Evaluating Habitat Enhancements of an Urban Intertidal Seawall: Ecological Responses and Management Implications

Maureen Goff

A thesis submitted in partial fulfillment of the requirements for the degree of

Master of Science

University of Washington

2010

Program Authorized to Offer Degree: School of Aquatic and Fishery Sciences

In presenting this thesis in partial fulfillment of the requirements for a Master‟s degree at the University of Washington, I agree that the Library shall make its copies freely available for inspection. I further agree that extensive copying of this thesis is allowable for scholarly purposes, consistent with “fair use” as prescribed in the U.S. Copyright

Law. Any other reproduction for any purposes or by any means shall not be allowed without my written permission.

Signature______

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TABLE OF CONTENTS

Table of Contents ...... i List of Figures ...... iv List of Tables ...... v Acknowledgements ...... vi Introduction ...... 1 Elliott Bay and downtown Seattle shorelines...... 2 Habitat enhancement along Seattle‟s central waterfront seawall ...... 3 Objectives ...... 3 Chapter 1: Succession of intertidal algae and invertebrates on an urban seawall and effects of added complexity on ecologically important species ...... 5 Introduction: Seawalls in the intertidal zone ...... 5 Disturbance and succession on hard substrates ...... 5 Armored shorelines and comparability to natural rocky shorelines ...... 6 Objectives ...... 8 Methods ...... 8 Study area ...... 8 Habitat panel sites ...... 8 Habitat enhancement test panel treatments ...... 10 Study design ...... 10 Data collection ...... 11 Data analysis ...... 12 Results ...... 14 Recruitment, colonization, and succession of algae and invertebrates on panels ...... 14 Convergence of test panels with reference and control sections ...... 19 Taxa richness and community composition ...... 20 Species-Specific responses to slope and texture ...... 21 Discussion ...... 27 Succession and convergence on habitat test panels ...... 27 Importance of microhabitat and physical features of substrate and how they relate to habitat panel features ...... 29

Panel design and surface: species-specific responses ...... 30 Summary ...... 33 Chapter 2: Epibenthic Meiofauna Responses to Intertidal Habitat Enhancement with a Focus on Juvenile Salmon Prey ...... 34 Introduction ...... 34 Puget Sound juvenile salmon and link to nearshore ...... 34 The highly altered urban shoreline of Elliott Bay ...... 35 The link between habitat complexity and ecological capacity ...... 36 Objectives ...... 37 Methods ...... 37 Data collection ...... 37 Data analysis ...... 39 Results ...... 40 Taxa richness ...... 40 Comparisons of densities: juvenile salmon prey species ...... 43 Whole assemblage composition comparisons ...... 47 Temporal shifts in whole assemblage composition ...... 47 Relationships among assemblage composition and panel design ...... 49 Discussion ...... 49 Increased taxa richness and densities of harpacticoid copepods ...... 49 Insect prey densities ...... 50 Summary ...... 51 Chapter 3: Management Implications of Habitat Enhancement Opportunities on the Seattle Seawall ...... 52 Ecological impacts of shoreline armoring in the intertidal zone ...... 52 Puget Sound, Elliott Bay, and Seattle ...... 53 Juvenile salmon migration and rearing along Seattle shoreline ...... 53 Limitations to restoration in urban estuaries ...... 54 Habitat enhancement as an alternative to restoration ...... 55 Opportunity and collaboration ...... 56 Implementation and monitoring ...... 57 Summary of monitoring results 2008 - 2009 ...... 59 Caveats ...... 61 Adaptive management opportunity and “Desired Environmental States” ...... 61

Landscape perspective: Seattle Seawall “Greenway” as a link in a chain of other restoration efforts ... 62 Broader Implications ...... 63 Summary ...... 64 References ...... 65 Appendix A ...... 70 Appendix B ...... 91 Appendix C ...... 94

iii

LIST OF FIGURES PAGE Figure 1.1. Location map and study sites...... 9 Figure 1.2. Habitat enhancement test panel designs used in this study...... 10 Figure 1.3. Site panorama of randomly located panels at Aquarium site ...... 10 Figure 1.4. Quadrat sampling on a fin...... 11 Figure 1.5. Succession of algae and invertebrates through beginning and endpoints of year 1 and 2 monitoring...... 15 Figure 1.6. Average percent cover of functional groups of algae showing succession over monitoring period ...... 17 Figure 1.7. Convergence measured through relative difference of mean percent dissimilarity ...... 19 Figure 1.8. Overlap of community composition of all panel types with the reference sections of seawall, approaching convergence by August 2009...... 20 Figure 1.9. MDS plot of August 2009 (monitoring endpoint) middle elevation community composition data...... 21 Figure 1.10. Average taxa richness of reference, control, and test panels at endpoints of year one and two ...... 21 Figure 1.11. Average percent cover of Fucus distichus by panel type and elevation at monitoring endpoint (August 2009) ...... 22 Figure 1.12. Average percent cover of Fucus distichus by elevation, substrate angle, and surface treatment at monitoring endpoint (August 2009) ...... 23 Figure 1.13. Average limpet densities at monitoring endpoint (August 2009) by species, elevation, and panel type ...... 24 Figure 1.14. Average limpet densities at monitoring endpoint (August 2009) by elevation, substrate angle, and surface treatment...... 24 Figure 1.15. Average percent cover and size class of Mytilus by panel type during final season of monitoring (2009)...... 26 Figure 1.16. Average percent cover of mussels at monitoring endpoint (August 2009) by elevation, substrate angle, and surface treatment ...... 26 Figure 2.1. Epibenthic pump sampling for meiofauna...... 39 Figure 2.2. Stratified random epibenthic sampling of various panel surfaces...... 39 Figure 2.3. Comparisons of epibenthic taxa richness by panel, all sampling events combined...... 41 Figure 2.4. Mean density of prey insects by panel type...... 44 Figure 2.5. Mean density of prey insects by substrate angle and surface treatment...... 45 Figure 2.6. Mean density of prey harpacticoids by panel type...... 46 Figure 2.7. Mean density of prey harpacticoids by substrate angle and surface treatment...... 46 Figure 2.8. Mean densities of most abundant prey amphipods by panel type...... 47 Figure 2.9. MDS plot of temporal shift in epibenthic community composition with Pearson correlation vectors (> 0.4) by principal taxa...... 48 Figure 2.10. Top ten most abundant harpacticoid copepod taxa by sampling event ...... 49 Figure 3.1. Fabrication of a precast concrete "fin" habitat enhancement test panel...... 58 Figure 3.2. Lowering of panels onto seawall using backhoe from sidewalk above ...... 58

LIST OF TABLES PAGE

Table 1.1. List of taxa and groupings identified in seawall quadrat sampling 2008-2009……………..16

Table 1.2. Results from 2-way fixed factor ANOVAs per tidal elevation on effects of substrate angle and surface treatment on Fucus cover (August 2009)………………………………………………………23

Table 1.3. Results from 2-way fixed factor ANOVAs per tidal elevation on effects of substrate angle and surface treatment on limpet densities (August 2009)…………………………………….…….……….25

Table 1.4. Results from 2-way fixed factor ANOVAs per tidal elevation on effects of substrate angle and surface treatment on mussel cover (August 2009)………………………………………….……….…..27

Table 2.1. Sampling events, dates, and ID status for epibenthic sample collection………………….…38

Table 2.2. Comparison matrix of Tukey post hoc test on differences in epibenthic taxa richness……...41

Table 2.3. All epibenthic taxa exclusive to panels with fins and steps and total count of individuals….42

Table 2.4. All epibenthic taxa exclusive to flat panels and total count of individuals…………….…….43

Table 2.5. Tukey post hoc test for prey insect densities by panel type……………………………...... 45

Table 2.6. Tukey post hoc test of prey harpacticoid densities by panel type……………………..……..46

Table 3.1. Summary of observed habitat enhancement effects on Seattle seawall…………….…...... 59

Table 3.2. Summary of surface areas of various panel designs, with descriptions of physical and biological attributes…………………………………………………………………………..……….…60

ACKNOWLEDGEMENTS

I would like to express my sincere appreciation to my committee members: Si Simenstad, Jeffery Cordell, Megan Dethier, and Loveday Conquest. I would also like to thank Jason Toft for his patient support through copious and assorted statistical analyses. Many thanks also go to the WET team field volunteers who accompanied me on early mornings in sometimes challenging urban conditions. Your contribution and pleasant company made this project both achievable and enjoyable.

Support from the School of Aquatic and Fisheries Sciences, Washington Sea Grant, King Conservation District, and the City of Seattle for my graduate assistantship is greatly appreciated. I am also grateful to Judith Noble and John Arneson, along with other folks at the City of Seattle in the Waterfront Ecology Team, who had the inspiration and foresight to re-imagine seawalls.

INTRODUCTION

Marine biodiversity is a global conservation issue and has been negatively affected in coastal areas, with large declines due to the many conflicting uses of coastal habitat that include industry, seaports, extraction of natural resources, and conservation needs (Gray 1997). In temperate estuaries and coastal seas around the world, habitat loss is second only to exploitation as the cause of most (> 90%) species depletions and extinctions (Lotze, Lenihan et al. 2006). Additionally, coastal areas provide almost half (43%) of the worlds ecosystem goods and services (Costanza, Arge et al. 1997). Marine shorelines and coastal areas around the world are being transformed as the demand for commercial, transportation, residential and tourist infrastructure increases and shoreline alteration is projected to increase and accelerate as populations along coastal areas grow (Bulleri and Chapman 2010). The consequences of shoreline armoring in the marine environment are two-fold: destruction of the existing shoreline habitat and introduction of a new, novel habitat, the effects of which have only recently received attention (Glasby and Connell 1999; Bulleri and Chapman 2010). Often, hard seawalls and armoring are built among soft sediments to prevent erosion and provide stabilization and protection from wave energy and can alter both the physical habitat and biological community. Introduction of shoreline armoring transforms the nature of the substrate, altering physical processes in the surrounding unconsolidated substrate with changes in wave energy, scouring, and sedimentation, reducing habitat for existing soft substrate species, creating additional habitat for species from nearby natural rocky intertidal environments, and creating novel habitat for introduced species (Ahn and Choi 1998; Glasby and Connell 1999; Airoldi, Abbiati et al. 2005; Glasby, Connell et al. 2007; Bulleri and Chapman 2010). Different forms of armoring such as groins, breakwaters, riprap, and seawalls have different effects (both positive and negative) on biodiversity and distribution of species, which is often associated with the complexity of the structures (Davis, Levin et al. 2002; Bacchiocchi and Airoldi 2003; Bulleri and Chapman 2004). Seawalls are the least complex of shoreline armoring structures, typically built of smooth vertical concrete slabs. Compared to natural rocky shores, seawalls tend to support fewer taxa in the intertidal zone, where features like crevices are known to be important refuge for mobile and sessile invertebrates (Bergeron and Bourget 1986; Archambault and Bourget 1996; McKindsey and Bourget 2001; Petraitis and Dudgeon 2005; Moreira, Chapman et al. 2007). Seawalls also reduce the surface area available, increasing competition and stress, and they lack sloping surfaces that modify patterns of wave energy, shading, and other physical characteristics that influence the recruitment and distribution of sessile invertebrates (Wethey 1984; Bergeron and Bourget 1986; Helmuth and Hofmann 2001; Chapman 2003; Blockley and Chapman 2006; Moreira, Chapman et al. 2006; Blockley and Chapman 2008; Chapman and Blockley 2009). Seawalls may support some similar taxa as natural rocky intertidal shorelines at lower

intertidal elevations but effects there are more often manifest in species-specific abundance, density, distribution, size, and reproductive capabilities (Chapman 2003; Chapman and Bulleri 2003; Moreira, Chapman et al. 2006).

ELLIOTT BAY AND DOWNTOWN SEATTLE SHORELINES

Puget Sound is a deep glacial fjord and estuary in Washington State, with primarily glacial sediment beaches and mudflat /tidal marsh shorelines. Rocky coasts are limited mostly to the San Juan islands and the western Strait of Juan de Fuca, but beaches in Puget Sound are being increasingly modified by the addition of hard substrate through armoring, intertidal fills, groins and jetties, and overwater structures (Shipman 2008). Approximately one-third of the Puget Sound shoreline is modified with rip-rap, seawalls, docks, and other forms of shoreline (WDNR 1999; Simenstad, Ramirez et al. In press). Urban bays within Puget Sound have had much higher declines in natural shoreline with 68% of the shoreline modified in King County, where Elliott Bay and the City of Seattle are located (WDNR 1999).

Elliott Bay was originally characterized by low to high bank bluff-backed mixed gravel-cobble beaches and low tide terrace, but there are now over 3 kilometers (or over 2 miles) of seawall along the Seattle central waterfront with very few remaining shallow sloping intertidal beaches (WDNR 1999). Despite the highly altered nature of the shoreline, Elliott Bay and Seattle still serve as an important migratory corridor and rearing habitat for juvenile salmon from the nearby Duwamish/Green River system and from other watersheds around Puget Sound (Ruggerone and Volk 2003), with chum and pink salmon abundant along the shoreline of Elliott Bay directly adjacent to the downtown Seattle seawall (Toft, Cordell et al. 2007; Toft, Heerhartz et al. 2009). In Elliott Bay and Puget Sound, diets of chum and Chinook are closely linked to the nearshore with chum feeding mostly on a select group of small epibenthic crustaceans and Chinook feeding on riparian insects, or on benthic and epibenthic prey in more urbanized areas (Brennan, Higgins et al. 2004; Gray 2005). The cumulative impact of shoreline development along Seattle‟s waterfront is unknown, but is of increasing concern, particularly because juvenile salmon migrating and rearing here include Chinook salmon, a culturally and economically important species listed as threatened under the federal Endangered Species Act (ESA). Prey quality and availability for juvenile salmon is extremely important in early life because mortality of young salmon entering the open ocean is high and probably size dependent (Quinn 2005). Restoration projects in and around Elliott Bay have increased the variety and abundance of epibenthic prey and fish (Cordell, Toft et al. 2008; Toft, Heerhartz et al. 2009).

HABITAT ENHANCEMENT ALONG SEATTLE’S CENTRAL WATERFRONT SEAWALL

In heavily urbanized areas of estuaries, restoration opportunities are often limited. This is especially true along Seattle‟s central waterfront where the current seawall supports infrastructure and industry that, in many cases, cannot be relocated. Landward, the seawall supports roads and public utilities. On the seaward side, the seawall is often adjacent to steep drop-offs on bathymetry. In many areas, this leaves no lateral space for restoration, pocket beaches, or construction of more naturally sloped beaches. An alternative to restoration is habitat enhancement, where physical and biological characteristics that promote fish and wildlife use are integrated into highly modified habitats (Simenstad, Tanner et al. 2005; Chapman and Blockley 2009). Studies of effects of armored shorelines and the well documented relationship between habitat complexity and biodiversity strongly suggest that there is reduced ecological capacity on the current seawall in downtown Seattle and that added complexity and surface area could improve ecological functions of extensively altered urban shorelines (Chapman 2003; Moreira, Chapman et al. 2007; Chapman and Blockley 2009; Toft, Heerhartz et al. 2009).

The seawall in downtown Seattle is currently in disrepair and is scheduled for replacement starting in 2012, presenting a unique opportunity to evaluate the potential benefits of alternative seawall designs to intertidal ecology. A collaborative effort between City of Seattle engineers and planners, consultants, and University of Washington researchers, has led to the design, installation, and evaluation of “habitat enhancement test panels” that integrate important physical features such as slope and surface texture to mimic natural intertidal microhabitats. These experimental panels were tested along Seattle‟s central waterfront in Elliott Bay, Washington to evaluate possible designs for the future seawall.

Test panel treatments include three panel designs with various slopes and two surface treatments (smooth and “cobble”) for a total of six treatments. The test panels, approximately 5 feet wide by 7.5 feet high, were constructed from precast reinforced concrete and, in January 2008, mounted with large bolts onto the existing seawall in the intertidal zone at three sites along the Seattle waterfront.

OBJECTIVES

The overall objective of this study is to evaluate the various seawall habitat enhancement designs that incorporate slope and texture on a concrete vertical seawall by measuring the potential of these designs to provide microhabitat and to improve ecology of the intertidal zone in a built environment.

The objectives of Chapter 1 are to 1) follow the successional trajectory of sessile invertebrates and algae on the test panels, 2) evaluate the developing communities for convergence with the surrounding seawall, and 3) to then make comparisons among the panel types and compare panels to

original sections of seawall to identify any differences in taxa richness or community composition. The discussion addresses the succession of the panels in context of other intertidal disturbance studies on rocky shores, describes some of the species interactions contributing to the community development of the test panels and seawall, and further describes findings of some ecologically important species-specific responses to the slope and surface treatments of the habitat test panels.

The primary objective of Chapter 2 (on epibenthic meiofauna) is to evaluate various test panel designs for effectiveness in providing juvenile salmon prey resources by identifying differences in taxa richness and abundance, and secondarily to characterize the key differences in overall assemblage composition among panel types and compared with reference sections of seawall. The results and discussion focus on taxa richness and juvenile salmon prey species density differences among test panel designs related to specific features of the panels. Findings are further discussed in the context of epibenthic microhabitats and comparisons are made to data collected from nearby seawalls and restoration sites.

Chapter 3 addresses the management implications of this study with a focus on meeting the many conflicting needs (infrastructure, civic, transportation, cultural, and environmental) in the upcoming seawall rebuild and details the background and development of the habitat test panel project. Chapter 3 also summarizes the results of test panel monitoring, discusses adaptive management strategies for including ecological criteria into seawall design, addresses alternative designs not tested in this study, and provides recommendations on what type of future seawall design may provide the greatest ecological benefits.

Chapter 1 SUCCESSION OF INTERTIDAL ALGAE AND INVERTEBRATES ON AN URBAN SEAWALL AND EFFECTS OF ADDED COMPLEXITY ON ECOLOGICALLY IMPORTANT SPECIES

INTRODUCTION: SEAWALLS IN THE INTERTIDAL ZONE

Seawalls and other hard shoreline armoring structures often transform complex habitats into less heterogeneous substrate. Their effects on formerly unconsolidated habitats depend largely on the scales at which they are considered. At a regional scale, they may increase habitat heterogeneity by introducing a novel hard substrate (Airoldi, Abbiati et al. 2005). However, at local scales they can reduce it by dominating the shoreline with structures that often lack complexity and microhabitat features (Airoldi, Abbiati et al. 2005). Locally, the introduction of hard substrate can alter both the physical habitat and biological community. Physically, fragments of unaltered soft sediment shorelines adjacent to seawalls may experience changes in water flow often resulting in changes of wave energy, severe sand scouring, and changes in sediment sources and deposition resulting in coarsening of surrounding loose substrate (Ahn and Choi 1998; Airoldi, Abbiati et al. 2005). Biologically, there may be changes to native species assemblages in the surrounding environment and native assemblages can be replaced by new assemblages colonizing hard substrata of shoreline armoring such as seawalls (Airoldi, Abbiati et al. 2005; Glasby, Connell et al. 2007).

DISTURBANCE AND SUCCESSION ON HARD SUBSTRATES

Introduction of seawalls into the coastal environment can be viewed as a major acute disturbance that is followed by a succession of species colonizing the newly available substrate and modified intertidal environment. The mechanisms, trajectories, rates, and possible outcomes of succession, which is influenced by colonization, recruitment, and species interactions, have been well studied in the rocky intertidal zone (Branch 1986; Farrell 1988; Farrell 1991; McKindsey and Bourget 2001). Early views of succession in rocky intertidal habitats suggested that a predictable and repeatable series of species would develop into a stable community, but a more contemporary view is that successional trajectories and rates of development can be altered by many biotic and abiotic factors and that the outcome is not a stable state but rather a community subject to change through disturbance (Farrell 1991). The complexity of successional mechanisms has been increasingly recognized and includes various models of succession (facilitation, inhibition, and tolerance) working simultaneously, with the outcomes of direct and indirect species interactions influenced by environmental conditions (Viejo, Arenas et al. 2008). Clearing size

(Petraitis and Dudgeon 2005; Petraitis and Methratta 2006) and edge effect (Schoener 1981) are also among the many factors further complicating succession and possibly leading to divergent successional pathways. However, communities with low species diversity may have a more predictable succession of species because there are fewer alternative communities possible (Farrell 1991). The initial colonization by ephemeral algae and sessile invertebrates gradually replaced by larger perennial algae is a fairly typical successional trajectory in rocky intertidal habitats (Dayton 1971; Farrell 1991; Chapman and Underwood 1998) . However, it may be more difficult to predict the rate of succession which is highly variable and depends largely on the timing and magnitude of the initial colonizers (Farrell 1991). The length of time required for a disturbance or clearing to converge with the surrounding intertidal community, often measured as a comparison of variability within the disturbance to the variability of the surrounding community, can take months to years (Dayton 1971; Farrell 1991; Chapman and Underwood 1998; Viejo, Arenas et al. 2008). To what extent previous studies and theories of rates and trajectories of succession following a disturbance in rocky intertidal habitats can predict succession on artificial hard structures such as seawalls has not been investigated.

ARMORED SHORELINES AND COMPARABILITY TO NATURAL ROCKY SHORELINES

Vertical concrete shoreline armoring such as seawalls typically support only some of the same taxa that occur in natural rocky intertidal habitats because they lack the complexity of natural shorelines, resulting in altered recruitment, colonization, survival, densities, fecundity, and species interactions (Chapman and Bulleri 2003; Bulleri and Chapman 2010). Seawalls have been found to support fewer mobile species than rocky shores but more often biological effects are manifest in changes of density, size, and reproductive capability (Chapman 2003; Bulleri and Chapman 2004).

One key difference between seawalls and natural rocky intertidal shorelines is the lack of habitat heterogeneity and complexity associated with slope, rugosity, crevices, and overhangs that provide refuge from thermal stress, desiccation, and physical disturbances. The effects of slope have been well documented for certain species, such as barnacles and oysters, through aquaculture and fouling studies (Pomerat and Reiner 1942). Studies in intertidal rocky habitats have also found that slope and shade can affect intertidal communities in several ways, usually associated with recruitment, thermal stress, desiccation, and survival (Wethey 1984; Menconi, Benedetti-Cecchi et al. 1999; Helmuth and Hofmann 2001; Blockley and Chapman 2006). Surface rugosity (small-scale variations in the height of a surface) and crevices are important habitat features especially in areas of physical disturbance. Some invertebrates, like mussels, chitons, limpets, and Littorina snails rely on crevices on smooth surfaces such as seawalls (Bergeron and Bourget 1986; Faller-Fritsch and Emson 1986; Menconi, Benedetti-Cecchi et al. 1999; McKindsey and Bourget 2001; Moreira, Chapman et al. 2007). While food (e.g., sessile and

drift algae, epiphytic microalgae) is often a limiting resource for mobile invertebrates, crevices have been identified as a main limiting resource for Littorina snails (Faller-Fritsch and Emson 1986). Availability of crevices is also known to extend the upper vertical distribution of mussels in rocky intertidal habitats (Suchanek 1986).

Another key difference between seawalls and natural hard substrata is that seawalls have less surface area and space is a major limiting resource in rocky intertidal habitats (Little and Kitching 1996; Raffaelli and Hawkins 1996). Seawalls have more abrupt vertical zonation than naturally craggy, sloped rocky shorelines due to limited space and may make organisms more vulnerable to increased competition and predation (Bulleri 2010). For instance, limpets on seawalls are more crowded with higher densities on seawalls than on natural rocky shorelines and the increased densities result in smaller limpets with reduced fecundity, creating an ecological sink (Moreira, Chapman, & Underwood 2006).

In Puget Sound, a glacial fjord in Washington state, shorelines are primarily glacial sediment beaches, embayments and deltas, including mudflats and tidal marshes, with rocky coasts limited mostly to the San Juan islands and the western Strait of Juan de Fuca (Shipman 2008). However, beaches in Puget Sound are being increasingly modified by the addition of hard substrata through armoring, intertidal fills, seawalls, groins and jetties, and overwater structures (Shipman 2008). Approximately 27% of the Puget Sound shoreline is modified with rip-rap, seawalls, docks, and other forms of shoreline armoring (Simenstad, Ramirez et al. In press.). Urban bays within Puget Sound have had much higher declines in natural shoreline with 68% of the shoreline modified in King County, where Elliott Bay and the City of Seattle are located (WDNR 1999). Elliott Bay was originally characterized by low to high bank bluff-backed mixed gravel-cobble beaches and low tide terrace. However, there are now over 3 kilometers of seawall along the Seattle central waterfront with very little remaining shallow sloping intertidal beach (WDNR 1999). The seawall in downtown Seattle is currently in disrepair and is scheduled for replacement starting in 2012, presenting a unique opportunity to evaluate the potential benefits of alternative seawall designs that could enhance the ecological functionality of the urban shoreline.

This study represents several years of collaboration among engineers and scientists from the City of Seattle and University of Washington to develop and test alternative seawall designs (see Chapter 3 for a comprehensive description of the background and process of the habitat enhancement test panel project). Some important physical characteristics that provide microhabitats and promote biological diversity may be integrated into future seawall design. The potential benefits of slopes and crevices were tested along Seattle‟s Elliott Bay seawall in Puget Sound, Washington. These elements were built into

habitat enhancement test panels to test whether engineered complexity could provide microhabitats that would increase species diversity and abundance on the seawall.

OBJECTIVES The overall objective of this study was to evaluate test panels with various designs (treatments) that incorporate slope and texture on a concrete vertical seawall and to test the potential of these designs to provide microhabitat and increase sessile invertebrate and algal taxa richness and abundance. This study examines data from the first two years after deployment of the test panels with the goals to (1) determine whether test panels converged with the surrounding seawall; (2) estimate where test panel assemblages were along a successional trajectory; and (3) compare panel treatments to original sections of seawall to identify differences in taxa richness, community composition, or abundance of algae and invertebrates.

METHODS

STUDY AREA Study sites were located on the central waterfront in downtown Seattle, Washington along the shoreline of Elliott Bay, located in central Puget Sound. The project spans a large portion of the Seattle central waterfront seawall (Figure 1.1). Elliott Bay is a partly enclosed estuarine environment with freshwater input from the Duwamish/Green River system. Although highly altered by urban and industrial pressures along its length, the Duwamish River estuary and Elliott Bay still serve as migratory corridor and rearing habitat for several species of salmon. Organisms on Seattle‟s seawall are subjected to extreme temperatures with winter low tides at night and summer spring low tides usually occurring mid-day. Orientation of the seawall is southwest, with exposure to intense afternoon sun in summer during low tides and exposure to wind and waves, primarily from the southwest in winter.

HABITAT PANEL SITES

Three sites were selected for the installation of habitat enhancement test panels based on the following criteria: (1) enough space for all experimental panels plus control and reference sections of seawall; (2) similar proximity to overwater structures; (3) similar orientation (west-facing); and (4) similar adjacent subtidal conditions (depth, presence of rip-rap).

Figure 1.1. Location map and study sites.

The northern-most site is Clay Street, a narrow expanse of seawall between two piers (Piers 69 and 70), with an approximate overall length of 40 m. The seawall at this site was partially constructed with Ekki wood (from the base of the seawall up to approximately + 0.7 m MLLW). For this reason, panels were mounted with a gap of approximately 0.3 m from the seawall face. Clay Street has the deepest adjacent water, and differs from the other sites in that the bottom of the habitat panels is not near the rip-rap substrate at the toe of the seawall. Just south of Clay Street is the Vine Street site, between the Victoria Clipper dock at Pier 69 to the north and the Edgewater hotel to the south. The overall length of this site is approximately 80 m, considerably longer than the other two sites, but the panels only occupy the southern 40 m of the site. Rip-rap adjacent to the seawall is at an average depth of 0 m MLLW. The southern-most site is located between a large pier (Pier 62/63) to the north and the Seattle Aquarium pier to the south. The overall length of the site is also approximately 40 m. Rip-rap adjacent to the seawall is also at an average depth of around 0 m MLLW.

HABITAT ENHANCEMENT TEST PANEL TREATMENTS

Test panel treatments include three panel designs (finned, stepped, and flat) and two surface textures (smooth and “cobble”) for a total of six treatments (Figure 1.2). Panels, approximately 1.5 m (5 feet) wide by 2.3 m (7.5 feet) high, were constructed from precast reinforced concrete using formliners to create the two surface textures. The habitat enhancement test panels were deployed in January 2008. Monitoring began in May 2008 and ended in August 2009.

Figure 1.2. Habitat enhancement test panel designs used in this study. Each panel design is shown here in front and side views. Panel dimensions are 1.5 meters (5 feet) wide by 2.3 meters (7.5 feet) tall. Each panel was made with two surface textures: smooth and cobble (with cobble shown here) (Harn 2007).

STUDY DESIGN Replication for the study is at the site level (N= 3). Habitat enhancement test panels were randomly placed within sites and mounted onto the existing seawall in January of 2008 at 0 m MLLW (Figure 1.3). Reference (undisturbed original seawall) and control (pressure-washed seawall) sections were also randomly selected at each site at the same time panels were installed to provide a comparison to existing conditions and to a “time-zero”.

Figure 1.3. Site panorama of randomly located panels at Aquarium site. Overall length of the site is approximately 40 meters and approximate tidal elevation in photo is 0 m MLLW.

DATA COLLECTION

Quadrat sampling

Invertebrate and algae monitoring was conducted in 2008 and 2009 to examine initial colonization and succession on the panels. Monitoring occurred monthly May-August 2008 and April, June, and August 2009 to track the trajectory of peak recruitment and development.

Quadrat sampling was used to quantify species composition and percent cover of sessile invertebrates and algae at three panel height zones to span macroinvertebrate and algal zonation in this macrotidal setting: (1) “upper” from approximately 1.5 m to 2.3 m (+5‟ to +7.5‟) MLLW, (2) “middle” from approximately 0.7 m to 1.5 m (+2.5‟ to +5‟) MLLW, and (3) “lower” from approximately 0 m to 0.7 m (0‟ to +2.5‟) MLLW. Three random quadrat locations (Raffaelli and Hawkins 1996) were chosen at each elevation (upper, middle, and lower) for a total of nine quadrats per panel. Quadrat corners were measured from fixed locations on the panel and locations were revisited thereafter to provide a time series of fixed plots. On step and fin panels, samples were taken from both vertical and sloped substrate at each elevation and classified as such to enable separate analyses of different substrate angles (Figure 1.4). Areas on the underside of fins and steps were not sampled with quadrats due to time constraints.

Figure 1.4. Quadrat sampling on a fin.

Some quadrat locations within panels in June and August 2009 (Vine, Clay) were not measured due to time constraints resulting from rapidly falling and rising tides. Step and fin panel quadrats were prioritized because they were the most different from the existing seawall and an entire set of quadrats was measured on those panels to characterize both sloped and vertical surfaces. Flat panel quadrats (including control and reference panels) had less within-panel structural variability and were given lower priority, consisting of only one quadrat at each elevation in some cases. These within-panel quadrats were not intended for statistical replication and do not contribute to the power of the tests, because replication is at the site level with N=3. At Clay Street, lower sections of seawall were removed due to

deterioration, leaving only the metal sheet pile substructure. As a result, lower quadrats on control and reference sections of seawall were collected at the lowest available elevation (approximately +1 m MLLW).

Invertebrates and algae were visually scanned in 25-cm x 25-cm gridded quadrats to identify species and estimate percent cover (Murray, Ambrose et al. 2006). Invertebrates and algae falling within each of 25 regularly spaced grid cells within the quadrats were identified and a percent cover was estimated for the entire quadrat (Dethier, Graham et al. 1998). When a primary organism and an epibiont occupied the same space within a grid cell, for example green algae on a barnacle, both organisms were recorded. When necessary, representative specimens from outside the quadrat were collected to make a positive identification.

Species for which identification remained uncertain were grouped into categories, for example „„bryozoans.‟‟ Lottia pelta/Tectura persona were combined as these two limpet species cannot be easily distinguished from one another without dissection. Mussels of the genus Mytilus were not identified to species. M. trossulus is a native species to the north Atlantic and north Pacific, including Puget Sound and M. galloprovincialis is native to the Mediterranean and Western Europe, introduced to Puget Sound through ballast water or aquaculture, but were classified together because while they are distinct species (and can hybridize), they can only be distinguished using genetics or height-length ratios (difficult to collect in situ, and biotic and abiotic factors can affect shell shape) (Elliott, Holmes et al. 2008).

DATA ANALYSIS

Convergence

As described by Chapman and Underwood (1998), variability in early successional stages of localized disturbances or clearings is expected to be higher than that of more established surrounding later succession communities. To test convergence of test panels with reference and control panels, the differences between within-panel variability and between-panel variability were calculated for each sampling event. Control panels were included in the study design to give a comparison point for convergence of new substrate to the surrounding community. However, control panels appeared to experience some secondary succession due to traces of algae left on the seawall after pressure washing. Therefore, flat smooth panels were also included in the analysis to give a second baseline for convergence of new substrate to the surrounding seawall community. As the difference between within-panel variability and between-panel variability approaches zero, variability within the new panels (control and flat smooth) is hypothesized to reflect the natural variability of the more established reference panel, indicating that panels of a similar design and surface texture (flat and smooth) have converged (Chapman

and Underwood 1998). This analysis was done using multivariate Bray-Curtis quantitative dissimilarity measures calculated with PRIMER v.6 (PRIMER-E Ltd, Plymouth, UK) using SIMPER (similarity percentage sample discrimination) to compare the variability within each panel type to the variability between panels (Clarke 1993). The average within-panel dissimilarity measure was subtracted from the between-panel dissimilarity measure. For instance, within panel dissimilarity was measured on the flat smooth panel among all quadrats for each sampling event and the same was done for the reference. Between-panel dissimilarity comparing the reference and control quadrats was measured and subtracted from the average within-panel dissimilarity for flat-smooth and reference treatments. All three panel types were evaluated in this way for each sampling event. Only quadrats from reference, control, and flat- smooth panels were selected to test for convergence to reduce the possible effects or differences due to alternative panel designs with fins or steps and from cobble surface treatments.

Community composition

As another more direct measure of overlap and convergence, I used the R-statistic to compare community compositions among all panel types. ANOSIM (Analysis of Similarity) tests were conducted using PRIMER v.6 on square-root transformed data with no rare taxa (excluding taxa contributing less than 3% cover) and a Bray-Curtis resemblance matrix. ANOSIM and pair-wise tests by panel type were used to measure similarity of community composition of all panel types compared to reference sections of seawall. These pair-wise tests for each sampling event measured whether there was increasing overlap and convergence with alternative panel designs as well as control sections of seawall (Clarke 1993).

Community composition among panels was also compared with multivariate nonmetric multidimensional scaling (NMDS) ordination. Algal species fluctuated from month to month and functional groupings were used to reduce temporal instability (Steneck and Dethier 1994). Data from taxa contributing 3% or more were imported into PRIMER and square root transformed. PRIMER was used to construct a resemblance matrix using the Bray-Curtis measure of similarity (Bray & Curtis 1957) and to generate the NMDS plot.

Community composition and taxa richness data were also plotted graphically using Excel (Microsoft Corporation, Redmond, Washington), with standard errors to provide an estimation of precision on the mean with N=3 (Zar 1999). Specific taxa groups known to affect successional development and community composition, such as limpets, canopy forming algae (Fucus distichus), and Mytilus, were individually examined and statistically tested at each elevation independently for differences in abundances associated with panel design features. Univariate two-way ANOVA (Analysis of Variance) was used in SPLUS to test for species-specific differences due to substrate angle (vertical or

sloped) and surface treatment (cobble or smooth) as well as interaction effects from these two factors. Percent cover data were also arcsine-square root transformed for univariate analyses but did not substantially improve homogeneity of variances or normal distribution in this case, so raw percent cover data were used for univariate statistical analyses (Zar 1999). Reference and control sections of seawall were not included to limit comparisons to test panels only and to maintain relatively equal sample sizes. When significant differences were found using ANOVA, Tukey‟s post hoc test for multiple comparisons was used to identify specific differences between all possible pairs of means (Zar 1999).

RESULTS

RECRUITMENT, COLONIZATION, AND SUCCESSION OF ALGAE AND INVERTEBRATES ON

PANELS

During the monitoring period, a primary succession of algae and invertebrates developed on test panels, while the reference panel community remained relatively stable and the control panel exhibited some secondary succession (see section on convergence) (Figure 1.5). Thirty-six taxa were identified in addition to bare space, barnacle scars, dead algae and dead barnacles (Table 1.1) across all sites, panels, and monitoring events. Averages of percent cover of major taxa groups from each panel, elevation, and sampling event (with standard error on the average of sites) can be found in Appendix A.

2008

By the first sampling in May 2008, the habitat test panels were almost completely covered with algae (over 80%) with small patches of bare space (Figure 1.5). Pioneering algal species appeared on the panels with upper and middle elevations of panels dominated by foliose algae (Porphyra sp. and ulvoids) and some biofilm (green and brown scum consisting of microalgae and diatoms), and dense mats of the filamentous alga Acrosiphonia coalita at lower elevations. Invertebrates on the panels were limited to the first incidences of new barnacle recruits and the small marine snails Littorina spp. In contrast, the reference panels had much lower percent cover of algae, primarily Mastocarpus papillatus (a more established perennial alga) and Porphyra sp., with minor occurrences of Acrosiphonia coalita, Mazzaella splendens, ulvoids and biofilm. The reference panel also had more bare space, barnacles (mostly Semibalanus cariosus and Balanus glandula with some Chthamalus dalli and a few new barnacle recruits), mobile invertebrates (Lottia pelta, Tectura persona, T. scutum, L. digitalis, Littorina spp.), and dead algae and invertebrates. The control panel was colonized by species of both the ephemeral pioneering assemblages found on the new substrate of the test panels and by all mobile invertebrate

species and some of the more established, perennial algal species found on the reference panels (particularly M. papillatus).

By June 2008, the perennial algae Pterosiphonia dendroidea mixed with Cryptosiphonia woodii and some of Fucus distichus appeared on the reference panel. Porphyra spp. remained dominant on test panels along with high percent cover of biofilm and ulvoids. Ulva linza also appeared on test panels in small amounts. Acrosiphonia coalita coverage declined and was dying off on reference, control, and test panels. Percent cover of new barnacle recruits on test panels increased as individuals grew in size but were still too small to identify to species. Snails and limpets (T. scutum) began to appear on flat panels only.

Percent Cover Quadrat Data 100% 90% Bare 80% Mussels 70% 60% Mobile Inverts 50% 40% Dead 30% Barnacles 20% 10% Algae

Cobble Cobble Cobble Cobble Cobble Cobble Cobble Cobble Cobble Cobble Cobble Cobble

Smooth Smooth Smooth Smooth Smooth Smooth Smooth Smooth Smooth Smooth Smooth Smooth Smooth Smooth Smooth Smooth Smooth Smooth Smooth Smooth

R C Flat Step Fin R C Flat Step Fin R C Flat Step Fin R C Flat Step Fin

MAY 2008 AUGUST 2008 APRIL 2009 AUGUST 2009

Figure 1.5. Succession of algae and invertebrates through beginning and endpoints of year 1 and 2 monitoring. "R” is reference and “C” is control.

In July 2008, overall algal coverage on the test panels and reference had begun to decline. Porphyra spp. and Ulva linza percent cover declined and Ulvoid 1 and Acrosiphonia coalita died off and generally disappeared from all panels. Fin panels had the highest cover of dead algae (mostly Ulva linza) and barnacles. Small Mytilus began to appear in the grooves of the fin-cobble and step-cobble panels. Pterosiphonia dendroidea mixed with Cryptosiphonia woodii disappeared on the reference sections of seawall. Pterosiphonia bipinnata with the epiphytic parasite Leachealla pacifica appeared on the reference and control panels in July 2008 only. As algae died off, bare space increased on all panels, with greater increases on control and reference panels. The number of mobile invertebrates on the references and controls also dropped in July 2008.

Table 1.5. List of taxa and groupings identified in seawall quadrat sampling 2008-2009.

Algae Microalgae Biofilm (diatoms, bacteria, etc) Navicula - colonial diatom Foliose algae Porphyra sp. 1 Porphyra cf. perforata Ulva linza Ulvoid 1 Ulvoid 2 Ulvoid 3 Filamentous algae Acrosiphonia coalita Bangia sp. Polysiphonia sp. Corticated macrophytes Mastocarpus papillatus Mazzaella splendens Pterosiphonia bipinnata w/ epiphytic parasite Leachealla pacifica Pterosiphonia dendroidea mixed w/ Cryptosiphonia woodii Leathery macrophytes Costaria costata Cryptopleura sp. Fucus distichus Crustose Mastocarpus papillatus, crustose form Mobile Invertebrate Chiton Mopalia sp. Insect Flies Limpet Lottia digitalis Lottia Pelta/Tectura persona Tectura scutum Snails Littorina spp. (Periwinkles) Sessile Invertebrates Barnacles Balanus crenatus Balanus glandula Chthamalus dalli New barnacle recruit Semibalanus cariosus Mussels Mytilus sp. Ascidian Ascidiacea Tube worm Tube worms Anemone Anemone Bryozoan Bryozoan Bare Space Bare Bare Barnacle scars Dead algae & barnacles Dead Algae Dead Barnacles

By the end of the 2008 sampling season in August, total percent cover of algae on the test panels had declined slightly and was made up primarily of an assemblage of Porphyra spp., ulvoid 1, and biofilm. Barnacle, bare space, and dead algae and invertebrate cover increased on the test panels over the course of the sampling season. New barnacle recruits were still too small to identify to species. Most of the mobile invertebrate species found on the reference panels were also found on the test panels and control but were far fewer in number than on the references. Also by August 2008, algal cover on the reference panel was greatly reduced to about 25% and bare space and dead algae and invertebrates comprised the remainder.

2009 Barnacle coverage increased dramatically on all habitat test panels from the end of 2008 sampling to the start of year two sampling in April 2009. Test panels appeared quite different in year two and, even in 2009 spring sampling, algal cover never reached the high percents seen in spring 2008. There was also a major shift in community composition on the test panels, with a decrease in percent cover of foliose algae (ulvoids and Porphyra) and filamentous algae (Acrosiphonia coalita, Polysiphonia sp.), and increased percent cover of corticated macrophytes (Mastocarpus papillatus, Pterosiphonia dendroidea mixed with Cryptosiphonia woodii), the leathery macrophyte Fucus distichus and the crustose form of Mastocarpus papillatus (Figure 1.6). Percent cover of microalgae such as diatoms and biofilm remained somewhat constant.

100 90 80 70 Dead Algae 60 Leathery 50 Crustose 40 Corticated 30 Foliose 20 Average Percent Cover Percent Average Filamentous 10 Microalgae

C C C C

R R R R

Fin Fin Fin Fin

Flat Flat Flat Flat

Step Step Step Step

MAY 2008 AUGUST 2008 APRIL 2009 AUGUST 2009

Figure 1.6. Average percent cover of functional groups of algae showing succession over monitoring period, with standard error on the average of three sites.

Navicula, a genus of colonial diatom, appeared on habitat test panels by April 2009, but was absent from reference and control panels. Algae on habitat test panels consisted mainly of ulvoids, Ulva linza, Navicula, and biofilm. Acrosiphonia coalita returned to the panels in small amounts, mostly at lower elevations. Mastocarpus papillatus began to colonize the test panels in small amounts. By this time, algal assemblages on the references and controls were very similar and percent cover of M. papillatus on the control panel matched or surpassed that on the reference. Barnacle assemblages among reference, control, and test panels were very similar and the most abundant species was Balanus glandula. Chthamalus dalli was only present on reference, control, and flat panels. Another new set of barnacle recruits was observed in April 2009. Mobile invertebrates (limpets) were present on all panels at slightly lower numbers than on the references and controls and the limpet T. scutum was absent from step panels. Mytilus had higher percent cover on all test panel than on reference or control panels, with the highest abundance on step and fin panels with the cobble surface.

Algal cover decreased by the July 2009 sampling, commensurate with decreases in the colonial diatom, Navicula, and of the alga Acrosiphonia coalita. Fucus distichus, present in trace amounts on reference panels since June 2008, was present on test panels, particularly on sloped portions of fin panels. Chthamalus dalli became more abundant on the test panels, and Balanus crenatus began to colonize lower elevations. Otherwise, barnacle assemblages were similar to the previous sampling and assemblages on panels were similar to references and controls. The abundance of mobile invertebrates (primarily limpets) increased on test panels and, in some cases, was higher on test panels than on the reference or control. Percent cover of Mytilus also increased on test panels and, to a lesser extent, on the references and controls.

Algal cover remained stable between June and August 2009. Pterosiphonia dendroidea mixed with Cryptosiphonia woodii reappeared on the reference and fin panels. Fucus distichus percent cover increased, particularly on fin panels. Mazzaella splendens was again seen on reference, control, and also on fin-smooth panels and to a lesser extent on flat panels. A sixth set of new barnacle recruits was observed in August 2009. Test panels appeared to have slightly higher percent cover of barnacles, particularly at lower elevations, than did the reference or control panels, but overall assemblages were very similar. Balanus glandula was the dominant barnacle on all panel types and all sampling events. Abundance of Mytilus declined slightly between June and August 2009, while mobile invertebrate densities remained stable.

CONVERGENCE OF TEST PANELS WITH REFERENCE AND CONTROL SECTIONS In a comparison of the within-in panel dissimilarity (or variance) of quadrats on reference, control, and flat smooth panels to the between-panel measures of dissimilarity, the differences approached zero by August 2009, indicating that the flat-smooth panels had converged with the surrounding seawall community (Figure 1.7). ANOSIM R values under 0.4 indicated very similar communities and showed increasing overlap of community compositions among all panel types as they approached zero (Figure 1.8). Control and flat smooth panels were quite similar in community composition at the earliest sampling dates in 2008. Control and flat smooth panels began to diverge in 2008 as the control panel developed later successional community composition sooner than the flat smooth panel, perhaps undergoing a secondary succession (see Discussion). As a result, controls converged with references earlier (by April of 2009) than flat smooth panels, but the flat smooth panels also converged with the references and controls by August 2009.

20 Reference & Control Reference & Flat Smooth 10 Control & Flat Smooth 0

-10

Relative difference % Relativedissimilarity

JULY JULY 2008

MAY 2008 MAY

JUNE 2008 JUNE 2009 JUNE

APRIL 2009 APRIL

AUGUST 2008 AUGUST 2009 AUGUST

Figure 1.7. Convergence measured through relative difference of mean percent dissimilarity within and between panels.

1 0.9 0.8 Control 0.7 0.6 Flat Smooth

0.5 Flat Cobble values

- 0.4 Step Smooth R 0.3 Step Cobble 0.2 Fin Smooth 0.1 Fin Cobble 0 May June August April June August 2008 2008 2008 2009 2009 2009

Figure 1.8. ANOSIM R values < 0.4 indicate very similar communities compared to reference sections of seawall. Overlap of community composition of all panel types with the reference sections of seawall is seen here, approaching convergence by August 2009.

TAXA RICHNESS AND COMMUNITY COMPOSITION

In MDS plots, even those using 2009 data only, sampling event and elevation produced strong clusters, but site did not, suggesting low variability among sites for overall community composition. MDS plots of endpoint monitoring data (August 2009) generally illustrated high overlap of biological communities among panel types and surfaces, as exemplified by the middle elevation data from August 2009 (Figure 1.9). MDS stress was high (0.22), indicating a poor fit for distinct groups.

Figure 1.9. MDS plot of August 2009 (monitoring endpoint) middle elevation community composition data.

Taxa richness increased on test panels and on control and reference sections of seawall from the endpoint of year one to the endpoint of year two (Figure 1.10). At the end of monitoring in August 2009, there was no difference in taxa richness between test panels, references, and controls for the major taxa groupings. Convergence and endpoints of communities compared using ANOSIM and MDS plots (Figures 1.8 & 1.9) also suggest that the community composition and percent cover were similar among the reference, control, and habitat enhancement test panels.

20 18 16 14 12 10 8 Sessile

Average # Taxa # Average Inverts 6 Mobile 4 Inverts Algae 2

Cobble Cobble Cobble Cobble Cobble Cobble

Smooth Smooth Smooth Smooth Smooth Smooth Smooth Smooth Smooth Smooth

R C Flat Step Fin R C Flat Step Fin

AUGUST 2008 AUGUST 2009

Figure 1.10. Average taxa richness of reference, control, and test panels at endpoints of year one and two, with standard error on the average of three sites.

SPECIES-SPECIFIC RESPONSES TO SLOPE AND TEXTURE

Although community composition of major taxa groupings was very similar among reference, control, and habitat test panels, some differences were observed in densities, percent cover, and size of some taxa, including three ecologically important taxa: the canopy forming alga Fucus distichus, limpets,

and Mytilus mussels. These differences were typically associated with slope or surface texture of the test panels. Responses to slope and texture often varied by elevation and were not apparent at coarser scales of whole-community analyses.

Fucus distichus

Fucus distichus appeared to be more abundant on sloped surfaces by the end of the monitoring in August 2009, particularly on the fins of finned panels, although there was some variation by site and elevation. F. distichus developed higher percent cover earlier (June 2009) at Clay Street which also had the highest abundance of this species overall, contributing to large standard error among site replicates (Figure 1.11). F. distichus cover was most abundant at the middle elevations and the consistent pattern of higher percent cover on fin panels was most distinct at this elevation (Figure 1.11). Combining all quadrats into substrate angle categories (sloped and vertical) graphically shows percent cover of Fucus is higher on sloped surfaces (Figure 1.12). Sloped surfaces were the major contributing factor of higher percent cover of F. distichus as demonstrated by the significance of August 2009 F. distichus percent cover data on substrate angle and surface treatment at lower and middle elevations (two-way fixed factor ANOVA; Table 1.2). Surface treatment did not have an effect and did not interact with substrate angle.

Average Percent Cover Percent Average 5

Cobble Cobble Cobble Cobble Cobble Cobble Cobble Cobble Cobble

Smooth Smooth Smooth Smooth Smooth Smooth Smooth Smooth Smooth Smooth Smooth Smooth Smooth Smooth Smooth

R C Flat Step Fin R C Flat Step Fin R C Flat Step Fin

Upper Middle Lower

Figure 1.11. Average Percent cover of Fucus distichus by panel type and elevation at monitoring endpoint (August 2009). Error bars are standard error on the average of three sites.

Substrate Angle Surface Treatment 25 25

20 20

15 15 Vertical Smooth 10 Sloped 10 Cobble

Average percent cover percent Average 5 5

0 0 Upper Middle Lower Upper Middle Lower

Figure 1.12. Average percent cover of Fucus distichus by elevation, substrate angle, and surface treatment at monitoring endpoint (August 2009). Error bars are standard error on the average of three sites.

Table 1.2. Results from 2-way fixed factor ANOVAs per tidal elevation on effects of substrate angle and surface treatment on Fucus cover (August 2009).

Substrate Angle Surface Treatment Interaction Elevation (df=1) (df=1) (df=1)

Upper P=0.18989 P= 0.91014 P=0.83003

Middle P=0.00086 P=0.44584 P=0.15839

Lower P=0.00040 P=0.21804 P=0.36676

Limpet Densities

Limpets began to appear on test panels early in 2008, but were present only at very low abundances. Abundances on test panels started out relatively low in April 2009 but had increased on all test panel types by June and August 2009. Limpets on reference, control, and test panels followed the same general patterns of abundance throughout the 2009 sampling season. Lottia Pelta/Tectura persona were the most dense limpet species. In August 2009, limpets were usually more dense on flat panels, including reference, control, and flat test panels, especially at the middle elevation (Figure 1.13). Limpets were most abundant at the middle elevation and were primarily L. pelta/T. persona with fewer Tectura scutum. Limpet densities were lowest at the upper elevation where Lottia digitalis was present in noticeably higher proportions, although the assemblage was still dominated by L.pelta/T. persona and T.

scutum. Limpets were more abundant on vertical surfaces in the upper and middle elevations of panels than they were on sloped surfaces (Figure 1.14). A two-way ANOVA on August 2009 total limpet densities (untransformed data) testing substrate angle and surface treatment as factors indicated that substrate angle was the main factor at middle and upper elevations, with higher densities of limpets on vertical surfaces (Table 1.3). The upper elevation densities were also affected by surface treatment, with higher numbers on smooth surface treatments than on cobble and with some interaction effects between angle and surface. Surface treatment was also an important factor at lower elevations, but with higher densities on the cobble surface treatments.

20 18 16 14 12 10 8 6 4 2

Cobble Cobble Cobble Cobble Cobble Cobble Cobble Cobble Cobble

Smooth Smooth Smooth Smooth Smooth Smooth Smooth Smooth Smooth Smooth Smooth Smooth Smooth Smooth Smooth Density per 0.0625 m2 0.0625per Density R C Flat Step Fin R C Flat Step Fin R C Flat Step Fin

Upper Middle Lower

Lottia digitalis L. Pelta/T. persona Tectura scutum

Figure 1.13. Average Limpet densities at monitoring endpoint (August 2009) by species, elevation, and panel type. Error bars are standard error on the average of three sites.

Substrate Angle Surface Treatment

16 16 2 14 14 12 12 10 10 8 Vertical 8 Smooth 6 6 Sloped Cobble 4 4 2 2

Density per 0.0625 m 0.0625per Density 0 0 Upper Middle Lower Upper Middle Lower

Figure 1.14. Average limpet densities at monitoring endpoint (August 2009) by elevation, substrate angle, and surface treatment. Error bars are standard error on the average of three sites.

Table 1.3. Results from 2-way fixed factor ANOVAs per tidal elevation on effects of substrate angle and surface treatment on limpet densities (August 2009).

Substrate Angle Surface Treatment Interaction Elevation (df=1) (df=1) (df=1)

Upper P=0.00000 P=0.03054 P=0.05735

Middle P=0.01069 P=0.86020 P=0.22553

Lower P=0.53834 P=0.00530 P=0.40764

Mytilus

Over the two-year monitoring, Mytilus began to appear in small numbers on test panels starting in July 2008, with the highest percent cover observed in June 2009 followed by a slight decrease measured in August 2009. Percent cover was also lowest at the upper elevation with middle and lower elevations having similar coverage. Comparisons among panels indicated that percent cover was highest on cobble panels, especially those with fins or steps (Figure 1.15). The cobble surface had increased percent cover on flat, fin, and step panels. On average, percent cover of Mytilus on flat-cobble panels was twice that found on smooth flat panels in 2009. Percent cover of Mytilus on fin and step panels with the cobble texture was also approximately double that on the fin and step panels with the smooth texture. The most striking difference was between the average percent cover of Mytilus on flat smooth panels (reference, control, and flat smooth) and the fin cobble panels: the fin cobble panels had more than eight times the cover of Mytilus than the flat smooth panels in 2009. Most Mytilus observed were in the 0-10 mm size classes. However, a higher proportion of Mytilus on fin and step panels and on flat cobble panels were of larger size classes (> 1 cm) than on the reference, control, and flat smooth panels. Mytilus of 2cm or larger were observed only on step and fin panels with the cobble surface.

2.5

1.5 > 2 CM 1 Percent cover Percent 1-2 CM 0.5 5-10 MM

0 0-5 MM

Cobble Cobble Cobble Cobble Cobble Cobble Cobble Cobble Cobble

Smooth Smooth Smooth Smooth Smooth Smooth Smooth Smooth Smooth Smooth Smooth Smooth Smooth Smooth Smooth

R C Flat Step Fin R C Flat Step Fin R C Flat Step Fin

APRIL 2009 JUNE 2009 AUGUST 2009

Figure 1.15. Average percent cover and size class of Mytilus by panel type during final season of monitoring (2009). June reference & control (R&C) were missing replicates at Clay St, therefore, June R&C averages are from 2 sites only. Error bars are standard error on the average of the sites.

Substrate Angle Surface Treatment 2.5 2.5

2 2

1.5 1.5 Vertical Smooth 1 Sloped 1 Cobble

Average Percent Cover Percent Average 0.5 0.5

0 0 Upper Middle Lower Upper Middle Lower

Figure 1.16. Average percent cover of mussels at monitoring endpoint (August 2009) by elevation, substrate angle, and surface treatment. Error bars are standard error on the average of three sites.

By August 2009, cobble surface treatment was the key contributing factor to higher Mytilus coverage on test panels at all elevations (two-way fixed factor ANOVA conducted independently for upper, middle, and lower elevations; untransformed data with substrate angle [vertical and sloped] and

surface treatment [cobble and smooth] as main factors). Slopes did not have an effect on Mytilus and there was no interaction effect with slope and surface treatment (Table 1.4).

Table 1.6. Results from 2-way fixed factor ANOVAs per tidal elevation on effects of substrate angle and surface treatment on mussel cover (August 2009).

Substrate Angle Surface Treatment Interaction Elevation (df=1) (df=1) (df=1)

Upper P=0.15425 P=0.00876 P=0.56248

Middle P=0.17444 P=0.04582 P=0.886217

Lower P=0.81816 P=0.01189 P=0.89626

DISCUSSION In this study, new substrata that incorporate microhabitat features were introduced into the intertidal zone along an urban seawall. These newly introduced surfaces were tested for convergence with the surrounding seawall and found to have developed a late successional stage biological community by the end of the two-year monitoring. Microhabitat features were then compared to existing sections of seawall and differences in the abundance of ecologically important species (Fucus distichus, limpets, and mussels), associated with slope and surface treatment, were identified.

SUCCESSION AND CONVERGENCE ON HABITAT TEST PANELS Algae are the primary producers and main source of energy in rocky intertidal habitats and also serve as an important structural component of the community (Hicks 1986; Southward 1986). Panels followed a fairly typical successional trajectory of algae, as described in previous studies of disturbance in rocky intertidal habitats around Puget Sound and other temperate regions (Dayton 1971; Norton 1986; Farrell 1991; Little and Kitching 1996). The initial dominance by ephemeral algae and sessile invertebrates gradually replaced by larger perennial algae is a common successional trajectory in rocky intertidal communities (Dayton 1971; Farrell 1991; Chapman and Underwood 1998). Succession in algae does not necessarily consist of a linear sequence of colonizers. Rather, some species out-compete others in growth. Such is the case with Fucus which settles early to new substrate but is covered by ephemeral species. Fucus becomes more apparent later in succession, when the ephemeral species die off, allowing Fucus to grow larger (Norton 1986). Ephemeral species of algae such as foliose and filamentous algae appeared early on the test panels and were later supplemented or replaced with more perennial and heartier corticated and leathery macrophytes.

Facilitation among algae and macroinvertebrates was also evident. The red alga Mastocarpus remained dominant on the reference sections of seawall and may have benefited from limpets. Limpets facilitate Mastocarpus, which has a heteromorphic life cycle that includes a crustose form as a response to grazers. The upright form of Mastocarpus is prevalent in winter, when grazing is low, and in summer crustose forms benefit from grazing limpets which prevent overgrowth of the crusts by other species of algae (Branch 1986). Invertebrates colonized test panels later in the first year and the lack of limpets on test panels early in the monitoring may also have been an important factor in the community development on the panels. Limpets can hinder barnacle recruitment by bulldozing (Branch 1986). In turn, barnacles can inhibit the growth of ephemeral algae and facilitate Fucus (Branch 1986). In some cases, particularly on smooth substrate, barnacles can facilitate colonization of Fucus and the main mechanism associated with the facilitation is increasing rugosity of the substrate, which also inhibits the foraging activities of limpets (Branch 1986; Farrell 1991).

Communities on cleared patches (control) and test panels of similar complexity (flat-smooth panels) converged with surrounding assemblages (reference sections of seawall) in approximately 20 months, which is within the range of other studies of convergence in temperate rocky intertidal habitat (Dayton 1971; Farrell 1991; Chapman and Underwood 1998; Viejo, Arenas et al. 2008). The time of disturbance and clearing size can also affect the early successional stage assemblages which could result in different trajectories before converging. Cleared areas also have higher variability than more established surroundings - variability decreases over time but could last up to four years (Chapman and Underwood 1998). However, the convergence of control and flat smooth panels with the surrounding seawall community does suggest that the test panels have been on the seawall long enough to evaluate and compare the performance of the various panel designs.

While controls, references, and flat panels converged in taxa composition and variance in less than two years, another measure of stability, constancy (i.e., stability or persistence of species), was not tested in this study. Stability is controversial and difficult to identify, involving measures of resistance, amplitude, and elasticity (Connell and Sousa 1983). To identify persistence of species temporally, monitoring must occur beyond the time scale of the life span of the organisms so that variability can be scaled to the life history of that population (Moore and Seed 1986). This may require monitoring over six generations for statistical validity and several long-lived species identified on the seawall may have complete turnover only every 10-20 years (Moore and Seed 1986). Spatial scales are also important; small areas of study like the Seattle seawall are more vulnerable to localized perturbations or disturbances, decreasing the likelihood of persistence or constancy (Moore and Seed 1986). However, the reference panel of pre-existing seawall that has been in place for nearly a century can be assumed to be in

a “mature” successional stage and since control and flat smooth panels have converged with reference sections, they may also be considered “mature”. Future monitoring of panels may indicate whether some species (such as Fucus and Mytilus) will continue to increase in abundance.

Some unintended treatment attributes may have influenced succession and community structure, such as clearing size, or in this case panel size, which can have an effect on succession and species composition in rocky intertidal environments. A study of rocky intertidal community structure in Maine indicated no evidence for geographic distances as a factor but that clearing size was a better predictor, where larger clearings (8 m diameter) demonstrated divergent successional pathways compared to the surrounding area and to smaller clearings (Petraitis and Dudgeon 2005). Related to clearing size is the surface area–to-edge ratio (ie. the edge effect), where resources are more available along the perimeter, and may result in different rates of growth on small and medium sized panels (Odum 1971; Schoener and Schoener 1981). A study done in Elliott Bay with various panel sizes analogous to “islands” placed in the subtidal zone illustrated different rates of colonization related to size (Schoener and Schoener 1981). These disturbance size factors should be considered in scaling up to the replacement of the entire seawall.

Numerous random factors (i.e., those not associated with habitat test panel features) are known to affect the development of intertidal communities. These have been used in various models of succession (facilitative, inhibitive, and tolerance), can operate simultaneously, and include factors such as direct and indirect species interactions, patchiness of recruitment, and abiotic factors such as clearing size and local environmental conditions (Dayton 1971; Anderson and Underwood 1994; Beck 2000; Petraitis and Dudgeon 2005; Viejo, Arenas et al. 2008). In this study, environmental factors and biological interactions on the flat smooth, control, and reference treatments apparently acted similarly, resulting in nearly identical communities (nearly 100% overlap) by the end of the study period. For this reason, differences in community composition between reference sections of seawall and habitat enhancement test panels can most likely be attributed to panel features.

IMPORTANCE OF MICROHABITAT AND PHYSICAL FEATURES OF SUBSTRATE AND HOW THEY RELATE TO HABITAT PANEL FEATURES Two main components of intertidal substrate structure have been clearly defined and include heterogeneity (how many different structural components are present like pits, cracks, crevices, and tidepools) and complexity (the number of structural components of any certain type) (Beck 2000). Studies of various intertidal species show effects of these components on a variety of ecological processes that determine the structure of intertidal assemblages (Beck 2000; Bulleri and Chapman 2004). These effects are scale-dependent, and independent effects created by individual features that cause variations in water

flow, wave energy dynamics, moisture, temperature, and shading are difficult to characterize (Beck 2000). Effects of complexity are also often confounded by external factors including species interactions and responses to the various structural types are often species-specific (Moore and Seed 1986; Beck 2000). Species-specific responses to habitat panels have been identified in this study and are primarily associated with sloped features and crevices from the cobble surfaces, but distinct mechanisms have not been identified. While wave energy was not tested on panels, the protruding fins and steps likely increase or decrease wave force on the various surfaces. Crevices in the cobble surface may also provide some protection from waves and wave-related disturbances. Wave energy is an important feature of intertidal nearshore and estuarine habitats in Puget Sound (Dethier 1990). Waves can have direct (physical) and indirect (behavior, species interactions) taxa-specific effects, both positive and negative (decreasing desiccation in splash zone, decreased predation and grazing with increased wave exposure, reduced settlement, increased mortality from log strikes and other wave-induced disturbances). Wave exposure changes abundance, size and distribution of taxa on seawalls depending on shoreline elevation (Blockley and Chapman 2008). Species-specific responses to wave energy include increased abundances of limpets and sessile filter feeders (barnacles, tubeworms) on wave exposed and semi-protected hard substrate and higher abundance of fucoids on sheltered shores (Moore and Seed 1986; Blockley and Chapman 2008). Thermal stress is another important environmental factor that can be mediated by increased complexity, particularly through shading associated with slope and crevices, both of which can reduce thermal stress and desiccation. Crevices in particular have been shown to extend the upper vertical limit of Mytilus by providing refuge (Moore and Seed 1986).

PANEL DESIGN AND SURFACE: SPECIES-SPECIFIC RESPONSES Seawalls can support some taxa similar to natural rocky shorelines and only a limited number of species are adapted to the intertidal elevations I studied. Thus, there are fewer alternative communities possible (Farrell 1991) and adding habitat complexity/heterogeneity may not increase the absolute number of taxa, but does appear to have an effect on the abundance and size of certain taxa. This was found with three taxa on the Seattle seawall: Fucus distichus, limpets, and Mytilus.

Fucus distichus The increased Fucus found on sloped portions of the test panels could be related to either wave force and/or limpet density (Branch 1986; Moore and Seed 1986; Schoch and Dethier 1996). The main purpose of this study was to identify differences in taxa and percent cover among alternative seawall test panel designs and surface treatments but the data did not identify the possible mechanisms contributing to these differences. Fucus generally occurs more on sloped surfaces (Schoch and Dethier 1996) on

sheltered or semi-sheltered shorelines and has reduced abundance and stunted growth with increased wave exposure (Moore and Seed 1986). Fucus was more abundant on fins and steps of test panels, which may result from reduced wave energy on sloped surfaces (especially fins which, due to orientation, are more protected from direct wave strikes). Increased Fucus may also be related to lower densities of limpets on sloped surfaces of test panels. The effect of limpets on algae has been well documented and wave energy may enhance the interaction, with limpets prevailing in wave exposed shores and Fucus in sheltered zones (Branch 1986).

Fucus can initially have negative effects on intertidal assemblages, inhibiting ulvoids and some species of barnacles (Viejo, Arenas et al. 2008). However, as succession progresses, Fucus distichus increases species richness in middle to high intertidal elevations by forming canopies that provide structural heterogeneity, shelter, and food for a variety understory organisms and meiofauna including large numbers of herbivorous gastropods and crustaceans (Moore and Seed 1986; Van Alstyne 1988; McKindsey and Bourget 2001; Viejo, Arenas et al. 2008). Thus, increased abundance of Fucus could be an important addition to the biological community of the seawall in downtown Seattle.

Limpets Increased limpet densities on flat vertical walls and panels could be related to either angle and/or wave force (Branch 1986). At middle and upper elevations, higher densities of limpets were associated with vertical surfaces of flat panels. Vertical portions of the step and fin panels are often shaded and consequently do not support much algae, and could experience decreased wave energy, possibly explaining why limpets were less abundant on those panels. The upper elevation also had higher densities of limpets on smooth surfaces. Angle is an important factor affecting desiccation for limpets, which lose water more slowly as angle of substrate increases, and some species have strong associations with vertical or steep sloped substrate (Branch 1986). Limpets in rocky natural substrates that lack shelter from desiccation, such as those in the tropics, are most common on vertical surfaces or in crevices (Branch 1986). Limpets are also typically more abundant on semi-sheltered or exposed rocky coasts, rather than sheltered shores, and wave energy on flat seawall and test panels could be higher. Slope was not an important factor at lower tidal elevations but surface was. Juvenile limpets are known to occupy lower intertidal elevations and these findings may suggest that crevices could be important in early life stages (Moore and Seed 1986). Limpets have been widely recognized as important components of intertidal ecology, structuring communities by creating bare space for new colonization by primary space occupiers (Branch 1986; Norton 1986; Raffaelli and Hawkins 1996). However, limpets can facilitate dominant species (as in the case with the red alga Mastocarpus) and hinder barnacle recruitment by bulldozing,

leading to increased ephemeral algae and decreased substrate for Fucus (Dayton 1971; Moore and Seed 1986; Farrell 1991).

Mytilus Mytilus were more abundant on panels with cobble surfaces, including flat panels with no fins or steps. In areas of high disturbance, mussels have been found to occur only in crevices and crevices can expand the upper vertical distribution of mussels (Moore and Seed 1986; McKindsey and Bourget 2001). Fins and steps appear to increase the effect of the cobble surface although substrate angle was not a statistically significant factor. Slope has been found to affect the thermal stress experienced by mussels, with higher temperatures on horizontal surfaces and lower temperatures on vertical substrate, likely associated with increased shade on vertical surfaces (Helmuth and Hofmann 2001).

Mussels are known as ecosystem engineers; they can have profound effects on habitat complexity and species richness and mussel beds have been identified as key structures for consideration in conservation and management goals (Borthagaray and Carranza 2007). Some studies comparing mussel beds (invasive species included) to soft substrate or to more complex turf/coralline algae assemblages have found negative effects or decreased species diversity. However, studies comparing mussel beds to nearby rocky intertidal communities are more analogous to seawall conditions. Mussels can dominate the intertidal zone and exclude some species requiring primary space. However, mussels have a positive effect on many secondary space inhabitants. They support species exclusive to mussel beds and increase abundance of generalist species and these effects can increase with mussel bed age and size (Moore and Seed 1986; Borthagaray and Carranza 2007). Some species of mussels have been documented to increase species richness by hundreds of species. Sixty-nine associated species were found to be more abundant in or exclusively occurred in Mytilus edulis beds due to the physical structure of the mussel matrix, which was found to be the most important factor in species diversity (H‟) (Suchanek 1986). Polychaetes were among the taxa exclusively supported or occurring in greater abundance within mussel beds. In addition, mussels provide prey for birds, fish, and a variety of marine invertebrates, particularly asteroids (Moore and Seed 1986; Suchanek 1986). Organisms within the mussel matrix were not sampled in this study, though they may be developing, and may contribute to epifaunal communities in the future.

Studies of habitat and geographic distributions of Mytilus in Puget Sound show low M. galloprovincialis and hybrid genotype frequencies in Elliot Bay (Elliott, Holmes et al. 2008). High frequencies of M. galloprovincialis and hybrids are found on subtidal and low intertidal zones of urban structures like pilings and floating docks, but frequencies on intertidal portions of concrete walls were low (Elliott, Holmes et al. 2008).

SUMMARY

The successional trajectory observed on the test panels was fairly typical and the rate of convergence with undisturbed surrounding communities was within the range of other studies on natural temperate rocky intertidal shores. Convergence occurred on panels with a similar configuration to the original seawall and suggests that observed differences in community structure are likely due to microhabitat features. While causal mechanisms have not been identified, two taxa known to increase taxa richness by enhancing structural heterogeneity and providing food have been found in higher abundance on seawall test panels. In this seawall experiment, Fucus and Mytilus responded to different elements of habitat heterogeneity and had varying degrees of response depending on elevation. Fucus was more abundant on sloped surfaces, particularly at the 0 to +5 foot tidal elevation. This study also confirms that crevices are important for Mytilus and benefits to Mytilus may increase on sloped surfaces. These small alternative communities of Fucus and Mytilus may continue to develop on habitat enhancement test panels and have broader impacts on community structure and species diversity. Limpets are also important in maintaining diversity by creating bare space for new colonizers through grazing and were found to be associated with the vertical portions of seawall test panels. These findings suggest that angled surfaces, both sloped and vertical, are important components of future seawall design as well as crevices provided by more complex surface texture, benefitting ecologically important species that could continue to structure habitat and increase species diversity along Seattle‟s seawall.

Chapter 2 EPIBENTHIC MEIOFAUNA RESPONSES TO INTERTIDAL HABITAT ENHANCEMENT WITH A FOCUS ON JUVENILE SALMON PREY

INTRODUCTION In this chapter, I describe potential impacts from shoreline development on the estuarine nearshore phase of early life histories of Pacific salmon. I evaluate various intertidal seawall habitat enhancements for effectiveness in providing juvenile salmon prey resources. The abundance of juvenile salmon prey species are evaluated as well as the differences in epibenthic taxa richness and assemblage among different panel designs and surface treatments and compared to the existing seawall.

PUGET SOUND JUVENILE SALMON AND LINK TO NEARSHORE Ocean survival of Pacific salmon (Oncorhynchus spp.) is closely linked to growth in early life stages, which in turn depend on the availability and quality of habitat and prey (Beamish and Mahnken 2001; Quinn 2005; Quinn, Dickerson et al. 2005). Estuaries are especially important, providing a crucial link between the salmons‟ natal streams and the ocean, with the estuarine nearshore zone playing an important role in providing habitat and prey resources (Simenstad, Fresh et al. 1982; Brennan, Higgins et al. 2004; Quinn 2005). The Puget Sound, a deep glacial fjord and estuary in Washington State (USA), is an important rearing habitat for juvenile Pacific salmon, including ESA (Endangered Species Act) listed Chinook (O. tshawytscha) (NMFS 1999), chum (O. keta), pink (O. gorbuscha ), and coho (O. kisutch). After leaving natal streams and estuarine wetland habitats, juvenile Pacific salmon tend to occupy and rear along shallow and nearshore habitats of Puget Sound (Simenstad, Fresh et al. 1982). The nearshore zone in Puget Sound is particularly important for juvenile chum and Chinook salmon foraging. Juvenile chum are recognized as very reliant on estuarine habitat after emerging from their natal streams, typically occupying shallow waters along the Puget Sound shoreline (Toft, J. Cordell et al. 2004; Toft and Cordell 2006; Young 2009). Prey availability and growth is extremely important in early life because mortality of juvenile salmon entering the open ocean is high and probably size dependent (Quinn 2005). In estuaries, chum salmon feed mostly on a select group of the potential prey items available to them, particularly small epibenthic crustaceans including harpacticoid copepods and gammarid amphipods (Sibert, Brown et al. 1977; Sibert 1979). Studies of juvenile chum diets in the Nanaimo River showed that chum targeted harpacticoid copepods (Sibert, Brown et al. 1977; Sibert 1979). Chinook also commonly occupy and feed along nearshore habitats of Puget Sound early in their marine life history, with terrestrial riparian insects constituting a prominent prey item (Ruggerone and Volk 2003; Brennan, Higgins et al. 2004). Insects are nearly twice as energy rich as epibenthic crustaceans as prey for juvenile salmonids (Gray 2005). With

the exception of the smallest size class of juvenile Chinook (< 90 mm), Brennan et al. (2004) found that insects dominated the diets of juvenile Chinook salmon in Puget Sound, illustrating the value of terrestrial linkages within the estuarine environment. However, potential insect food sources have been significantly reduced in areas where shoreline vegetation has been removed due to armoring (Romanuk and Levings 2003; Sobocinski 2003). Puget Sound shorelines have been extensively altered, particularly in Elliott Bay, along the central waterfront of downtown Seattle, which is armored by a concrete seawall, rip-rap, and large docks and piers. Despite the highly altered shoreline, juvenile salmon continue to be abundant along the shallow areas of Elliott Bay directly adjacent to the Seattle seawall and other built nearshore structures (Toft, Cordell et al. 2007). They occur in greater densities in shallow compared to deeper nearshore areas (Toft, Cordell et al. 2007). Fish abundance, distribution, and behavior data were collected during the course of this study, showing that juvenile salmon are present and feeding in waters directly adjacent to the Seattle seawall (and test panels) during outmigration (see Appendix B). Juvenile salmon species migrating and rearing here include Green River Chinook, which are among the five historically independent Chinook populations from the Central Puget Sound sub-basin identified as being at high risk for extinction (Ruggerone and Volk 2003; SSPS 2007). Juvenile Chinook from the Green River migrate rapidly in order to find suitable nearshore marine habitats in and around Elliott Bay, and juvenile salmon from other watersheds also enter and rear in Elliott Bay (Nelson, Ruggerone et al. 2004). Average residence time in Elliott Bay of naturally produced juvenile Chinook is approximately 20 days and for hatchery juvenile Chinook residence time was up to 60 days (Ruggerone and Volk 2003; Nelson, Ruggerone et al. 2004). However, reduced feeding opportunities and degraded habitat in estuaries may reduce residence times, causing juvenile salmon to leave in search of higher quality prey (Healey 1982; Simenstad, Fresh et al. 1982). Riparian vegetation is sparse along most of the urban waterfronts in Puget Sound, and in particular Elliott Bay, with the exception of the restoration areas (the Lower Duwamish Waterway and the Olympic Sculpture Park) (Nelson, Ruggerone et al. 2004; Toft and Cordell 2006). While terrestrial insect prey can dominate juvenile Chinook salmon diets in less populated and relatively undeveloped parts of Puget Sound, juvenile Chinook diets along altered urban and industrial shorelines in Central Puget Sound rely more on marine benthic and epibenthic invertebrates (Brennan, Higgins et al. 2004; Toft, J. Cordell et al. 2004).

THE HIGHLY ALTERED URBAN SHORELINE OF ELLIOTT BAY The urban intertidal estuarine habitat of Elliott Bay in Seattle, Washington, was originally low to high bank bluff-backed gravel-cobble beaches but the shoreline has been extensively modified and the majority is now hard substrate (WDNR 1999). A smooth vertical seawall was constructed in Elliott Bay in the 1930‟s and was built out onto the intertidal beaches. Unconsolidated, shallow, gently-sloping

substrate was replaced by hard vertical substrate resulting in only a few remaining shallow areas. The previous intertidal beach was cut off from the estuarine environment and filled in. Now, there are over two miles of seawall along the Elliott Bay intertidal zone in downtown Seattle (WDNR 1999).

The effects of armored shorelines have received increased attention. Some studies have found lower diversity and abundances of organisms on seawalls than on rocky shores, particularly for mobile invertebrates, presumably due to reduced food resources and space and due to homogenous substrates lacking microhabitats that protect organisms from physiological stress (Moreira, Chapman et al. 2006; Moreira, Chapman et al. 2007). Studies focused on established seawall communities, mostly in Sydney Harbor, Australia, and in marinas in Italy, have been limited to algae and larger sessile and mobile invertebrates (Bacchiocchi and Airoldi 2003; Chapman 2003; Chapman and Bulleri 2003; Bulleri and Chapman 2004; Pinn, Mitchell et al. 2005; Blockley and Chapman 2006; Moreira, Chapman et al. 2006; Moreira, Chapman et al. 2007; Blockley and Chapman 2008; Chapman and Blockley 2009; Bulleri and Chapman 2010). However, small meiofaunal invertebrates occupy an important niche in the rocky intertidal community, between the macro-organisms (> 2 mm) and microscopic bacteria and diatoms (< 0.1 mm) and include epibenthic amphipods and copepods that serve as important prey to juvenile salmon and other small nearshore fishes. Meiofauna on altered shorelines have not been included in most studies, but have recently been characterized at multiple habitat types in Elliott Bay. A recent study comparing seawall, riprap, a habitat bench, and a restored pocket beach at the Olympic Sculpture Park (OSP) near the Seattle central waterfront found similar taxa richness among the habitat enhancements there and at other sites within Elliott Bay (Toft, Heerhartz et al. 2009). However, compared to other habitat types at OSP and in Elliott Bay, the seawall had among the lowest densities of harpacticoid copepods and amphipods and the lowest percent in community composition of the harpacticoid species identified as important juvenile salmon prey (Toft, Heerhartz et al. 2009).

THE LINK BETWEEN HABITAT COMPLEXITY AND ECOLOGICAL CAPACITY

Studies of effects of armored shorelines and the well-documented relationship between habitat complexity and biodiversity strongly suggest that there is reduced ecological capacity on the current seawall in downtown Seattle. More complex habitats are known to support greater biodiversity and abundance by providing increased surface area, a greater range of microhabitat niches, and crevices that create refuge from predators, physical disturbances, and desiccation (Newell 1970; Little and Kitching 1996; Underwood and Chapman 1996). Adding complexity to seawalls in Sydney Harbor has increased the number of species that recruited to engineered experimental rock-pools and cavities in the seawall compared to surrounding unmodified seawalls (Chapman and Blockley 2009). In central Puget Sound,

low gradient gently sloping beaches with varied sediment types had the highest taxa richness of epibenthic meiofauna compared with steeper shorelines with less varied substrata (Toft, Heerhartz et al. 2009). Evaluations of the habitat restoration areas nearby in the estuary of the Duwamish River, also located in Seattle, have found that restoration increases the abundance of marine benthic–epibenthic prey species and other ecological functions (Nelson, Ruggerone et al. 2004; Simenstad, Tanner et al. 2005; Cordell, Toft et al. 2006). In aggregate, these findings suggest that there are opportunities to improve ecological functions of extensively altered urban shorelines. While restoration to natural conditions is not an option along the central Seattle waterfront, the seawall does present a unique opportunity to evaluate potential benefits from shoreline habitat enhancement. The seawall needs replacement and/or major repairs and a collaborative effort between City of Seattle and University of Washington researchers has led to the design and installation of seawall habitat enhancement test panels (see Chapter 1) that incorporate slope and texture. This represents a controlled experimental study testing new seawall design concepts that may enhance ecological functions along the armored urban shoreline by adding structure and complexity to the seawall.

OBJECTIVES

This portion of the study focuses on the epibenthic meiofauna assemblage and potential availability of juvenile salmon prey species along the central waterfront seawall in downtown Seattle where the intertidal zone is presumed to be negatively affected by the reduced complexity of the extant seawall. The main objective is to evaluate the various enhancement test panel designs for effectiveness in providing juvenile salmon prey resources in the built environment by comparing 1) taxa richness of the epibenthic meiofauna assemblages and 2) densities of juvenile salmon prey species among test panel designs. These comparisons are also made to the original seawall to determine if panel configurations provide better juvenile salmon resources. Primary differences in epibenthic assemblages were also characterized and compared among panel types and reference sections of seawall, identifying which species and test panel features contribute most to differences.

METHODS

See Chapter 1 for study area, sites, test panel, and study design figures and descriptions.

DATA COLLECTION

I sampled epibenthos in 2008 and 2009 during the peak of juvenile salmon outmigration that occurs between April and July (Table 2.1). In 2008, sampling occurred monthly at all sites April through

August, except in July, when sampling was disrupted by a sewage leak at a nearby hotel. In 2009, epibenthic samples were collected monthly April-August, but only samples from April and June were analyzed due to limited resources. Table 2.7. Sampling events, dates, and ID status for epibenthic sample collection.

Epibenthic - Dates collected Year Event Date Samples Identified

April/May 2008 4/30/2008 - 5/1/2008 √ May 2008 5/28/2008 √ 2008 June 2008 6/25/2008 √ July 2008 - Aquarium 7/24/2008 √ only August 2008 8/5-7/2008 √ April 2009 4/20-21/2009 √ May 2009 5/16-18/2009 2009 June 2009 6/28-29/2009 √ July 2009 7/27-29/2009 August 2009 8/24-25/2009

An epibenthic pump (14.8 cm diameter, 150-um mesh size) was used to collect mobile macro- and meiofaunal invertebrates from the surface of habitat test panels (Figure 2.1). The pump works by vacuuming invertebrates inside a cylinder of known volume from 172 cm2 surface area of submerged substrate. The sampler was modified to better fit the contours of the cobble relief surfaces of the test panels by adding a brush edge to the sampler bottom.

Stratified random sampling was conducted on the lower elevation of each habitat test panel, from approximately 0 m MLLW to 0.9 m MLLW (3 ft). Epibenthic pump samples were collected to characterize species assemblage and density on both vertical and sloped surfaces. To minimize fine-scale variability, vertical and sloped strata were sampled separately (Raffaelli and Hawkins 1996). Sampling was conducted at three spots and combined into a composite sample. Sample locations were randomly stratified over vertical sections and over the lower step of the stepped panels, the lower two fins of the fin design panels, and the lower one-third of the flat panels (Figure 2.2). Samples were also collected from the lower one-third of the pressure-washed control area and from the reference area of pre-existing seawall at the same elevation.

Figure 2.1. Epibenthic pump sampling for meiofauna.

Figure 2.2. Stratified random epibenthic sampling of various panel surfaces. For each panel/stratum, three pump samples were combined into a single composite sample.

Epibenthic samples were fixed in 10% buffered formalin. Invertebrate taxa from known salmon prey groups such as large harpacticoid copepods, gammarid amphipods, other crustaceans, and mobile polychaete worms were identified to species; other taxa were identified to family level or lower.

DATA ANALYSIS

Taxa richness was measured for all panel types and sampling events and then averaged among the three sites. Differences among mean taxa richness were tested using univariate two-way (with interaction) ANOVA for differences among sampling events and among panel designs and surfaces on untransformed data. I used the SIMPER analysis (Similarity percentages for species contributions) in the PRIMER v6 multivariate statistics program (Clarke 1993) to identify the main species characterizing each panel type. To further characterize differences in taxa, taxa lists were cross-referenced to identify any taxa

unique to certain panel designs or occurring at a much higher frequency (at least twice the frequency than on other panels).

Densities for three major groupings of juvenile salmonid prey species (amphipods, harpacticoid copepods, and insects) were estimated for all panel types and sampling events and then averaged among the three sites. Densities (+1) were transformed (log10) to manage zeros and satisfy parametric test assumptions. I tested for differences among sampling events and among panel designs and surfaces with univariate two-way ANOVA with interaction. Differences in prey insect and prey harpacticoid copepod densities were examined graphically between substrate angle and surface treatments.

To characterize differences among panel types of whole assemblage compositions using species and density of epibenthic invertebrates, I used PRIMER to generate MDS ordination plots and ANOSIM two-way crossed comparisons (with replicates) of factors including sampling events, sites, and panel types and surfaces. However, factors for comparisons were limited to two per test to maintain sufficient degrees of freedom. Because of the strong effect of sampling event on epibenthos assemblage composition (see Results, Figure 2.9), each individual sampling event was then evaluated separately in PRIMER using MDS plots and ANOSIM two-way crossed (with replicates) comparison of factors.

RESULTS

TAXA RICHNESS

A total of 139 taxa were identified across all panel types, sites, and sampling events including: 18 amphipods; 58 harpacticoid copepods; 10 insect taxa including larvae, pupae, and adults of chironomids, dipterans, coleopterans, collembolans, and others; and 53 other taxa (including isopods, polychaetes, gastropods, barnacles, and other crustaceans) (Appendix C). Taxa richness was very similar by site with only a slightly higher number of taxa at Vine Street. Taxa richness was lowest in early months (April and May) of 2008 and 2009 across all panel types and sites and the total average number of taxa increased in summer months both years.

Total taxa richness was significantly higher on panels with steps and fins (Figure 2.3); this pattern was consistent across all sampling events and sites with the exception of the first sampling in April/May 2008 (data not shown) when taxa richness was only slightly higher on the flat smooth panel than all other panels. Differences among sampling event (ANOVA, p<0.01) and panel type (p<0.01) were significant, with no interaction effect. A post hoc Tukey test verified that taxa richness on flat panels (reference, control, flat-smooth, and flat-cobble) was significantly lower than on panels with fins and steps (Table 2.2). Surface treatments (smooth or cobble surfaces) did not have a significant effect on taxa richness.

Figure 2.3. Comparisons of epibenthic taxa richness by panel, all sampling events combined. (± SE of the averages of three sites).

Table 2.2. Comparison matrix of Tukey post hoc test on differences in taxa richness. Bold text highlights significant (p<.05) differences (denoted by asterisk) between flat panels and panels with fins and steps.

Flat Flat Step Step Fin Fin R C Smooth Cobble Smooth Cobble Smooth Cobble R C - Flat Smooth - - Flat Cobble - - - Step Smooth * * * * Step Cobble * * * * - Fin Smooth * * * * - * Fin Cobble * * * * - - -

A total of 36 taxa, including many harpacticoid copepods, occurred exclusively on panels with fins or steps, but most of these were rare, with only one or two total occurrences across all sites and sampling events (Table 2.3. All epibenthic taxa exclusive to panels with fins and steps and total count of individuals….). An additional 31 species had at least twice the frequency of occurrence on stepped or finned panels than on flat panels (Appendix C).

Table 2.38. All taxa exclusive to panels with fins and steps and total count of individuals (listed in decreasing order) across all

sampling events and sites.

Control

Reference

Fin Cobble

Flat Cobble Flat Fin Smooth

Flat Smooth Flat Step Cobble Major Groupings Lowest Grouping Step Smooth Harpacticoid Stenhelia sp. 1 1 2 Harpacticoid Harpacticus sp. nauplii 3 Harpacticoid Harpacticoida other 1 1 1 Cyclopoid Corycaeus anglicus 1 2 Calanoid Stephos sp. 1 2 Polychaete Ampharetidae juveniles 3 Gammarid amphipod Aoroides sp. 1 1 Gammarid amphipod Corophiidae juveniles 1 1 Harpacticoid Harpacticoida nauplii 1 1 Harpacticoid Thalestris sp. 1 1 Harpacticoid Amenophia sp. 2 Harpacticoid Leimia vaga 2 Cumacean Cumella vulgaris 1 1 Isopod Idotea wonsnesenskii 1 1 Oligochaete Oligochaeta 1 1 Opisthobranch Opisthobranchia 1 1 Gastropod Littorina scutulata 2 Polychaete Nereidae juveniles 2 Harpacticoid Amonardia normani 1 Harpacticoid Bulbamphiascus sp. 1 Harpacticoid Danielssenia typica 1 Harpacticoid Heterolaophonte discophora 1 Harpacticoid Parastenhelia hornelli 1 Harpacticoid Thalestridae unidentified 1 Gammarid amphipod Ampithoe dalli 1 Gammarid amphipod Dulichia sp. 1 Gammarid amphipod Desdimelita desdichada 1 Caprellid amphipod Caprella sp. 1 Decapod Cancridae megalopa 1 Decapod Pinnotheridae 1 Gammarid amphipod Jassa sp. 1 Tanaidacean Leptochelia savignyi 1 Decapod Heptacarpus sp. 1 Dipteran Diptera adults 1 Isopod Uromunna ubiquita 1 Larval Fish Teleosti larvae 1

Flat panels had 15 exclusive species compared to panels with fins or steps, but these were also mostly rare species with only one or two total occurrences across all sites and sampling events (Table 2.4). An additional seven species had at least twice the frequency on flat panels than on panels with steps or fins.

Table 2.4. All taxa exclusive to flat panels and total count of individuals (listed in decreasing order) across all sampling events

and sites.

Control

Reference

Fin Cobble

Flat Cobble Flat Fin Smooth

Flat Smooth Flat Step Cobble Major Groupings Lowest Grouping Step Smooth Gammarid amphipod Hyale sp. 5 Isopod Idotea spp. 1 2 Isopod Exosphaeroma inornata 2 1 Decapod Pinnotheridae zoea 2 Isopod Isopoda unidentified 2 Gammarid amphipod Oligochinus lighti 1 1 Gammarid amphipod Monocorophium sp. 1 Cyclopoid Clausidiidae 1 Caprellid amphipod Caprella laeviuscula 1 Tanaidacean Tanaidacea 1 Mollusc Littorina sp. 1 Gastropod Sacoglossa 1 Isopod Munna sp. 1 Larval Fish Cottidae juveniles 1 Isopod Pseudosphaeroma sp. 1

COMPARISONS OF DENSITIES: JUVENILE SALMON PREY SPECIES Juvenile salmon prey taxa were identified in epibenthic samples of reference, control, and habitat test panels and the following taxa groups were selected for analyses:

 Insects: chironomid larvae, chironomid pupae, Diptera pupae, Collembola

 Harpacticoid copepods: Harpacticus spp., Tisbe spp., Zaus spp., and Dactylopusia spp.

 Amphipods: Paracalliopiella pratti, Calliopius sp., Pontogenia rostrata, Aoroides sp., Ischyrocerus sp., Calliopiidae juveniles, and Gammaridea juveniles

Major groupings of epibenthic juvenile salmon prey taxa showed some patterns of density among the various panel designs. Panels with fins and steps had consistently higher densities of prey insects (dominated by chironomid larvae) (Figure 2.4) and prey harpacticoids (primarily Harpacticus spp.) (Figure 2.6). Among all panel types, step-smooth had the highest densities of prey insects, and step- smooth and fin-smooth had the highest densities of prey harpacticoids. Flat panels including reference and control had higher densities of prey amphipods, with Paracalliopiella pratti in highest abundance (Figure 2.8). Site differences contributed to large standard errors in averages.

4000 ) 2 3500 3000 2500 2000 Chironomidae larvae 1500 Density (no. Density m / Chironomidae pupae 1000 500 Diptera pupae 0 Smooth Smooth Smooth Cobble Smooth Cobble Smooth Cobble

R C Flat Step Fin

Figure 2.4. Mean density of prey insects by panel type. (± SE of the averages of three sites).

Differences in prey insect densities and in prey harpacticoid densities among sampling event (two-way ANOVA, p<0.01) and panel type (p<0.01) were significant, with no interaction effect between panel type and sampling event. Densities of prey insects, were significantly (post hoc Tukey test) higher on panels with fins and steps than on the reference and control sections of seawall (Table 2.5). However, with one exception, differences between flat test panels were not significantly different from the control and reference or from the test panels with fins and steps. Substrate angle (vertical or sloped) and surface treatments (smooth or cobble surfaces) did not have an effect on prey insect densities (Figure 2.5). Densities of prey harpacticoids were significantly lower on the control panel compared to all test panels with fins and steps but the reference was significantly lower than only step-smooth and fin-smooth (Table 2.10). Step-smooth and fin-smooth had the highest densities of prey harpacticoids among test panels, significantly higher than all flat panels with the exception of flat-cobble. Higher densities of prey harpacticoids were found on the vertical portions of the test panel rather than the sloped portion of the fin or step (Figure 2.7). Higher densities of these harpacticoid copepods were primarily due to Harpacticus

spp. (Harpacticus compressus, H. obscurus grp, H. septentrionalis, H. sp. A, H. sp. B, and Harpacticus sp. copepodids).

Table 2.9. Tukey post hoc test for prey insect densities by panel type. Significant (p<.05) differences between panel types denoted by asterisk.

Flat Flat Step Step Fin Fin R C Smooth Cobble Smooth Cobble Smooth Cobble R C - Flat Smooth - * Flat Cobble - - - Step Smooth * * - - Step Cobble * * - - - Fin Smooth * * - - - - Fin Cobble * * - * - - -

Substrate Angle Surface Treatment

1200 1200 ) 2 1000 1000 800 800 600 600 400 400

200 200 Density (no. Density m / 0 0 Vertical Slope Smooth Cobble

Figure 2.5. Mean density of prey insects by substrate angle and surface treatment. (± SE of the averages of three sites).

3500

) 3000 2 2500 2000 1500 Zaus 1000 Tisbe

Density (no. Density m / 500 Harpacticus spp. 0

Dactylopusia spp.

Cobble Cobble Cobble

Smooth Smooth Smooth Smooth Smooth

R C Flat Flat Step Step Fin Fin

Figure 2.6. Mean density of prey harpacticoids by panel type. (± SE of the averages of three sites).

Table 2.10. Tukey post hoc test of prey harpacticoid densities by panel type. Significant (p<.05) differences between panel types denoted by asterisk.

Flat Flat Step Step Fin Fin R C Smooth Cobble Smooth Cobble Smooth Cobble R C - Flat Smooth - - Flat Cobble - - - Step Smooth * * * - Step Cobble - * - - - Fin Smooth * * * - - - Fin Cobble - * - - - - -

Substrate Angle Surface Treatment

1000 1000 ) 2 800 800

600 600

400 400

200 200 Density (no. Density m / 0 0 Vertical Slope Smooth Cobble

Figure 2.7. Mean density of prey harpacticoids by substrate angle and surface treatment. (± SE of the averages of three sites).

Mean amphipod densities were slightly higher on flat panels but differences among panel types and surfaces were not significant (Figure 2.8).

30000

25000

20000

Paracalliopiella pratti

) 2 15000 Pontogenia rostrata

10000 Ischyrocerus sp. Gammarid Amphipod - juvenile 5000

Calliopius sp. Density (no. Density m /

0 Calliopiidae juvenile

Cobble Cobble Cobble

Smooth Smooth Smooth Smooth Smooth

R C Flat Step Fin

Figure 2.8. Mean densities of most abundant prey amphipods by panel type. (± SE of the averages of three sites).

WHOLE ASSEMBLAGE COMPOSITION COMPARISONS

TEMPORAL SHIFTS IN WHOLE ASSEMBLAGE COMPOSITION Distinct groupings of epibenthic taxa occurred among sampling dates for all epibenthic samples (MDS plot, Figure 2.9). MDS groupings were primarily driven by high densities of amphipods in April/May 2008 and by the increased densities of Balanamorpha and Acarina in April and June 2009, as indicated by Pearson correlation > 0.4. No obvious patterns or groupings related to panel type, surface type, or feature (vertical face, fins, or steps) were evident at this grouping scale, indicating that sampling event was the strongest factor influencing community composition. However, stress of the MDS was high (0.24, indicating potential poor representation of a 2-d plot) so community composition data were further examined graphically (see below).

Shifts in assemblage composition related to sampling events were primarily due to amphipod (primarily the gammarid amphipod Paracalliopiella pratti ) and insect densities (primarily chironomid larvae). Extremely high numbers of P. pratti were observed in the first sampling conducted in April/May 2008. Densities of amphipods were lower in both April and June 2009 than in any sampling month of 2008. Insect densities were highest in June of both 2008 and 2009.

Figure 2.9. MDS plot of temporal shift in epibenthic community composition with Pearson correlation vectors (> 0.4) by principal taxa.

Epibenthic copepods were primarily comprised of harpacticoid copepods and composition of this assemblage shifted throughout the sampling seasons. Harpacticus spp. copepodids had among the highest densities for all sampling events with the exception of August 2008, when they contributed very little to the overall density (Figure 2.10). Typically, Harpacticus spp. copepodids, Diosaccus spinatus, Harpacticus compressus, Tisbe spp., Harpacticus sp. A, Harpacticus sp. B, Heterolaophonte sp. A, Harpacticus septentrionalis, Amphiascopsis cinctus, Rhynchothalestris helgolandica, Dactylopusia cf. glacialis, and Diarthrodes sp. were among the top ten most dense taxa. A major shift of species composition occurred between prior months and August 2008, which was characterized by higher proportions of Ectinosomatidae, Heterolaophonte sp. A, Dactylopusia cf. glacialis, Ameiridae, and Harpacticus obscurus group. These taxa made up only very low proportions of overall density in all other sampling events (below the top 10). Another notable shift in species included Zaus spp., which had higher proportions in August of both 2008 and 2009 but was not among the top ten at any other sampling time. Conversely, Amphiascopsis cinctus was present at relatively high proportions only in the earlier springtime samplings of April in both 2008 and 2009.

100%

90%

80% Zaus sp. 70% Ectinosomatidae 60% Dactylopusia cf. glacialis 50% Amphiascopsis cinctus

40% Harpacticus compressus Harpacticus sp. A 30% Diosaccus spinatus 20% Harpacticus sp. B 10% Heterolaophonte sp. A

0% Tisbe sp.

Harpacticus sp copepodid

May 2008 May

June 2008 June 2009 June

April 2009 April

August 2008 August April/May 2008 April/May

Figure 2.10. Top ten most abundant harpacticoid copepod taxa by sampling event, showing temporal shifts of community composition.

RELATIONSHIPS AMONG ASSEMBLAGE COMPOSITION AND PANEL DESIGN Differences in the overall epibenthic assemblage composition among the various panel designs and surface treatments could not be tested statistically due to the high variability found among sites. However, an evaluation of epibenthic density using SIMPER for comparisons of major contributing species by panel type, indicated that abundances of P. pratti contributed most to the differences among panels. In general, P. pratti was most dense on reference, control, and both cobble and smooth flat panels. Calliopius sp. was second in contributing to species composition for reference, control, and the flat-cobble test panels, while all other test panels were characterized secondarily by chironomid larvae.

DISCUSSION

INCREASED TAXA RICHNESS AND DENSITIES OF HARPACTICOID COPEPODS

Enhancement test panels installed along Seattle‟s central waterfront seawall in early 2008 were colonized by diverse assemblages of epibenthic invertebrates . Higher taxa richness was measured on panels with fins and steps than on flat panels and several taxa exclusive to panels with fins and steps were

identified, although most occurred in low frequencies and abundances (Appendix B). Taxa richness of epibenthic meiofauana at a similar elevation on seawall, rip rap and a restored pocket beach at the nearby Olympic Sculpture Park (OSP) was very similar to that of the fin and step test panels (Toft, Heerhartz et al. 2009). The OSP study also measured epibenthos at other sites around Elliott Bay and found that sites with the highest densities of harpacticoids also had the highest taxa richness values (Toft, Heerhartz et al. 2009). Increased taxa richness on the seawall test panels with fins and steps was mostly due to harpacticoids, and these panels also had higher densities of species that constitute prey for juvenile salmon such as Harpacticus spp., Tisbe spp., Dactylopusia spp., and Zaus spp. Although many potential prey items available to juvenile chum salmon in estuaries, they feed selectively on small epibenthic crustaceans, primarily these species of harpacticoid copepods and gammarid amphipods (Sibert, Brown et al. 1977; Sibert 1979).

Harpacticoid copepods are often the dominant meiobenthic taxa on the fronds and blades of algae (Hicks 1986). The increased surface area and complexity of algae can lead to increased copepod densities and/or species (Hicks and Coull 1983; Hicks 1986). Macroalgae is reputed to play an important role in harpacticoid habitat and feeding, providing increased habitat structure and refuge and providing food in the form of the algal surface film, comprised of diatoms and bacteria that break down detritus and algal mucilage (Sibert, Brown et al. 1977; Hicks and Coull 1983). Grazing by harpacticoid copepods on the bacteria and other heterotrophs capable of processing estuarine detritus provides an essential link in the carbon cycle and food web (Sibert, Brown et al. 1977). Harpacticoid species in this study were found at higher densities on the vertical portions of fins and steps, which are generally devoid of macroalgae (as described in Chapter 1) and primarily covered with barnacles and brown scum (a biofilm presumably made up of bacteria, diatoms and other microalgae with traces of dead macroalgae). The vertical portions of panels with fins and steps are often shaded which may be providing protection from desiccation and thermal stress. Although wave energy was not measured in this study, another possible explanation of higher densities and taxa richness on vertical habitats could be wave attenuation on the vertical substrate from the adjacent sloped surfaces.

INSECT PREY DENSITIES

Chironomid larvae were the dominant insect taxa in epibenthic samples from the seawall and test panels and were found in higher densities on panels with fins and steps. Chironimid larvae in this study were not identified to species, so it is more difficult to infer the reasons they are more abundant on test panels with fins and steps. There are many estuarine or marine species with varied life histories, and larvae adopt several strategies for survival and habitat selection, occupying intertidal habitats including intertidal soft substrates in marshes and wetlands and in rocky intertidal habitat. On rocky intertidal

shores, they are often associated with algae, feeding on diatoms (De Haas, Wagner et al. 2006; Tarakhovskaya and Garbary 2009). Chironomid larval density, while higher on panels with fins and steps, was not correlated with the macroalgae-laden sloped surfaces of the fins or steps (see Chapter 1) versus the vertical portions of the test panel, typically devoid of macroalgae but often covered with a biofilm that includes diatoms. Possible explanations of the higher densities of chironomid larvae on these panels could be that they are feeding on diatoms rather than or in addition to macroalge or they are experiencing decreased wave energy on both sloped and vertical surfaces of these panels.

SUMMARY

The habitat enhancement panels that were deployed along the highly developed Seattle shoreline appear to provide ecological benefits in the form of increased taxa richness and potential benefits for juvenile salmon from increased densities of prey taxa. Fins and steps are the main panel elements that contributed to increasing taxa richness and increasing densities of harpacticoids and insects for juvenile salmon. Increased densities of these prey taxa are not directly linked to the sloped substrate, but to conditions created by steps and fins, possibly increased shading or wave attenuation. As in other studies comparing various degrees of complexity in urban shoreline structures, increased taxa richness and productivity (for certain taxa) was found on more structured panels, in this case those with sloped surfaces. Prey availability alone does not determine the value of these experimental habitats as a food source for juvenile salmon. Other factors must be considered, such as juvenile salmon density and use of the nearshore study area. Assessing the true value of a microhabitat requires more complex measures of growth, survival, and recruitment of juveniles (Young 2009).

Chapter 3 MANAGEMENT IMPLICATIONS OF HABITAT ENHANCEMENT OPPORTUNITIES ON THE SEATTLE SEAWALL

Coastal shorelines around the world are being transformed as populations along coasts grow, and the demand for commercial, transportation, residential and tourist infrastructure increases. Shoreline alterations such as breakwaters and seawalls have become a necessity in urban coastal areas and in economically important bays and ports to stabilize natural soft substrates and protect shorelines from erosion and wave energy, to support infrastructure like piers and docks, and to prevent upland flooding (Bulleri and Chapman 2010). Coastal cities worldwide support a large populace and more than 75% of the population is expected to live in coastal areas by 2025 (Bulleri and Chapman 2010). In the United States, over half (53% in 2003) of the population of the United States lived in coastal counties. The total number of people residing along the coasts is projected to increase by over 12 million by 2015 (Bulleri and Chapman 2010). As human populations along the coasts increase, transformation of shorelines will accelerate. An increased demand for urban infrastructure to reduce erosion along shorelines is also expected if storm frequency and intensity increase and/or climate changes as predicted (Bulleri and Chapman 2010).

ECOLOGICAL IMPACTS OF SHORELINE ARMORING IN THE INTERTIDAL ZONE

At least two general consequences of shoreline armoring in the marine environment are evident: alteration of the existing shoreline geomorphology with consequent effects on ecological structure and function, and introduction of new, novel habitats, the effects of which have only recently received attention (Glasby and Connell 1999; Bulleri and Chapman 2010). Different forms of armoring have different effects (both positive and negative) on biodiversity and distribution of species as well as physical effects on the surrounding environment associated with changes in wave energy, scouring, and sediment supply. Compared to natural rocky shores, smooth vertical seawalls in particular tend to support fewer taxa at high intertidal elevations, where features like crevices are known to provide important refuge for mobile invertebrates (Bergeron and Bourget 1986; Archambault and Bourget 1996; Moreira, Chapman et al. 2007). Seawalls may support some taxa similar similar to those found on natural rocky intertidal shorelines at lower and middle tidal elevations but should not be considered surrogates to natural intertidal habitat because effects on abundance, density, distribution, size, and reproductive capabilities are often species-specific (Chapman 2003; Chapman and Bulleri 2003; Moreira, Chapman et al. 2006). Many of the effects of seawalls on intertidal communities are related to a lack of habitat heterogeneity and complexity, reducing resources such as space and refuge and increasing competition

and stress (Bergeron and Bourget 1986; Helmuth and Hofmann 2001; Chapman 2003; Moreira, Chapman et al. 2006). Seawalls also change patterns of wave energy, shading, and other physical characteristics that can influence the recruitment and distribution of sessile and infaunal invertebrates (Wethey 1984; Bergeron and Bourget 1986; Helmuth and Hofmann 2001; Blockley and Chapman 2006; Blockley and Chapman 2008; Chapman and Blockley 2009).

PUGET SOUND, ELLIOTT BAY, AND SEATTLE

The Puget Sound, a large deep glacial fjord estuary in Washington State, has attracted substantial human settlement because of its scenic beauty, diverse landscapes, geography, maritime opportunities, and abundant natural resources such as fisheries and timber. These attributes and conflicting needs have also complicated shoreline management issues. Like other urbanized estuaries around the world, increased demands for commercial development and other uses of shoreline property have led to declines in intact natural shorelines in the Puget Sound, approximately 1,290 km (800 mi; 30%) of which have been altered (Simenstad, Ramirez et al. In press). Urban bays within Puget Sound have had much higher declines in natural shoreline, with 68% of the shoreline modified in King County, where Elliott Bay and the City of Seattle are located (WDNR 1999).

Elliott Bay‟s nearshore was originally characterized by low to high bank bluff-backed beach with a mixed gravel-cobble beach and low tide terrace (Simenstad, Ramirez et al. In press). The City of Seattle, located in Elliott Bay near the mouth of the Duwamish River estuary, needed deep water ports. To accomplish this, in 1911-1934 the City built a concrete vertical seawall at the outer edges of the intertidal beach adjacent to the deeper waters of Elliott Bay. The shoreline was transformed into a deepwater port and the intertidal zone was cut off from the marine environment, drained, and filled in. There are now over 3.2 km (2 mi) of seawall along the Seattle central waterfront with very few remaining shallow sloping intertidal areas (WDNR 1999).

The building of Seattle‟s seawall was driven mostly by seaport industry. Today, the economic value of Seattle‟s waterfront relies more on recreation, leisure, and tourism. The Seattle seawall supports an important tourist area with gift shops, the Seattle Aquarium, sight-seeing and cruise ship terminals, hotels, and marinas. It also continues to support important transportation infrastructure, offices located in piers along the waterfront, and public utilities such as water, electric, and gas lines.

JUVENILE SALMON MIGRATION AND REARING ALONG SEATTLE SHORELINE

Despite its highly altered nature, the shoreline of Elliott Bay and Seattle still serves as an important migratory corridor and rearing habitat for juvenile salmon from the nearby Duwamish/Green River

system and from other watersheds around Puget Sound (Ruggerone and Volk 2003). The cumulative impact of shoreline development along Seattle‟s waterfront is unknown, but is of increasing concern, particularly because juvenile salmon migrating and rearing here include Chinook salmon, a culturally and economically important species listed as threatened under the federal endangered Species Act (ESA), and coho salmon, a candidate species under ESA. Green River Chinook are among the five historically independent Chinook populations from the central Puget Sound identified as being at high risk for extinction (SSPS 2007).

Puget Sound shorelines are presumed to be important in the early life history of Chinook and other salmon that migrate and rear along shallow estuarine and nearshore marine waters at a relatively small size. Even with the scarcity of shallow-water habitat, chum and pink salmon juveniles are abundant along the shoreline of Elliott Bay directly adjacent to the Seattle seawall (Toft, Cordell et al. 2007; Toft, Heerhartz et al. 2009). Studies of juvenile salmon along Seattle‟s seawall and riprap shorelines have shown significantly greater densities in shallow (directly along shore, 2.3-m water depth) than in deep water (10-m from shore, 4.3-m water depth) (Toft, Cordell et al. 2007). The truncated intertidal zone along seawalls and riprap shorelines have denser distributions of juvenile salmon than more natural gradient intertidal beach types (Toft, Cordell et al. 2007).

Terrestrial riparian insects, known to be a common prey item of juvenile Chinook salmon and nearly twice as energy rich as epibenthic crustaceans that also appear in their diet, can dominate juvenile Chinook salmon diets in less populated shorelines of Puget Sound (Brennan, Higgins et al. 2004). However, along urban/industrial shorelines, juvenile Chinook rely more on marine benthic and epibenthic invertebrates (Brennan, Higgins et al. 2004). Such is the case in Central Puget Sound, where shorelines of many deltas and estuaries are highly altered and juvenile Chinook of the smallest size class (< 90 mm) have diets dominated in weight by benthic and epibenthic prey (Brennan, Higgins et al. 2004). Additional epibenthic prey items such as herbivorous polychaete worms, algae-associated amphipods, and barnacle parts were common and sometimes dominant, especially in smaller salmon early in the year (Brennan, Higgins et al. 2004).

LIMITATIONS TO RESTORATION IN URBAN ESTUARIES

Restoration opportunities are often limited in heavily urbanized estuaries. This is the case with Seattle‟s shoreline. While the Seattle central waterfront is no longer the primary seaport hub of the city, the seawall still supports urban infrastructure and industry that, in some cases, cannot be relocated. On the seaward side, the seawall is often adjacent to steep gradient bathymetry. In many areas, this leaves no cross-shore space for habitat restoration such as pocket beaches or construction of more naturally sloped

shorelines. An alternative to restoration is enhancement, where physical and biological characteristics that promote fish and wildlife use are integrated into highly modified, built shorelines. While many of the critical processes and functions of the original shoreline have been irreversibly lost, such as sediment supply and natural hydrologic flow regimes, some ecological functions may be improved (Simenstad and Thom 1992; Simenstad, Tanner et al. 2005).

Along the Seattle shoreline, habitat enhancement projects have locally increased taxa richness and densities of epibenthic prey and fish. Just north of the central Seattle waterfront, the Seattle Art Museum‟s (SAM) Olympic Sculpture Park (OSP) has undergone extensive shoreline enhancement including removal of seawalls, the creation of a pocket beach and “habitat bench” and additional riprap to provide shallow-water habitat for shoreline fish, invertebrates and wildlife; at this site there has been an increased overall diversity and taxa richness of the epibenthos (Toft, Heerhartz et al. 2009).

HABITAT ENHANCEMENT AS AN ALTERNATIVE TO RESTORATION

Terrestrial conservation efforts have also had success with introducing fish and wildlife microhabitat elements like nesting boxes and engineered refuges for birds, mammals and reptiles. The potential ecological benefit of including enhancement criteria into the design and management of seawalls and other marine structures is receiving increased attention (Glasby and Connell 1999; Davis, Levin et al. 2002; Chapman and Bulleri 2003; Airoldi, Abbiati et al. 2005; Chapman and Blockley 2009; Dyson 2009). The use of ecological criteria in seawall design may mitigate some of the negative impacts of urbanization and development of shorelines while still serving societal needs of erosion protection and infrastructure support (Bulleri and Chapman 2010).

Seawall enhancement has been tested in Sydney Harbor, Australia, where recent research (Chapman 2003; Moreira, Chapman et al. 2006; Moreira, Chapman et al. 2007) suggests that the scarcity of many mobile animals on seawalls is caused by a lack of microhabitats that retain water and provide refuge. Their research suggests that intertidal seawalls may be improved by: (1) including cavities or crevices that retain water during low tide; and (2) constructing seawalls with gentle slopes or a combination of horizontal and vertical surfaces. Adding complexity to seawalls in Sydney Harbor appears to have had the intended effect; the number of species that recruited to engineered experimental rock-pools and cavities in the seawall was much greater than those found on the surrounding unmodified seawalls (Moreira, Chapman et al. 2007; Chapman and Blockley 2009).

The benefits to intertidal organisms of increased habitat heterogeneity and complexity have been well documented, including benefits to survival and/or fitness and the reduction of physiological stresses

like temperature extremes, desiccation, and osmotic fluctuations through the increased availability of suitable shelter (Newell 1970; Little and Kitching 1996; Lohrer, Fukui et al. 2000). Appropriate shelter also provides refuge from terrestrial and avian predators during low tide and from marine predators during high tide (Moksnes, Pihl et al. 1998). 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 (Holbrook and Schmitt 1988; Sih, Englund et al. 1998). Crevices and depressions associated with complex shorelines accumulate sediment and organic material, increasing opportunities for both infaunal and epifaunal species (Olabarria, Underwood et al. 2002; Kelaher 2003; Kelaher and Carlos Castilla 2005) and the relatively greater surface area of such complex habitats increases available space for these species.

Some physical characteristics that mimic natural intertidal substrate complexity can be integrated into future designs for Seattle‟s seawall. Slope, crevices, and texture are important physical features of natural shores and the value of these features were tested along Seattle‟s Elliott Bay seawall in Puget Sound, Washington. Slope and surface texture were built into habitat enhancement panels to test whether engineered substrates would provide benefits to the intertidal ecology. This project presents an opportunity to test concepts about the functionality of intertidal substrate enhancement in urban areas, including: (1) working within the limiting constraints of the urban shoreline environment; (2) exploring innovative approaches that can include adaptive management experiments; and, (3) expanding institutional commitments to urban restoration and their connection to social and cultural values (Simenstad, Tanner et al. 2005).

OPPORTUNITY AND COLLABORATION

The opportunity and impetus for assessing the potential benefits of shoreline enhancement along Seattle‟s waterfront arose from a convergence of circumstances including the ESA listing of Puget Sound Chinook salmon and the deterioration of the seawall. This confluence of events led to a collaboration by engineers, planners, and scientists to develop habitat enhancement designs and test them experimentally along the Seattle seawall.

After the Nisqually earthquake in 2001, concerns were raised about the condition of Seattle‟s seawall. The City found that a 30-m long by 3-m wide (100-ft x 10-ft) section of a surface street adjacent to Seattle‟s shoreline settled and that the wooden foundation of the seawall was extremely deteriorated due to wood-boring invertebrates. Despite regular maintenance and extensive repairs, the seawall needs to be replaced and construction is slated to begin in 2012. The City of Seattle saw this as an opportunity

to explore designs for improving the ecological function of the intertidal environments created by the new seawall along the city‟s shoreline.

Tasked with meeting the conflicting needs of infrastructure, civic, transportation, and environment in the upcoming seawall rebuild, the City of Seattle formed the Waterfront Ecology Team (WET). This interdisciplinary group of planners, engineers and scientists from five city departments collectively led efforts to research the current state of Seattle‟s nearshore ecology and develop alternative designs for the urban shoreline armoring. Scientists, local environmental consultants, and City of Seattle engineers and environmental planners collaborated on developing the basic concept of seawall enhancement for Seattle‟s central waterfront. The ability to test this concept was realized when the City provided resources to design, build, and deploy experimental habitat enhancement panels along the Seattle seawall. The City and Washington Sea Grant provided further funds that allowed for an in-situ, a priori experiment and initial scientific testing of these panels to inform the planning and design phase of seawall construction.

IMPLEMENTATION AND MONITORING

The initial phase of the project included design, fabrication, and installation of habitat enhancement test panels. Two elements of habitat heterogeneity that could potentially be built cost effectively into large expanses of seawall were incorporated into the test panel design: slope and texture. Slope was considered an important microhabitat element in the design and was built into vertical panels using angled fins and steps. Long continuous slopes protruding out perpendicular to the seawall were considered but were replaced with the fins and steps due to engineering and ecological concerns (e.g., the shelf may have been subject to catching logs during storm events, and would have shaded the adjacent substrate). In addition, each panel type was made in two textures: smooth and cobble. The cobble texture was intended to provide more interstices and crevices for colonization by invertebrates. The panels, measuring about 2.3 m by 1.5 m (7.5 ft by 5 ft), were constructed of pre-cast, reinforced concrete in wood forms (Figure 3.1). Prefabricated concrete formliners were used to make the “faux patio stone” cobble texture.

Figure 3.1. Fabrication of a precast concrete "fin" habitat enhancement test panel

In January 2008, the test panels were lowered from the sidewalk above using backhoes (Figure 3.2) and mounted with large bolts onto the existing seawall in the intertidal zone at three sites along the City‟s waterfront. Test panels and reference and control sections of seawall were monitored for colonization and endpoint community composition of algae, macroinvertebrates, and epibenthic meiofauna in 2008 and 2009. Monitoring methods and full results can be found in Chapters 1 and 2.

Figure 3.2. Lowering of panels onto seawall using backhoe from sidewalk above

SUMMARY OF MONITORING RESULTS 2008 - 2009

Habitat enhancement of seawalls along the highly developed City of Seattle shoreline appears to provide some potential ecological benefits in the form of increased biodiversity and increased densities of important species compared to existing seawall conditions (summarized from Chapters 1 and 2, Table 3.1). Crevices created by the cobble surface texture increase coverage of mussels. Slope increases Fucus distichus but has a negative effect on limpets, which are more numerous on vertical surfaces. And the addition of structures like fins or steps appears to have improved conditions on the adjacent vertical surfaces for the insect larvae and harpacticoid copepods that are prey for some species of juvenile salmon.

Table 3.11. Summary of observed habitat enhancement effects on Seattle seawall. “↑” denotes increase, “↓” denotes decrease, “-“ denotes no change.

Elevation Fins, Crevices m (MLLW) Steps (ft, MLLW) 0 to +0.76m Epibenthic meiofauna taxa diversity ↑ - (0 to +2.5 ft) 0 to +2.3m Algae and sessile invertebrate taxa diversity - - (0 to +7.5 ft) Epibenthic juvenile salmon prey densities: Harpacticoid copepod prey taxa and insect larvae known to be important prey items for juvenile salmon. 0 to +0.76m ↑ - Increased densities are found on panels with fins and (0 to +2.5 ft) steps but not strongly linked to sloped surfaces and may be a result of shading or wave attenuation. Mussel (size and abundance): Important habitat 0 to +2.3m structuring species, providing food and shelter for - ↑ (0 to +7.5 ft) numerous other species (Suchanek 1986). Canopy forming algae (Fucus distichus): Important 0 to +1.52m habitat structuring species, providing food and shelter ↑ (0 to +5 ft) for numerous other species (Moore and Seed 1986). +1.52 to+2.3m ↓ ↓ Limpets: Important habitat structuring species, (+5 to +7.5 ft) maintaining bare space for colonization of algae and +0.76 to +1.52m ↓ - sessile invertebrates (Branch 1986). More abundant on (+2.5 to 5 ft) vertical surfaces. 0 to +0.76m - ↑ (0 to +2.5 ft)

In addition to microhabitat, the panels provided increased surface area. Space is perhaps the definitive limiting resource to many organisms in the intertidal zone, with density dependent interactions and competition strongly affecting the distribution, abundance, and size of many species. Surface areas calculated in Table 3.2 include bottoms and sides of fins and steps that were not sampled but contribute to the overall surface area and create unique habitat, including permanently shaded and inverted substrate

known to support sessile invertebrates (Pomerat and Reiner 1942; Dayton 1971; Wethey 1984; Blockley and Chapman 2006). Fin panels increased surface area the most and provide the most benefit for certain species (Fucus distichus abundance and juvenile salmon prey species density). Vertical sections of fin panels have lower abundances of limpets than flat panels and are often shaded and may have lower wave energy. Cobble texture also increases surface area at a smaller scale (not measured) as well as increasing Mytilus abundance and size.

Table 3.2. Summary of surface areas of various panel designs, with descriptions of physical and biological attributes.

Surface Area Physical Features Biological Attributes (sq. ft.) Flat Panels

Vertical Vertical, Full sun and Increased densities of 37.5 wave exposure limpets Fin Panels

Front of fin Smooth, vertical (not measured) 9.5 Vertical Vertical, shaded, Increased densities of 28 possibly with wave prey harpacticoids and attenuation from prey insect larvae for adjacent fins juvenile salmon Top of fins Sloped, sun Increased abundance of 28.5 Fucus distichus Bottom of fins Sloped, smooth, (not measured) 28.5 inverted, shaded Sides of fins Smooth, vertical (not measured) 16.00 Total Fin Panel 110 Surface Area Step Panels

Vertical Vertical, shaded, Increased densities of 10.7 possibly with wave prey harpacticoids and attenuation from prey insect larvae for adjacent steps juvenile salmon Top of step Sloped, sun Increased abundance of 33.5 Fucus distichus Bottom of step Sloped, smooth, (not measured) 30 inverted, shaded Sides of step Smooth, vertical (not measured) 9 Total Step Panel 82.7 Surface Area

CAVEATS

Some caveats should be made when scaling up the finding of this study to larger sections of seawall. Clearing size, or in this case, panel size, can have an effect on succession and species composition in rocky intertidal habitats. For example, a study of rocky intertidal habitat in Maine shows no evidence for geographic distances as a factor in succession and community composition but that clearing size was a better predictor (Petraitis and Dudgeon 2005). However, larger clearings of 8 meters in diameter showed divergent successional pathways compared to surrounding area and to smaller clearings and should be considered in scaling up to the replacement of the entire seawall (Petraitis and Dudgeon 2005). Habitat enhancement test panels are just over 3 m2 in total area.

Before applying these findings to projects beyond Elliott Bay, consideration should be given to ecological processes that vary over time and space. Biological variation suggests that quantitative predictions beyond the study area cannot be made reliably. However, some fairly dependable predictions can be made with the proper understanding and localized knowledge of the causal mechanisms and interactions involved with life history, habitat, abundance, and distribution of intertidal organisms (Airoldi, Abbiati et al. 2005).

One common conservation goal of waterfront planners, agencies, and managers is to increase species diversity. However, studies on seawalls elsewhere have shown that they can sometimes support taxa similar to those on nearby rocky intertidal habitats. The nearshore intertidal community is comprised of a limited pool of species adapted to the intertidal environment and the effects from seawalls are often species-specific, and may only be manifest in abundance, distribution, recruitment, survival, size, and reproduction of the species present rather than by presence/absence or taxa richness. Although this study did not include comparisons to natural rocky shorelines, results suggest that even with increased substrate heterogeneity and complexity, species richness may not increase and may not be the right metric to capture impacts to armored shores and potential benefits of enhancements to armored shores.

ADAPTIVE MANAGEMENT OPPORTUNITY AND “DESIRED ENVIRONMENTAL STATES”

Airoldi, Abbiatti et al. 2005, propose a management focus on “desired environmental states” as an alternative to comparing designs or mitigation measures to natural, unaltered habitats or reference sites, which is not as useful where restoration to “natural” is not feasible. One benefit of an in situ experiment prior to large-scale change is that it allows for adaptive management strategies prior to design.

The two main features tested in this study, substrate angle and surface texture, increased the size and abundance of certain species; some of which would have been expected based on previous intertidal

studies. Other microhabitat features have been shown to change communities or to benefit certain species but were not tested in this study. Tide pools and cavities have been built into seawalls and are shown to increase diversity, abundance, and the vertical distribution of species compared to surrounding unmodified seawalls (Chapman and Blockley 2009). Shading and finer-scale texture such as roughened concrete (brushed or raked) may promote recruitment of barnacles and other sessile invertebrates (Pomerat and Weiss 1946; Wethey 1984; Anderson and Underwood 1994; Blockley and Chapman 2006). Crevices of different widths and depths were not tested here but intertidal organisms partition crevices much like they do other spatial resources (especially Fucus, mussels, and barnacles) and the shape and amplitude of crevices could determine how space is partitioned (Bergeron and Bourget 1986; Archambault and Bourget 1996; Moreira, Chapman et al. 2007). These examples of microhabitat use suggest that certain species or communities can be attracted to artificial shoreline structures to create “desired environmental states” if the causal mechanisms are well understood.

An important feature of natural shorelines not addressed in this study is riparian vegetation which provides ecological functions such as shade to mediate thermal stress of intertidal organisms, refuge at high tide for fish from avian predators, and an important link between terrestrial and marine environments through insect prey (Romanuk and Levings 2003; Brennan 2007). Riparian vegetation could be integrated into future seawall designs; it is sparse along most of the urban waterfronts in Puget Sound, and in particular Elliott Bay, with the exception of the restoration areas in the Lower Duwamish Waterway and at the Olympic Sculpture Park (Nelson, Ruggerone et al. 2004; Toft and Cordell 2006).

Some important elements of nearshore ecology were not monitored during this study but should be considered for future monitoring of the habitat enhancement test panels. Crabs and other mobile invertebrates that may use the panels when they are submerged were not included in this study. Wave energy on sloped surfaces, adjacent vertical surfaces, and fronting beach (i.e., rip-rap) of the seawall and habitat enhancement panels was not monitored but may be a central factor in forming intertidal communities and in explaining differences among various surfaces. This should be investigated during future monitoring of the seawall panels.

LANDSCAPE PERSPECTIVE: SEATTLE SEAWALL “GREENWAY” AS A LINK IN A CHAIN OF OTHER RESTORATION EFFORTS

Rather than focusing on a species or population, conservation and biodiversity policy is increasingly focused on ecosystem-based management. In this paradigm, landscapes must be considered as a mosaic of interconnected ecosystems (Gray 1997). The ecological value of greenways and corridors has been recognized in terrestrial urban environments and includes parks, tree lined streets, and greenbelts,

incorporating habitat complexity and quality to increase the numbers of regional species of insects, birds, and mammals supported by urban environments (Dyson 2009). The enhancement of Seattle‟s seawall could be seen as a link in the landscape chain that salmon use during their life cycle, linking habitat enhancements at the nearby Olympic Sculpture Park (OSP), restoration efforts in Lower Duwamish Waterway/Green River, and other fishery management and conservation efforts. Even in this highly urbanized environment, the enhanced habitats at OSP that mimic more natural conditions increase overall diversity and taxa richness of the system. OSP is among the few shallow water habitats along Seattle‟s central waterfront and had high densities of small larval fish that may be using these beaches as refuge habitats (Toft, Heerhartz et al. 2009). At the south end of the Seattle central waterfront seawall is the Lower Duwamish/Green River system which has also undergone major enhancement or restoration activities (Cordell, Toft et al. 2008). Habitat enhancement along the central waterfront seawall may be able to link these projects and work synergistically to augment the benefits provided to fish that move through this landscape mosaic.

BROADER IMPLICATIONS

Estuaries support natural and recreational resources while also supporting large populations, tourism, major shipping ports, and economically important fisheries. Planning and management in these complex environments must address the many conflicting needs of society and environmental values. Several federal and state regulations, strategic planning policies, and stakeholders play a role in Seattle‟s waterfront planning, including the federal Endangered Species Act listing for Chinook salmon, Critical Areas Ordinance, the Shoreline Management Act, Seattle‟s Draft Waterfront Concept Plan, Seattle‟s Urban Blueprint, and the Puget Sound Partnership, among others. Collectively, their goals include targets for conservation, restoration, species protection, and sustainable stewardship of coastal resources and must be balanced with conflicting needs and uses of the waterfront, and the restraints imposed by engineering and maintaining the urban infrastructure.

Increasing habitat, aesthetic, social, and cultural values of the seawall can be compatible with and could help resolve some of the many conflicting needs and uses of Seattle‟s central waterfront. While restoration to natural conditions is not an option in many urban areas, including the intertidal zone along Seattle‟s central waterfront, the Seattle seawall presents a unique opportunity for ecological enhancement along a highly urbanized shoreline. Seawall enhancements could yield benefits to intertidal organisms and to federally-listed juvenile salmon, an economically and culturally important resource. While the differences between habitat test panels and original sections of seawall are subtle and species-specific, the potential area (over 0.6 km [2 miles] of shoreline) and duration (decades) of habitat enhancement along

Seattle‟s seawall would strengthen the overall benefit for juvenile salmon occupying Seattle nearshore for decades.

In addition, the land-water interface of Seattle‟s central waterfront is a highly visible element of the City‟s character, and habitat enhancement could have social, educational, and aesthetic benefits. Thus, ecological improvement could be viewed in broader terms as an opportunity for economic, social, cultural, and ecological enhancement by making it an integral part of urban waterfront redevelopment that could create educational and research opportunities and embrace elements of aesthetics and design.

SUMMARY

Crevices created by the cobble surface of the test panels support mussels and may continue to develop more extensive mussel beds. Both crevices and the mussels beds they support can accumulate sediment and organic material, increasing opportunities for both infaunal and epifaunal species. Sloped substrate contributes to increased harpacticoid copepod and insect prey densities for juvenile salmon and, particularly on fin panels, to increased Fucus (known to create habitat structure and support many other taxa). The strong ties between early life stage juvenile salmon diets and the intertidal food web suggest that enhancements including sloped substrate could yield benefits to juvenile salmon migrating and rearing directly adjacent to Seattle‟s central waterfront seawall. In addition, limpets benefit from vertical smooth walls, and are also important in structuring intertidal communities by maintaining bare space. The species specific responses to microhabitats identified in this study and also documented in scientific literature suggest that habitat enhancement on shoreline armoring structures can be tailored to benefit intertidal communities on a broader scale. A mosaic of sloped surfaces and textures integrated into seawall designs may provide benefits to the largest range of algae and invertebrates, increasing taxa richness, food web resilience, and densities of certain preferred prey for juvenile salmon.

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APPENDIX A Averages of percent cover of major taxa groups from each panel, elevation, and sampling event (with standard error on the average of sites).

Average of 3 quadrats per panel per elevation

Bare

Total

Algae

Mussels

Bryozo

Barnacles

Mobile Invertebrate Mobile

Dead algae & barnacles & algae Dead Other Sessile Invertebrate Sessile Other EVENT PANEL SURFACE ELEVATION SITE MAY 2008 Reference Smooth Upper Aquarium 42.7 21.7 22.3 0.0 11.3 1.0 1.3 0.0 100.3 MAY 2008 Reference Smooth Upper Clay 11.3 27.3 22.7 0.0 40.0 0.1 0.5 0.0 102.0 MAY 2008 Reference Smooth Upper Vine 18.7 28.7 30.7 0.0 21.3 1.4 0.5 0.0 101.3 MAY 2008 Reference Smooth Upper Average 24.2 25.9 25.2 0.0 24.2 0.9 0.8 0.0 101.2 MAY 2008 Reference Smooth Upper SE 15.1 10.9 6.4 0.0 8.9 0.4 0.3 0.0 MAY 2008 Reference Smooth Middle Aquarium 93.3 0.0 6.7 0.0 4.0 0.7 0.5 0.0 105.2 MAY 2008 Reference Smooth Middle Clay 20.7 23.7 23.0 0.0 32.0 0.8 0.5 0.0 100.6 MAY 2008 Reference Smooth Middle Vine 82.0 3.3 7.0 0.0 8.0 0.6 0.2 0.0 101.1 MAY 2008 Reference Smooth Middle Average 65.3 9.0 12.2 0.0 14.7 0.7 0.4 0.0 102.3 MAY 2008 Reference Smooth Middle SE 19.7 6.6 6.8 0.0 8.3 0.3 0.2 0.0 MAY 2008 Reference Smooth Lower Clay 60.0 3.3 10.3 0.0 26.7 0.1 0.0 0.0 100.4 MAY 2008 Reference Smooth Lower Vine 88.0 11.7 1.3 0.0 0.0 0.1 0.0 0.0 101.1 MAY 2008 Reference Smooth Lower Average 74.0 7.5 5.8 0.0 13.3 0.1 0.0 0.0 100.7 MAY 2008 Reference Smooth Lower SE 14.0 7.9 4.3 0.0 9.4 0.1 0.0 0.0 MAY 2008 Control Smooth Upper Aquarium 78.7 21.3 0.2 0.0 0.0 0.2 0.0 0.0 100.4 MAY 2008 Control Smooth Upper Clay 72.7 27.3 0.0 0.0 0.0 0.2 0.0 0.0 100.2 MAY 2008 Control Smooth Upper Vine 37.3 62.7 0.2 0.0 0.0 0.4 0.0 0.0 100.5 MAY 2008 Control Smooth Upper Average 62.9 37.1 0.1 0.0 0.0 0.3 0.0 0.0 100.4 MAY 2008 Control Smooth Upper SE 21.3 21.3 0.1 0.0 0.0 0.1 0.0 0.0 MAY 2008 Control Smooth Middle Aquarium 100.3 0.7 0.0 0.0 0.0 0.0 0.0 0.0 101.0 MAY 2008 Control Smooth Middle Clay 98.7 1.3 0.0 0.0 0.0 0.0 0.0 0.0 100.0 MAY 2008 Control Smooth Middle Vine 98.0 2.0 0.0 0.0 0.0 0.1 0.0 0.0 100.1 MAY 2008 Control Smooth Middle Average 99.0 1.3 0.0 0.0 0.0 0.0 0.0 0.0 100.4 MAY 2008 Control Smooth Middle SE 1.5 1.3 0.0 0.0 0.0 0.1 0.0 0.0 MAY 2008 Control Smooth Lower Aquarium 93.3 6.7 0.0 0.0 0.0 0.1 0.0 0.0 100.1 MAY 2008 Control Smooth Lower Clay 99.3 0.7 0.2 0.0 0.0 0.0 0.0 0.0 100.2 MAY 2008 Control Smooth Lower Vine 75.3 1.3 0.0 0.0 23.3 0.0 0.0 0.0 100.0 MAY 2008 Control Smooth Lower Average 89.3 2.9 0.1 0.0 7.8 0.0 0.0 0.0 100.1 MAY 2008 Control Smooth Lower SE 13.0 1.8 0.1 0.0 13.5 0.0 0.0 0.0 71

MAY 2008 Flat Smooth Upper Aquarium 98.0 2.0 0.0 0.0 0.0 0.0 0.0 0.0 100.0 MAY 2008 Flat Smooth Upper Clay 102.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 102.0 MAY 2008 Flat Smooth Upper Vine 86.7 13.3 0.0 0.0 0.0 0.2 0.0 0.0 100.2 MAY 2008 Flat Smooth Upper Average 95.6 5.1 0.0 0.0 0.0 0.1 0.0 0.0 100.7 MAY 2008 Flat Smooth Upper SE 5.9 5.6 0.0 0.0 0.0 0.1 0.0 0.0 MAY 2008 Flat Smooth Middle Aquarium 99.3 0.7 0.0 0.0 0.0 0.0 0.0 0.0 100.0 MAY 2008 Flat Smooth Middle Clay 100.0 0.0 0.5 0.0 0.0 0.0 0.0 0.0 100.5 MAY 2008 Flat Smooth Middle Vine 98.0 2.0 0.0 0.0 0.0 0.0 0.0 0.0 100.0 MAY 2008 Flat Smooth Middle Average 99.1 0.9 0.2 0.0 0.0 0.0 0.0 0.0 100.2 MAY 2008 Flat Smooth Middle SE 0.8 0.8 0.1 0.0 0.0 0.0 0.0 0.0 MAY 2008 Flat Smooth Lower Aquarium 98.7 1.3 0.0 0.0 0.0 0.0 0.0 0.0 100.0 MAY 2008 Flat Smooth Lower Clay 99.3 0.0 0.2 0.0 0.0 0.0 0.0 0.0 99.5 MAY 2008 Flat Smooth Lower Vine 23.3 0.0 0.0 0.0 76.7 0.0 0.0 0.0 100.0 MAY 2008 Flat Smooth Lower Average 73.8 0.4 0.1 0.0 25.6 0.0 0.0 0.0 99.8 MAY 2008 Flat Smooth Lower SE 22.1 0.8 0.1 0.0 22.4 0.0 0.0 0.0 MAY 2008 Flat Cobble Upper Aquarium 96.0 4.3 0.0 0.0 0.0 0.2 0.0 0.0 100.5 MAY 2008 Flat Cobble Upper Clay 34.7 65.3 0.0 0.0 0.0 0.0 0.0 0.0 100.0 MAY 2008 Flat Cobble Upper Vine 66.7 33.3 0.0 0.0 0.0 0.0 0.0 0.0 100.0 MAY 2008 Flat Cobble Upper Average 65.8 34.3 0.0 0.0 0.0 0.1 0.0 0.0 100.2 MAY 2008 Flat Cobble Upper SE 17.6 17.5 0.0 0.0 0.0 0.1 0.0 0.0 MAY 2008 Flat Cobble Middle Aquarium 95.7 4.3 0.0 0.0 0.0 0.0 0.0 0.0 100.0 MAY 2008 Flat Cobble Middle Clay 84.7 15.7 0.2 0.0 0.0 0.0 0.0 0.0 100.5 MAY 2008 Flat Cobble Middle Vine 88.0 12.0 0.2 0.0 0.0 0.0 0.0 0.0 100.2 MAY 2008 Flat Cobble Middle Average 89.4 10.7 0.1 0.0 0.0 0.0 0.0 0.0 100.2 MAY 2008 Flat Cobble Middle SE 5.7 5.7 0.1 0.0 0.0 0.0 0.0 0.0 MAY 2008 Flat Cobble Lower Aquarium 98.7 1.3 0.0 0.0 0.0 0.0 0.0 0.0 100.0 MAY 2008 Flat Cobble Lower Clay 94.7 5.3 0.3 0.0 0.0 0.0 0.0 0.0 100.3 MAY 2008 Flat Cobble Lower Vine 100.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 100.0 MAY 2008 Flat Cobble Lower Average 97.8 2.2 0.1 0.0 0.0 0.0 0.0 0.0 100.1 MAY 2008 Flat Cobble Lower SE 2.0 2.0 0.1 0.0 0.0 0.0 0.0 0.0 MAY 2008 Step Smooth Upper Aquarium 98.0 2.0 0.0 0.0 0.0 0.0 0.0 0.0 100.0 MAY 2008 Step Smooth Upper Clay 92.7 7.3 0.0 0.0 0.0 0.0 0.0 0.0 100.0 MAY 2008 Step Smooth Upper Vine 91.3 8.7 0.0 0.0 0.0 0.0 0.0 0.0 100.0 MAY 2008 Step Smooth Upper Average 94.0 6.0 0.0 0.0 0.0 0.0 0.0 0.0 100.0 MAY 2008 Step Smooth Upper SE 3.2 3.2 0.0 0.0 0.0 0.0 0.0 0.0 MAY 2008 Step Smooth Middle Aquarium 100.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 100.0 MAY 2008 Step Smooth Middle Clay 100.7 0.0 0.0 0.0 0.0 0.0 0.0 0.0 100.7 MAY 2008 Step Smooth Middle Vine 86.7 12.7 0.7 0.0 0.0 0.0 0.0 0.0 100.0 MAY 2008 Step Smooth Middle Average 95.8 4.2 0.2 0.0 0.0 0.0 0.0 0.0 100.2 MAY 2008 Step Smooth Middle SE 7.8 7.3 0.4 0.0 0.0 0.0 0.0 0.0 MAY 2008 Step Smooth Lower Aquarium 100.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 100.0

MAY 2008 Step Smooth Lower Clay 100.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 100.0 MAY 2008 Step Smooth Lower Vine 87.3 6.7 0.2 0.0 6.7 0.0 0.0 0.0 100.8 MAY 2008 Step Smooth Lower Average 95.8 2.2 0.1 0.0 2.2 0.0 0.0 0.0 100.3 MAY 2008 Step Smooth Lower SE 5.0 3.8 0.1 0.0 3.8 0.0 0.0 0.0 MAY 2008 Step Cobble Upper Aquarium 100.3 0.0 0.0 0.0 0.0 0.0 0.0 0.0 100.3 MAY 2008 Step Cobble Upper Vine 84.0 16.0 0.0 0.0 0.0 0.0 0.0 0.0 100.0 MAY 2008 Step Cobble Upper Average 92.2 8.0 0.0 0.0 0.0 0.0 0.0 0.0 100.2 MAY 2008 Step Cobble Upper SE 6.4 6.3 0.0 0.0 0.0 0.0 0.0 0.0 MAY 2008 Step Cobble Middle Aquarium 100.7 0.0 0.2 0.0 0.0 0.0 0.0 0.0 100.8 MAY 2008 Step Cobble Middle Clay 92.0 8.0 0.0 0.0 0.0 0.0 0.0 0.0 100.0 MAY 2008 Step Cobble Middle Vine 87.0 13.3 0.7 0.0 0.0 0.0 0.0 0.0 101.0 MAY 2008 Step Cobble Middle Average 93.2 7.1 0.3 0.0 0.0 0.0 0.0 0.0 100.6 MAY 2008 Step Cobble Middle SE 8.2 8.1 0.2 0.0 0.0 0.0 0.0 0.0 MAY 2008 Step Cobble Lower Aquarium 100.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 100.0 MAY 2008 Step Cobble Lower Clay 100.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 100.0 MAY 2008 Step Cobble Lower Vine 99.7 0.0 0.3 0.0 0.0 0.0 0.0 0.0 100.0 MAY 2008 Step Cobble Lower Average 99.9 0.0 0.1 0.0 0.0 0.0 0.0 0.0 100.0 MAY 2008 Step Cobble Lower SE 0.2 0.0 0.2 0.0 0.0 0.0 0.0 0.0 MAY 2008 Fin Smooth Upper Aquarium 97.3 2.7 0.0 0.0 0.0 0.1 0.0 0.0 100.1 MAY 2008 Fin Smooth Upper Clay 100.7 0.0 0.0 0.0 0.0 0.0 0.0 0.0 100.7 MAY 2008 Fin Smooth Upper Vine 96.7 3.3 0.0 0.0 0.0 0.0 0.0 0.0 100.0 MAY 2008 Fin Smooth Upper Average 98.2 2.0 0.0 0.0 0.0 0.0 0.0 0.0 100.3 MAY 2008 Fin Smooth Upper SE 2.4 2.3 0.0 0.0 0.0 0.1 0.0 0.0 MAY 2008 Fin Smooth Middle Aquarium 76.0 24.0 0.0 0.0 0.0 0.0 0.0 0.0 100.0 MAY 2008 Fin Smooth Middle Clay 100.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 100.0 MAY 2008 Fin Smooth Middle Vine 99.3 0.0 0.7 0.0 0.0 0.0 0.0 0.0 100.0 MAY 2008 Fin Smooth Middle Average 91.8 8.0 0.2 0.0 0.0 0.0 0.0 0.0 100.0 MAY 2008 Fin Smooth Middle SE 13.8 13.9 0.4 0.0 0.0 0.0 0.0 0.0 MAY 2008 Fin Smooth Lower Aquarium 70.0 0.0 0.0 0.0 30.0 0.0 0.0 0.0 100.0 MAY 2008 Fin Smooth Lower Clay 100.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 100.0 MAY 2008 Fin Smooth Lower Vine 89.0 0.0 0.0 0.0 13.3 0.0 0.0 0.0 102.3 MAY 2008 Fin Smooth Lower Average 86.3 0.0 0.0 0.0 14.4 0.0 0.0 0.0 100.8 MAY 2008 Fin Smooth Lower SE 17.2 0.0 0.0 0.0 17.1 0.0 0.0 0.0 MAY 2008 Fin Cobble Upper Aquarium 59.3 40.7 0.0 0.0 0.0 0.0 0.0 0.0 100.0 MAY 2008 Fin Cobble Upper Clay 47.3 52.7 0.0 0.0 0.0 0.0 0.0 0.0 100.0 MAY 2008 Fin Cobble Upper Vine 100.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 100.0 MAY 2008 Fin Cobble Upper Average 68.9 31.1 0.0 0.0 0.0 0.0 0.0 0.0 100.0 MAY 2008 Fin Cobble Upper SE 21.7 21.7 0.0 0.0 0.0 0.0 0.0 0.0 MAY 2008 Fin Cobble Middle Aquarium 97.3 2.7 0.0 0.0 0.0 0.0 0.0 0.0 100.0 MAY 2008 Fin Cobble Middle Clay 80.3 19.7 0.0 0.0 0.0 0.0 0.0 0.0 100.0 MAY 2008 Fin Cobble Middle Vine 93.3 6.7 0.3 0.0 0.0 0.0 0.0 0.0 100.3

MAY 2008 Fin Cobble Middle Average 90.3 9.7 0.1 0.0 0.0 0.0 0.0 0.0 100.1 MAY 2008 Fin Cobble Middle SE 11.3 11.3 0.2 0.0 0.0 0.0 0.0 0.0 MAY 2008 Fin Cobble Lower Aquarium 73.3 7.3 0.2 0.0 20.0 0.0 0.0 0.0 100.8 MAY 2008 Fin Cobble Lower Clay 86.7 13.3 0.0 0.0 0.0 0.0 0.0 0.0 100.0 MAY 2008 Fin Cobble Lower Vine 98.7 1.3 0.0 0.0 0.0 0.0 0.0 0.0 100.0 MAY 2008 Fin Cobble Lower Average 86.2 7.3 0.1 0.0 6.7 0.0 0.0 0.0 100.3 MAY 2008 Fin Cobble Lower SE 12.9 5.0 0.1 0.0 11.5 0.0 0.0 0.0 JUNE 2008 Reference Smooth Upper Aquarium 45.0 29.3 14.7 0.0 10.0 1.6 0.7 0.0 101.3 JUNE 2008 Reference Smooth Upper Clay 21.3 43.3 13.3 0.0 20.0 2.0 0.2 0.0 100.2 JUNE 2008 Reference Smooth Upper Vine 16.7 40.3 25.7 0.0 16.7 4.0 0.2 0.0 103.5 JUNE 2008 Reference Smooth Upper Average 27.7 37.7 17.9 0.0 15.6 2.5 0.3 0.0 101.6 JUNE 2008 Reference Smooth Upper SE 17.6 12.0 5.4 0.0 4.0 1.5 0.3 0.0 JUNE 2008 Reference Smooth Middle Aquarium 87.0 2.7 10.7 0.0 0.0 0.9 0.3 0.0 101.5 JUNE 2008 Reference Smooth Middle Clay 71.0 7.3 7.3 0.0 16.0 0.3 0.0 0.0 102.0 JUNE 2008 Reference Smooth Middle Vine 94.7 2.7 4.0 0.0 0.0 0.3 0.0 0.0 101.7 JUNE 2008 Reference Smooth Middle Average 84.2 4.2 7.3 0.0 5.3 0.5 0.1 0.0 101.7 JUNE 2008 Reference Smooth Middle SE 8.8 4.0 2.1 0.0 5.0 0.3 0.1 0.0 JUNE 2008 Reference Smooth Lower Aquarium 95.7 1.7 2.7 0.0 1.3 0.5 0.2 0.0 102.0 JUNE 2008 Reference Smooth Lower Clay 77.3 12.0 10.7 0.0 0.0 0.0 0.0 0.0 100.0 JUNE 2008 Reference Smooth Lower Vine 92.7 6.0 3.3 0.0 1.3 0.3 0.0 0.0 103.7 JUNE 2008 Reference Smooth Lower Average 88.6 6.6 5.6 0.0 0.9 0.3 0.1 0.0 101.9 JUNE 2008 Reference Smooth Lower SE 5.5 4.3 2.6 0.0 0.8 0.2 0.1 0.0 JUNE 2008 Control Smooth Upper Aquarium 72.3 27.0 0.8 0.0 0.0 2.0 0.0 0.0 102.2 JUNE 2008 Control Smooth Upper Clay 72.0 28.0 0.0 0.0 0.0 0.0 0.0 0.0 100.0 JUNE 2008 Control Smooth Upper Vine 77.7 22.3 0.0 0.0 0.0 2.7 0.0 0.0 102.7 JUNE 2008 Control Smooth Upper Average 74.0 25.8 0.3 0.0 0.0 1.6 0.0 0.0 101.6 JUNE 2008 Control Smooth Upper SE 10.2 10.2 0.3 0.0 0.0 1.6 0.0 0.0 JUNE 2008 Control Smooth Middle Aquarium 83.0 16.7 0.5 0.0 0.0 1.0 0.0 0.0 101.2 JUNE 2008 Control Smooth Middle Clay 99.3 0.7 0.0 0.0 0.0 0.0 0.0 0.0 100.0 JUNE 2008 Control Smooth Middle Vine 92.0 8.0 0.0 0.0 0.0 0.0 0.0 0.0 100.0 JUNE 2008 Control Smooth Middle Average 91.4 8.4 0.2 0.0 0.0 0.3 0.0 0.0 100.4 JUNE 2008 Control Smooth Middle SE 9.3 9.1 0.2 0.0 0.0 0.6 0.0 0.0 JUNE 2008 Control Smooth Lower Aquarium 96.7 3.3 0.3 0.0 0.0 1.3 0.0 0.0 101.7 JUNE 2008 Control Smooth Lower Clay 100.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 100.0 JUNE 2008 Control Smooth Lower Vine 100.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 100.0 JUNE 2008 Control Smooth Lower Average 98.9 1.1 0.1 0.0 0.0 0.4 0.0 0.0 100.6 JUNE 2008 Control Smooth Lower SE 1.3 1.3 0.1 0.0 0.0 0.6 0.0 0.0 JUNE 2008 Flat Smooth Upper Aquarium 96.0 4.0 0.0 0.0 0.0 0.0 0.0 0.0 100.0 JUNE 2008 Flat Smooth Upper Clay 68.7 0.0 0.0 0.0 31.3 0.0 0.0 0.0 100.0 JUNE 2008 Flat Smooth Upper Vine 100.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 100.0 JUNE 2008 Flat Smooth Upper Average 88.2 1.3 0.0 0.0 10.4 0.0 0.0 0.0 100.0

JUNE 2008 Flat Smooth Upper SE 11.1 1.5 0.0 0.0 11.4 0.0 0.0 0.0 JUNE 2008 Flat Smooth Middle Aquarium 96.0 34.0 0.5 0.0 0.0 0.0 0.0 0.0 130.5 JUNE 2008 Flat Smooth Middle Clay 86.7 13.0 0.5 0.0 0.3 0.0 0.0 0.0 100.5 JUNE 2008 Flat Smooth Middle Vine 97.3 2.7 0.3 0.0 0.0 0.0 0.0 0.0 100.3 JUNE 2008 Flat Smooth Middle Average 93.3 16.6 0.4 0.0 0.1 0.0 0.0 0.0 110.4 JUNE 2008 Flat Smooth Middle SE 7.4 19.1 0.2 0.0 0.2 0.0 0.0 0.0 JUNE 2008 Flat Smooth Lower Aquarium 90.0 10.0 0.3 0.0 0.0 0.2 0.0 0.0 100.5 JUNE 2008 Flat Smooth Lower Clay 100.0 0.0 0.5 0.0 0.0 0.0 0.0 0.0 100.5 JUNE 2008 Flat Smooth Lower Vine 100.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 100.0 JUNE 2008 Flat Smooth Lower Average 96.7 3.3 0.3 0.0 0.0 0.1 0.0 0.0 100.3 JUNE 2008 Flat Smooth Lower SE 5.8 5.8 0.2 0.0 0.0 0.1 0.0 0.0 JUNE 2008 Flat Cobble Upper Aquarium 79.0 21.0 0.3 0.0 0.0 0.2 0.0 0.0 100.6 JUNE 2008 Flat Cobble Upper Clay 76.7 23.0 0.2 0.0 0.3 0.0 0.0 0.0 100.2 JUNE 2008 Flat Cobble Upper Vine 88.0 12.0 0.0 0.0 0.0 0.0 0.0 0.0 100.0 JUNE 2008 Flat Cobble Upper Average 81.2 18.7 0.2 0.0 0.1 0.1 0.0 0.0 100.2 JUNE 2008 Flat Cobble Upper SE 7.8 7.7 0.1 0.0 0.2 0.1 0.0 0.0 JUNE 2008 Flat Cobble Middle Aquarium 91.3 8.7 0.5 0.0 0.0 0.0 0.0 0.0 100.5 JUNE 2008 Flat Cobble Middle Clay 92.0 8.0 0.5 0.0 0.0 0.0 0.0 0.0 100.5 JUNE 2008 Flat Cobble Middle Vine 88.0 11.3 0.8 0.0 0.0 0.0 0.0 0.0 100.2 JUNE 2008 Flat Cobble Middle Average 90.4 9.3 0.6 0.0 0.0 0.0 0.0 0.0 100.4 JUNE 2008 Flat Cobble Middle SE 3.4 3.3 0.1 0.0 0.0 0.0 0.0 0.0 JUNE 2008 Flat Cobble Lower Aquarium 88.0 12.0 0.7 0.0 0.0 0.0 0.0 0.0 100.7 JUNE 2008 Flat Cobble Lower Clay 98.7 0.0 1.5 0.0 0.0 0.0 0.0 0.0 100.2 JUNE 2008 Flat Cobble Lower Vine 96.7 3.3 0.3 0.0 0.0 0.3 0.0 0.0 100.7 JUNE 2008 Flat Cobble Lower Average 94.4 5.1 0.8 0.0 0.0 0.1 0.0 0.0 100.5 JUNE 2008 Flat Cobble Lower SE 3.5 3.7 0.4 0.0 0.0 0.2 0.0 0.0 JUNE 2008 Step Smooth Upper Aquarium 98.0 2.0 0.0 0.0 0.0 0.0 0.0 0.0 100.0 JUNE 2008 Step Smooth Upper Clay 78.0 0.0 0.0 0.0 22.0 0.0 0.0 0.0 100.0 JUNE 2008 Step Smooth Upper Vine 96.7 3.3 0.0 0.0 0.0 0.0 0.0 0.0 100.0 JUNE 2008 Step Smooth Upper Average 90.9 1.8 0.0 0.0 7.3 0.0 0.0 0.0 100.0 JUNE 2008 Step Smooth Upper SE 10.4 1.6 0.0 0.0 10.7 0.0 0.0 0.0 JUNE 2008 Step Smooth Middle Aquarium 98.7 1.3 0.0 0.0 0.0 0.0 0.0 0.0 100.0 JUNE 2008 Step Smooth Middle Clay 98.3 1.3 0.3 0.0 0.0 0.0 0.0 0.0 100.0 JUNE 2008 Step Smooth Middle Vine 99.3 0.3 0.3 0.0 0.0 0.0 0.0 0.0 100.0 JUNE 2008 Step Smooth Middle Average 98.8 1.0 0.2 0.0 0.0 0.0 0.0 0.0 100.0 JUNE 2008 Step Smooth Middle SE 0.8 0.8 0.3 0.0 0.0 0.0 0.0 0.0 JUNE 2008 Step Smooth Lower Aquarium 100.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 100.0 JUNE 2008 Step Smooth Lower Clay 97.0 2.7 0.7 0.0 0.0 0.0 0.0 0.0 100.3 JUNE 2008 Step Smooth Lower Vine 98.7 1.3 0.2 0.0 0.0 0.0 0.0 0.0 100.2 JUNE 2008 Step Smooth Lower Average 98.6 1.3 0.3 0.0 0.0 0.0 0.0 0.0 100.2 JUNE 2008 Step Smooth Lower SE 1.6 1.6 0.2 0.0 0.0 0.0 0.0 0.0

JUNE 2008 Step Cobble Upper Aquarium 98.0 2.0 0.0 0.0 0.0 0.0 0.0 0.0 100.0 JUNE 2008 Step Cobble Upper Clay 58.0 42.0 0.3 0.0 0.0 0.0 0.0 0.0 100.3 JUNE 2008 Step Cobble Upper Vine 90.0 10.0 0.0 0.0 0.0 0.0 0.0 0.0 100.0 JUNE 2008 Step Cobble Upper Average 82.0 18.0 0.1 0.0 0.0 0.0 0.0 0.0 100.1 JUNE 2008 Step Cobble Upper SE 11.6 11.6 0.2 0.0 0.0 0.0 0.0 0.0 JUNE 2008 Step Cobble Middle Aquarium 96.0 4.0 0.3 0.0 0.0 0.0 0.0 0.0 100.3 JUNE 2008 Step Cobble Middle Clay 93.3 6.7 0.5 0.0 0.0 0.0 0.0 0.0 100.5 JUNE 2008 Step Cobble Middle Vine 100.0 0.0 0.3 0.0 0.0 0.0 0.0 0.0 100.3 JUNE 2008 Step Cobble Middle Average 96.4 3.6 0.4 0.0 0.0 0.0 0.0 0.0 100.4 JUNE 2008 Step Cobble Middle SE 2.4 2.4 0.1 0.0 0.0 0.0 0.0 0.0 JUNE 2008 Step Cobble Lower Aquarium 84.0 16.0 0.7 0.0 0.0 0.0 0.0 0.0 100.7 JUNE 2008 Step Cobble Lower Clay 100.0 0.0 0.8 0.0 0.0 0.0 0.0 0.0 100.8 JUNE 2008 Step Cobble Lower Vine 99.3 0.0 0.7 0.0 0.0 0.0 0.0 0.0 100.0 JUNE 2008 Step Cobble Lower Average 94.4 5.3 0.7 0.0 0.0 0.0 0.0 0.0 100.5 JUNE 2008 Step Cobble Lower SE 7.5 7.6 0.4 0.0 0.0 0.0 0.0 0.0 JUNE 2008 Fin Smooth Upper Aquarium 93.3 6.7 0.0 0.0 0.0 0.0 0.0 0.0 100.0 JUNE 2008 Fin Smooth Upper Clay 60.7 0.0 0.0 0.0 39.3 0.0 0.0 0.0 100.0 JUNE 2008 Fin Smooth Upper Vine 95.3 4.7 0.0 0.0 0.0 0.0 0.0 0.0 100.0 JUNE 2008 Fin Smooth Upper Average 83.1 3.8 0.0 0.0 13.1 0.0 0.0 0.0 100.0 JUNE 2008 Fin Smooth Upper SE 16.3 2.8 0.0 0.0 17.2 0.0 0.0 0.0 JUNE 2008 Fin Smooth Middle Aquarium 100.0 0.0 0.2 0.0 0.0 0.0 0.0 0.0 100.2 JUNE 2008 Fin Smooth Middle Clay 100.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 100.0 JUNE 2008 Fin Smooth Middle Vine 96.7 0.0 0.2 0.0 3.3 0.0 0.0 0.0 100.2 JUNE 2008 Fin Smooth Middle Average 98.9 0.0 0.1 0.0 1.1 0.0 0.0 0.0 100.1 JUNE 2008 Fin Smooth Middle SE 1.9 0.0 0.1 0.0 1.9 0.0 0.0 0.0 JUNE 2008 Fin Smooth Lower Aquarium 100.0 0.0 0.2 0.0 0.0 0.0 0.0 0.0 100.2 JUNE 2008 Fin Smooth Lower Clay 100.0 0.0 0.3 0.0 0.0 0.0 0.0 0.0 100.3 JUNE 2008 Fin Smooth Lower Vine 80.7 0.0 0.0 0.0 19.3 0.0 0.0 0.0 100.0 JUNE 2008 Fin Smooth Lower Average 93.6 0.0 0.2 0.0 6.4 0.0 0.0 0.0 100.2 JUNE 2008 Fin Smooth Lower SE 11.2 0.0 0.2 0.0 11.2 0.0 0.0 0.0 JUNE 2008 Fin Cobble Upper Aquarium 78.0 22.0 0.0 0.0 0.0 0.0 0.0 0.0 100.0 JUNE 2008 Fin Cobble Upper Clay 74.7 25.3 0.0 0.0 0.0 0.0 0.0 0.0 100.0 JUNE 2008 Fin Cobble Upper Vine 98.0 2.0 0.2 0.0 0.0 0.0 0.0 0.0 100.2 JUNE 2008 Fin Cobble Upper Average 83.6 16.4 0.1 0.0 0.0 0.0 0.0 0.0 100.1 JUNE 2008 Fin Cobble Upper SE 15.2 15.2 0.1 0.0 0.0 0.0 0.0 0.0 JUNE 2008 Fin Cobble Middle Aquarium 100.0 0.0 0.5 0.0 0.0 0.0 0.0 0.0 100.5 JUNE 2008 Fin Cobble Middle Clay 99.7 0.0 0.5 0.0 0.0 0.0 0.0 0.0 100.2 JUNE 2008 Fin Cobble Middle Vine 100.0 0.0 0.3 0.0 0.0 0.0 0.0 0.0 100.3 JUNE 2008 Fin Cobble Middle Average 99.9 0.0 0.4 0.0 0.0 0.0 0.0 0.0 100.3 JUNE 2008 Fin Cobble Middle SE 0.2 0.0 0.2 0.0 0.0 0.0 0.0 0.0 JUNE 2008 Fin Cobble Lower Aquarium 73.0 0.0 0.7 0.0 26.7 0.0 0.0 0.0 100.3

JUNE 2008 Fin Cobble Lower Clay 100.0 0.0 0.8 0.0 0.0 0.0 0.0 0.0 100.8 JUNE 2008 Fin Cobble Lower Vine 73.3 0.0 0.2 0.0 26.7 0.0 0.0 0.0 100.2 JUNE 2008 Fin Cobble Lower Average 82.1 0.0 0.6 0.0 17.8 0.0 0.0 0.0 100.4 JUNE 2008 Fin Cobble Lower SE 20.2 0.0 0.3 0.0 20.4 0.0 0.0 0.0 JULY 2008 Reference Smooth Upper Aquarium 42.7 34.0 21.3 0.0 2.0 1.1 0.3 0.0 101.5 JULY 2008 Reference Smooth Upper Clay 36.0 40.0 16.7 0.0 6.7 1.3 0.0 0.0 100.6 JULY 2008 Reference Smooth Upper Vine 37.3 44.7 13.0 0.0 4.0 2.3 0.8 0.0 102.2 JULY 2008 Reference Smooth Upper Average 38.7 39.6 17.0 0.0 4.2 1.6 0.4 0.0 101.4 JULY 2008 Reference Smooth Upper SE 13.9 12.9 2.5 0.0 1.9 0.5 0.2 0.0 JULY 2008 Reference Smooth Middle Aquarium 68.0 18.7 13.3 0.0 0.0 0.7 0.0 0.0 100.7 JULY 2008 Reference Smooth Middle Clay 18.7 62.7 18.3 0.0 0.0 0.9 0.0 0.0 100.6 JULY 2008 Reference Smooth Middle Vine 87.7 2.0 10.3 0.0 0.0 0.8 0.3 0.0 101.1 JULY 2008 Reference Smooth Middle Average 58.1 27.8 14.0 0.0 0.0 0.8 0.1 0.0 100.8 JULY 2008 Reference Smooth Middle SE 18.8 16.4 3.9 0.0 0.0 0.2 0.1 0.0 JULY 2008 Reference Smooth Lower Aquarium 80.3 17.0 2.7 0.0 0.0 0.6 0.0 0.0 100.6 JULY 2008 Reference Smooth Lower Clay 45.3 47.3 7.5 0.0 0.0 0.5 0.0 0.0 100.6 JULY 2008 Reference Smooth Lower Vine 93.0 6.0 1.2 0.0 0.0 0.1 0.0 0.0 100.3 JULY 2008 Reference Smooth Lower Average 72.9 23.4 3.8 0.0 0.0 0.4 0.0 0.0 100.5 JULY 2008 Reference Smooth Lower SE 15.4 13.7 1.8 0.0 0.0 0.2 0.0 0.0 JULY 2008 Control Smooth Upper Aquarium 89.7 4.3 6.0 0.0 0.0 0.2 0.0 0.0 100.2 JULY 2008 Control Smooth Upper Clay 55.0 39.0 6.0 0.0 0.0 0.5 0.0 0.0 100.5 JULY 2008 Control Smooth Upper Vine 45.0 44.0 11.0 0.0 0.0 0.2 0.0 0.0 100.2 JULY 2008 Control Smooth Upper Average 63.2 29.1 7.7 0.0 0.0 0.3 0.0 0.0 100.3 JULY 2008 Control Smooth Upper SE 21.1 19.2 3.8 0.0 0.0 0.2 0.0 0.0 JULY 2008 Control Smooth Middle Aquarium 78.3 17.7 4.0 0.0 0.0 0.2 0.0 0.0 100.2 JULY 2008 Control Smooth Middle Clay 99.3 0.0 0.8 0.0 0.0 0.0 0.0 0.0 100.2 JULY 2008 Control Smooth Middle Vine 100.0 0.0 0.2 0.0 0.0 0.0 0.0 0.0 100.2 JULY 2008 Control Smooth Middle Average 92.6 5.9 1.7 0.0 0.0 0.1 0.0 0.0 100.2 JULY 2008 Control Smooth Middle SE 9.4 8.3 1.2 0.0 0.0 0.1 0.0 0.0 JULY 2008 Control Smooth Lower Aquarium 93.7 4.0 2.0 0.0 0.0 0.2 0.0 0.0 99.8 JULY 2008 Control Smooth Lower Clay 93.3 6.7 0.2 0.0 0.0 0.0 0.0 0.0 100.2 JULY 2008 Control Smooth Lower Vine 94.0 0.7 0.0 0.0 5.3 0.0 0.0 0.0 100.0 JULY 2008 Control Smooth Lower Average 93.7 3.8 0.7 0.0 1.8 0.1 0.0 0.0 100.0 JULY 2008 Control Smooth Lower SE 3.9 3.4 0.6 0.0 3.1 0.0 0.0 0.0 JULY 2008 Flat Smooth Upper Aquarium 88.3 0.0 9.3 0.0 2.3 0.0 0.0 0.0 100.0 JULY 2008 Flat Smooth Upper Clay 52.0 24.0 16.7 0.0 6.7 0.0 0.0 0.0 99.4 JULY 2008 Flat Smooth Upper Vine 90.7 6.0 3.3 0.0 0.0 0.0 0.0 0.0 100.0 JULY 2008 Flat Smooth Upper Average 77.0 10.0 9.8 0.0 3.0 0.0 0.0 0.0 99.8 JULY 2008 Flat Smooth Upper SE 12.8 9.3 4.5 0.0 2.3 0.0 0.0 0.0 JULY 2008 Flat Smooth Middle Aquarium 95.3 0.0 4.8 0.0 0.0 0.0 0.0 0.0 100.2 JULY 2008 Flat Smooth Middle Clay 36.7 29.3 34.7 0.0 0.0 0.0 0.0 0.0 100.7

JULY 2008 Flat Smooth Middle Vine 81.3 0.0 18.7 0.0 0.0 0.0 0.0 0.0 100.0 JULY 2008 Flat Smooth Middle Average 71.1 9.8 19.4 0.0 0.0 0.0 0.0 0.0 100.3 JULY 2008 Flat Smooth Middle SE 15.7 9.1 8.0 0.0 0.0 0.0 0.0 0.0 JULY 2008 Flat Smooth Lower Aquarium 98.7 1.3 0.5 0.0 0.0 0.0 0.0 0.0 100.5 JULY 2008 Flat Smooth Lower Clay 88.0 0.0 12.0 0.0 0.0 0.0 0.0 0.0 100.0 JULY 2008 Flat Smooth Lower Vine 97.7 0.0 2.3 0.0 0.0 0.0 0.0 0.0 100.0 JULY 2008 Flat Smooth Lower Average 94.8 0.4 4.9 0.0 0.0 0.0 0.0 0.0 100.2 JULY 2008 Flat Smooth Lower SE 3.6 0.5 3.8 0.0 0.0 0.0 0.0 0.0 JULY 2008 Flat Cobble Upper Aquarium 76.7 3.3 10.7 0.0 9.3 0.1 0.0 0.0 100.1 JULY 2008 Flat Cobble Upper Clay 80.0 0.0 9.3 0.0 10.7 0.0 0.0 0.0 100.0 JULY 2008 Flat Cobble Upper Vine 78.7 0.0 21.3 0.0 0.0 0.0 0.0 0.0 100.0 JULY 2008 Flat Cobble Upper Average 78.4 1.1 13.8 0.0 6.7 0.0 0.0 0.0 100.0 JULY 2008 Flat Cobble Upper SE 5.5 1.9 6.3 0.0 5.0 0.1 0.0 0.0 JULY 2008 Flat Cobble Middle Aquarium 59.3 0.0 40.0 0.0 0.0 0.0 0.0 0.0 99.3 JULY 2008 Flat Cobble Middle Clay 71.0 5.7 22.7 0.0 0.7 0.0 0.0 0.0 100.0 JULY 2008 Flat Cobble Middle Vine 75.3 0.0 24.7 0.0 0.0 0.0 0.0 0.0 100.0 JULY 2008 Flat Cobble Middle Average 68.6 1.9 29.1 0.0 0.2 0.0 0.0 0.0 99.8 JULY 2008 Flat Cobble Middle SE 5.2 2.9 5.0 0.0 0.4 0.0 0.0 0.0 JULY 2008 Flat Cobble Lower Aquarium 81.3 0.0 15.3 0.0 3.3 0.0 0.0 0.0 100.0 JULY 2008 Flat Cobble Lower Clay 61.3 0.0 38.7 0.0 0.0 0.0 0.0 0.0 100.0 JULY 2008 Flat Cobble Lower Vine 80.0 0.0 1.8 0.0 18.3 0.0 0.0 0.0 100.2 JULY 2008 Flat Cobble Lower Average 74.2 0.0 18.6 0.0 7.2 0.0 0.0 0.0 100.1 JULY 2008 Flat Cobble Lower SE 9.9 0.0 11.6 0.0 7.5 0.0 0.0 0.0 JULY 2008 Step Smooth Upper Aquarium 98.0 0.0 0.3 0.0 1.3 0.0 0.0 0.0 99.7 JULY 2008 Step Smooth Upper Clay 86.7 10.7 2.7 0.0 0.0 0.0 0.0 0.0 100.0 JULY 2008 Step Smooth Upper Vine 91.3 8.7 0.5 0.0 0.0 0.0 0.0 0.0 100.5 JULY 2008 Step Smooth Upper Average 92.0 6.4 1.2 0.0 0.4 0.0 0.0 0.0 100.1 JULY 2008 Step Smooth Upper SE 6.3 5.6 1.1 0.0 0.8 0.0 0.0 0.0 JULY 2008 Step Smooth Middle Aquarium 96.0 0.0 4.2 0.0 0.0 0.0 0.0 0.0 100.2 JULY 2008 Step Smooth Middle Clay 62.0 20.7 17.3 0.0 0.0 0.0 0.0 0.0 100.0 JULY 2008 Step Smooth Middle Vine 74.7 1.3 24.0 0.0 0.0 0.0 0.0 0.0 100.0 JULY 2008 Step Smooth Middle Average 77.6 7.3 15.2 0.0 0.0 0.0 0.0 0.0 100.1 JULY 2008 Step Smooth Middle SE 16.9 9.9 8.7 0.0 0.0 0.0 0.0 0.0 JULY 2008 Step Smooth Lower Aquarium 100.0 0.0 0.3 0.0 0.0 0.0 0.0 0.0 100.3 JULY 2008 Step Smooth Lower Clay 90.0 0.0 10.0 0.0 0.0 0.0 0.0 0.0 100.0 JULY 2008 Step Smooth Lower Vine 90.7 0.0 7.0 0.0 2.7 0.0 0.0 0.0 100.3 JULY 2008 Step Smooth Lower Average 93.6 0.0 5.8 0.0 0.9 0.0 0.0 0.0 100.2 JULY 2008 Step Smooth Lower SE 5.3 0.0 5.4 0.0 1.5 0.0 0.0 0.0 JULY 2008 Step Cobble Upper Aquarium 95.3 4.7 0.5 0.0 0.0 0.0 0.0 0.0 100.5 JULY 2008 Step Cobble Upper Clay 77.3 22.3 0.7 0.0 0.0 0.0 0.0 0.0 100.3 JULY 2008 Step Cobble Upper Vine 98.0 2.0 0.5 0.0 0.0 0.0 0.0 0.0 100.5

JULY 2008 Step Cobble Upper Average 90.2 9.7 0.6 0.0 0.0 0.0 0.0 0.0 100.4 JULY 2008 Step Cobble Upper SE 8.2 8.1 0.1 0.0 0.0 0.0 0.0 0.0 JULY 2008 Step Cobble Middle Aquarium 76.7 7.3 16.0 0.0 0.0 0.0 0.0 0.0 100.0 JULY 2008 Step Cobble Middle Clay 60.7 22.7 16.7 0.0 0.0 0.0 0.0 0.0 100.0 JULY 2008 Step Cobble Middle Vine 78.7 0.0 20.0 0.0 1.3 0.0 0.0 0.0 100.0 JULY 2008 Step Cobble Middle Average 72.0 10.0 17.6 0.0 0.4 0.0 0.0 0.0 100.0 JULY 2008 Step Cobble Middle SE 15.3 13.2 6.2 0.0 0.8 0.0 0.0 0.0 JULY 2008 Step Cobble Lower Aquarium 94.0 0.0 6.0 0.0 0.0 0.0 0.0 0.0 100.0 JULY 2008 Step Cobble Lower Clay 79.3 0.0 11.3 0.0 9.3 0.0 0.0 0.0 100.0 JULY 2008 Step Cobble Lower Vine 69.3 18.0 12.7 0.0 0.0 0.0 0.0 0.0 100.0 JULY 2008 Step Cobble Lower Average 80.9 6.0 10.0 0.0 3.1 0.0 0.0 0.0 100.0 JULY 2008 Step Cobble Lower SE 12.9 10.4 5.3 0.0 5.4 0.0 0.0 0.0 JULY 2008 Fin Smooth Upper Aquarium 96.7 1.3 2.2 0.0 0.0 0.0 0.0 0.0 100.2 JULY 2008 Fin Smooth Upper Clay 86.0 0.0 7.5 0.0 6.7 0.0 0.0 0.0 100.2 JULY 2008 Fin Smooth Upper Vine 86.7 0.0 13.3 0.0 0.0 0.0 0.0 0.0 100.0 JULY 2008 Fin Smooth Upper Average 89.8 0.4 7.7 0.0 2.2 0.0 0.0 0.0 100.1 JULY 2008 Fin Smooth Upper SE 4.9 0.8 4.9 0.0 3.8 0.0 0.0 0.0 JULY 2008 Fin Smooth Middle Aquarium 82.7 0.0 17.5 0.0 0.0 0.0 0.0 0.0 100.2 JULY 2008 Fin Smooth Middle Clay 84.7 0.0 15.3 0.0 0.0 0.0 0.0 0.0 100.0 JULY 2008 Fin Smooth Middle Vine 80.0 0.0 13.3 0.0 6.7 0.0 0.0 0.0 100.0 JULY 2008 Fin Smooth Middle Average 82.4 0.0 15.4 0.0 2.2 0.0 0.0 0.0 100.1 JULY 2008 Fin Smooth Middle SE 8.6 0.0 8.8 0.0 3.8 0.0 0.0 0.0 JULY 2008 Fin Smooth Lower Aquarium 77.3 0.0 2.2 0.0 20.7 0.0 0.0 0.0 100.2 JULY 2008 Fin Smooth Lower Clay 74.7 0.0 7.5 0.0 18.0 0.0 0.0 0.0 100.2 JULY 2008 Fin Smooth Lower Vine 60.7 0.0 2.8 0.0 36.7 0.0 0.0 0.0 100.2 JULY 2008 Fin Smooth Lower Average 70.9 0.0 4.2 0.0 25.1 0.0 0.0 0.0 100.2 JULY 2008 Fin Smooth Lower SE 17.5 0.0 2.9 0.0 18.5 0.0 0.0 0.0 JULY 2008 Fin Cobble Upper Aquarium 91.7 0.0 8.3 0.0 0.0 0.0 0.0 0.0 100.0 JULY 2008 Fin Cobble Upper Clay 87.7 3.3 5.7 0.0 3.3 0.0 0.0 0.0 100.0 JULY 2008 Fin Cobble Upper Vine 82.7 0.0 17.3 0.0 0.0 0.0 0.0 0.0 100.0 JULY 2008 Fin Cobble Upper Average 87.3 1.1 10.4 0.0 1.1 0.0 0.0 0.0 100.0 JULY 2008 Fin Cobble Upper SE 7.0 1.9 7.0 0.0 1.9 0.0 0.0 0.0 JULY 2008 Fin Cobble Middle Aquarium 73.3 4.0 22.7 0.0 0.0 0.0 0.0 0.0 100.0 JULY 2008 Fin Cobble Middle Clay 84.0 2.7 13.3 0.0 0.0 0.0 0.0 0.0 100.0 JULY 2008 Fin Cobble Middle Vine 86.0 0.0 14.0 0.0 0.0 0.0 0.0 0.0 100.0 JULY 2008 Fin Cobble Middle Average 81.1 2.2 16.7 0.0 0.0 0.0 0.0 0.0 100.0 JULY 2008 Fin Cobble Middle SE 6.8 2.6 4.8 0.0 0.0 0.0 0.0 0.0 JULY 2008 Fin Cobble Lower Aquarium 52.7 2.0 18.8 0.0 26.7 0.0 0.0 0.0 100.2 JULY 2008 Fin Cobble Lower Clay 90.7 0.0 9.3 0.0 0.0 0.0 0.0 0.0 100.0 JULY 2008 Fin Cobble Lower Vine 61.7 0.0 8.3 0.0 30.0 0.0 0.0 0.0 100.0 JULY 2008 Fin Cobble Lower Average 68.3 0.7 12.2 0.0 18.9 0.0 0.0 0.0 100.1

JULY 2008 Fin Cobble Lower SE 19.0 1.2 7.0 0.0 21.7 0.0 0.0 0.0 AUGUST 2008 Reference Smooth Upper Aquarium 71.0 8.7 12.3 0.0 7.3 0.8 0.2 0.0 100.3 AUGUST 2008 Reference Smooth Upper Clay 41.3 45.0 13.7 0.0 0.0 0.8 0.2 0.0 101.0 AUGUST 2008 Reference Smooth Upper Vine 17.7 57.7 19.3 0.0 6.7 1.0 0.2 0.0 102.5 AUGUST 2008 Reference Smooth Upper Average 43.3 37.1 15.1 0.0 4.7 0.9 0.2 0.0 101.2 AUGUST 2008 Reference Smooth Upper SE 14.8 13.7 2.7 0.0 3.0 0.2 0.1 0.0 AUGUST 2008 Reference Smooth Middle Aquarium 30.0 51.3 17.3 0.0 1.3 1.3 0.0 0.0 101.3 AUGUST 2008 Reference Smooth Middle Clay 13.0 63.3 22.3 0.0 1.3 1.3 0.3 0.0 101.6 AUGUST 2008 Reference Smooth Middle Vine 32.3 47.3 18.3 0.0 2.0 1.0 0.3 0.0 101.3 AUGUST 2008 Reference Smooth Middle Average 25.1 54.0 19.3 0.0 1.6 1.2 0.2 0.0 101.4 AUGUST 2008 Reference Smooth Middle SE 8.0 6.9 2.9 0.0 0.8 0.2 0.2 0.0 AUGUST 2008 Reference Smooth Lower Aquarium 89.0 5.0 5.0 0.0 1.0 0.3 0.0 0.0 100.3 AUGUST 2008 Reference Smooth Lower Clay 62.0 28.0 10.0 0.0 0.0 2.3 0.0 0.0 102.3 AUGUST 2008 Reference Smooth Lower Vine 96.3 0.3 3.7 0.0 0.7 0.1 0.0 0.0 101.1 AUGUST 2008 Reference Smooth Lower Average 82.4 11.1 6.2 0.0 0.6 0.9 0.0 0.0 101.2 AUGUST 2008 Reference Smooth Lower SE 10.4 7.9 2.8 0.0 0.5 1.1 0.0 0.0 AUGUST 2008 Control Smooth Upper Aquarium 87.3 8.0 2.7 0.0 2.0 0.1 0.0 0.0 100.1 AUGUST 2008 Control Smooth Upper Clay 80.7 9.3 11.3 0.0 0.0 0.0 0.0 0.0 101.4 AUGUST 2008 Control Smooth Upper Vine 37.0 45.0 17.3 0.0 0.7 0.4 0.0 0.0 100.4 AUGUST 2008 Control Smooth Upper Average 68.3 20.8 10.4 0.0 0.9 0.2 0.0 0.0 100.6 AUGUST 2008 Control Smooth Upper SE 21.0 15.8 5.5 0.0 1.2 0.2 0.0 0.0 AUGUST 2008 Control Smooth Middle Aquarium 84.7 5.0 7.3 0.0 3.0 0.1 0.0 0.0 100.1 AUGUST 2008 Control Smooth Middle Clay 98.7 0.0 1.3 0.0 0.0 0.0 0.0 0.0 100.0 AUGUST 2008 Control Smooth Middle Vine 98.3 0.0 0.3 0.0 1.3 0.0 0.0 0.0 100.0 AUGUST 2008 Control Smooth Middle Average 93.9 1.7 3.0 0.0 1.4 0.0 0.0 0.0 100.0 AUGUST 2008 Control Smooth Middle SE 4.8 1.5 2.5 0.0 1.6 0.0 0.0 0.0 AUGUST 2008 Control Smooth Lower Aquarium 86.7 8.0 5.3 0.0 0.0 0.3 0.0 0.0 100.3 AUGUST 2008 Control Smooth Lower Clay 92.0 4.7 3.3 0.0 0.0 0.0 0.0 0.0 100.0 AUGUST 2008 Control Smooth Lower Vine 94.3 0.0 0.7 0.0 4.7 0.0 0.0 0.0 99.7 AUGUST 2008 Control Smooth Lower Average 91.0 4.2 3.1 0.0 1.6 0.1 0.0 0.0 100.0 AUGUST 2008 Control Smooth Lower SE 4.5 3.2 1.5 0.0 2.7 0.1 0.0 0.0 AUGUST 2008 Flat Smooth Upper Aquarium 78.7 1.3 23.0 0.0 0.0 0.1 0.0 0.0 103.1 AUGUST 2008 Flat Smooth Upper Clay 69.3 5.3 25.3 0.0 0.0 0.0 0.0 0.0 100.0 AUGUST 2008 Flat Smooth Upper Vine 72.7 0.0 24.0 0.0 3.3 0.0 0.0 0.0 100.0 AUGUST 2008 Flat Smooth Upper Average 73.6 2.2 24.1 0.0 1.1 0.0 0.0 0.0 101.0 AUGUST 2008 Flat Smooth Upper SE 8.8 3.1 6.0 0.0 1.5 0.0 0.0 0.0 AUGUST 2008 Flat Smooth Middle Aquarium 89.3 4.0 6.7 0.0 0.0 0.2 0.0 0.0 100.2 AUGUST 2008 Flat Smooth Middle Clay 42.0 14.7 43.3 0.0 0.0 0.0 0.0 0.0 100.0 AUGUST 2008 Flat Smooth Middle Vine 74.7 1.3 21.3 0.0 2.7 0.0 0.0 0.0 100.0 AUGUST 2008 Flat Smooth Middle Average 68.7 6.7 23.8 0.0 0.9 0.1 0.0 0.0 100.1 AUGUST 2008 Flat Smooth Middle SE 13.9 4.3 10.4 0.0 1.5 0.1 0.0 0.0

AUGUST 2008 Flat Smooth Lower Aquarium 92.7 3.7 2.3 0.0 1.3 0.1 0.0 0.0 100.1 AUGUST 2008 Flat Smooth Lower Clay 90.0 0.0 10.0 0.0 0.0 0.0 0.0 0.0 100.0 AUGUST 2008 Flat Smooth Lower Vine 42.0 0.0 4.0 0.0 54.0 0.0 0.0 0.0 100.0 AUGUST 2008 Flat Smooth Lower Average 74.9 1.2 5.4 0.0 18.4 0.0 0.0 0.0 100.0 AUGUST 2008 Flat Smooth Lower SE 14.4 1.3 2.6 0.0 15.5 0.1 0.0 0.0 AUGUST 2008 Flat Cobble Upper Aquarium 74.7 1.3 23.7 0.0 0.0 0.2 0.0 0.0 99.8 AUGUST 2008 Flat Cobble Upper Clay 77.3 0.0 22.7 0.0 0.0 0.0 0.0 0.0 100.0 AUGUST 2008 Flat Cobble Upper Vine 62.7 2.7 25.3 0.0 9.3 0.0 0.0 0.0 100.0 AUGUST 2008 Flat Cobble Upper Average 71.6 1.3 23.9 0.0 3.1 0.1 0.0 0.0 99.9 AUGUST 2008 Flat Cobble Upper SE 7.5 1.6 5.2 0.0 3.0 0.1 0.0 0.0 AUGUST 2008 Flat Cobble Middle Aquarium 64.7 0.0 35.3 0.0 0.0 0.0 0.0 0.0 100.0 AUGUST 2008 Flat Cobble Middle Clay 62.7 2.7 34.7 0.0 0.0 0.0 0.0 0.0 100.0 AUGUST 2008 Flat Cobble Middle Vine 42.7 1.3 45.3 0.0 12.0 0.0 0.0 0.0 101.4 AUGUST 2008 Flat Cobble Middle Average 56.7 1.3 38.4 0.0 4.0 0.0 0.0 0.0 100.5 AUGUST 2008 Flat Cobble Middle SE 8.3 1.6 5.5 0.0 3.7 0.0 0.0 0.0 AUGUST 2008 Flat Cobble Lower Aquarium 83.0 1.0 13.7 0.0 2.3 0.0 0.0 0.0 100.0 AUGUST 2008 Flat Cobble Lower Clay 76.7 0.0 23.3 0.0 0.0 0.0 0.0 0.0 100.0 AUGUST 2008 Flat Cobble Lower Vine 52.0 1.3 8.0 0.0 38.0 0.1 0.0 0.0 99.4 AUGUST 2008 Flat Cobble Lower Average 70.6 0.8 15.0 0.0 13.4 0.0 0.0 0.0 99.8 AUGUST 2008 Flat Cobble Lower SE 13.3 0.8 6.7 0.0 15.1 0.0 0.0 0.0 AUGUST 2008 Step Smooth Upper Aquarium 73.3 0.0 8.3 0.0 20.3 0.0 0.0 0.0 102.0 AUGUST 2008 Step Smooth Upper Clay 90.0 0.0 10.0 0.0 0.0 0.0 0.0 0.0 100.0 AUGUST 2008 Step Smooth Upper Vine 47.3 26.0 4.7 0.0 22.0 0.0 0.0 0.0 100.0 AUGUST 2008 Step Smooth Upper Average 70.2 8.7 7.7 0.0 14.1 0.0 0.0 0.0 100.7 AUGUST 2008 Step Smooth Upper SE 15.2 11.0 2.3 0.0 11.6 0.0 0.0 0.0 AUGUST 2008 Step Smooth Middle Aquarium 94.7 0.7 5.3 0.0 0.0 0.0 0.0 0.0 100.7 AUGUST 2008 Step Smooth Middle Clay 64.7 2.7 32.7 0.0 0.0 0.0 0.0 0.0 100.0 AUGUST 2008 Step Smooth Middle Vine 61.7 2.7 33.3 0.0 3.3 0.0 0.0 0.0 101.0 AUGUST 2008 Step Smooth Middle Average 73.7 2.0 23.8 0.0 1.1 0.0 0.0 0.0 100.6 AUGUST 2008 Step Smooth Middle SE 16.2 1.4 15.8 0.0 1.5 0.0 0.0 0.0 AUGUST 2008 Step Smooth Lower Aquarium 97.3 0.3 2.3 0.0 0.0 0.0 0.0 0.0 100.0 AUGUST 2008 Step Smooth Lower Clay 84.7 0.0 15.3 0.0 0.0 0.0 0.0 0.0 100.0 AUGUST 2008 Step Smooth Lower Vine 79.7 0.7 9.4 0.0 10.0 0.0 0.0 0.0 99.7 AUGUST 2008 Step Smooth Lower Average 87.2 0.3 9.0 0.0 3.3 0.0 0.0 0.0 99.9 AUGUST 2008 Step Smooth Lower SE 8.2 0.4 7.9 0.0 3.9 0.0 0.0 0.0 AUGUST 2008 Step Cobble Upper Aquarium 78.7 0.0 8.0 0.0 13.3 0.0 0.0 0.0 100.0 AUGUST 2008 Step Cobble Upper Clay 97.3 0.0 2.7 0.0 0.0 0.0 0.0 0.0 100.0 AUGUST 2008 Step Cobble Upper Vine 85.3 2.7 6.0 0.0 5.3 0.0 0.0 0.0 99.3 AUGUST 2008 Step Cobble Upper Average 87.1 0.9 5.6 0.0 6.2 0.0 0.0 0.0 99.8 AUGUST 2008 Step Cobble Upper SE 8.3 1.5 1.7 0.0 7.9 0.0 0.0 0.0 AUGUST 2008 Step Cobble Middle Aquarium 66.7 1.3 29.3 0.0 2.7 0.0 0.0 0.0 100.0

AUGUST 2008 Step Cobble Middle Clay 74.7 0.0 25.3 0.0 0.0 0.0 0.0 0.0 100.0 AUGUST 2008 Step Cobble Middle Vine 52.7 2.0 41.3 0.0 4.0 0.0 0.0 0.0 100.0 AUGUST 2008 Step Cobble Middle Average 64.7 1.1 32.0 0.0 2.2 0.0 0.0 0.0 100.0 AUGUST 2008 Step Cobble Middle SE 11.9 1.3 12.0 0.0 2.0 0.0 0.0 0.0 AUGUST 2008 Step Cobble Lower Aquarium 86.3 3.0 10.7 0.0 0.0 0.0 0.0 0.0 100.0 AUGUST 2008 Step Cobble Lower Clay 80.7 6.7 12.7 0.0 0.0 0.0 0.0 0.0 100.0 AUGUST 2008 Step Cobble Lower Vine 69.3 1.3 13.3 0.0 16.0 0.0 0.0 0.0 100.1 AUGUST 2008 Step Cobble Lower Average 78.8 3.7 12.2 0.0 5.3 0.0 0.0 0.0 100.0 AUGUST 2008 Step Cobble Lower SE 6.7 3.6 5.2 0.0 5.0 0.0 0.0 0.0 AUGUST 2008 Fin Smooth Upper Aquarium 79.0 0.0 17.7 0.0 2.7 0.0 0.0 0.0 99.3 AUGUST 2008 Fin Smooth Upper Clay 73.3 0.0 26.7 0.0 0.0 0.0 0.0 0.0 100.0 AUGUST 2008 Fin Smooth Upper Vine 69.3 0.0 20.7 0.0 10.0 0.0 0.0 0.0 100.0 AUGUST 2008 Fin Smooth Upper Average 73.9 0.0 21.7 0.0 4.2 0.0 0.0 0.0 99.8 AUGUST 2008 Fin Smooth Upper SE 11.6 0.0 11.5 0.0 3.1 0.0 0.0 0.0 AUGUST 2008 Fin Smooth Middle Aquarium 70.0 2.0 28.0 0.0 0.0 0.0 0.0 0.0 100.0 AUGUST 2008 Fin Smooth Middle Clay 76.7 0.0 23.3 0.0 0.0 0.0 0.0 0.0 100.0 AUGUST 2008 Fin Smooth Middle Vine 75.7 0.0 17.3 0.0 7.0 0.0 0.0 0.0 100.0 AUGUST 2008 Fin Smooth Middle Average 74.1 0.7 22.9 0.0 2.3 0.0 0.0 0.0 100.0 AUGUST 2008 Fin Smooth Middle SE 15.2 0.8 14.4 0.0 3.8 0.0 0.0 0.0 AUGUST 2008 Fin Smooth Lower Aquarium 77.3 0.7 3.3 0.0 18.7 0.0 0.0 0.0 100.0 AUGUST 2008 Fin Smooth Lower Clay 41.3 0.0 10.0 0.0 48.7 0.0 0.0 0.0 100.0 AUGUST 2008 Fin Smooth Lower Vine 6.7 0.0 6.3 0.0 86.3 0.0 0.0 0.0 99.3 AUGUST 2008 Fin Smooth Lower Average 41.8 0.2 6.6 0.0 51.2 0.0 0.0 0.0 99.8 AUGUST 2008 Fin Smooth Lower SE 19.1 0.4 3.2 0.0 18.9 0.0 0.0 0.0 AUGUST 2008 Fin Cobble Upper Aquarium 80.7 2.7 15.3 0.0 1.3 0.0 0.0 0.0 100.0 AUGUST 2008 Fin Cobble Upper Clay 88.0 0.0 12.0 0.0 0.0 0.0 0.0 0.0 100.0 AUGUST 2008 Fin Cobble Upper Vine 64.7 0.0 22.7 0.0 12.7 0.0 0.0 0.0 100.0 AUGUST 2008 Fin Cobble Upper Average 77.8 0.9 16.7 0.0 4.7 0.0 0.0 0.0 100.0 AUGUST 2008 Fin Cobble Upper SE 8.2 1.0 6.8 0.0 4.1 0.0 0.0 0.0 AUGUST 2008 Fin Cobble Middle Aquarium 71.3 2.7 23.3 0.0 2.7 0.0 0.0 0.0 100.0 AUGUST 2008 Fin Cobble Middle Clay 78.7 0.0 21.3 0.0 0.0 0.0 0.0 0.0 100.0 AUGUST 2008 Fin Cobble Middle Vine 73.7 3.0 16.0 0.0 7.3 0.1 0.0 0.0 100.1 AUGUST 2008 Fin Cobble Middle Average 74.6 1.9 20.2 0.0 3.3 0.0 0.0 0.0 100.0 AUGUST 2008 Fin Cobble Middle SE 7.8 1.3 5.4 0.0 3.3 0.1 0.0 0.0 AUGUST 2008 Fin Cobble Lower Aquarium 39.3 6.0 28.7 0.0 26.0 0.0 0.0 0.0 100.0 AUGUST 2008 Fin Cobble Lower Clay 48.7 0.0 17.3 0.0 34.0 0.0 0.0 0.0 100.0 AUGUST 2008 Fin Cobble Lower Vine 54.7 0.7 9.3 0.0 34.7 0.0 0.0 0.0 99.3 AUGUST 2008 Fin Cobble Lower Average 47.6 2.2 18.4 0.0 31.6 0.0 0.0 0.0 99.8 AUGUST 2008 Fin Cobble Lower SE 13.7 1.8 8.4 0.0 15.3 0.0 0.0 0.0 APRIL 2009 Reference Smooth Upper Aquarium 23.2 39.0 33.8 0.0 4.0 1.0 0.0 0.0 101.1 APRIL 2009 Reference Smooth Upper Clay 32.3 7.3 37.7 0.0 22.3 1.1 0.1 0.0 100.8

APRIL 2009 Reference Smooth Upper Vine 24.2 56.7 19.3 0.0 1.3 1.6 0.0 0.0 103.1 APRIL 2009 Reference Smooth Upper Average 26.6 34.3 30.3 0.0 9.2 1.2 0.0 0.0 101.7 APRIL 2009 Reference Smooth Upper SE 10.2 16.1 12.1 0.0 7.2 0.3 0.0 0.0 APRIL 2009 Reference Smooth Middle Aquarium 80.7 5.3 13.8 0.0 0.0 0.9 0.0 0.0 100.7 APRIL 2009 Reference Smooth Middle Clay 39.7 5.0 30.8 0.0 26.3 0.5 0.1 0.0 102.5 APRIL 2009 Reference Smooth Middle Vine 84.0 6.7 8.8 0.0 0.0 0.8 0.0 0.0 100.3 APRIL 2009 Reference Smooth Middle Average 68.1 5.7 17.8 0.0 8.8 0.7 0.1 0.0 101.2 APRIL 2009 Reference Smooth Middle SE 14.2 0.7 6.9 0.0 9.2 0.2 0.1 0.0 APRIL 2009 Reference Smooth Lower Aquarium 92.7 2.0 5.2 0.0 0.3 0.2 0.0 0.0 100.3 APRIL 2009 Reference Smooth Lower Vine 58.0 2.0 0.0 0.0 40.0 0.0 0.0 0.0 100.0 APRIL 2009 Reference Smooth Lower Average 84.0 2.0 3.9 0.0 10.3 0.1 0.0 0.0 100.3 APRIL 2009 Reference Smooth Lower SE 10.1 0.9 1.7 0.0 11.5 0.1 0.0 0.0 APRIL 2009 Control Smooth Upper Aquarium 12.5 41.0 43.0 0.0 3.3 1.1 0.1 0.0 101.0 APRIL 2009 Control Smooth Upper Clay 38.3 12.0 27.0 0.0 21.7 2.0 0.1 0.0 101.1 APRIL 2009 Control Smooth Upper Vine 40.7 29.3 26.3 0.0 3.3 0.9 0.0 0.0 100.6 APRIL 2009 Control Smooth Upper Average 30.5 27.4 32.1 0.0 9.4 1.3 0.1 0.0 100.9 APRIL 2009 Control Smooth Upper SE 11.5 14.6 12.7 0.0 10.3 0.4 0.1 0.0 APRIL 2009 Control Smooth Middle Aquarium 82.3 4.0 8.7 0.0 4.7 1.5 0.0 0.0 101.1 APRIL 2009 Control Smooth Middle Clay 19.3 13.3 30.5 0.0 37.7 1.7 0.1 0.0 102.6 APRIL 2009 Control Smooth Middle Vine 67.7 27.7 4.7 0.0 0.0 0.8 0.0 0.0 100.8 APRIL 2009 Control Smooth Middle Average 56.4 15.0 14.6 0.0 14.1 1.3 0.0 0.0 101.5 APRIL 2009 Control Smooth Middle SE 20.2 13.1 7.6 0.0 13.9 0.3 0.0 0.0 APRIL 2009 Control Smooth Lower Aquarium 90.3 3.3 3.2 0.0 3.3 0.3 0.0 0.0 100.5 APRIL 2009 Control Smooth Lower Vine 79.3 2.3 0.8 0.0 17.7 0.0 0.0 0.0 100.2 APRIL 2009 Control Smooth Lower Average 84.8 2.8 2.0 0.0 10.5 0.2 0.0 0.0 100.4 APRIL 2009 Control Smooth Lower SE 11.5 0.8 1.1 0.0 12.1 0.1 0.0 0.0 APRIL 2009 Flat Smooth Upper Aquarium 22.7 4.3 55.8 0.0 17.7 0.8 0.0 0.0 101.3 APRIL 2009 Flat Smooth Upper Clay 11.0 10.7 67.7 0.0 10.0 0.3 0.0 0.0 99.7 APRIL 2009 Flat Smooth Upper Vine 0.3 5.7 80.5 0.0 13.7 0.2 0.0 0.0 100.3 APRIL 2009 Flat Smooth Upper Average 11.3 6.9 68.0 0.0 13.8 0.4 0.0 0.0 100.4 APRIL 2009 Flat Smooth Upper SE 6.9 3.0 11.7 0.0 6.7 0.3 0.0 0.0 APRIL 2009 Flat Smooth Middle Aquarium 8.0 6.0 54.0 0.0 32.3 1.0 0.0 0.0 101.4 APRIL 2009 Flat Smooth Middle Clay 1.0 4.7 79.0 0.0 15.7 0.3 0.0 0.0 100.7 APRIL 2009 Flat Smooth Middle Vine 1.8 6.0 87.3 0.0 4.7 0.5 0.0 0.0 100.4 APRIL 2009 Flat Smooth Middle Average 3.6 5.6 73.4 0.0 17.6 0.6 0.0 0.0 100.8 APRIL 2009 Flat Smooth Middle SE 2.1 0.8 11.9 0.0 10.9 0.3 0.0 0.0 APRIL 2009 Flat Smooth Lower Aquarium 10.3 8.7 9.0 0.0 72.3 0.5 0.1 0.0 101.0 APRIL 2009 Flat Smooth Lower Clay 17.0 4.7 37.7 0.0 41.0 0.1 0.1 0.0 100.6 APRIL 2009 Flat Smooth Lower Vine 4.0 6.3 8.7 0.0 81.3 0.3 0.1 0.0 100.7 APRIL 2009 Flat Smooth Lower Average 10.4 6.6 18.4 0.0 64.9 0.3 0.1 0.0 100.8 APRIL 2009 Flat Smooth Lower SE 4.6 1.8 9.4 0.0 11.4 0.2 0.1 0.0

APRIL 2009 Flat Cobble Upper Aquarium 51.0 3.0 29.2 0.0 16.7 0.5 0.0 0.0 100.3 APRIL 2009 Flat Cobble Upper Clay 15.7 6.7 77.7 0.0 0.0 0.4 0.0 0.0 100.4 APRIL 2009 Flat Cobble Upper Vine 5.3 4.7 54.2 0.0 36.3 0.2 0.0 0.0 100.7 APRIL 2009 Flat Cobble Upper Average 24.0 4.8 53.7 0.0 17.7 0.4 0.0 0.0 100.5 APRIL 2009 Flat Cobble Upper SE 14.6 1.7 16.6 0.0 12.0 0.2 0.0 0.0 APRIL 2009 Flat Cobble Middle Aquarium 20.0 7.0 50.8 0.0 22.7 0.6 0.2 0.0 101.2 APRIL 2009 Flat Cobble Middle Clay 3.0 5.3 61.2 0.0 31.0 0.2 0.1 0.0 100.8 APRIL 2009 Flat Cobble Middle Vine 50.2 9.3 14.0 0.0 27.3 0.6 0.0 0.0 101.5 APRIL 2009 Flat Cobble Middle Average 24.4 7.2 42.0 0.0 27.0 0.5 0.1 0.0 101.2 APRIL 2009 Flat Cobble Middle SE 12.1 2.1 14.2 0.0 8.0 0.2 0.1 0.0 APRIL 2009 Flat Cobble Lower Aquarium 73.3 10.7 7.0 0.0 8.7 0.2 0.2 0.0 100.1 APRIL 2009 Flat Cobble Lower Clay 11.0 8.7 43.2 0.0 37.7 0.3 0.1 0.0 100.9 APRIL 2009 Flat Cobble Lower Vine 4.7 10.7 8.7 0.0 77.0 0.2 0.2 0.2 101.6 APRIL 2009 Flat Cobble Lower Average 29.7 10.0 19.6 0.0 41.1 0.2 0.2 0.1 100.9 APRIL 2009 Flat Cobble Lower SE 19.1 3.6 11.5 0.0 18.3 0.1 0.1 0.1 APRIL 2009 Step Smooth Upper Aquarium 71.3 2.0 21.3 0.0 5.3 0.5 0.0 0.0 100.5 APRIL 2009 Step Smooth Upper Clay 29.7 17.7 53.3 0.0 0.0 0.4 0.0 0.0 101.1 APRIL 2009 Step Smooth Upper Vine 49.8 12.7 28.8 0.0 8.7 0.7 0.0 0.0 100.7 APRIL 2009 Step Smooth Upper Average 50.3 10.8 34.5 0.0 4.7 0.5 0.0 0.0 100.7 APRIL 2009 Step Smooth Upper SE 12.4 4.5 10.4 0.0 2.8 0.2 0.0 0.0 APRIL 2009 Step Smooth Middle Aquarium 1.3 3.3 31.5 0.0 64.0 0.2 0.1 0.0 100.4 APRIL 2009 Step Smooth Middle Clay 3.3 5.3 61.7 0.0 29.7 0.5 0.5 0.0 101.0 APRIL 2009 Step Smooth Middle Vine 21.3 29.7 49.2 0.0 4.0 0.6 0.3 0.0 105.0 APRIL 2009 Step Smooth Middle Average 8.7 12.8 47.4 0.0 32.6 0.4 0.3 0.0 102.2 APRIL 2009 Step Smooth Middle SE 6.1 8.0 11.3 0.0 17.1 0.2 0.2 0.0 APRIL 2009 Step Smooth Lower Aquarium 30.0 1.7 2.0 0.0 66.3 0.0 0.0 0.0 100.0 APRIL 2009 Step Smooth Lower Clay 9.7 5.0 15.3 0.0 70.0 0.0 0.2 0.0 100.2 APRIL 2009 Step Smooth Lower Vine 5.3 49.7 9.8 0.0 35.3 0.2 0.5 0.0 100.9 APRIL 2009 Step Smooth Lower Average 15.0 18.8 9.1 0.0 57.2 0.1 0.2 0.0 100.3 APRIL 2009 Step Smooth Lower SE 13.2 13.5 4.2 0.0 14.5 0.1 0.1 0.0 APRIL 2009 Step Cobble Upper Aquarium 56.0 7.3 37.5 0.0 0.0 0.0 0.0 0.0 100.9 APRIL 2009 Step Cobble Upper Clay 60.7 6.0 33.3 0.0 0.0 0.9 0.0 0.0 100.9 APRIL 2009 Step Cobble Upper Vine 33.7 1.3 50.2 0.0 15.0 0.0 0.0 0.0 100.2 APRIL 2009 Step Cobble Upper Average 50.1 4.9 40.3 0.0 5.0 0.3 0.0 0.0 100.6 APRIL 2009 Step Cobble Upper SE 12.1 2.8 9.4 0.0 5.8 0.3 0.0 0.0 APRIL 2009 Step Cobble Middle Aquarium 39.3 4.7 32.7 0.0 23.7 0.4 1.1 0.0 101.9 APRIL 2009 Step Cobble Middle Clay 2.0 10.7 25.7 0.0 61.7 0.0 0.6 0.0 100.6 APRIL 2009 Step Cobble Middle Vine 7.8 10.0 54.3 0.0 28.0 0.5 0.4 0.0 101.1 APRIL 2009 Step Cobble Middle Average 16.4 8.4 37.6 0.0 37.8 0.3 0.7 0.0 101.2 APRIL 2009 Step Cobble Middle SE 14.9 2.5 12.0 0.0 15.4 0.2 0.3 0.0 APRIL 2009 Step Cobble Lower Aquarium 4.0 4.0 9.3 0.0 82.7 0.1 0.1 0.8 101.0

APRIL 2009 Step Cobble Lower Clay 6.8 25.3 18.7 0.0 49.7 0.0 0.3 0.0 100.8 APRIL 2009 Step Cobble Lower Vine 22.0 10.7 9.3 0.0 58.0 0.3 0.2 0.0 100.4 APRIL 2009 Step Cobble Lower Average 10.9 13.3 12.4 0.0 63.4 0.1 0.2 0.3 100.7 APRIL 2009 Step Cobble Lower SE 11.1 6.8 4.0 0.0 15.0 0.1 0.1 0.5 APRIL 2009 Fin Smooth Upper Aquarium 33.0 13.5 35.5 0.0 18.3 0.2 0.5 0.0 101.0 APRIL 2009 Fin Smooth Upper Clay 9.7 4.0 75.0 0.0 11.3 0.1 0.0 0.0 100.1 APRIL 2009 Fin Smooth Upper Vine 22.7 13.3 24.0 0.0 40.0 0.3 0.1 0.0 100.4 APRIL 2009 Fin Smooth Upper Average 21.8 10.3 44.8 0.0 23.2 0.2 0.2 0.0 100.5 APRIL 2009 Fin Smooth Upper SE 17.1 8.6 16.5 0.0 15.1 0.2 0.3 0.0 APRIL 2009 Fin Smooth Middle Aquarium 2.3 14.3 19.3 0.0 64.0 0.2 0.2 0.0 100.4 APRIL 2009 Fin Smooth Middle Clay 7.3 1.3 54.2 0.0 37.3 0.0 0.4 0.0 100.6 APRIL 2009 Fin Smooth Middle Vine 29.7 3.0 14.3 0.0 53.0 0.0 0.5 0.0 100.5 APRIL 2009 Fin Smooth Middle Average 13.1 6.2 29.3 0.0 51.4 0.1 0.4 0.0 100.5 APRIL 2009 Fin Smooth Middle SE 12.9 7.5 15.3 0.0 20.3 0.1 0.2 0.0 APRIL 2009 Fin Smooth Lower Aquarium 56.7 5.3 8.0 0.0 30.0 0.0 0.0 0.0 100.0 APRIL 2009 Fin Smooth Lower Clay 26.0 5.0 26.8 0.0 42.3 0.0 0.2 0.0 100.4 APRIL 2009 Fin Smooth Lower Vine 35.3 7.3 9.3 0.0 48.7 0.1 0.0 0.0 100.8 APRIL 2009 Fin Smooth Lower Average 39.3 5.9 14.7 0.0 40.3 0.0 0.1 0.0 100.4 APRIL 2009 Fin Smooth Lower SE 22.3 1.8 8.6 0.0 16.7 0.1 0.1 0.0 APRIL 2009 Fin Cobble Upper Aquarium 56.0 8.3 30.2 0.0 5.7 0.2 0.0 0.0 100.4 APRIL 2009 Fin Cobble Upper Clay 16.0 10.0 58.0 0.0 16.0 0.1 0.9 0.0 101.0 APRIL 2009 Fin Cobble Upper Vine 35.3 9.3 38.7 0.0 16.7 0.2 0.4 0.0 100.6 APRIL 2009 Fin Cobble Upper Average 35.8 9.2 42.3 0.0 12.8 0.2 0.4 0.0 100.6 APRIL 2009 Fin Cobble Upper SE 21.0 4.3 14.3 0.0 12.3 0.2 0.5 0.0 APRIL 2009 Fin Cobble Middle Aquarium 1.7 5.3 47.5 0.0 45.0 0.2 0.7 0.0 100.4 APRIL 2009 Fin Cobble Middle Clay 2.7 17.0 28.7 0.0 51.7 0.0 1.6 0.0 101.6 APRIL 2009 Fin Cobble Middle Vine 60.0 2.7 14.2 0.0 23.3 0.2 0.4 0.0 100.7 APRIL 2009 Fin Cobble Middle Average 21.4 8.3 30.1 0.0 40.0 0.1 0.9 0.0 100.9 APRIL 2009 Fin Cobble Middle SE 17.9 7.1 12.6 0.0 12.5 0.1 0.6 0.0 APRIL 2009 Fin Cobble Lower Aquarium 26.3 3.3 19.0 0.0 51.0 0.2 0.3 0.0 100.1 APRIL 2009 Fin Cobble Lower Clay 4.7 11.3 23.3 0.0 60.7 0.0 0.3 0.0 100.3 APRIL 2009 Fin Cobble Lower Vine 18.0 10.0 12.7 0.0 59.3 0.1 0.2 0.0 100.3 APRIL 2009 Fin Cobble Lower Average 16.3 8.2 18.3 0.0 57.0 0.1 0.2 0.0 100.2 APRIL 2009 Fin Cobble Lower SE 9.8 3.3 8.6 0.0 13.6 0.1 0.1 0.0 JUNE 2009 Reference Smooth Upper Aquarium 48.0 4.7 41.7 0.0 5.7 0.8 0.0 0.0 100.8 JUNE 2009 Reference Smooth Upper Clay 17.0 2.3 67.2 0.0 13.0 0.7 0.0 0.0 100.2 JUNE 2009 Reference Smooth Upper Vine 13.0 10.0 33.0 0.0 44.0 0.8 0.0 0.0 100.8 JUNE 2009 Reference Smooth Upper Average 29.7 4.4 51.4 0.0 14.3 0.7 0.0 0.0 100.5 JUNE 2009 Reference Smooth Upper SE 12.8 1.9 12.7 0.0 10.1 0.2 0.0 0.0 JUNE 2009 Reference Smooth Middle Aquarium 35.3 1.3 58.3 0.0 8.3 1.6 0.3 0.0 105.3 JUNE 2009 Reference Smooth Middle Clay 26.0 1.0 33.0 0.0 40.0 0.6 0.0 0.0 100.6

JUNE 2009 Reference Smooth Middle Vine 67.0 8.0 29.0 0.0 0.0 2.5 0.0 0.0 106.5 JUNE 2009 Reference Smooth Middle Average 39.8 2.6 47.4 0.0 13.0 1.6 0.2 0.0 104.6 JUNE 2009 Reference Smooth Middle SE 9.9 2.0 9.4 0.0 9.9 0.6 0.2 0.0 JUNE 2009 Reference Smooth Lower Aquarium 90.0 1.3 11.0 0.0 0.0 0.3 0.1 0.0 102.7 JUNE 2009 Reference Smooth Lower Vine 85.0 4.0 11.5 0.0 0.0 0.8 0.0 0.5 101.8 JUNE 2009 Reference Smooth Lower Average 88.8 2.0 11.1 0.0 0.0 0.4 0.1 0.1 102.5 JUNE 2009 Reference Smooth Lower SE 2.4 0.9 1.3 0.0 0.0 0.2 0.1 0.1 JUNE 2009 Control Smooth Upper Aquarium 50.2 7.3 27.5 0.0 14.7 0.5 0.0 0.0 100.2 JUNE 2009 Control Smooth Upper Clay 7.7 9.3 39.3 0.0 43.7 1.4 0.4 0.0 101.8 JUNE 2009 Control Smooth Upper Vine 15.0 4.0 55.0 0.0 26.0 0.2 0.0 0.0 100.2 JUNE 2009 Control Smooth Upper Average 26.9 7.7 36.5 0.0 28.7 0.8 0.2 0.0 100.9 JUNE 2009 Control Smooth Upper SE 15.0 2.7 7.1 0.0 12.1 0.4 0.2 0.0 JUNE 2009 Control Smooth Middle Aquarium 49.3 6.0 27.7 0.0 17.3 1.5 0.2 0.0 102.0 JUNE 2009 Control Smooth Middle Clay 56.3 7.3 29.3 0.0 6.7 2.6 0.1 0.0 102.4 JUNE 2009 Control Smooth Middle Vine 68.0 6.0 26.0 0.0 0.0 2.1 0.0 0.0 102.1 JUNE 2009 Control Smooth Middle Average 55.0 6.6 28.1 0.0 10.3 2.1 0.1 0.0 102.2 JUNE 2009 Control Smooth Middle SE 12.9 2.1 5.4 0.0 10.2 0.4 0.1 0.0 JUNE 2009 Control Smooth Lower Aquarium 73.5 5.3 19.5 0.0 2.0 1.3 0.1 0.0 101.8 JUNE 2009 Control Smooth Lower Vine 97.0 1.0 2.0 0.0 0.0 0.1 0.0 0.0 100.1 JUNE 2009 Control Smooth Lower Average 79.4 4.3 15.1 0.0 1.5 1.0 0.1 0.0 101.4 JUNE 2009 Control Smooth Lower SE 6.9 1.7 5.2 0.0 1.1 0.5 0.0 0.0 JUNE 2009 Flat Smooth Upper Aquarium 5.0 6.7 84.5 0.0 5.3 0.8 0.1 0.0 102.3 JUNE 2009 Flat Smooth Upper Clay 11.8 6.7 83.7 0.0 2.7 1.4 0.4 0.0 106.6 JUNE 2009 Flat Smooth Upper Vine 3.0 4.0 81.0 0.0 14.0 0.3 0.0 0.0 102.3 JUNE 2009 Flat Smooth Upper Average 7.6 6.3 83.6 0.0 5.4 1.0 0.2 0.0 104.2 JUNE 2009 Flat Smooth Upper SE 2.8 1.0 2.6 0.0 2.6 0.3 0.2 0.0 JUNE 2009 Flat Smooth Middle Aquarium 14.3 8.0 75.2 0.0 3.3 1.8 0.3 0.0 103.0 JUNE 2009 Flat Smooth Middle Clay 63.0 10.0 17.0 0.0 8.0 2.2 0.6 0.0 100.8 JUNE 2009 Flat Smooth Middle Vine 12.0 7.0 41.0 0.0 40.0 0.9 0.2 0.0 101.1 JUNE 2009 Flat Smooth Middle Average 23.6 8.2 56.7 0.0 11.6 1.7 0.3 0.0 102.2 JUNE 2009 Flat Smooth Middle SE 13.1 2.3 16.4 0.0 9.3 0.6 0.2 0.0 JUNE 2009 Flat Smooth Lower Aquarium 35.7 13.3 44.5 0.0 6.7 1.2 0.3 0.0 101.7 JUNE 2009 Flat Smooth Lower Clay 16.3 41.3 27.2 0.0 13.3 5.4 1.6 0.2 105.4 JUNE 2009 Flat Smooth Lower Vine 61.0 4.0 29.0 0.0 6.0 0.6 0.2 0.0 100.8 JUNE 2009 Flat Smooth Lower Average 31.0 24.0 34.9 0.0 9.4 2.9 0.9 0.1 103.2 JUNE 2009 Flat Smooth Lower SE 13.9 13.4 8.4 0.0 3.6 2.8 0.5 0.1 JUNE 2009 Flat Cobble Upper Aquarium 14.3 6.7 69.8 0.0 9.7 1.7 0.2 0.0 102.4 JUNE 2009 Flat Cobble Upper Clay 19.2 8.2 67.0 0.0 6.3 0.5 1.2 0.0 102.4 JUNE 2009 Flat Cobble Upper Vine 3.0 18.0 69.5 0.0 9.0 1.2 0.4 0.0 101.1 JUNE 2009 Flat Cobble Upper Average 14.8 8.9 68.6 0.0 8.1 1.1 0.7 0.0 102.2 JUNE 2009 Flat Cobble Upper SE 8.0 5.2 11.6 0.0 2.9 0.5 0.6 0.0

JUNE 2009 Flat Cobble Middle Aquarium 23.7 13.3 63.3 0.0 0.0 1.5 0.9 0.0 102.7 JUNE 2009 Flat Cobble Middle Clay 23.3 22.7 49.7 0.0 4.0 0.9 1.5 0.0 102.1 JUNE 2009 Flat Cobble Middle Vine 51.0 10.0 19.5 0.0 20.0 1.1 0.7 0.0 102.3 JUNE 2009 Flat Cobble Middle Average 27.4 16.9 51.2 0.0 4.6 1.2 1.1 0.0 102.4 JUNE 2009 Flat Cobble Middle SE 11.0 5.9 14.7 0.0 4.3 0.2 0.4 0.0 JUNE 2009 Flat Cobble Lower Aquarium 52.3 10.7 30.3 0.0 7.3 1.3 1.5 0.0 103.5 JUNE 2009 Flat Cobble Lower Clay 26.0 30.7 28.8 0.0 12.0 1.0 2.9 0.0 101.4 JUNE 2009 Flat Cobble Lower Vine 65.0 8.0 17.0 0.0 10.0 0.7 0.6 0.0 101.3 JUNE 2009 Flat Cobble Lower Average 42.9 18.9 27.8 0.0 9.7 1.1 2.0 0.0 102.3 JUNE 2009 Flat Cobble Lower SE 12.7 10.4 9.6 0.0 3.4 0.2 0.7 0.0 JUNE 2009 Step Smooth Upper Aquarium 48.7 0.7 50.8 0.0 0.0 0.2 0.0 0.0 100.3 JUNE 2009 Step Smooth Upper Clay 87.3 0.0 13.7 0.0 2.0 0.0 1.3 0.0 104.3 JUNE 2009 Step Smooth Upper Vine 80.0 4.0 12.0 0.0 6.0 0.0 0.0 0.0 102.0 JUNE 2009 Step Smooth Upper Average 69.7 0.9 29.4 0.0 1.7 0.1 0.5 0.0 102.3 JUNE 2009 Step Smooth Upper SE 14.4 0.9 14.6 0.0 1.7 0.1 0.8 0.0 JUNE 2009 Step Smooth Middle Aquarium 18.8 5.0 76.3 0.0 0.3 0.1 0.9 0.0 101.6 JUNE 2009 Step Smooth Middle Clay 28.0 15.0 54.0 0.0 3.0 0.3 1.2 0.0 101.5 JUNE 2009 Step Smooth Middle Vine 63.5 10.0 23.0 0.0 4.0 1.0 1.0 0.0 102.5 JUNE 2009 Step Smooth Middle Average 34.2 9.3 54.7 0.0 2.1 0.4 1.0 0.0 101.8 JUNE 2009 Step Smooth Middle SE 14.2 4.0 17.4 0.0 1.6 0.3 0.2 0.0 JUNE 2009 Step Smooth Lower Aquarium 65.0 2.3 18.7 0.0 14.0 0.0 0.1 0.0 100.1 JUNE 2009 Step Smooth Lower Clay 0.0 6.0 68.0 0.0 26.0 0.0 2.3 0.0 102.3 JUNE 2009 Step Smooth Lower Vine 58.5 6.0 34.0 0.0 3.0 0.4 1.3 0.0 103.2 JUNE 2009 Step Smooth Lower Average 52.0 4.2 32.0 0.0 12.3 0.1 0.9 0.0 101.5 JUNE 2009 Step Smooth Lower SE 17.7 1.4 13.0 0.0 9.7 0.2 0.6 0.0 JUNE 2009 Step Cobble Upper Aquarium 78.0 0.7 23.3 0.0 0.0 0.0 0.0 0.0 102.0 JUNE 2009 Step Cobble Upper Clay 85.3 2.0 14.0 0.0 0.0 0.1 2.4 0.0 103.9 JUNE 2009 Step Cobble Upper Vine 52.0 1.0 44.0 0.0 0.0 0.0 0.0 0.0 97.0 JUNE 2009 Step Cobble Upper Average 77.4 1.3 22.3 0.0 0.0 0.1 1.0 0.0 102.1 JUNE 2009 Step Cobble Upper SE 9.1 1.3 8.8 0.0 0.0 0.1 1.6 0.0 JUNE 2009 Step Cobble Middle Aquarium 11.0 6.7 78.7 0.0 4.7 1.4 2.4 0.0 104.8 JUNE 2009 Step Cobble Middle Clay 24.0 11.3 61.7 0.0 6.0 0.1 5.2 0.0 108.3 JUNE 2009 Step Cobble Middle Vine 37.5 12.5 47.8 0.0 3.0 0.9 2.0 0.0 103.6 JUNE 2009 Step Cobble Middle Average 22.5 9.9 64.6 0.0 4.8 0.8 3.4 0.0 105.8 JUNE 2009 Step Cobble Middle SE 10.6 3.5 13.1 0.0 1.4 0.4 1.4 0.0 JUNE 2009 Step Cobble Lower Aquarium 65.8 8.7 22.0 0.0 4.0 1.3 0.9 0.0 102.7 JUNE 2009 Step Cobble Lower Clay 17.7 31.3 26.8 0.0 20.7 0.1 3.6 0.0 100.2 JUNE 2009 Step Cobble Lower Vine 33.5 12.0 19.8 0.0 35.0 2.5 0.2 0.0 102.9 JUNE 2009 Step Cobble Lower Average 39.7 18.0 23.3 0.0 18.0 1.1 1.7 0.0 101.8 JUNE 2009 Step Cobble Lower SE 16.8 8.9 2.5 0.0 15.8 0.6 1.0 0.0 JUNE 2009 Fin Smooth Upper Aquarium 17.7 4.3 68.0 0.0 7.7 0.4 2.0 0.0 100.1

JUNE 2009 Fin Smooth Upper Clay 7.0 2.0 83.3 0.0 7.3 0.1 0.8 0.0 100.6 JUNE 2009 Fin Smooth Upper Vine 34.3 6.7 47.0 0.0 12.7 0.0 0.6 0.0 101.3 JUNE 2009 Fin Smooth Upper Average 19.7 4.3 66.1 0.0 9.2 0.2 1.1 0.0 100.7 JUNE 2009 Fin Smooth Upper SE 10.8 1.8 11.0 0.0 6.8 0.2 0.8 0.0 JUNE 2009 Fin Smooth Middle Aquarium 45.0 7.7 43.3 0.0 4.7 0.3 1.9 0.0 102.9 JUNE 2009 Fin Smooth Middle Clay 6.0 2.0 82.0 0.0 10.0 0.2 2.5 0.0 102.7 JUNE 2009 Fin Smooth Middle Vine 39.3 6.0 33.2 0.0 22.0 0.7 0.5 0.0 101.7 JUNE 2009 Fin Smooth Middle Average 37.0 6.1 44.5 0.0 12.9 0.5 1.4 0.0 102.4 JUNE 2009 Fin Smooth Middle SE 12.6 2.3 12.1 0.0 9.7 0.3 0.8 0.0 JUNE 2009 Fin Smooth Lower Aquarium 26.0 2.3 44.3 0.0 27.7 0.5 0.2 0.0 101.1 JUNE 2009 Fin Smooth Lower Clay 20.0 8.0 72.5 0.0 0.0 0.7 1.3 0.0 102.5 JUNE 2009 Fin Smooth Lower Vine 30.2 3.3 11.5 0.0 55.7 0.4 0.1 0.2 101.3 JUNE 2009 Fin Smooth Lower Average 26.9 3.6 34.3 0.0 35.7 0.5 0.3 0.1 101.4 JUNE 2009 Fin Smooth Lower SE 14.3 1.4 18.0 0.0 23.4 0.3 0.3 0.1 JUNE 2009 Fin Cobble Upper Aquarium 20.0 13.0 51.3 0.0 13.3 3.2 1.2 0.0 102.0 JUNE 2009 Fin Cobble Upper Clay 22.7 14.7 57.7 0.0 3.7 0.4 2.3 0.0 101.4 JUNE 2009 Fin Cobble Upper Vine 22.0 21.3 39.5 0.0 17.3 0.8 2.3 0.0 103.2 JUNE 2009 Fin Cobble Upper Average 21.6 16.3 49.5 0.0 11.4 1.5 1.9 0.0 102.2 JUNE 2009 Fin Cobble Upper SE 7.5 5.5 9.6 0.0 10.2 1.8 1.0 0.0 JUNE 2009 Fin Cobble Middle Aquarium 47.0 12.0 38.7 0.0 2.7 0.9 1.8 0.0 103.0 JUNE 2009 Fin Cobble Middle Clay 18.0 8.7 53.5 0.0 19.3 0.3 4.5 0.0 104.3 JUNE 2009 Fin Cobble Middle Vine 46.3 6.7 37.5 0.0 10.0 0.7 2.0 0.0 103.2 JUNE 2009 Fin Cobble Middle Average 37.1 9.1 43.2 0.0 10.7 0.6 2.8 0.0 103.5 JUNE 2009 Fin Cobble Middle SE 13.2 2.9 9.9 0.0 7.3 0.3 1.0 0.0 JUNE 2009 Fin Cobble Lower Aquarium 55.3 9.3 31.3 0.0 5.3 1.1 1.0 0.0 103.5 JUNE 2009 Fin Cobble Lower Clay 44.0 38.5 15.8 0.0 2.0 0.5 3.4 0.0 104.1 JUNE 2009 Fin Cobble Lower Vine 10.7 5.0 39.2 0.0 47.7 0.6 0.8 0.0 103.9 JUNE 2009 Fin Cobble Lower Average 35.8 15.0 30.4 0.0 20.4 0.8 1.5 0.0 103.8 JUNE 2009 Fin Cobble Lower SE 14.5 12.0 10.9 0.0 16.6 0.3 0.8 0.0 AUGUST 2009 Reference Smooth Upper Aquarium 53.7 4.0 42.3 0.0 0.0 0.8 0.0 0.0 100.8 AUGUST 2009 Reference Smooth Upper Clay 44.0 3.0 45.7 0.0 7.3 0.3 0.1 0.0 100.4 AUGUST 2009 Reference Smooth Upper Vine 11.0 3.0 34.5 0.0 50.5 1.1 0.0 0.0 100.1 AUGUST 2009 Reference Smooth Upper Average 39.4 3.4 41.6 0.0 15.4 0.7 0.0 0.0 100.5 AUGUST 2009 Reference Smooth Upper SE 11.4 0.5 7.0 0.0 13.2 0.3 0.0 0.0 AUGUST 2009 Reference Smooth Middle Aquarium 56.7 6.7 36.7 0.0 0.0 1.6 0.1 0.0 101.7 AUGUST 2009 Reference Smooth Middle Clay 52.0 4.3 41.5 0.0 2.0 0.7 0.2 0.0 100.7 AUGUST 2009 Reference Smooth Middle Vine 42.7 6.0 48.7 0.0 1.3 1.1 0.1 0.0 99.9 AUGUST 2009 Reference Smooth Middle Average 50.4 5.7 42.3 0.0 1.1 1.1 0.1 0.0 100.8 AUGUST 2009 Reference Smooth Middle SE 8.0 1.3 8.4 0.0 1.3 0.3 0.1 0.0 AUGUST 2009 Reference Smooth Lower Aquarium 90.3 3.0 5.7 1.0 0.0 0.3 0.1 0.0 100.4 AUGUST 2009 Reference Smooth Lower Clay 79.0 5.0 10.0 0.0 6.0 0.2 0.3 0.0 100.5

AUGUST 2009 Reference Smooth Lower Vine 89.7 2.7 9.7 0.7 0.0 0.8 0.0 0.0 103.5 AUGUST 2009 Reference Smooth Lower Average 88.4 3.1 8.0 0.7 0.9 0.5 0.1 0.0 101.7 AUGUST 2009 Reference Smooth Lower SE 5.3 1.3 2.7 0.5 1.3 0.3 0.1 0.0 AUGUST 2009 Control Smooth Upper Aquarium 29.3 2.7 68.0 0.0 0.0 0.6 0.0 0.0 100.6 AUGUST 2009 Control Smooth Upper Clay 43.0 9.3 47.0 0.0 0.0 1.7 0.2 0.0 101.3 AUGUST 2009 Control Smooth Upper Vine 16.5 1.5 36.0 0.0 46.0 0.8 0.0 0.0 100.8 AUGUST 2009 Control Smooth Upper Average 31.3 4.9 52.1 0.0 11.5 1.1 0.1 0.0 100.9 AUGUST 2009 Control Smooth Upper SE 10.4 2.4 11.6 0.0 12.4 0.4 0.1 0.0 AUGUST 2009 Control Smooth Middle Aquarium 40.0 6.3 53.5 0.0 0.0 2.0 0.2 0.0 102.0 AUGUST 2009 Control Smooth Middle Clay 54.7 9.3 33.3 0.0 2.7 1.2 0.4 0.0 101.6 AUGUST 2009 Control Smooth Middle Vine 51.7 13.7 32.8 0.0 0.0 2.2 0.0 0.0 100.3 AUGUST 2009 Control Smooth Middle Average 48.8 9.8 39.9 0.0 0.9 1.8 0.2 0.0 101.3 AUGUST 2009 Control Smooth Middle SE 6.6 5.3 7.8 0.0 1.5 0.4 0.1 0.0 AUGUST 2009 Control Smooth Lower Aquarium 85.7 4.0 10.0 0.0 1.3 1.3 0.0 0.0 102.3 AUGUST 2009 Control Smooth Lower Clay 91.0 0.0 7.5 1.0 0.0 0.8 0.0 0.0 100.3 AUGUST 2009 Control Smooth Lower Vine 94.7 0.3 2.7 0.7 0.0 0.7 0.1 0.2 99.3 AUGUST 2009 Control Smooth Lower Average 90.3 1.9 6.5 0.4 0.6 1.0 0.0 0.1 100.7 AUGUST 2009 Control Smooth Lower SE 2.9 1.2 2.3 0.3 0.6 0.2 0.0 0.1 AUGUST 2009 Flat Smooth Upper Aquarium 46.3 10.3 43.2 0.0 0.0 0.6 0.2 0.0 100.7 AUGUST 2009 Flat Smooth Upper Clay 11.7 3.3 77.8 0.0 8.0 1.3 0.4 0.0 102.5 AUGUST 2009 Flat Smooth Upper Vine 11.7 8.3 40.7 0.0 38.7 1.2 0.1 0.0 100.6 AUGUST 2009 Flat Smooth Upper Average 23.2 7.3 53.9 0.0 15.6 1.0 0.2 0.0 101.3 AUGUST 2009 Flat Smooth Upper SE 11.2 3.9 13.6 0.0 13.8 0.2 0.1 0.0 AUGUST 2009 Flat Smooth Middle Aquarium 12.3 7.3 63.2 0.0 17.3 2.2 0.1 0.0 102.5 AUGUST 2009 Flat Smooth Middle Clay 46.3 8.7 29.0 0.0 16.0 1.1 1.5 0.0 102.6 AUGUST 2009 Flat Smooth Middle Vine 26.7 5.3 52.7 0.0 14.7 1.7 0.5 0.0 101.5 AUGUST 2009 Flat Smooth Middle Average 28.4 7.1 48.3 0.0 16.0 1.6 0.7 0.0 102.2 AUGUST 2009 Flat Smooth Middle SE 10.1 1.5 9.6 0.0 5.3 0.6 0.4 0.0 AUGUST 2009 Flat Smooth Lower Aquarium 56.7 8.0 28.8 0.0 6.7 1.1 0.3 0.0 101.6 AUGUST 2009 Flat Smooth Lower Clay 50.3 5.3 19.3 0.0 25.0 0.4 1.8 0.0 102.2 AUGUST 2009 Flat Smooth Lower Vine 81.0 6.0 13.7 0.0 2.3 0.4 0.0 0.0 103.4 AUGUST 2009 Flat Smooth Lower Average 62.7 6.4 20.6 0.0 11.3 0.6 0.7 0.0 102.4 AUGUST 2009 Flat Smooth Lower SE 8.4 1.5 4.2 0.0 6.4 0.2 0.5 0.0 AUGUST 2009 Flat Cobble Upper Aquarium 35.3 11.3 36.3 0.0 17.0 0.6 0.2 0.0 100.8 AUGUST 2009 Flat Cobble Upper Clay 10.3 8.0 81.3 0.0 0.0 0.9 1.2 0.0 101.7 AUGUST 2009 Flat Cobble Upper Vine 47.5 16.0 34.5 0.0 3.0 0.1 0.1 0.0 101.2 AUGUST 2009 Flat Cobble Upper Average 29.0 11.3 52.8 0.0 7.1 0.6 0.6 0.0 101.2 AUGUST 2009 Flat Cobble Upper SE 14.0 3.9 14.9 0.0 10.3 0.3 0.4 0.0 AUGUST 2009 Flat Cobble Middle Aquarium 37.3 8.7 54.0 0.0 0.0 2.0 0.4 0.0 102.3 AUGUST 2009 Flat Cobble Middle Clay 19.3 10.3 69.0 0.0 1.3 0.8 1.5 0.0 102.3 AUGUST 2009 Flat Cobble Middle Vine 38.0 6.7 23.7 0.0 31.0 1.1 0.3 0.0 100.7

AUGUST 2009 Flat Cobble Middle Average 31.6 8.6 48.9 0.0 10.8 1.3 0.7 0.0 101.8 AUGUST 2009 Flat Cobble Middle SE 9.3 1.8 12.3 0.0 11.9 0.5 0.4 0.0 AUGUST 2009 Flat Cobble Lower Aquarium 53.7 8.0 35.8 0.0 2.0 1.3 1.3 0.0 102.0 AUGUST 2009 Flat Cobble Lower Clay 65.3 11.3 16.0 0.0 6.7 1.2 4.2 0.0 104.7 AUGUST 2009 Flat Cobble Lower Vine 46.7 5.3 29.0 0.0 19.0 0.5 0.1 0.1 100.7 AUGUST 2009 Flat Cobble Lower Average 55.2 8.2 26.9 0.0 9.2 1.0 1.8 0.0 102.5 AUGUST 2009 Flat Cobble Lower SE 8.9 2.3 5.6 0.0 8.9 0.3 1.2 0.0 AUGUST 2009 Step Smooth Upper Aquarium 13.0 1.7 85.3 0.0 0.0 0.0 0.0 0.0 100.0 AUGUST 2009 Step Smooth Upper Clay 87.3 2.7 8.7 0.0 0.0 0.3 0.0 0.0 98.9 AUGUST 2009 Step Smooth Upper Vine 79.7 2.7 16.7 0.0 0.0 0.0 0.0 0.0 99.0 AUGUST 2009 Step Smooth Upper Average 60.0 2.3 36.9 0.0 0.0 0.1 0.0 0.0 99.3 AUGUST 2009 Step Smooth Upper SE 21.1 1.0 21.5 0.0 0.0 0.2 0.0 0.0 AUGUST 2009 Step Smooth Middle Aquarium 15.0 1.7 51.5 0.0 31.7 0.4 0.5 0.0 100.7 AUGUST 2009 Step Smooth Middle Clay 55.3 8.7 32.7 0.0 3.3 0.4 1.1 0.0 101.5 AUGUST 2009 Step Smooth Middle Vine 52.0 7.3 33.7 0.0 7.3 1.2 1.2 0.0 102.7 AUGUST 2009 Step Smooth Middle Average 40.8 5.9 39.3 0.0 14.1 0.7 0.9 0.0 101.7 AUGUST 2009 Step Smooth Middle SE 12.9 2.2 10.0 0.0 13.4 0.3 0.4 0.0 AUGUST 2009 Step Smooth Lower Aquarium 76.0 3.3 16.7 0.7 2.7 0.3 0.0 0.2 99.8 AUGUST 2009 Step Smooth Lower Clay 63.0 10.3 18.0 2.7 6.0 0.2 0.4 0.0 100.6 AUGUST 2009 Step Smooth Lower Vine 57.7 22.7 17.0 0.7 2.0 0.6 0.4 0.0 100.9 AUGUST 2009 Step Smooth Lower Average 65.6 12.1 17.2 1.3 3.6 0.3 0.2 0.1 100.4 AUGUST 2009 Step Smooth Lower SE 10.7 10.7 2.9 1.5 2.2 0.1 0.1 0.1 AUGUST 2009 Step Cobble Upper Aquarium 52.7 5.0 42.3 0.0 0.0 0.0 0.2 0.0 100.2 AUGUST 2009 Step Cobble Upper Clay 81.0 6.0 13.7 0.0 0.0 0.2 0.2 0.0 101.1 AUGUST 2009 Step Cobble Upper Vine 79.3 3.3 10.3 0.0 7.7 0.0 0.1 0.0 100.8 AUGUST 2009 Step Cobble Upper Average 71.0 4.8 22.1 0.0 2.6 0.1 0.2 0.0 100.7 AUGUST 2009 Step Cobble Upper SE 10.8 1.0 10.7 0.0 3.8 0.1 0.2 0.0 AUGUST 2009 Step Cobble Middle Aquarium 40.3 10.3 47.2 0.0 2.0 1.4 1.1 0.0 102.4 AUGUST 2009 Step Cobble Middle Clay 51.0 16.0 29.0 0.0 4.0 0.5 2.3 0.0 102.8 AUGUST 2009 Step Cobble Middle Vine 41.3 14.0 38.7 0.0 6.0 0.4 1.9 0.0 102.3 AUGUST 2009 Step Cobble Middle Average 44.2 13.4 38.3 0.0 4.0 0.8 1.8 0.0 102.5 AUGUST 2009 Step Cobble Middle SE 7.6 3.9 9.4 0.0 3.0 0.4 0.5 0.0 AUGUST 2009 Step Cobble Lower Aquarium 55.0 10.0 33.0 1.3 0.0 1.0 0.4 0.2 100.9 AUGUST 2009 Step Cobble Lower Clay 13.3 37.7 18.0 2.7 25.3 0.4 2.8 0.7 100.9 AUGUST 2009 Step Cobble Lower Vine 48.3 6.0 27.0 1.3 17.3 1.3 1.3 0.0 102.6 AUGUST 2009 Step Cobble Lower Average 38.9 17.9 26.0 1.8 14.2 0.9 1.5 0.3 101.5 AUGUST 2009 Step Cobble Lower SE 15.5 10.8 4.5 1.1 15.0 0.5 0.8 0.4 AUGUST 2009 Fin Smooth Upper Aquarium 36.3 7.3 56.3 0.0 0.0 0.5 0.3 0.0 100.8 AUGUST 2009 Fin Smooth Upper Clay 37.0 8.7 42.3 0.0 11.3 0.7 0.6 0.0 100.6 AUGUST 2009 Fin Smooth Upper Vine 24.0 8.7 28.0 0.0 40.3 0.0 0.0 0.0 101.0 AUGUST 2009 Fin Smooth Upper Average 32.4 8.2 42.2 0.0 17.2 0.4 0.3 0.0 100.8

AUGUST 2009 Fin Smooth Upper SE 9.0 2.1 11.8 0.0 12.1 0.3 0.2 0.0 AUGUST 2009 Fin Smooth Middle Aquarium 58.0 8.0 34.0 0.0 0.0 0.6 0.3 0.0 100.9 AUGUST 2009 Fin Smooth Middle Clay 70.0 6.7 12.0 0.0 11.3 0.2 1.0 0.0 101.2 AUGUST 2009 Fin Smooth Middle Vine 45.0 6.0 19.3 0.0 29.3 0.5 0.7 0.0 100.8 AUGUST 2009 Fin Smooth Middle Average 57.7 6.9 21.8 0.0 13.6 0.4 0.7 0.0 101.0 AUGUST 2009 Fin Smooth Middle SE 15.3 2.7 8.1 0.0 11.4 0.2 0.4 0.0 AUGUST 2009 Fin Smooth Lower Aquarium 55.7 4.7 24.3 1.3 14.0 1.0 0.3 0.0 101.3 AUGUST 2009 Fin Smooth Lower Clay 48.7 8.7 18.7 5.3 18.7 0.2 1.8 0.0 102.0 AUGUST 2009 Fin Smooth Lower Vine 25.0 6.7 17.7 2.3 48.0 0.4 0.1 0.1 100.3 AUGUST 2009 Fin Smooth Lower Average 43.1 6.7 20.2 3.0 26.9 0.5 0.7 0.0 101.2 AUGUST 2009 Fin Smooth Lower SE 11.0 2.2 7.9 2.3 15.1 0.3 0.6 0.0 AUGUST 2009 Fin Cobble Upper Aquarium 57.0 10.7 32.5 0.0 0.0 0.2 0.2 0.0 100.6 AUGUST 2009 Fin Cobble Upper Clay 43.0 14.7 42.3 0.0 0.0 0.1 1.4 0.0 101.5 AUGUST 2009 Fin Cobble Upper Vine 59.7 6.7 31.0 0.0 2.7 0.4 1.7 0.0 102.1 AUGUST 2009 Fin Cobble Upper Average 53.2 10.7 35.3 0.0 0.9 0.3 1.1 0.0 101.4 AUGUST 2009 Fin Cobble Upper SE 7.6 3.9 7.4 0.0 1.5 0.1 0.6 0.0 AUGUST 2009 Fin Cobble Middle Aquarium 54.0 8.7 37.2 0.0 0.0 1.0 0.7 0.0 101.6 AUGUST 2009 Fin Cobble Middle Clay 54.7 14.0 31.2 0.0 0.0 0.2 2.2 0.0 102.2 AUGUST 2009 Fin Cobble Middle Vine 58.7 10.0 21.3 0.0 10.0 0.4 0.6 0.0 101.0 AUGUST 2009 Fin Cobble Middle Average 55.8 10.9 29.9 0.0 3.3 0.5 1.2 0.0 101.6 AUGUST 2009 Fin Cobble Middle SE 7.6 3.1 7.9 0.0 5.0 0.3 0.5 0.0 AUGUST 2009 Fin Cobble Lower Aquarium 57.3 6.0 31.0 2.0 4.0 1.1 0.7 0.0 102.2 AUGUST 2009 Fin Cobble Lower Clay 31.3 23.3 20.0 1.7 23.7 1.1 2.1 0.0 103.2 AUGUST 2009 Fin Cobble Lower Vine 16.3 7.7 33.3 3.0 39.7 0.2 0.5 0.3 101.1 AUGUST 2009 Fin Cobble Lower Average 35.0 12.3 28.1 2.2 22.4 0.8 1.1 0.1 102.2 AUGUST 2009 Fin Cobble Lower SE 13.9 7.3 10.5 1.8 16.3 0.3 0.7 0.2

APPENDIX B

Fish observations Fish observations occurred bi-weekly during peak juvenile salmon (JS) rearing and migration (estimated April-July in 2008 and 2009) at high tides when panels were submerged.

2009 fish observations were delayed due to the late appearance of JS at the nearby Olympic Sculpture Park (OSP) monitoring. Heavy rain and wind the week of May 4 further delayed observations until May 11, 2009.

2008 2009

4/16/2008 late arrival of outmigrating juvenile 4/17/2008 salmon followed by poor visibility 5/5/2008

5/15-16/2008 5/12/2009

6/2/2008 6/2/2009

6/12-13/2008 6/18/2009

7/1/2008 7/2/2009

7/14/2008 7/17/2009

7/24/2008 Poor visibility

7/30/2008 7/30/2009

Methods: Fish Presence and Behavior Fish presence and behavior was characterized using a combination of overwater observations and underwater video during high tides when the panels were completely submerged. Overwater observations included walking transects along the seawall looking down from the sidewalk level with polarized glasses. Observations included schools and, if possible, species, adjacent to the seawall at habitat test panel sites. Underwater video transects were performed at each site in 2008. The underwater video camera was kept at approximately 5-6 feet from the seawall, capturing the majority of habitat test panel elevation. The following data was logged from overwater observations:

o Fish species (when possible) and approximate count o Water column position of fish (surface, mid-water, bottom) o Distance from shoreline (seawall) o Fish behavior (unaffected, swimming away, fleeing, feeding, not moving, schooling, hiding)

Results Results from overwater observations indicate juvenile salmon are abundant along the seawall, occur closer to the seawall than in deeper areas, and are feeding along the seawall.

% Fish Composition along downtown seawall, 2008-2009

Chinook/Coho

Chum Shiner Perch

Pile Perch Chum/Pink Perch Surf Smelt Herring

Juvenile Salmon, unk. Trout

Closest distance from sidewalk overhang of fish observations, 2008-2009 4000 Juvenile 3500 Salmon Shiner Perch 3000 2500 Herring 2000 1500

number offish number 1000 500 0 0 1 2 4 5 6 8 10 >10 Distance from sidewalk overhang (feet)

Fish Behavior along downtown seawall, 2008-2009

100%

80%

Unaffected 60% Swimming Schooling/Swimming Schooling 40% Fleeing Feeding

20%

0% Herring Juvenile Salmon Shiner Perch

Underwater video was of poor quality and data extracted from it could not reliably be standardized by distance or time due to constraints while capturing the video. JS seemed to also avoid the camera while it was in the water, creating a halo effect of fish 2-3 feet from the camera (which was sometimes beyond the visibility). JS also seemed to be startled from overwater movement from the suspension pole used during filming transects. Qualitatively, underwater observations from video did not reveal any striking patterns. Short video clips do reveal JS and other fish in close proximity to the seawall and habitat test panels.

APPENDIX C Complete taxa list from epibenthic sampling with total number of taxa by panel type and sample counts of individuals by taxa

across all sites and sampling events.

Control

Reference

Fin Cobble Fin

Flat Cobble Flat

Fin Smooth Fin

Step Cobble Step

Flat Smooth Flat Step Smooth Step

Total Taxa Count by Panel Type 71 75 76 80 85 79 98 90

Major Groupings Lowest Grouping Amphipod Gammarid amphipod Ampithoe dalli 1 Ampithoe sp. 1 1 1 Gammarid amphipod Aoroides sp. 1 1 Gammarid amphipod Calliopiidae juvenile 183 364 280 151 183 176 300 223 Calliopius sp. 781 1437 1728 2783 1312 1400 1505 1422 Gammarid amphipod Corophiidae juveniles 1 1 Monocorophium sp. juv. 1 Dulichia sp. 1 Gammarid amphipod Gammaridea juvenile 324 1339 590 1323 184 753 1098 1751 Paracalliopiella pratti 9873 15076 13819 16308 6227 9976 9506 8011 Oligochinus lighti 1 1 Protohyale frequens 16 13 3 2 1 9 3 19 Protohyale sp. juveniles 62 34 3 173 39 25 17 49 Ischyrocerus sp. 2 2 2 2 1 Hyale sp. 5 Hyalidae 1 1 5 1 Hyalidae juveniles 1 1 Gammarid amphipod Desdimelita desdichada 1 Gammarid amphipod Jassa sp. 1 Pontogenia rostrata 1 19 4 3 Annelids Polychaete Ampharetidae juveniles 3 Polychaeta 2 1 3 5 2 2 6 Polychaeta larva 1 2 2 6 2 5 3 Spionidae juveniles 2 1 1 1 1 Syllidae juveniles 1 1 2 Barnacles Balanomorpha 33 68 177 284 336 303 238 449 Barnacle cyprid 47 44 67 184 172 209 190 238 Barnacle exuvia 169 66 40 130 144 184 219 249 Barnacle nauplii 101 108 49 31 176 161 191 199 Copepods 95

Cyclopoid Clausidiidae 1 Cyclopoid Cyclopoidia 1 1 6 4 4 4 Corycaeus anglicus 1 2 Harpacticoid Ameiridae 16 58 13 14 113 48 61 25 Amenophia sp. 2 Amonardia normani 1 Amonardia perturbata 7 15 6 4 34 15 23 19 Amphiascoides sp. 1 3 3 10 4 Amphiascopsis cinctus 17 38 7 92 32 64 67 121 Amphiascus sp. 1 3 2 5 13 7 33 6 Bulbamphiascus sp. 1 Dactylopusia cf. glacialis 76 36 18 39 141 74 72 49 Dactylopusia copepodids 57 12 7 10 80 74 35 35 Dactylopusia crassipes 16 6 12 12 71 18 16 25 Dactylopusia sp. 1 3 2 4 4 Dactylopusia vulgaris 2 3 1 19 9 19 16 Danielssenia typica 1 Diarthrodes sp. 23 14 14 5 61 25 79 52 Diosaccus spinatus 35 270 149 174 145 127 203 84 Echinolaophonte sp. 1 1 1 8 1 Ectinosomatidae 68 49 28 35 85 64 37 28 Harpacticoida copepodid (unidentified) 18 17 17 10 106 41 28 15 Harpacticoida nauplii 1 1 Harpacticoida other 1 1 1 Harpacticus compressus 71 60 45 82 261 174 191 141 Harpacticus obscurus grp 15 14 26 19 98 47 60 52 Harpacticus septentrionalis 15 10 30 27 50 94 74 40 Harpacticus sp copepodid 66 76 141 548 1001 587 932 734 Harpacticus sp. A 57 48 81 44 219 170 370 137 Harpacticus sp. B 26 35 86 158 323 202 199 217 Harpacticus sp. nauplii 3 Harpacticus spp. 2 5 Harpacticus uniremis 5 3 3 13 3 16 3 Heterolaophonte discophora 1 Heterolaophonte longisetigera 14 8 8 71 54 38 77 58 Heterolaophonte sp. A 142 75 159 292 170 304 507 267 Idomene purpurocincta 1 3 2 Laophonte cornuta 1 2 1 5 1 14 8 Laophonte elongata 1 1 Laophontidae copepodid 14 2 1 9 8 9 21 17 Laophontidae unidentified 4 1 2 2 8 6 Leimia vaga 2 Mesochra pygmaea 12 6 11 16 34 19 43 19

Paradactylopodia spp. 2 3 2 3 30 8 1 6 Paralaophonte perplexa group 4 12 5 8 30 18 38 32 Paralaophonte sp. 1 1 1 2 Parastenhelia hornelli 1 Parastenhelia spinosa 9 12 9 13 70 6 18 10 Parathalestris sp. 5 10 2 3 3 4 7 Peltidium sp. 3 6 7 13 9 1 3 1 Porcellidium sp. 1 1 Pseudonychocamptus sp. 1 1 Rhynchothalestris helgolandica 5 8 15 22 101 64 44 25 Robertsonia cf. knoxi 1 1 2 2 2 1 Scutellidium sp. 1 1 3 2 8 2 Stenhelia sp. 1 1 2 Tegastidae 1 2 3 4 5 3 Thalestridae unidentified 1 Thalestris sp. 1 1 Tisbe spp. 215 321 123 257 378 271 217 178 Zaus spp. 41 46 39 42 94 85 38 39 Other crustacean Caprellid Amphipod Caprella laeviuscula 1 Caprella sp. 1 Decapod Cancridae megalopa 1 Pinnotheridae 1 Pinnotheridae zoea 2 Cumacean Cumella vulgaris 1 1 Tanaidaceani Leptochelia savignyi 1 Decapod Heptacarpus 1 Tanaidacean Tanaidacea 1 Mollusks Gastropod Acmaeidae juveniles 4 3 1 2 4 3 Juvenile Gastropoda 7 9 4 16 20 14 24 Littorina egg case 9 16 3 11 27 41 47 25 Littorina scutulata 2 Littorina sp. 1 Bivalve Mytilus sp. juveniles 68 88 71 124 976 2143 1536 723 Opisthobranch Sacoglossa 1 Gastropod Gastropoda 1 1 1 3 3 1 4 5 Insect Chironomid Chironomidae adults 1 1 1 1 Chironomidae larvae 209 200 771 522 2895 1879 1801 2201 Chironomidae pupae 1 3 8 4 6 13 15 Coleopteran Coleoptera larvae 1 1 1 1 2 3 Collembolan Collembola 1 1 1

Hypogastruridae 1 1 1 Dipteran Diptera adults 1 Diptera pupae 2 1 1 7 7 Staphylinid Staphylinidae 1 1 Thysanopteran Thysanoptera 1 1 Isopod Isopod Idotea spp. 1 2 Idotea wonsnesenskii 1 1 Dynamenella glabra 1 1 1 2 Dynamenella sheareri 5 4 2 4 5 1 2 1 Epicaridea 7 4 4 3 7 4 7 7 Exosphaeroma inornata 2 1 Exosphaeroma sp. 1 3 Gnorimosphaeroma insulare 1 2 1 Gnorimosphaeroma oregonense 3 2 1 3 Munna sp. 1 Sphaeromatidae 2 1 1 3 2 Uromunna ubiquita 1 Isopod Isopoda unidentified 2 Other Larval Fish Cottidae juveniles 1 Teleosti larvae 1 Acarina Acarina 178 129 191 273 515 321 349 424 Hydrozoan Hydrozoa 1 1 3 1 1 Foraminiferan Foraminiferan 5 35 8 46 99 69 320 218 Nematode Nematoda adult 24 26 13 32 140 116 199 94 Polychaete Nereidae juveniles 2 Oligochaete Oligochaeta 1 1 Opisthobranch Opisthobranchia 1 1 Ostracod Ostracoda 3 2 4 21 5 111 38 Isopod. Pseudosphaeroma sp. 1 Calanoid Stephos sp. 1 2 Turbellarian Turbellaria 2 1 6 7 5 12 9