Epibenthic Invertebrates at Two Beaches After Addition of Olympia Oysters, with Particular Reference to Prey of Juvenile Pacific Salmon

Jeffery Cordell, Brenda Bachman, and Lucinda Tear University of Washington, School of Aquatic and Fishery Sciences

2 Summary

1. Epibenthic pump samples designed to quantify juvenile Pacific salmon prey taxa were taken at two beaches in Puget Sound, Washington, before and after addition of Olympia oysters. Before-oyster sampling occurred at two plots at each beach in 2006 once in April and once in May. In 2007, after oysters had been added to one of the plots at each beach, sampling occurred again. 2. Seventy-one taxa of epibenthic organisms were collected at the two beaches, twelve of which were juvenile prey salmon taxa. 3. Taxa richness before and after addition of oyster was similar at both beaches. 4. Samples were dominated by harpacticoid , particularly the family Ectinosomatidae, and the juvenile salmon prey taxon Tisbe sp. 5. Densities of most taxa were higher in 2007 than in 2006. 6. Four-way Analysis of Variance, using treatment (oyster, no oyster), month, year, and location indicated that the treatment*year interaction was significant for many of the taxon densities, including total epibenthic organisms, total harpacticoids, and Tisbe sp. This resulted because the change in mean density from 2006 to 2007 was much greater in the oyster plots than in the no oyster plots. 7. We conclude that the addition of Olympia oysters to the two beaches studied increased overall epibenthic organism densities and those of the most abundant salmon prey harpacticoid copepods. This enhancement is probably due to increased habitat complexity which has been extensively demonstrated to increase abundance and diversity of intertidal organisms.

3

Introduction Extensive population growth and development in the Puget Sound region has led to a drastic decline in intact natural shorelines (Levings and Thom 1994). Overall, approximately one third of the Puget Sound shoreline is modified, with much larger proportions modified in counties in and around the metropolitan centers of Seattle and Tacoma (e.g., 68% modified in King County) (WDNR 1999). The construction of piers, docks, and shoreline armoring has resulted in extensive disruption of shoreline and intertidal habitats (Levings and Thom 1994, Nightingale and Simenstad 2001, Sobocinski 2003). The cumulative impact of this shoreline development is unknown, but is of increasing concern, particularly because of its potential to affect important species such as juvenile Chinook and chum salmon (Oncorhynchus tshawytscha, O. keta) that have been listed as “threatened” under the Endangered Species Act. It is known that “ocean- type salmon” (i.e., those that out-migrate to estuarine and nearshore marine waters at a relatively small size, soon after hatching), such as Chinook and chum extensively use nearshore habitats such as wetlands and in estuaries, shallow embayments, and outmigration corridors near river mouths (Kaczynski et al. 1973, Congleton 1978, Healey 1980, Healey 1982, Simenstad et al. 1982, D’Amours 1987, Shreffler et al. 1992, Webb 1989). One of the important functions of these wetlands is providing juvenile salmon with foraging opportunities, and patterns of invertebrate prey that the salmon use in these habitats are relatively well understood. For example, emergent and riparian vegetation produces insect prey such as larval and emergent midges, and shallow mudflat and eelgrass habitats produce prey such as amphipods and harpacticoid copepods. Although considerably less studied than estuarine wetlands, recent work has suggested that nearshore marine habitats in Puget Sound play a similar role for juvenile ocean-type salmon. A detailed examination of the stomachs of 819 juvenile Chinook salmon caught along central Puget Sound beaches in 2001 and 2002 revealed a link between intertidal habitats and the salmon diets (Brennan et al. 2004). In particular, this study found that intertidal polychaete worms, gammarid amphipods, and barnacles were common and sometimes dominant in the juvenile Chinook salmon diets

Epibenthic and epibiotic organisms provide food and shelter for many types of organisms and are important components of the biogenic structure of coastal habitats (Underwood et al. 1991). There is considerable scientific evidence that increasing habitat complexity also increases availability of suitable shelter, benefiting the survival and/or fitness of these intertidal organisms in several ways. First, shelter may reduce physiological stresses such as temperature extremes, desiccation, osmotic fluctuations, etc. (review by Newell 1970; Gibbons 1988, Lohrer et al. 2000). Second, without appropriate shelter are probably more vulnerable to terrestrial and avian predators during low tide and to fish and invertebrate marine predators during high tide (Moksnes et al. 1998). Third, highly complex habitats may enable some mobile species to forage with reduced threat of predation, whereas organisms with limited shelter may face risks of predation that force them to curtail their foraging activities (Sih 1987, Holbrook 1988). In addition to differences in availability of shelter, complex habitats may provide a greater quantity and/or variety of substrate types relative to structurally simple habitats; crevices and depressions associated with complex habitats accumulate sediment and organic material,

4 increasing opportunities for both infaunal and epifaunal species (Kelaher et al. 2001, Olabarría et al. 2002, Kelaher and Castilla 2005) and the relatively great surface area of complex habitats potentially increases available space for prey items.

Relatively little work has been done on the effects of oyster placement on invertebrate assemblages. However, oyster reefs are known to contain diverse and abundant communities of benthic meiofauna that provide potential prey for fish and decapods (Castel et al. 1989), and in Willapa Bay, Washington, Hosack et al. (2006) found that the densities of epibenthic invertebrates, including known prey of fish and decapods, were significantly higher in oyster and eelgrass habitats compared to adjacent unstructured mudflats. In this project we evaluate paired oyster-no-oyster intertidal plots at two sites in Puget Sound, Washington, both before and after placement of Olympia oysters, and our working hypothesis is that increased habitat complexity associated with oyster placement increases diversity and abundance of intertidal epibenthic invertebrates. Thus, the main goals of the study were to determine (1) if oyster habitat increases numbers and diversity of epibenthic invertebrates; and (2) if observed increases include juvenile salmon prey species. The information generated will help scientists, aquaculturists, and habitat managers in improving and maintaining biological function associated with aquaculture and other human impacts in intertidal habitats.

Methods Mobile macro- and meiofaunal invertebrates such as amphipods and harpacticoid copepods that live on the surface of the substrate were sampled using an epibenthic pump (14.8 cm diameter, 150-µm mesh size; Fig. 1). This type of pump has been used extensively in intertidal habitats in the Pacific Northwest to sample juvenile salmon prey invertebrates (Simenstad et al. 1991). The pump works by vacuuming invertebrates inside a cylinder of known volume from the surface layer of substrate. Seven replicate samples were taken on each plot in April and May 2006 (pre-oyster placement) and 2007. Samples were fixed in 10% buffered formalin in the field. Invertebrate taxa from known salmon prey groups such as large harpacticoid copepods, gammarid amphipods, other peracarid , and mobile polychaete worms were identified to species; other taxa will be identified to lower taxonomic levels. For purposes of this study, calanoid copepods, which are water-column dwelling that were probably obtained during pump-clearing between samples, and nematode worms, which are primarily benthic infauna, were omitted from analyses.

Mean densities of selected taxa from each plot were graphed by year and coded by month, location, and treatment to show patterns of change from year one to year two. Four way Analysis of Variance was conducted using treatment (oyster, no oyster), month (April, May), year (2006, 2007), location (Dogfish, Lemolo), and all interaction terms except those including month. ANOVA results were interpreted in the context of the patterns observed in corresponding graphs. Since both oyster and no oyster plots began with no oysters and oysters were added after the 2006 sampling, the ANOVA must be interpreted carefully to in order to isolate the terms that express the way that densities changed between 2006 and 2007 in the two treatments. The ANOVA factor that most directly describes differences in how the treatment plots changed is the treatment*year

5 interaction term. If this term is significant, then changes over time (average for both sites and both sampling months) in the two treatments were not equal. If this term is not significant, then changes in the two treatments were similar. The treatment factor, which describes the differences between the mean densities in the two treatments (average of both sites, months, and years), is not the best term for summarizing the change after oysters were added, since it includes densities in the oyster plots before oysters were added. Consequently, in this ANOVA, the "treatment" factor estimates differences between the overall mean for each of the two treatments, but does not describe change in densities due to treatments. Differences between the effects of the treatment at the different sites is expressed by the site*year*treatment interaction.

6 Results We identified 71 epibenthic invertebrate taxa from pump samples taken at Dogfish and Lemolo Beaches (Appendix Table 1). Of these, 12 taxa were designated as juvenile salmon prey organisms. Taxa richness was higher in 2007 than in 2006, but on a given sampling date, it was similar among the test plots (Fig. 2).

At both Dogfish and Lemolo beaches, the epibenthic assemblages was dominated by two taxa of harpacticoid copepods: Tisbe sp. and the family Ectinosomatidae (Fig. 3). Of these two taxa, Ectinosomatidae were more abundant in 2006 and Tisbe sp. were more abundant in 2007. In 2007, after placement of the oysters, Tisbe sp. were consistently more abundant in terms of percent composition at the plots with oysters as compared to the non-oyster plots.

For all epibenthic invertebrates combined, and most prominent individual taxa, mean densities were greater in 2007 than in 2006 (Figs. 4, 5). Densities tended to be higher at Lemolo beach than at Dogfish Beach. Densities of total invertebrates and Tisbe sp. were highest at Lemolo Beach in April 2007, and lowest at Dogfish Beach in April 2006.

The treatment*year interaction term was significant for many of the taxon densities, including total organisms, harpacticoid copepods, and the dominant salmon prey harpacticoid Tisbe sp. (Table 1). In most cases, we interpreted the graphical analyses to indicate that the reason this term was significant was because the change in mean density from 2006 to 2007 was greater in the oyster plots than in the no oyster plots (e.g., Fig. 4). For many taxa, densities increased in both treatments, but the increase in the oyster treatment was greater than in the no oyster treatment. The differences between the slopes of the lines connecting the 2006 and 2007 means for each treatment expresses this interaction: if the slopes had been the same, the interaction would not have been significant.

Discussion In summary, the presence of habitat structure in the form of Olympia oysters resulted in increased abundance of total epibenthic organisms, harpacticoid copepods, and the dominant harpacticoid prey taxon Tisbe sp. at the two beaches studied. This was evidenced by the fact that increases in the oyster plots were greater than the increases seen in non-oyster plots and indicate that the oyster treatment increased densities over and above effects of other factors. For many taxa, densities increased in 2007 in both oyster and non-oyster plots. These increases could have been caused by interannual variation due to weather or other factors. It is also possible that it was due to an augmentation effect from the treatment plots: we note that the oyster and no-oyster plots were directly adjacent to each other. At Dogfish and Lemolo beaches, placement of Olympia oysters had a positive influence on abundance of epibenthic organisms, particularly harpacticoid copepods.

Our findings were similar to those of Simenstad et al. (1991) who found that adding gravel to sand and mud Puget Sound beaches for hardshell clam enhancement significantly increased abundances of harpacticoid copepods, including salmon prey

7 species. In general, adding complexity appears to increase faunal abundance and diversity in keeping with the principle that complex habitats support higher abundance and more species than simple ones (Bell et al. 1991). For example, increased abundance and diversity of harpacticoids and other epifaunal organisms have been recorded in both natural and artificial seagrasses relative to nearby unvegetated habitat (e.g., Hicks 1986, Lee et al. 2001, Jenkins et al. 2002). The factors leading to these increases may include increased living spaces and microhabitats, increased food resources, refuge from predation and physical disturbance, and hydrodynamic effects on larval recruitment. In the present study, addition of the oysters may have provided a habitat that specifically enhanced the dominant harpacticoid Tisbe sp., by adding substrate for increased attachment of algae. Tisbe spp. are known to be abundantly associated with algae in other regions (Steinarsdottir et al. 2003, Hicks 1980), and especially with green ulvoids in the Pacific Northwest (J. Cordell, personal observation).

Addition of Olympia oysters at Dogfish and Lemolo beaches did not result in increased taxonomic richness. These results are similar to those obtained by Jenkins et al. (2002) using artificial units, and as these authors suggest, the results imply that increased abundances in the oyster plots represented an increase in the abundance of taxa within the shared pool of species at each site, rather than the addition of new taxa. The pool of available species may largely be determined by the scale of the site with little scope for variation at the experimental plot level. As with Jenkins et al., in our study, identification was generally to the rather than the species level and therefore a lack of taxonomic resolution may have also played a role in the taxa richness results.

8 Tables

Table 1. P values for different factors and three major taxa groups in ANOVA, bold type indicates significant result at alpha=0.05.

Salmon Tisbe Prey sp. Factor(s) Tested All Taxa Taxa Interpretation Oyster > No Oyster (averaged over all TREATMENT 0.02 0.00 0.00 other factors) Lemolo > Dogfish (averaged over all other SITE 0.00 0.00 0.00 factors) 2007 > 2006 (averaged over all other YEAR 0.00 0.00 0.00 factors) MONTH 0.00 0.00 0.00 April > May (averaged over all other factors) Differences between treatments greater at Lemolo than at Dogfish; differences between Lemolo and Dogfish greater in TREATMENT * Oyster treatments than in No Oyster SITE 0.01 0.02 0.01 treatments Oyster and No Oyster treatments increase over time (average of both sites) at different TREATMENT * rates. Rate of increase is greater in Oyster YEAR 0.07 0.01 0.01 plots. Differences between sites greater in 2007, SITE * YEAR 0.00 0.00 0.00 between-year difference greater at Lemolo. Changes over time significantly different for TREATMENT * all treatment*site combinations and all SITE * YEAR 0.06 0.02 0.01 variables except All Taxa

9

Figures

Figure 1. Left, epibenthic pump sampling of aquatic invertebrates; right, epibenthic pump apparatus.

Taxa Richness

Figure 2. Taxa richness of organisms from epibenthic pump samples taken at Dogfish and Lemolo beaches, April and May, 2006 and 2007.

10 2006 (Pre-Oyster) 100% Tisbe spp. Ectinosomatidae 80% Microarthridion littorale Longipedia spp. 60% Amphiascus spp. Other Cyclopinidae 40% Other Cyclopoida Cumella vulgaris

20% Other

0% No Oyster No Oyster No Oyster No Oyster Oyster Oyster Oyster Oyster

April May April May

Dogfish Lemolo

2007 (Post-Oyster)

100%

80%

60%

40%

20%

0% No Oyster No Oyster No Oyster No Oyster Oyster Oyster Oyster Oyster

April May April May

Dogfish Lemolo

Figure 3. Percent composition of epibenthic organisms from pump samples taken on control and treatment plots before (top) and after (bottom) placement of oysters

11

2006 (Pre-Oyster) 9000.0 Tisbe spp. 8000.0 Ectinosomatidae

7000.0 Other Harpacticoida Other 6000.0

5000.0

4000.0

3000.0

2000.0

1000.0

0.0 No Oyster Oyster No Oyster Oyster No Oyster Oyster No Oyster Oyster April May April May Dogfish Lemolo

2007 (Post-Oyster) 90000.0

80000.0

70000.0

60000.0

50000.0

40000.0

30000.0

20000.0

10000.0

0.0 No Oyster Oyster No Oyster Oyster No Oyster Oyster No Oyster Oyster April May April May Dogfish Lemolo

Figure 4. Mean density of epibenthic organisms from pump samples taken on control and treatment plots before (top) and after (bottom) placement of oysters. Note scale differences on graphs.

12 -2 Mean Total Density, No. m No. Density, Total Mean

-2 Density, No. m Tisbe Mean

Figure 5. Mean density of all invertebrates combined (top) and Tisbe sp. (bottom) from epibenthic pump samples.

13

Literature Cited Bell S.S., E.D. McCoy, and H.R. Mushinsky (eds) (1991) Habitat structure: the physical arrangement of objects in space. Chapman and Hall, London 604 Brennan, J.S., K.F. Higgins, J.R. Cordell, and V.A. Stamatiou. 2004. Juvenile salmon composition, distribution, and diet in nearshore waters of central Puget Sound in 2001-2002. King County Department of Natural Resources and Parks, Seattle, WA. 164 pp. Castel, J., P. J. Labourg, V. Escaravage, I. Auby, and M. E. Garcia. 1989. Influence of seagrass beds and oyster parks on the abundance and biomass patterns of meio- and macrobenthos in tidal flats. Estuarine Coastal and Shelf Science 28:71–85 Congleton, J.L. 1978. Feeding patterns of juvenile chum in the Skagit River salt marsh, pp 141-150 in: C.A. Simenstad and S.J. Lipovsky (eds.), Fish Food Habits Studies. 1st Pacific Northwest Technical Workshop, Workshop Proceedings, Washington Sea Grant, University of Washington, Seattle, Washington. WSG- WO-77-2. D’Amours, D. 1987. Trophic phasing of juvenile chum salmon Oncorhynchus keta Walbaum and harpacticoid copepods in the Fraser River estuary, British Columbia. Ph.D. thesis, University of British Columbia. 163 pp. Gibbons, M.J. 1988. The impact of sediment accumulations, relative habitat complexity and elevation on rocky shore meiofauna. J. Exp. Mar. Biol. Ecol. 122:225–241. Healey, M.C. 1980. Utilization of the Nanaimo River estuary by juvenile chinook salmon, Oncorhyncus tshawytscha. Fish. Bull. 77:653-668. Healey, M.C. 1982. The distribution and residency of juvenile Pacific salmon in the Strait of Georgia, British Columbia, in relation to foraging success. Report from the North Pacific Aquaculture Symposium. Hicks, G.R.F. 1986. Distribution and behaviour of meiofaunal copepods inside and outside seagrass beds. Mar. Ecol. Prog. Ser. 31:159–170. Hicks, G.R.F. 1980. Structure of phytal harpacticoid assemblages and the influence of habitat complexity and turbidity. J. Exp. Mar. Biol. Ecol. 44:157-192. Holbrook, S.J. and R.J. Schmitt. 1988. The combined effects of predation risk and food reward on patch selection. Ecology 69(1):125–134. Hosack, G.R, B.R. Dumbauld, J.L. Ruesink, and D.A. Armstrong. 2006. Habitat associations of estuarine species: comparisons of intertidal mudflat, seagrass (Zostera marina), and oyster (Crassostrea gigas) habitats. Est. Coast. 29(6B):1150-1160. Jenkins, G.P., G.K. Walker-Smith, and Paul A. Hamer. 2002. Elements of habitat complexity that influence harpacticoid copepods associated with seagrass beds in a temperate bay. Oecologia 131:598-605.

14 Kaczynski, V.W., R.J. Feller, J. Clayton, and R.J. Gerke. 1973. Trophic analysis of juvenile pink and chum salmon (Oncoryhnchus gorbuscha and O. keta) in Puget Sound. J. Fish Res. Board Can. 30:1003-1008. Kelaher, B.P., M.G. Chapman, and A.J. Underwood. 2001. Spatial patterns of diverse macrofaunal assemblages in coralline turf and their association with environmental variables. J. Ma. Biol. Assoc. Unit. King. 81:1–14. Kelaher, B.P. and C.J. Castilla. 2005. Habitat characteristics influence macrofaunal communities in coralline turf more than mesoscale coastal upwelling on the coast of Northern Chile. Estuarine, Coastal and Shelf Science 63:155-165. Lee S.Y., Fong C.W., and Wu R.S.S. (2001) The effects of seagrass (Zostera japonica) canopy structure on associated fauna: a study using artificial seagrass units and sampling of natural beds. J. Exp. Mar. Biol. Ecol. 259:23–50. Levings, C.D. and R.N. Thom. 1994. Habitat changes in Georgia Basin: implications for resource management and restoration. Can. Tech. Rep. Fish. Aquat. Sci. Lohrer, A.M., Y. Fukui, K. Wada, and R.B. Whitlatch. 2000. Structural complexity and vertical zonation of intertidal crabs, with focus on habitat requirements of the invasive Asian shore crab, Hemigrapsus sanguineus (de Haan). J. Exp. Mar. Biol. Ecol. 244(2):203-217. Moksnes, P.-O., L. Pihl, and J. van Montfrans. 1998. Predation on postlarvae and juveniles of the shorecrab Carcinus maenus: importance of shelter, size, and cannibalism. Mar. Ecol. Prog. Ser. 166:211–225. Newell, R.C., 1970. Biology of Intertidal Animals. American Elsevier Pub. Co., Inc, New York. Nightingale, B., and C.A. Simenstad. 2001. Overwater structures: marine issues. Washington State Transportation Center report number WA-RD 508.1a. University of Washington. 133 pp. Olabarría, C., A.J. Underwood, and M.G. Chapman. 2002. Appropriate experimental design to evaluate preferences for microhabitat: an example of preferences by species of microgastropods. Oecologia 132:159–166. Shreffler, D. C. Simenstad, and R. Thom. 1992. Foraging by juvenile salmon in a restored estuarine wetland. Estuaries 15:204-213. Sih, A. 1987. Predators and prey lifestyles: an evolutionary and ecological overview. In: Kerfoot, W.C. and Sih, A. Editors, 1987. Predation: Direct and Indirect Impacts on Aquatic Communities. University Press of New England, Hanover, NH, pp. 203–224. Simenstad, C.A., K. Fresh, and E. Salo. 1982. The role of Puget Sound and Washington coastal estuaries in the life history of Pacific salmon: an unappreciated function. Pages 343-364 in v. Kennedy, editor. Estuarine Comparisons. Academic Press, New York.

15 Simenstad, C., C. Tanner, C. Crandell, J. White, and J. Cordell. 2005. Challenges of habitat restoration in a heavily urbanized estuary: evaluating the investment. J. Coast. Res. 40:6-23. Simenstad, C.A., C.D. Tanner, R.M. Thom, and L.L. Conquest. 1991. Estuarine Habitat Assessment Protocol. Report to U. S. Environmental Protection Agency, Region 10, Seattle, Washington. EPA 910/9-91-037. 201 p + appendices. Simenstad, C.A, J.R. Cordell, and L.A. Weitkamp. 1991. Effects of substrate modification on littoral flat meiofauna: assemblage structure changes associated with adding gravel. FRI-UW-9111, School of Aquatic and Fishery Sciences, University of Washington. Steinarsdottir, M.B., A. Ingolfsson, and E Olafsson. 2003. Seasonality of harpacticoids (Crustacea, Copepoda) in a tidal pool in subarctic south-western Iceland. Hydrobiologia 503:211-221. Sobocinski, K.L. 2003. The impact of shoreline armoring on supratidal beach fauna of central Puget Sound. MS Thesis, University of Washington School of Aquatic and Fishery Sciences. 83 pp. Underwood, A.J., Kingsford, M.J., and N.L. Andrew. 1991. Patterns in shallow subtidal marine assemblages along the coast of New South Wales. Aust. J. Ecol. 6, 231– 249. Webb, D.G. 1989. Predation by juvenile salmonids on harpacticoid copepods in a shallow subtidal seagrass bed: effects on copepods community structure and dynamics. Ph.D. thesis, University of British Columbia, Vancouver, British Columbia. 246 pp. WDNR. 1999. Shorezone Inventory. Washington Department of Natural Resources, Olympia.

16 Appendix Table 1. Epibenthic invertebrate taxa identified from Dogfish and Lemolo Bays, April and May, 2006-2007.

Salmonid prey/ Phylum Subphylum Class Subclass Order Taxon non prey Arthropoda Arachnida Acarina Halacaridae non prey Arthropoda Crustacea Malacostraca Peracarida Amphipoda Amphipoda non prey Arthropoda Crustacea Malacostraca Peracarida Amphipoda Anisogammarus pugettensis prey Arthropoda Crustacea Malacostraca Peracarida Amphipoda Aoroides sp. non prey Arthropoda Crustacea Malacostraca Peracarida Amphipoda Corophium sp. prey Arthropoda Crustacea Malacostraca Peracarida Cumacea Cumella vulgaris prey Arthropoda Crustacea Malacostraca Peracarida Cumacea Nippoleucon hinumensis non prey Arthropoda Crustacea Malacostraca Eucarida Decapoda Brachyura non prey Arthropoda Crustacea Malacostraca Eucarida Decapoda Caridea non prey Arthropoda Crustacea Malacostraca Eucarida Decapoda Crangon sp. non prey Arthropoda Crustacea Malacostraca Peracarida Isopoda Epicaridea non prey Arthropoda Crustacea Malacostraca Peracarida Isopoda Isopoda non prey Arthropoda Crustacea Malacostraca Peracarida Isopoda Munna sp. non prey Arthropoda Crustacea Copepoda Calanoida Calanoida non prey Arthropoda Crustacea Maxillopoda Copepoda Calanoida Calanoida non prey Arthropoda Crustacea Maxillopoda Copepoda Cyclopoida Cyclopinidae non prey Arthropoda Crustacea Maxillopoda Cyclopoida Cyclopoida non prey Arthropoda Crustacea Maxillopoda Copepoda Harpacticoida Acrenhydrosoma sp. non prey Arthropoda Crustacea Maxillopoda Copepoda Harpacticoida Ameira longipes non prey Arthropoda Crustacea Maxillopoda Copepoda Harpacticoida Ameiridae non prey Arthropoda Crustacea Maxillopoda Copepoda Harpacticoida Amonardia normani non prey Arthropoda Crustacea Maxillopoda Copepoda Harpacticoida Amonardia perturbata non prey Arthropoda Crustacea Maxillopoda Copepoda Harpacticoida Amphiascoides sp. non prey Arthropoda Crustacea Maxillopoda Copepoda Harpacticoida Amphiascoides sp. A non prey Arthropoda Crustacea Maxillopoda Copepoda Harpacticoida Amphiascopsis cinctus non prey Arthropoda Crustacea Maxillopoda Copepoda Harpacticoida Amphiascus minutus non prey Arthropoda Crustacea Maxillopoda Copepoda Harpacticoida Amphiascus sp. non prey Arthropoda Crustacea Maxillopoda Copepoda Harpacticoida Bulbamphiascus sp. non prey Arthropoda Crustacea Maxillopoda Copepoda Harpacticoida Cletodidae non prey Arthropoda Crustacea Maxillopoda Copepoda Harpacticoida Dactylopusia crassipes prey Arthropoda Crustacea Maxillopoda Copepoda Harpacticoida Dactylopusia sp. prey Arthropoda Crustacea Maxillopoda Copepoda Harpacticoida Dactylopusia vulgaris prey Arthropoda Crustacea Maxillopoda Copepoda Harpacticoida Danielssenia typica non prey Arthropoda Crustacea Maxillopoda Copepoda Harpacticoida Diarthrodes sp. non prey 17 Arthropoda Crustacea Maxillopoda Copepoda Harpacticoida Diosaccidae non prey Appendix Table 1, continued.

Arthropoda Crustacea Maxillopoda Copepoda Harpacticoida Ectinosomatidae non prey Arthropoda Crustacea Maxillopoda Copepoda Harpacticoida Enhydrosoma sp. non prey Arthropoda Crustacea Maxillopoda Copepoda Harpacticoida Harpacticoida non prey Arthropoda Crustacea Maxillopoda Copepoda Harpacticoida Harpacticoida non prey Arthropoda Crustacea Maxillopoda Copepoda Harpacticoida Harpacticus septentrionalis prey Arthropoda Crustacea Maxillopoda Copepoda Harpacticoida Harpacticus sp. prey Arthropoda Crustacea Maxillopoda Copepoda Harpacticoida Harpacticus spinulosus non prey Arthropoda Crustacea Maxillopoda Copepoda Harpacticoida Harpacticus uniremis prey Arthropoda Crustacea Maxillopoda Copepoda Harpacticoida Harpacticus-obscurus group prey Arthropoda Crustacea Maxillopoda Copepoda Harpacticoida Heterolaophonte discophora non prey Arthropoda Crustacea Maxillopoda Copepoda Harpacticoida Heterolaophonte hamondi non prey Arthropoda Crustacea Maxillopoda Copepoda Harpacticoida Heterolaophonte longisetigera non prey Arthropoda Crustacea Maxillopoda Copepoda Harpacticoida Huntemannia jadensis non prey Arthropoda Crustacea Maxillopoda Copepoda Harpacticoida Laophontidae non prey Arthropoda Crustacea Maxillopoda Copepoda Harpacticoida Longipedia sp. non prey Arthropoda Crustacea Maxillopoda Copepoda Harpacticoida Mesochra sp. non prey Arthropoda Crustacea Maxillopoda Copepoda Harpacticoida Microarthridion littorale non prey Arthropoda Crustacea Maxillopoda Copepoda Harpacticoida Normanella sp. non prey Arthropoda Crustacea Maxillopoda Copepoda Harpacticoida Orthopsyllus illgi non prey Arthropoda Crustacea Maxillopoda Copepoda Harpacticoida Paradactylopodia sp. non prey Arthropoda Crustacea Maxillopoda Copepoda Harpacticoida Paralaophonte sp. non prey Arthropoda Crustacea Maxillopoda Copepoda Harpacticoida Parastenhelia hornelli non prey Arthropoda Crustacea Maxillopoda Copepoda Harpacticoida Parathalestris californica non prey Arthropoda Crustacea Maxillopoda Copepoda Harpacticoida Robertgurneya sp. non prey Arthropoda Crustacea Maxillopoda Copepoda Harpacticoida Robertsonia sp. non prey Arthropoda Crustacea Maxillopoda Copepoda Harpacticoida Scutellidium sp. non prey Arthropoda Crustacea Maxillopoda Copepoda Harpacticoida Stenhelia peniculata non prey Arthropoda Crustacea Maxillopoda Copepoda Harpacticoida Tachidius triangularis non prey Arthropoda Crustacea Maxillopoda Copepoda Harpacticoida Tisbe sp. prey Arthropoda Crustacea Maxillopoda Copepoda Harpacticoida Typhlamphiascus pectinifer non prey Arthropoda Crustacea Maxillopoda Copepoda Harpacticoida Zaus sp. prey Arthropoda Crustacea Maxillopoda Copepoda Poecilostomatoida Corycaeus anglicus non prey Arthropoda Crustacea Maxillopoda Balanomorpha non prey Annelida Oligochaeta Oligochaeta non prey Annelida Polychaeta Polychaeta non prey 18 Nematoda Nematoda non prey

19