrelationship between benthic invertebrate densities and H and E values (Figs. 3 and 4).\nHowever, invertebrate densities were a poor predictor of H and E. Stations with the highest\ndensities, although often having above average number of taxa, generally had lower H and E\nvalues due to the dominance of one or more taxa. Stations with highest H and E values\nusually had a low to above average number of taxa, but no numerically dominant taxa. This\nwas reflected in the strong direct relationship between H and E (Fig. 5) (r2 = 0.91, P < 0.01).\nThe results of benthic invertebrate station cluster analysis are displayed in Figures 6\nand 7. Stations designated by letters A through E should not be confused with cluster groups\nA through E. Five cluster groups (stations with similar benthic invertebrate species and\ndensities) were identified, but six stations were not included in any grouping. The largest\ntwo cluster groups were composed of six stations (Groups A and C). Although cluster Group\nC was composed of adjacent stations, Group A had only three adjacent stations. The next\nlargest cluster group, D, was comprised of five contiguous deeper-water stations located just\nwest of ODMDS B off the mouth of the Columbia River. For cluster Groups A and B, the\nsand dollar Dendraster excentricus and the polychaetes Spiochaetopterus costarum and\nMagelona spp. were the primary invertebrate species. However, these cluster groups had\ndifferent invertebrate densities (11,104 organisms/m² for Group A versus 5,120 organisms/m²\nfor Group B). Cluster groups C and D had polychaetes as primary species, while Group E\nhad the cumaceans Diastylopsis tenuis and Diastylopsis spp. and the polychaete Prionospio\nlighti as its primary species.","11\n6\n5\nr2 = 0.29\n4\n3\n2\n1\n0\n5.00\n3.00\n4.00\n2.00\n1.00\n0.00\nInvertebrate density (log(mean number/m²)\nFigure 3. Regression at relationship between benthic invertebrate density and diversity (H)\n28 stations offshore from the Columbia River, July 1993.","12\n0.9\n0.8\n0.7\nr2 2 = 0.54\n0.6\n0.5\n0.4\n0.3\n0.2\n0.1\n0\n4.00\n5.00\n2.00\n3.00\n1.00\n0.00\nInvertebrate density (log1o(mean number/m²)\nFigure 4. Regression relationship between benthic invertebrate density and equitability (E)\nat 28 stations offshore from the Columbia River, July 1993.","13\n0.8\n0.7\nr2 = 0.91\n0.6\n0.5\n0.4\n0.3\n0.2\n0.1\n0\n6\n4\n5\n2\n3\n1\n0\nDiversity (H)\nFigure 5. Linear regression between benthic invertebrate diversity (H) and equitability (E)\nat 28 stations offshore from the Columbia River, July 1993.","14\nWashington\nN\n12\nis\n15\nW\nE\nPacific Ocean\noomos\n30\n31\n32\n33\nColumbia River\nD\n36\n39\n37\nE\nOregon\nSouth\n53\nB\n52\n.54\nD1\nF2\nE3\nB2\nD4\n*\n42\nODMDS F\nC5\nA4\nD7\nB6\nis\n55\nA7\n57\n*\nC\n56 & 59\n-58\n60\nBenthic invertebrate and\nFeet\nsediment station\n4,000\n2,000\n2,000\n0\n45\n*\nSediment station only\nOcean Dredged-Material\n1,200\n600\n0\n600\nDisposal Site (ODMDS)\nMeters\nFigure 6. Locations of benthic invertebrate cluster groups (A-E) offshore from the Columbia River,\nJuly 1993. Stations 56 and 59 were in the same location. Six stations did not cluster.","15\nPrimary\nStation\nCluster\nMean\n2\nnumber/m\nspecies\ngroup\nA4\nD7\nDendraster excentricus\n60\nA\nSpiochaetopterus costarum\n11,104\nMagelona spp.\n12\n57\nE3\nB6\nDendraster excentricus\nMagelona spp.\nB\n5,120\nD1\nSpiochaetopterus costarum\n37\nF2\nB2\n45\nSpiochaetopterus costarum\nC\nPrionospio lighti\n56\n11,139\nPhyllodoce hartmanae\n59\n55\n58\n30\n36\nPrionospio lighti\nD\nMediomastus californiensis\n52\n12,082\nPholoe minuta\n53\n31\n15\n33\n32\nDiastylopsis tenuis\n39\nE\nDiastylopsis spp.\n6,538\n54\nPrionospio lighti\nC5\n42\n0.2\n0.0\n1.0\n0.8\n0.6\n0.4\nDissimilarity\nFigure 7. Dendrogram results from cluster analysis of benthic invertebrate\ndensities at 28 stations off the mouth of the Columbia River, July 1993.","16\nStations in shallow water near the mouth of the Columbia River generally had lower\nbenthic invertebrate densities than deeper water stations away from the Columbia River (Fig.\n8).\nSediments\nPhysical Analyses\nOverall average median grain size was 0.16 mm, percent silt/clay was 10.6%, and\nvolatile solids were 1.7% (Table 3). There was less variation in median grain size than in\npercent silt/clay, which ranged from 1.1% to 77.2%. The highest silt/clay value was\nmeasured at Station 54, which is almost directly off the mouth of the Columbia River.\nStations with highest percent silt/clay were generally deeper on the north side of the\nColumbia River mouth (Fig. 9). Percent volatile solids were generally low, ranging from 0.6\nto 3.4% at all stations except Station 54, where it was 9.0%.\nWe identified a significant but relatively poor relationship between percent silt/clay\nand median grain size (regression, r2 = 0.62, P < 0.01) (Fig. 10). However, there was a good\ndirect relationship between percent volatile solids and percent silt/clay (regression, 2 = 0.91,\nP < 0.01) (Fig. 11).\nSediment and Invertebrate Relationships\nWe found no significant relationships (regression, P > 0.05) between the various\nsediment characteristics (median grain size, percent silt/clay, and percent volatile solids) and\nbiological measurements (mean invertebrate densities, number of taxa, H, and E).","17\nN\n12\n15\nW\nE\nPacific Ocean\n30\n31\nOOMOS\n32\n33\nColumbia River\n36\n39\n37\nSouth\n53\n52\n.54\nD1\nF2\nE3\nB2\nD4*\n42\nODMDS F\nC5\nA4\nD7\nBo\nDensities > 10,000/m²\n55\nA7*\n57\n10,000/m² > Densities > 5,000/m2\n56 & 59\nDensities < 5,000/m2\n58\n60\nBenthic invertebrate and\nFeet\nsediment station\n2,000\n2,000\n4,000\n0\n45\nSediment station only\nE\nOcean Dredged-Material\n600\n1,200\n600\n0\nDisposal Site (ODMDS)\nMeters\nFigure 8. Benthic invertebrate densities at 28 stations offshore from the Columbia River July 1993.\nStations 56 and 59 were in the same location.","18\nTable 3. Sediment characteristics at 30 stations located offshore from the Columbia River, July\n1993.\nPercent\nvolatile\nMedian grain\nPercent\nStation\nsolids\nsilt/clay\nsize (mm)\n1.1\n1.5\n0.19\nA4\n2.2\n1.1\n0.17\nA7\n1.1\n3.2\n0.17\nB2\n0.8\n2.1\n0.18\nB6\n0.9\n2.3\n0.21\nC5\n0.9\n4.6\n0.17\nD1\n0.7\n2.0\n0.15\nD7\n0.9\n1.7\n0.19\nE3\n1.8\n0.8\n0.22\nF2\n0.6\n1.1\n0.19\nG1\n0.8\n11.7\n0.10\n12\n0.7\n3.4\n0.13\n15\n3.1\n27.3\n0.09\n30\n2.7\n26.7\n0.09\n31\n3.3\n36.3\n0.08\n32\n1.0\n7.3\n0.14\n33\n1.5\n11.7\n36\n0.14\n1.2\n2.7\n0.19\n37\n3.4\n36.4\n0.13\n39\n0.6\n1.7\n0.17\n42\n1.2\n2.4\n0.16\n45\n3.4\n13.8\n0.16\n52\n3.1\n18.9\n0.15\n53\n9.0\n*\n77.2\n54\n1.2\n4.8\n0.17\n55\n1.1\n2.3\n0.16\n56\n0.7\n1.5\n0.15\n57\n1.5\n4.1\n0.17\n58\n1.0\n2.5\n0.16\n59\n0.7\n1.5\n0.15\n60\n1.7\n10.6\n0.16\nMean\n1.7\n16.3\n0.03\nSD\n* Classified as silt, no further analysis was performed.","19\nN\n15\nE\nPacific Ocean\n30\n31\nOOMOS\n32\n33\nColumbia River\n36\n39\n37\n53\n52\n.54\nD1 .F2\nE3\nB2\nD4*\n42\nODMDS F\nPercent silt/clay <10\nC5\nA4\nD7\n50> Percent silt/clay>10\n.B6\n55\nPercent silt/clay >50\nA7*\n57\n56 & 59\n58\n60\nE\nBenthic invertebrate and\nFeet\nsediment station\n2,000\n2,000\n4,000\n0\n45\nSediment station only\nOcean Dredged-Material\n600\n0\n600\n1,200\nDisposal Site (ODMDS)\nMeters\nFigure 9. Percent silt/clay at 30 stations offshore from the Columbia River, July 1993. Stations 56\nand 59 were in the same location.","20\n80.0\n70.0\n60.0\n50.0\n40.0\n30.0\n2 = 0.62\n20.0\n10.0\n0.0\n0.25\n0.20\n0.05\n0.10\n0.15\n0.00\nMedian grain size (mm)\nFigure 10. Regression relationship between median grain size and percent silt/clay at 30\nbenthic stations offshore from the Columbia River, July 1993.","21\n9.0\nr2 = 0.91\n8.0\n7.0\n6.0\n5.0\n4.0\n3.0\n2.0\n1.0\n0.0\n60.0\n80.0\n20.0\n40.0\n0.0\nPecent silt/clay\nFigure 11. Regression relationship between percent silt/clay and percent volatile solids at 30\nbenthic stations offshore from the Columbia River, July 1993.","22\nAnnual Fluctuation\nEight ODMDS F stations sampled in 1993 were previously sampled during 1989 to\n1992. Benthic invertebrate densities at these stations differed significantly from 1989 to 1992\n(ANOVA, P < 0.01), increasing by an order of magnitude from 1989 to 1992. Invertebrate\ndensities in 1993 were also high, but second to 1992 values (Table 4).\nThe number of benthic invertebrate taxa per station at and adjacent to ODMDS F\nincreased from 1989 to 1992, and decreased slightly in 1993 (Table 5). These differences\nwere significant (ANOVA, P < 0.01).\nDiversity (H) and equitability (E) at and adjacent to ODMDS F also differed\nsignificantly from 1989 to 1993 (Tables 6 and 7) (ANOVA, P < 0.01). Lowest mean values\nfor both indices occurred in 1992, with the second lowest values in 1993, showing that at\nleast in these studies diversity and equitability are evidently inversely related to benthic\ninvertebrate densities.\nEleven benthic invertebrate stations sampled in 1992 were also sampled in 1993\n(Table 8). Invertebrate densities were not significantly lower in 1993 than 1992 (ANOVA, P\n> 0.05), (Table 8). This was opposite to what we found at the eight stations at ODMDS F.\nAlso, unlike ODMDS F from 1992 to 1993, the number of taxa was significantly higher in\n1993 than in 1992 (ANOVA, P < 0.05) (Table 8). These differences were probably a result\nof different sample sizes. In 1992, single grabs were taken at seven stations and five grabs at\nfour stations, resulting in a total of 27 samples. In 1993, five grabs were taken at each\nstation, resulting in a total of 55 samples. The larger number of samples in 1993 increased\nthe number of uncommon taxa collected.","23\nTable 4. Densities (mean number/m² of benthic invertebrates at and adjacent to ODMDS F,\noffshore from the Columbia River, June/July 1989 through 1993. Station densities were\ncalculated by averaging replicates from each station.\n1991\n1992\n1993\n1990\nStation\n1989\n13,759\n9,278\n2,238\n3,599\nA4\n1,223\n8,807\n4,362\n14,027\nB2\n1,294\n3,262\n3,872\n11,479\n5,783\nB6\n871\n2,574\n3,833\n7,821\n1,542\nC5\n1,142\n2,978\n6,124\n4,001\n14,819\nD1\n1,517\n3,587\n12,381\n3,660\n6,646\nD7\n788\n2,584\n5,156\n6,823\n9,820\nE3\n992\n2,793\n5,760\n9,422\n3,101\n1,588\nF2\n1,046\n6,522\n4,489\n10,974\nMean\n1,109\n2,701\n617\n1,172\n3,036\n3,510\nSD\n237","24\nTable 5. Numbers of benthic invertebrate taxa at eight stations at and adjacent to ODMDS F\noffshore from the Columbia River, June/July 1989-1993.\n1993\n1991\n1992\nStation\n1989\n1990\n112\n99\n110\nA4\n71\n73\n121\n115\n93\n105\nB2\n68\n108\n111\nB6\n68\n72\n107\n110\n80\nC5\n67\n109\n106\n89\n107\n103\nD1\n80\n86\n100\n92\n118\nD7\n59\n71\n108\n111\n89\nE3\n58\n88\n93\n92\n73\n92\nF2\n71\n103\n101\n107\nMean\n68\n83\n7\n10\n14\nSD\n7\n13","25\nTable 6. Diversity (H) of benthic invertebrate taxa at eight stations at and adjacent to ODMDS F\noffshore from the Columbia River, June/July 1989-1993.\n1993\nStation\n1989\n1990\n1991\n1992\n5.13\n3.81\n3.79\nA4\n4.88\n4.75\nB2\n4.97\n4.90\n4.95\n3.50\n4.80\n3.98\n4.79\nB6\n5.08\n4.28\n5.27\nC5\n4.92\n5.20\n5.17\n4.17\n4.97\n4.72\nD1\n4.89\n4.84\n4.60\n3.66\nD7\n5.02\n4.19\n4.70\n3.96\n3.53\nE3\n4.71\n4.33\n4.95\n4.04\n3.38\n3.46\n4.42\nF2\n4.94\n4.71\n4.03\n4.85\n3.82\n4.30\nMean\n4.93\n4.65\n0.26\nSD\n0.11\n0.35\n0.40\n0.64","26\nTable 7. Equitability (E) of benthic invertebrate taxa at eight stations at and adjacent to ODMDS\nF offshore from the Columbia River, June/July 1989-1993.\n1993\n1991\n1992\nStation\n1989\n1990\n0.56\n0.77\n0.56\nA4\n0.79\n0.77\n0.51\n0.70\n0.75\n0.74\nB2\n0.82\n0.59\n0.71\n0.69\n0.78\nB6\n0.83\n0.61\n0.79\n0.77\n0.77\nC5\n0.81\n0.71\n0.71\n0.54\n0.77\n0.75\nD1\n0.51\n0.68\n0.71\n0.61\nD7\n0.85\n0.73\n0.59\n0.52\n0.80\n0.67\nE3\n0.53\n0.68\n0.80\n0.76\n0.62\nF2\n0.65\n0.73\n0.57\n0.81\n0.73\nMean\n0.05\n0.04\n0.10\nSD\n0.02\n0.04","27\nTable 8. Numbers of benthic invertebrate taxa and densities at 11 stations offshore from the\nColumbia River, 1992 and 1993. Most density values from 1992 are numbers/m² (single.\ngrabs) 1993 density values are mean numbers/m² 2 (five replicates).\n1993\nStation\n1992\nNumber\nDensity\nNumber\nDensity\nof taxa\nof taxa\n89\n13,171\n29,780\n12\n75\n80\n3,239\n68\n152,455\n15\n141\n12,329\n79\n23,132\n30\n46,661\n115\n9,353\n*31\n101\n7,613\n107\n*32\n63\n6,556\n844\n79\n5,145\n33\n11\n24,141\n135\n13,375\n*36\n130\n107\n3,653\n*37\n75\n1,955\n81\n5,937\n39\n37\n6,247\n65\n1,392\n42\n47\n4,679\n114\n9,802\n45\n59\n21,028\n101\n7,728\n68\n28,862\nMean\n24\n4,200\nSD\n31\n43,373\n* mean values from five grabs in 1992.","28\nDiversity (H) at these 11 stations was significantly lower in 1992 than in 1993\n(ANOVA, P < 0.05 ) (Table 9). However equitability (E) was not significantly different\nbetween the 2 years (ANOVA, P > 0.05). The values for both these community structure\nindices at the 11 stations in 1993 was similar that observed at ODMDS F in 1993.\nDISCUSSION\nThe benthic invertebrate community offshore from the Columbia River is subjected to\na variety of influences: river flow, upwelling, downwelling, seasonal winds, and currents, all\nof which affect species diversity and densities. As a result, benthic invertebrate species and\ndensities varied widely throughout the study area. This was illustrated clearly by cluster\nanalysis, which clustered 22 benthic invertebrate stations into 5 cluster groups and 6 stations\ninto no groups. The relatively large number of cluster groups and stations which did not\ncluster in such a small area indicates that a complex benthic invertebrate community exists off\nthe mouth of the Columbia River. This complexity is probably the result of widely\nfluctuating environmental conditions (e.g., high currents and wave actions and shifting\nsediments) creating many different micro-habitats.\nThe harsh environmental conditions in shallow-water habitats near the mouth of the\nColumbia River appear to depress benthic invertebrate densities. As a result, there is a\ngeneral trend toward higher benthic invertebrate densities with increasing distance westward\nfrom the mouth of the Columbia River. Environments deeper and farther offshore from the\nmouth of the Columbia River undoubtedly provide a more stable habitat for benthic\ninvertebrates. Stable sediments, characterized by higher percent silt/clay, enhance the","29\nTable 9. Benthic invertebrate diversity (H) and equitability (E) at 11 stations offshore from the\nColumbia River 1992 and 1993. Most values from 1992 were from single grab samples,\nwhereas 1993 mean values were calculated using five replicates from each station.\n1993\n1992\nStation\nH\nE\nH\nE\n2.70\n0.42\n2.89\n0.46\n12\n4.80\n0.76\n1.86\n0.31\n15\n0.67\n4.30\n0.68\n4.78\n30\n4.53\n0.66\n2.73\n0.41\n*31\n0.62\n3.55\n0.59\n4.17\n*32\n0.75\n2.28\n0.66\n4.71\n33\n4.49\n0.63\n4.61\n0.66\n*36\n5.13\n0.76\n*37\n4.76\n0.76\n4.14\n0.65\n3.67\n0.71\n39\n4.74\n0.79\n3.36\n0.60\n42\n4.27\n0.62\n45\n2.37\n0.40\n4.41\n0.67\n3.31\n0.57\nMean\n0.64\n0.10\n0.98\n0.14\nSD\n* mean values from five grabs in 1992.","30\nrecruitment and survival of many different benthic invertebrate species, especially tube-\ndwelling polychaetes.\nSimilar to previous benthic invertebrate surveys off the mouth of the Columbia River,\npolychaetes numerically dominated most stations (Siipola et al. 1993, Siipola 1994, Hinton\nand Emmett 1994). These studies revealed that most stations were dominated by the\npolychaetes Spiochaetopterus costarum and Owenia fusiformis, both tube-building surface\ndeposit feeders. Spiochaetopterus costarum presence is consistent with the findings of Siipola\net al. (1993) during the Tongue Point Monitoring Program, where it was the dominant\norganism in 1992, but was virtually non-existent in 1989-1991. Siipola et al. (1993)\nspeculated that environmental conditions were exceptionally favorable for this organism in\n1991 and 1992 (i.e., abundant food resources and stable substrate), resulting in excellent\nrecruitment. Although S. costarum was abundant at many stations, the most abundant\norganism during our study was Prionospio lighti. This polychaete worm was particularly\nabundant at cluster Group D. Prionospio lighti has not previously been reported to be highly\nabundant off Oregon or Washington (Lie and Kisker 1970, Richardson et al. 1977, Emmett et\nal. 1987, Miller et al. 1988, Emmett and Hinton 1992, Siipola et al. 1993, Hinton and Emmett\n1994).\nAlthough benthic invertebrate densities in 1993 were relatively high, data from the\npast 5 years at 8 stations indicate that benthic invertebrate densities declined from 1992 to\n1993. We hypothesize that low spring upwelling and resultant low primary productivity may\nhave caused this reduction. As shown in Figure 12, benthic invertebrate densities tend to\nfollow spring upwelling values, rising from 1989 to 1992 and then falling in 1993. Benthic","31\nAverage April-July upwelling\nInvertebrate densities (mean number/m²\n12,000\n50\n45\n10,000\n40\n35\n8,000\n30\n6,000\n25\n20\n4,000\n15\n10\n2,000\n5\n0\n0\n1993\n1991\n1992\n1989\n1990\nYear\nFigure 12. Plot of average upwelling during April through July and benthic\ninvertebrate densities at eight stations offshore from the Columbia River,\n1989-1993. Upwelling values are for 45N and 125W and were obtained from the\nPacific Fisheries Environmental Group, Monterey, CA.","32\ninvertebrates are probably responding directly to nutrient levels and the resultant primary\nproduction in the water column. This is not surprising, since many of the benthic invertebrate\nspecies identified during 1993 were suspension and surface deposit feeders (Fauchald and\nJumars 1979). These organisms are dependent on organic material (organic detritus and\nphytoplankton) settling on or near the bottom. Benthic invertebrate biomass has been directly\nrelated to pelagic productivity in the Bering and Chukchi Seas (Grebmeir et al. 1988), but no\nsuch studies have been conducted in the Pacific Northwest.\nThe distribution of sediment types offshore from the Columbia River observed during\nthis survey agrees with sediment distributions described in previous studies of the area (Kulm\net al. 1975, Sternberg et al. 1977). As expected, sediment grain size decreases with\nincreasing depth north of the entrance to the Columbia River.\nThe lobe of organically enriched fine-grained sediments to the west and northwest of\nODMDS B found in this survey and by Hinton and Emmett (1994) was previously described\nby Siipola et al. (1993) and Sternberg et al. (1977). Kulm et al. (1975) observed that the\nCascadia Channel receives sediment from the Columbia River through the Willapa Canyon,\nwhich has its head on the outer edge of the continental shelf 45 km north of the mouth of the\nColumbia River. A northwest offshore transport of coarse silt and very fine sand is required\nto supply Willapa Canyon with sediment for periodic submarine slumps. Studies of\nfine-grained, river-borne particulate matter labeled by radionuclides in shelf sediments derived\nfrom the Columbia River showed a net northward and westward transport toward the vicinity\nof Willapa Canyon (Gross 1972). Near-bottom current studies showed the same net transport\n(Kulm et al. 1975).","33\nBenthic sediment characteristics near the mouth of the Columbia River often vary\nannually. For example, percent fines at one benthic station in 1990, 1991, and 1992 were 1.2,\n19.6, and 0.8%, respectively (Siipola et al. 1993). These variations are independent of any\ndredged-material disposal event. The origin, fate, and significance of these transitory fine-\ngrained deposits are unknown, but were also noted by Kulm et al. (1975).\nBenthic invertebrates are important prey for many species of demersal fish and\nshellfish, especially juveniles, which are abundant off the Columbia River (Durkin and\nLipovsky 1977). Annual and longer-term fluctuations in benthic invertebrate abundance\nundoubtedly have direct effects on fish and shellfish populations, yet no long-term research or\nmonitoring program has been established to identify these relationships. For example,\nDungeness crab, Cancer magister, populations and landings fluctuate at roughly 10-year\nintervals. The exact cause of these population fluctuations is unknown, but variations in\nbenthic invertebrate standing crop, an important food for juvenile crabs, may be important.\nBenthic invertebrate abundance at individual stations appears to be related to specific\nphysical and biological habitat parameters such as sediment grain size, percent silt/clay,\npercent volatile solids, frequency of disturbance, and predation, while overall population\nabundances within a large area reflect broad environmental factors, such as upwelling and\nprimary production. A similar phenomenon was identified in the Bering and Chukchi Seas\n(Grebmeier et al. 1989).\nBenthic invertebrate populations often cycle at various time scales (Gray and Christie\n1983). Only by monitoring invertebrate species and populations over a wide area and long\ntime periods can effects of dredging be separated from overall annual population fluctuations.","34\nUnfortunately, some of the eight stations that we expected to provide long-term data\n(collections since 1989) were covered by dredged material in 1994, and no longer represent\n\"control\" sites.\nCONCLUSIONS\nBenthic invertebrate densities and community structure at numerous stations varied\nwidely off the mouth of the Columbia River in 1993. Cluster analysis identified five station\ngroupings and six stations that could not be grouped in any cluster. Annual fluctuations in\nbenthic invertebrate densities and diversity at eight stations increased significantly from 1989\nto 1991, did not change significantly 1992, and decreased significantly in 1993. The 1993\ndecrease perhaps reflected lower primary production resulting from lower spring upwelling.\nNevertheless, benthic invertebrate species distributions and densities off the mouth of the\nColumbia River are evidently determined primarily by sediment and hydraulic conditions (see\nLie and Kisker 1970, Brinkhurst 1987, and Ishikawa 1989) and secondarily by long-term\ncoastal primary production. Benthic invertebrate densities were lowest in shallow-water\nhabitats that are often disturbed by waves and currents (<40 m depth) immediately off the\nmouth of the Columbia River. This area should be investigated further when searching for\nnew dredged-material disposal sites.\nThis report does not constitute NMFS's formal comments under the Fish and Wildlife\nCoordination Act or the National Environmental Policy Act.","35\nACKNOWLEDGMENTS\nWe thank the COE, Portland District, for the sediment analyses. We also thank\nLawrence Davis and Dennis Umphfres for their assistance in data collections, and Howard\nJones, Susan Weeks, and Sandy Lipovsky for their diligence in processing benthic\ninvertebrate samples.","36\nREFERENCES\nBrinkhurst, R. O. (editor). 1987. Distribution and abundance of macrobenthic infauna from\nthe continental shelf off southwestern Vancouver Island, British Columbia. Can. Tech.\nRep. Hydrogr. Ocean Sci., No. 85, 92 p.\nClifford, H. T., and W. Stephenson. 1975. An introduction to numerical classification.\nAcademic Press, Inc., New York, 229 p.\nDurkin, J. T., and S. Lipovsky. 1977. Aquatic disposal field investigations Columbia River\ndisposal site, Oregon. Appendix E: Demersal fish and decapod shellfish studies.\nU.S. Army Corps of Engineers Tech. Rep. D-77-30, 159 p. plus appendices.\n(Available from Waterways Experiment Station, P.O. Box 631, Vicksburg, MS 39180.)\nEmmett, R. L., T. C. Coley, G. T. McCabe, Jr., and R. J. McConnell. 1987. Demersal fishes\nand benthic invertebrates at four interim dredge disposal sites off the Oregon coast.\nReport to U.S. Army Corps of Engineers, Contract DACW57-85-F-0210, 69 p. plus\nappendices. (Available from Northwest Fisheries Science Center, 2725 Montlake\nBoulevard East, Seattle, WA 98112.)\nEmmett, R. L., and S. A. Hinton. 1992. Benthic and epibenthic invertebrates, demersal\nfishes, and sediment structure off Tillamook Bay, Oregon, September 1990, with","37\ncomparisons to previous surveys. Report to the U.S. Army Corps of Engineers,\nContract E96900022, 25 p. plus appendices. (Available from Northwest Fisheries\nScience Center, 2725 Montlake Boulevard East, Seattle, WA 98112.)\nFauchald, K., and P. A. Jumars. 1979. The diet of worms: A study of polychaete feeding\nguilds. Oceanogr. Mar. Biol. Ann. Rev., 17:193-284.\nGrebmeier, J., C. P. McRoy, and H.M. Feder. 1988. Pelagic-benthic coupling on the shelf\nof the northern Bering and Chukchi Seas. I. Food supply source and benthic biomass.\nMar. Ecol. Prog. Ser. 48:57-67.\nGrebmeier, J. M., H. M. Feder, and C.P. McRoy. 1989. Pelagic-benthic coupling on the\nshelf of the northern Bering and Chukchi Seas. II. Benthic community structure.\nMar. Ecol. Prog. Ser. 51:253-268.\nGray, J.S., and H. Christie. 1983. Predicting long-term changes in marine benthic\ncommunities. Mar. Ecol. Prog. Ser. 13:87-94.\nGross, M. G. 1972. Sediment-associated radionuclides from the Columbia River. In A. T.\nPruter, and D. L. Alverson (editors), The Columbia River estuary and adjacent ocean\nwaters, p.736-754. Univ. Wash. Press, Seattle.","38\nHinton, S. A., and R. L. Emmett. 1994. Benthic infaunal, sediment, and fish offshore from\nthe Columbia River, July 1992. Report to the U.S. Army Corps of Engineers,\nContract E96920040, 60 p. plus appendices. (Available from Northwest Fisheries\nScience Center, 2725 Montlake Boulevard East, Seattle, WA 98112.)\nIshikawa, K. 1989. Relationship between bottom characteristics and benthic organisms in the\nshallow water of Oppa Bay, Miyagi. Mar. Biol. 102:265-273.\nKrebs, C. J. 1978. Ecology: The experimental analysis of distribution and abundance.\nHarper and Row. New York, 678 p.\nKulm, L. D., R. C. Roush, J. C. Harlett, R. H. Neudeck, D. M. Chambers, and E.J. Runge.\n1975. Oregon continental shelf sedimentation: Interrelationships of facies distribution\nand sedimentary process. J. Geol. 83:145-175.\nLie, U., and D. S. Kisker. 1970. Species composition and structure of benthic infauna\ncommunities off the coast of Washington. J. Fish. Res. Bd. Canada 27:2273-2285.\nMiller, D. R., R. L. Emmett, and R. J. McConnell. 1988. Benthic invertebrates and demersal\nfishes at an interim dredge-disposal site off Willapa Bay, Washington. Report to the\nU.S. Army Corps of Engineers, Contract DW-13931463-01-0, 20 p. plus appendices.","39\n(Available from U.S. Army Corps of Engineers, Portland District, P.O. Box 2946,\nPortland, OR 97208.)\nPequegnat, W. E., L. H. Pequegnat, P. Wilkinson, J. S. Young, and S. L. Kiessger. 1981.\nProcedural guide for designation surveys of ocean dredged material disposal sites.\nU.S. Army Corps of Engineers Tech. Rep. EL-81-1, 268 p. plus appendices.\nRichardson, M. D., A. G. Carey, and W. A. Colgate. 1977. Aquatic disposal field\ninvestigations Columbia River disposal site, Oregon. Appendix C: The effects of\ndredged material disposal on benthic assemblages. Report to U.S. Army Corps of\nEngineers, Contract DACW57-C0040, 65 p. plus appendices. (Available from\nWaterways Experiment Station, P.O. Box 631, Vicksburg, MS 39180.)\nSiipola, M. D. 1994. Reconnaissance level benthic infaunal, sediment and fish study\noffshore from the Columbia River, July 1992. Final Report. U.S. Army Corps of\nEngineers, Portland, OR. 69 p. plus appendices. (Available from U.S. Army Corps of\nEngineers, Portland District, P.O. Box 2946, Portland, OR 97208.)\nSiipola, M. D., R. L. Emmett, and S. A. Hinton. 1993. Tongue Point Monitoring Program\n1989-1992 final report. Report to U.S. Army Corps of Engineers, Contracts\nE96910024 and E96910025, 63 p. plus appendices. (Available from U.S. Army\nCorps of Engineers, Portland District, P.O. Box 2946, Portland, OR 97208.)","40\nSternberg, W. R., J. S. Creager, W. Glassley, and J. Johnson. 1977. Aquatic disposal field\ninvestigations Columbia River disposal site, Oregon. Appendix A: Investigation of\nthe hydraulic regime and physical nature of bottom sedimentation, final report. Report\nto U.S. Army Corps of Engineers, Contract DACW57-79-C0041, 327 p. plus\nappendices. (Available from Waterways Experiment Station, P.O. Box 631, Vicksburg,\nMS 39180.)","41\nWeight tray\nAppendix Figure 1. The 0.1-m2 box corer (Gray-O'Hara modification of a standard box corer)\nused for benthic invertebrate sampling offshore from the Columbia River\nJuly 1993. For deeper penetration, 113-kg (250-lb) weights were placed in\neach tray located on opposite sides of the sampler.","42\nAppendix Table 1. Geographic location, date of sampling, and water depth of benthic\ninvertebrate and sediment stations sampled offshore from the Columbia\nRiver, July 1993.\nLongitude\nLatitude\nDepth m (ft)\nStation\nDate\n124° 9.50'W\n46° 11.50N\n46.3\n(152)\n21 Jul\nA4\n8.96\n10.99\n46.0\n(151)\nA7\n21 Jul\n9.73\n11.99\n(145)\n44.2\nB2\n20 Jul\n9.10\n11.39\n21 Jul\n44.8\n(147)\nB6\n8.99\n11.80\n39.3\n(129)\nC5\n20 Jul\n9.52\n12.53\n20 Jul\n39.9\n(131)\nD1\n8.45\n11.47\n40.2\n(132)\nD7\n21 Jul\n9.00\n12.19\n36.0\n(118)\n20 Jul\nE3\n8.99\n12.61\n20 Jul\n35.1\n(115)\nF2\n8.99\n12.03\n37.8\n(124)\nG1\n20 Jul\n8.98\n18.98\n12\n19 Jul\n23.5\n(77)\n6.00\n18.98\n19 Jul\n12.2\n(40)\n15\n12.50\n15.00\n19 Jul\n53.6\n(176)\n30\n11.50\n15.00\n19 Jul\n43.0\n(141)\n31\n10.03\n15.02\n19 Jul\n20.4\n(67)\n32\n9.00\n15.00\n(45)\n19 Jul\n13.7\n33\n11.10\n14.01\n(176)\n19 Jul\n53.6\n36\n10.99\n13.98\n(120)\n19 Jul\n36.6\n37\n9.46\n14.00\n(73)\n20 Jul\n22.2\n39\n6.47\n12.03\n(85)\n21 Jul\n25.9\n42\n7.47\n9.02\n(156)\n21 Jul\n47.5\n45\n12.01\n11.01\n(194)\n20 Jul\n59.1\n52\n11.01\n12.99\n(165)\n20 Jul\n50.3\n53\n11.00\n13.00\n(134)\n20 Jul\n40.8\n54\n10.96\n11.00\n(200)\n21 Jul\n61.0\n55\n8.98\n10.50\n49.4\n(162)\n21 Jul\n56\n7.01\n11.00\n(116)\n21 Jul\n35.4\n57\n11.03\n10.00\n65.8\n(216)\n21 Jul\n58\n8.98\n10.50\n48.8\n(160)\n21 Jul\n59\n6.99\n10.00\n38.4\n(126)\n21 Jul\n60","43\nAppendix Table 2. Benthic and epibenthic invertebrate taxa collected by box corer offshore from the\nColumbia River, July 1993.\nIdentified\nTaxon\nCnidaria\nX\nAnthozoa\nCtenophora\nPleurobrachiidae\nPleurobrachia bachei\nX\nPlatyhelminthes\nX\nTurbellaria\nX\nNemertea\nAnnelida\nX\nPolychaeta\nAphroditidae\nX\nAphrodita spp.\nPolynoidae\nX\nBylgides macrolepidus\nX\nGattyana spp.\nX\nGattyana treadwelli\nX\nX\nTenonia priops\nSigalionidae\nX\nPholoe minuta\nX\nSthenelais tertiaglabra\nX\nSigalion mathildae\nX\nThalenessa spinosa\nX\nPhyllodocidae\nX\nEteone fauchaldi\nX\nEteone longa\nX\nEteone pacifica\nX\nEteone spilotus\nX\nX\nEteone spp.\nX\nEumida sanguinea\nX\nEumida spp.\nParanaitides (Phyllodoce) polynoides\nX\nPhyllodoce groenlandica\nX\nPhyllodoce hartmanae\nX\nX\nPhyllodoce mucosa","44\nAppendix Table 2. Continued.\nIdentified\nTaxon\nPhyllodoce spp.\nX\nHesionidae\nX\nHeteropodarke heteromorpha\nX\nMicrophthalmus sczelkowii\nX\nMicropodarke dubia\nX\nParandalia fauveli\nX\nPodarkeopsis glabrus\nX\nPilargidae\nPilargis berkelyae\nX\nSyllidae\nX\nEhlersia heterochaeta\nX\nProceraea cornutus\nX\nSphaerosyllis brandhorsti\nX\nSyllis elongata\nX\nNereidae\nX\nCheilonereis cyclurus\nX\nNereis spp.\nX\nNereis procera\nX\nNereis zonata\nX\nNephtyidae\nNephtys spp.\nX\nNephtys assignis\nX\nNephtys caeca\nX\nNephtys cornuta cornuta\nX\nNephtys rickettsi\nX\nNephtys ferruginea\nX\nNephtys caecoides\nX\nSphaerodoridae\nSphaerodoropsis minuta\nX\nGlyceridae\nGlycera spp.\nX\nGlycera capitata\nX\nGlycera tenuis\nX\nGlycera americana\nX\nGlycera convoluta\nX\nGlycera nana\nX\nGoniadidae\nGlycinde spp.\nX\nGlycinde armigera\nX","45\nAppendix Table 2. Continued.\nIdentified\nTaxon\nGlycinde picta\nX\nGoniada brunnea\nX\nOnuphidae\nX\nOnuphis iridescens\nX\nOnuphis elegans\nX\nLumbrineridae\nX\nEranno bicirrata\nX\nLumbrineris spp.\nX\nLumbrineris californiensis\nX\nLumbrineris limnicola\nX\nLumbrineris luti\nX\nArabellidae\nNotocirrus californiensis\nX\nDorvilleidae\nDorvillea pseudorubrovittata\nX\nOrbiniidae\nX\nLeitoscoloplos pugettensis\nX\nOrbinia (Phylo) felix\nX\nScoloplos armiger\nX\nParaonidae\nAricidea (Acesta) catherinae\nX\nLevinsenia gracilis\nX\nParaonella platybranchia\nX\nSpionidae\nX\nBoccardia pugettensis\nX\nLaonice cirrata\nX\nParaprionospio pinnata\nX\nPolydora spp.\nX\nPolydora brachycephala\nX\nPolydora socialis\nX\nPrionopsio lighti\nX\nPrionospio pinnata\nX\nPrionospio steenstrupi\nX\nPseudopolydora spp.\nX\nScolelepis squamata\nX\nSpio spp.\nX\nSpio butleri\nX\nSpio filicornis\nX\nSpiophanes spp.\nX","46\nAppendix Table 2. Continued.\nIdentified\nTaxon\nSpiophanes berkeleyorum\nX\nSpiophanes bombyx\nX\nMegelona\nMagelona spp.\nX\nMagelona hobsonae\nX\nMagelona longicornis\nX\nMagelona sacculata\nX\nTrochochaetidae\nTrochochaeta multisetosa\nX\nChaetopteridae\nX\nMesochaetopterus spp.\nX\nMesochaetopterus taylori\nX\nSpiochaetopterus spp.\nX\nSpiochaetopterus costarum\nX\nCirratulidae\nX\nAphelochaeta multifilis\nX\nAphelochaeta (Tharyx) secunda\nX\nChaetozone setosa\nX\nCossuridae\nCossura spp.\nX\nFlabelligeridae\nX\nPherusa spp.\nX\nScalibregmidae\nAsclerocheilus beringianus\nX\nOpheliidae\nX\nArmandia brevis\nX\nOphelia spp.\nX\nOphelina acuminata\nX\nTravisia brevis\nX\nTravisia japonica\nX\nCapitellidae\nX\nBarantolla americana\nX\nCapitella capitata complex\nX\nDecamastus gracilis\nX\nHeteromastus filiformis\nX\nHeteromastus filobranchus\nX\nNotomastus lineatus\nX\nMediomastus spp.\nX\nMediomastus ambiseta\nX","47\nAppendix Table 2. Continued.\nIdentified\nTaxon\nMediomastus californiensis\nX\nAberinicolidae\nX\nMaldanidae\nX\nAsychis spp.\nX\nEuclymene spp.\nX\nEuclymene zonalis\nX\nOweniidae\nGalathowenia oculata\nX\nOwenia fusiformis\nX\nPectinariidae\nPectinaria spp.\nX\nPectinaria californiensis\nX\nAmpharetidae\nX\nAmpharete spp.\nX\nAmpharete acutifrons\nX\nAsabellides lineata\nX\nMelinna elisabethae\nX\nTerebellidae\nX\nPista estevanica\nX\nPolycirrus spp. complex\nX\nSabellidae\nChone dunneri\nX\nEuchone hancocki\nX\nEuchone incolor\nX\nPolygordiidae\nPolygordius spp.\nX\nOligochaeta\nX\nHirudinea\nX\nMollusca\nGastropoda\nX\nTurbinidae\nSpiromoellaria quadrae\nX\nRissoidae\nAlvania compacta\nX\nEpitoniidae\nEpitonium spp.\nX","48\nAppendix Table 2. Continued.\nIdentified\nTaxon\nEpitonium indianorum\nX\nNitidascala caamanoi\nX\nNucellidae\nNucella spp.\nX\nNaticidae\nNitidella gouldi\nX\nNassariidae\nX\nNassarius spp.\nNassarius mendicus\nX\nNassarius fossatus\nX\nOlividae\nOlivella spp.\nX\nOlivella biplicata\nX\nOlivella baetica\nX\nOlivella pycna\nX\nTurridae\nKurtzia arteaga\nX\nKurtziella plumbea\nX\nOenopota spp.\nX\nOenopota crebicostata\nX\nOphiodermella inermis\nX\nPyramidellidae\nOdostomia spp.\nX\nTurbonilla spp.\nX\nCephalaspidea\nX\nCylichnidae\nX\nActeocina spp.\nCylichna attonsa\nX\nScaphander willetti\nX\nAglajidae\nMelanochlamys diomedea\nX\nGastropteridae\nGastropteron pacificum\nX\nDiaphanidae\nX\nDiaphana spp.\nDendronotidae\nDendronotus subramosus\nX\nArminidae\nArmina californica\nX","49\nAppendix Table 2. Continued.\nIdentified\nTaxon\nCuthonidae\nCuthona spp.\nX\nBivalvia\nX\nNuculidae\nAcila castrensis\nX\nNucula tenuis\nX\nYoldia spp.\nX\nYoldia scissurata\nX\nMytilidae\nX\nThyasiridae\nAxinopsida serricata\nX\nKellidae\nPseudopythina rugifera\nX\nMontacutidae\nMysella tumida\nX\nSolenidae\nSiliqua spp.\nX\nSiliqua sloati\nX\nTellinidae\nMacoma spp.\nX\nMacoma balthica\nX\nMacoma calcarea\nX\nMacoma nasuta\nX\nTellina spp.\nX\nTellina carpenteri\nX\nTellina modesta\nX\nTellina nuculoides\nX\nVeneridae\nSaxidomus giganteus\nX\nCompsomyax subdiaphana\nX\nPandoridae\nPandora filosa\nX\nPandora punctata\nX\nLyonsiidae\nLyonsia californica\nX","50\nAppendix Table 2. Continued.\nIdentified\nTaxon\nX\nScaphopoda\nDentaliidae\nDentalium spp.\nX\nArthropoda\nX\nArachnida\nHalacaridae\nX\nCrustacea\nBranchiopoda\nDaphnidae\nDaphnia spp.\nX\nOstracoda\nCylindroleberididae\nX\nPhilomedidae\nEuphilomedes spp.\nX\nEuphilomedes carcharodonta\nX\nCopepoda\nCalanoida\nX\nCalanidae\nCalanus spp.\nX\nTemoridae\nX\nEurytemora spp.\nPontellidae\nEpilabidocera longipedata\nX\nHarpacticoida\nX\nX\nCyclopoida\nCorycaeidae\nCorycaeus anglicus\nX\nX\nCirripedia\nChthamalidae\nX\nBalanus spp.","51\nAppendix Table 2. Continued.\nIdentified\nTaxon\nMalacostraca\nLeptostraca\nNebaliidae\nNebalia pugettensis\nX\nMysidacea\nMysidae\nX\nAcanthomysis columbiae\nX\nAcanthomysis macrops\nX\nArchaeomysis grebnitzkii\nX\nNeomysis spp.\nX\nNeomysis kadiakensis\nX\nCumacea\nLampropidae\nX\nHemilamprops spp.\nX\nHemilamprops californica\nX\nLeuconidae\nX\nLeucon spp.\nX\nEudorellopsis longirostris\nX\nColurostylidae\nColurostylis occidentalis\nX\nDiastylidae\nX\nDiastylis spp.\nX\nDiastylopsis spp.\nX\nDiastylopsis dawsoni\nX\nDiastylopsis tenuis\nX\nCampylaspidae\nCampylaspis spp.\nX\nNannastacidae\nCumella vulgaris\nX\nTanaidacea\nParatanaidae\nLeptognathia gracilis\nX\nIsopoda\nSphaeromatidae\nAncinus granulatus\nX","52\nAppendix Table 2. Continued.\nIdentified\nTaxon\nGnorimosphaeroma oregonensis\nX\nTecticeps convexus\nX\nIdoteidae\nEdotea spp.\nX\nEdotea sublittoralis\nX\nIdotea fewkesi\nX\nSynidoted spp.\nX\nSynidotea angulata\nX\nMunnidae\nX\nPleurogonium rubicundum\nX\nAmphipoda\nX\nGammaridea\nX\nAmpeliscidae\nAmpelisca spp.\nX\nAmpelisca agassizi\nX\nAmpelisca macrocephala\nX\nAmpelisca unsocalae\nX\nAoridae\nX\nAoroides spp.\nX\nAoroides columbiae\nX\nAgrissidae\nArgissa homatipes\nX\nAtylidae\nAtylus tridens\nX\nCorophidae\nCorophium spinicorne\nX\nGammaridae\nX\nMegaluropus spp.\nX\nHaustoridae\nEohaustorius spp.\nX\nEohaustorius estuarius\nX\nEohaustorius sencillus\nX\nEohaustorius washingtonianus\nX\nIsaeidae\nCheirimedia spp.\nX\nGammaropsis spp.\nX\nPhotis spp.\nX\nPhotis brevipes\nX","53\nAppendix Table 2. Continued.\nIdentified\nTaxon\nPhotis macinerneyi\nX\nPhotis parvidons\nX\nPodoceropsis spp.\nX\nProtomedeia spp.\nX\nProtomedeia articulata\nX\nLysianassidae\nX\nAnonyx liljeborgi\nX\nLepidepecreum gurjanovae\nX\nOpisa tridentata\nX\nOrchomene spp.\nX\nOrchomene pacifica\nX\nOrchomene pinquis\nX\nPachynus c.f. barnardi\nX\nPsammonyx longimerus\nX\nPrachynella spp.\nX\nOedicerotidae\nMonoculodes spinipes\nX\nSynchelidium spp.\nX\nSynchelidium shoemakeri\nX\nWestwoodilla caecula\nX\nPardaliscidae\nX\nPardalisca spp.\nX\nPhoxocephalidae\nFoxiphalus major\nX\nGrandifoxus grandis\nX\nMandibulophoxus spp.\nX\nMandibulophoxus gilesi\nX\nRhepoxynius spp.\nX\nRhepoxynius abronius\nX\nRhepoxynius bicuspidatus\nX\nRhepoxynius daboius\nX\nRhepoxynius tridentatus\nX\nRhepoxynius vigitegus\nX\nPleustidae\nX\nParapleustes spp.\nX\nParapleustes den\nX\nPleusymtes spp.\nX\nPleusmytes subglaber\nX","54\nAppendix Table 2. Continued.\nIdentified\nTaxon\nPodoceridae\nDulichia spp.\nX\nPodocerus spp.\nX\nStenothoidae\nX\nHyperiiidea\nHyperiidae\nParathemisto spp.\nX\nX\nCaprellidea\nCaprellidae\nX\nCaprella spp.\nX\nDecapoda\nHippolytidae\nX\nCrangonidae\nX\nCrangon spp.\nX\nCrangon alaskansis\nX\nCrangon franciscorum\nX\nCrangon nigricauda\nX\nLissocrangon stylirostris\nX\nRhynocrangon alata\nX\nCallianassidae\nX\nCallianassa spp.\nX\nCallianassa californiensis\nX\nX\nPaguridae\nX\nPagurus spp.\nX\nBrachyura\nCancridae\nX\nCancer spp.\nX\nCancer magister\nPinnotheridae\nX\nPinnixa spp.\nPinnixa eburna\nX\nInsecta\nX\nCollembola","55\nAppendix Table 2. Continued.\nTaxon\nIdentified\nSipuncula\nSipunculidae\nX\nSipunculus nudus\nX\nGolfingiidae\nGolfingia pugettensis\nX\nEchiurida\nX\nPhoronida\nX\nEchinodermata\nOphiuroidea\nX\nOphiura spp.\nX\nAmphiuridae\nAmphiodia spp.\nX\nA mphiura spp.\nX\nEchinoidea\nX\nDendraster excentricus\nX\nHolothuroidea\nX\nChaetognatha\nX\nSagittidae\nSagitta spp.\nX\nUrochordata\nOikopleuridae\nOikopleura spp.\nX","56\nAppendix Table 3. Summaries of benthic invertebrate collections, by station, for 28 stations\noffshore from the Columbia River, July 1993 (available upon request\nfrom National Marine Fisheries Service, Point Adams Biological Field\nStation, P.O. Box 155, Hammond, OR 97121)."]}