Section 2: Context

Section 2 sets a foundation for understanding the Salish Sea ecosystem by describing its fundamental biophysical processes and structure, including estuarine circulation, ecological productivity, and an overview of several important biogenic habitats

Section 6: Opportunities for Improving Assessment and Understanding of the Salish Sea

Section 6 offers a list of science-based needs and opportunities brought to light by the report and various existing efforts within the Salish Sea science community, representing opportunities for greater collaboration across geographic and jurisdictional boundaries

State of the Salish Sea: Executive Summary

This report synthesizes information on past, current, and emerging stressors within the Salish Sea estuarine ecosystem. The Salish Sea is a complex waterbody shared by Coast Salish Tribes and First Nations, Canada, and the United States. It is defined by multiple freshwater inputs and marine water from the Pacific Ocean that mix in two primary basins, Puget Sound and the Strait of Georgia. Human impacts are multifaceted and extensive within the Salish Sea, with a regional population of almost 9 million people. Population growth has driven urbanization and development, which in turn has triggered structural changes to the landscape and seascape. Meanwhile, the growing effects of climate change are fundamentally altering physical and biological processes. The report describes the most pervasive and damaging impacts affecting the transboundary ecosystem, recognizing that some are generated locally while others are the locally realized impacts from global-scale changes in climate, oceans, land use, and biodiversity. The Salish Sea is under relentless pressure from an accelerating convergence of global and local environmental stressors and the cumulative impacts of 150 years of development and alteration of our watersheds and seascape. Some of these impacts are well understood but many remain unknown or are difficult to predict. While strong science is critical to understanding the ecosystem, the report provides a spectrum of ideas and opportunities for how governments, organizations, and individuals can work together to meet the needs of science and science-driven management that will sustain the Salish Sea estuarine ecosystem

Section 4: Climate Change: A Global Problem With Local Impacts

Section 4 shifts from the local impacts of urbanization to the locally realized impacts of global climate change, including ocean acidification and sea level rise, followed by evidence of climate change in the ecosystem, ranging from phytoplankton and kelp, to wetlands, salmon, and marine birds

Section 1: Introduction

Section 1 is an introduction to the report and the Salish Sea as a whole. The introduction provides an overview of the Salish Sea, the concept of ecosystem health, and a roadmap to the rest of the report

Section 3: Urbanization and Human Impacts to the Seascape

Section 3 turns to an in-depth discussion of stressors and impacts to the ecosystem from population growth and urbanization, such as increases in impervious surfaces, hardening of shorelines, and the problems caused by a myriad of marine contaminants

Fishes in Seagrass Habitats: Species Composition, Trophic Interactions, and Production

The value of habitats in terms of biological production is of interest to ecologists and resource managers. Seagrasses are a commonly occurring habitat type in shallow marine waters and have been shown to support high abundances of fish and invertebrates. In lower Chesapeake Bay, seagrasses grow in a shallow fringe in the subtidal zone. Although, ample evidence exists for the value of these habitats as foraging and rearing areas for a variety of organisms, the connectivity among species and the benefits derived from these habitats in terms of production have not been well described, especially for small, seasonally occurring finfishes. The main objective of this research was to document fish occurrence and abundance, describe trophic interactions within the seagrass community, and quantify export of biomass from the habitat using a model species to demonstrate the value of these habitats in terms of finfish production.;To address the research objective, I employed a variety of models---statistical, ecosystem, and individual-based. In Chapter 1, I conducted as census of finfishes in seagrass habitats and compared contemporary occurrences and abundances to data from the 1970s. This chapter showed that the fish fauna in these habitats is dominated by a small number of abundant and commonly occurring species, including Spot (Leiostomus xanthurus), Silver Perch ( Bairdiella chrysoura), Bay Anchovy (Anchoa mitchilli), Atlantic Silverside (Menidia menidia), Dusky Pipefish ( Syngnathus floridae), and Northern Pipefish (Syngnathus fuscus ). While abundances had changed since the 1970s for some species, most were highly variable with no discernible trend. There was a small decrease in species richness from the historical dataset to the contemporary dataset and multivariate analysis showed a shift in community composition. The data from this chapter formed the basis for the ecosystem model developed in Chapter 2. In this model, biomass, production, and diet data were inputs, and using a mass-balance approach, a food web model was iteratively developed. There were 35 model compartments in the model and scenarios based upon historical data and future projections were developed for comparison. Mesozooplankton were the most highly connected group, while piscivorous birds, several piscivorous fishes, and mesograzers were all considered keystone groups, controlling food web dynamics. In Chapter 3, an individual-based model was developed for Silver Perch, to assess growth and production within a seagrass habitat. Because Silver Perch settle in this habitat, grow during the summer season, and migrate to deeper waters in the fall, they were an appropriate model species for determining the contribution of seagrass habitats to production. With high seasonal abundance and rapid growth (~0.19 g/d), this species contributes a considerable amount of biomass to Chesapeake Bay, biomass that originates in seagrass habitats and moved via trophic transfer.;This study presents a quantitative view of community ecology in lower Chesapeake Bay seagrass habitats. With changing temperatures and habitat loss, these habitats are at risk, and this study demonstrates that their value to the Chesapeake Bay food web extends beyond the small fringe of their occurrence

Section 7: The Future of the Salish Sea? A Call to Action

Section 7 provides perspective from the Salish Sea Institute, acknowledging that science alone will not resolve continuing problems or emerging issues. Stronger policies along with education, leadership, and collaboration are needed

Comparing marine survival among Chinook and coho salmon and steelhead trout in the Salish Sea

Recent work on marine survival in Chinook and coho salmon and steelhead trout has shown a decline in marine survival in the Salish Sea that was not evident in other regions. For Chinook, the decline was not explained well by oceanographic patterns, and for coho, regional-scale patterns were suggested as important in understanding survival. Recent work on the development of indicators of Puget Sound steelhead survival has shown that predator abundance and patterns in hatchery releases, as well as oceanographic conditions are informative in predicting marine survival. While the three species of focus for the Salish Sea Marine Survival Project have different life-histories, and are therefore subjected to variable pressures at multiple scales, this current analysis aims to answer three questions: 1.) Are there similarities in survival trends among the three species? 2.) Do regional patterns in survival emerge when survival trends are evaluated concurrently across the three species? 3.) Does release strategy (yearling or subyearling) confer a survival advantage, and if so, is this consistent across all species? To evaluate survival time series, we used multivariate time series analysis with multiple groupings (species, spatial, and release strategy) to identify commonalities among species. Observed commonalities will aid in the development of indicators of marine survival for coho and Chinook by focusing efforts on appropriate spatial or temporal attributes. A hypothesis-driven approach similar to that employed for the development of indicators for steelhead survival will be used to relate coho and Chinook to environmental, biological, and anthropogenic factors influencing survival

The combined effects of acidification and acute warming on the embryos of Pacific herring (Clupea pallasii)

Anthropogenic climate change is projected to affect marine ecosystems by challenging the environmental tolerance of individuals. Marine fishes may be particularly vulnerable to emergent climate stressors during early life stages. Here we focus on embryos of Pacific herring (Clupea pallasii), an important forage fish species widely distributed across the North Pacific. Embryos were reared under a range of temperatures (10-16°C) crossed with two pCO2 levels (600 and 2000 μatm) to investigate effects on metabolism and survival. We further tested how elevated pCO2 affects critical thermal tolerance (CTmax) by challenging embryos to short-term temperature fluctuations. Experiments were repeated on embryos collected from winter and spring spawning populations to determine if spawning phenology corresponds with different limits of environmental tolerance in offspring. We found that embryos could withstand acute exposure to 20°C regardless of spawning population or incubation treatment, but that survival was greatly reduced after 2-3 hours at 25°C. We found that pCO2 had limited effects on CTmax. The survival of embryos reared under chronically warm conditions (12°, 14°, or 16°C) was significantly lower relative to 10°C treatments in both populations. Oxygen consumption rates (MO2) were also higher at elevated temperatures and pCO2 levels. However, heart contraction measurements made 48 hours after CTmax exposure revealed a greater increase in heart rate in embryos reared at 10°C compared to 16°C, suggesting acclimation at higher incubation temperatures. Our results indicate that Pacific herring are generally tolerant of pCO2 but are vulnerable to acute temperature stress. Importantly, spring-spawning embryos did not clearly exhibit a higher tolerance to heat stress compared to winter offspring