Baseline assessment of Guánica Bay, Puerto Rico in support of watershed restoration

Guánica Bay is a major estuary on the southwest coast of Puerto Rico. Significant coral reef ecosystems are present outside the bay. These valuable habitats may be impacted by transport of sediments, nutrients and contaminants from the watershed, through the bay and into the offshore waters. The National Oceanic and Atmospheric Administration’s (NOAA) National Centers for Coastal Ocean Science (NCCOS), in consultation with local and regional experts, conducted an interdisciplinary assessment of coral reef ecosystems, contaminants, sedimentation rates and nutrient distribution patterns in and around Guánica Bay. This work was conducted using many of the same protocols as ongoing monitoring work underway elsewhere in the U.S. Caribbean and has enabled comparisons among coral reef ecosystems between this study and other locations in the region. This characterization of Guánica marine ecosystems establishes benchmark conditions that can be used for comparative documentation of future change, including possible negative outcomes due to future land use change, or improvement in environmental conditions arising from management actions. This report is organized into six chapters that represent a suite of interrelated studies. Chapter 1 provides a short introduction to the study area. Chapter 2 is focused on biogeographic assessments and benthic mapping of the study area, including new surveys of fish, marine debris and reef communities on hardbottom habitats in the study area. Chapter 3 quantifies the distribution and magnitude of a suite of contaminants (e.g., heavy metals, PAHs, PCBs, pesticides) in both surface sediments and coral tissues. Chapter 4 presents results of sedimentation measurements in and outside of the bay. Chapter 5 examines the distribution of nutrients in in the bay, offshore from the bay and in the watershed. Chapter 6 is a brief summary discussion that highlights key findings of the entire suite of studies.

Support for integrated ecosystem assessments of NOAA’s National Estuarine Research Reserve System (NERRS): assessment of ecological condition and stressor impacts in subtidal waters of the Sapelo Island National Estuarine Research Reserve

A study was conducted in June 2009 to assess the current status of ecological condition and potential human-health risks throughout subtidal estuarine waters of the Sapelo Island National Estuarine Research Reserve (SINERR) along the coast of Georgia. Samples were collected for multiple indicators of ecosystem condition, including water quality (dissolved oxygen, salinity, temperature, pH, nutrients and chlorophyll, suspended solids, fecal coliform bacteria and coliphages), sediment quality (granulometry, organic matter content, chemical contaminant concentrations), biological condition (diversity and abundance of benthic fauna, fish tissue contaminant levels and pathologies), and human dimensions (fish-tissue contaminant levels relative to human-health consumption limits, various aesthetic properties). Use of a probabilistic sampling design facilitated the calculation of statistics to estimate the spatial extent of the Reserve classified according to various categories (i.e., Good, Fair, Poor) of ecological condition relative to established thresholds of these indicators, where available. Overall, the majority of subtidal habitat in the SINERR appeared to be healthy, with over half (56.7 %) of the Reserve area having water quality, sediment quality, and benthic biological condition indicators rated in the healthy to intermediate range of corresponding guideline thresholds. None of the stations sampled had one or more indicators in all three categories rated as poor/degraded. While these results are encouraging, it should be noted that one or more indicators were rated as poor/degraded in at least one of the three categories over 40% of the Reserve study area, represented by 12 of the 30 stations sampled. Although measures of fish tissue chemical contamination were not included in any of the above estimates, a number of trace metals, pesticides, polybrominated diphenyl ethers (PBDEs), and polychlorinated biphenyls (PCBs) were found at low yet detectable levels in some fish at stations where fish were caught. Levels of mercury and total PCBs in some fish specimens fell within EPA guideline values considered safe, given a consumption rate of no more than four fish meals per month. Moreover, PCB congener profiles in sediments and fish in the SINERR exhibit a relative abundance of higher-chlorinated homologs which are uniquely characteristic of Aroclor 1268. It has been well-documented that sediments and fish in the creeks and marshes near the LCP Chemicals Superfund site, near Brunswick, Georgia, also display this congener pattern associated with Aroclor 1268, a highly chlorinated mixture of PCBs used extensively at a chlor-alkali plant that was in operation at the LCP site from 1955-1994. This report provides results suggesting that the protected habitats lying within the boundaries of the SINERR may be experiencing the effects of a legacy of chemical contamination at a site over 40km away. These effects, as well as other potential stressors associated with increased development of nearby coastal areas, underscore the importance of establishing baseline ecological conditions that can be used to track potential changes in the future and to guide management and stewardship of the otherwise relatively unspoiled ecosystems of the SINERR.

Assessment of natural resource conditions in and adjacent to Dry Tortugas National Park

This project characterized and assessed the condition of coastal water resources in the Dry Tortugas National Park (DRTO) located in the Florida Keys. The goal of the assessment was to: (1) identify the state of knowledge of natural resources that exist within the DRTO, (2) summarize the state of knowledge about natural and anthropogenic stressors and threats that affected these resources, and (3) describe strategies being implemented by DRTO managers to meet their resource management goals. The park, located in the Straits of Florida 113 km (70 miles) west of Key West, is relatively small (269 square kilometers) with seven small islands and extensive shallow water coral reefs. Significant natural resources within DRTO include coastal and oceanic waters, coral reefs, reef fisheries, seagrass beds, and sea turtle and bird nesting habitats. This report focuses on marine natural resources identified by DRTO resource managers and researchers as being vitally important to the Tortugas region and the wider South Florida ecosystem. Selected marine resources included physical resources (geology, oceanography, and water quality) and biological resources (coral reef and hardbottom benthic assemblages, seagrass and algal communities, reef fishes and macro invertebrates, and wildlife [sea turtles and sea-birds]). In the past few decades, some of these resources have deteriorated because of natural and anthropogenic factors that are local and global in scale. To meet mandated goals (Chapter 1), resource managers need information on: (1) the types and condition of natural and cultural resources that occur within the park and (2) the stressors and threats that can affect those resources. This report synthesizes and summarizes information on: (1) the status of marine natural resources occurring at DRTO; and (2) types of stressors and threats currently affecting those resources at the DRTO. Based on published information, the assessment suggests that marine resources at DRTO and its surrounding region are affected by several stressors, many of which act synergistically. Of the nine resource components assessed, one resource category – water quality – received an ecological condition ranking of "Good"; two components – the nonliving portion of coral reef and hardbottom and reef fishes – received a rating of "Caution"; and two components – the biotic components of coral reef and hardbottom substrates and sea turtles – received a rating of "Significant concern" (Table E-1). Seagrass and algal communities and seabirds were unrated for ecological condition because the available information was inadequate. The stressor category of tropical storms was the dominant and most prevalent stressor in the Tortugas region; it affected all of the resource components assessed in this report. Commercial and recreational fishing were also dominant stressors and affected 78% of the resource components assessed. The most stressed resource was the biotic component of coral reef and hardbottom resources, which was affected by 76% of the stressors. Water quality was the least affected; it was negatively affected by 12% of stressors. The systematic assessment of marine natural resources and stressors in the Tortugas region pointed to several gaps in the information. For example, of the nine marine resource components reviewed in this report, the living component of coral reefs and hardbottom resources had the best rated information with 25% of stressor categories rated "Good" for information richness. In contrast, the there was a paucity of information for seagrass and algal communities and sea birds resource components.

An integrated biogeographic assessment of reef fish populations and fisheries in Dry Tortugas: Effects of No-take Reserves

The Tortugas Integrated Biogeographic Assessment presents a unique analysis of demographic changes in living resource populations, as well as societal and socioeconomic benefits that resulted from the Tortugas Ecological Reserves during the first five years after their implementation. In 2001, state and federal agencies established two no-take reserves within the region as part of the Florida Keys National Marine Sanctuary. The northern reserve (Tortugas Ecological Reserve North) was established adjacent to the Dry Tortugas National Park, which was first declared a national monument in 1935. The reserves were designed to protect a healthy coral reef ecosystem that supports diverse faunal assemblages and fisheries, serves as important spawning grounds for groupers and snappers, and includes essential feeding and breeding habitats for seabirds. The unique ecological qualities of the Tortugas region were recognized as far back as 1850, and it remains an important ecosystem and research area today. The two main goals of the Tortugas Ecological Reserve Integrated Ecological Assessment were: 1) to determine if demographic changes such as increases in abundance, average size and spawning potential of exploited populations occurred in the Tortugas region after reserve implementation; and 2) whether short-term economic losses occurred to fishers displaced by the reserve. This project utilized a biogeographic approach in which information on the physical features (i.e., habitat) and oceanographic patterns were first used to determine the spatial distribution of selected fish populations within and outside the Tortugas Ecological Reserve. Before-and-after reserve implementation comparisons of selected fish populations were then conducted to determine if demographic changes occurred in reef fish assemblages. These comparisons were done for the Tortugas region and also for a subset of available habitats within the Tortugas Ecological Reserve Study Area. Social and economic impacts of the reserves were determined through: 1) analyses of commercial landings and revenues from fishers, operating in the Tortugas region before and after reserve implementation and 2) surveys of recreational tour guides. Analyses of the commercial landings and revenues excluded areas inside Dry Tortugas National Park because commercial fishing has been prohibited within park boundaries since 1992. Key findings and outcomes of this integrated ecological assessment are organized by chapter and listed below.

Baseline assessment of Fish and Coral bays, St. John, U.S. Virgin Islands in support of watershed restoration activities, part I: fish, coral and benthic habitats

This report provides baseline biological data on fishes, corals and habitats in Coral and Fish Bays, St. John, USVI. A similar report with data on nutrients and contaminants in the same bays is planned to be completed in 2013. Data from NOAA’s long-term Caribbean Coral Reef Ecosystem Monitoring program was compiled to provide a baseline assessment of corals, fishes and habitats from 2001 to 2010, data needed to assess the impacts of erosion control projects installed from 2010 to 2011. The baseline data supplement other information collected as part of the USVI Watershed Stabilization Project, a project funded by the American Recovery and Reinvestment Act of 2009 and distributed through the NOAA Restoration Center, but uses data which is not within the scope of ARRA funded work. We present data on 16 ecological indicators of fishes, corals and habitats. These indicators were chosen because of their sensitivity to changes in water quality noted in the scientific literature (e.g., Rogers 1990, Larsen and Webb 2009). We report long-term averages and corresponding standard errors, plot annual averages, map indicator values and list inventories of coral and fish species identified among surveys. Similar data will be needed in the future to make rigorous comparisons and determine the magnitude of any impacts from watershed stabilization.

A baseline assessment of the ecological resources of Jobos Bay, Puerto Rico

This baseline assessment of Jobos Bay and surrounding marine ecosystems consists of a two part series. The first report (Zitello et al., 2008) described the characteristics of the Bay and its watershed, including modeling work related to nutrients and sediment fluxes, based on existing data. The second portion of this assessment, presented in this document, presents the results of new field studies conducted to fill data gaps identified in previous studies, to provide a more complete characterization of Jobos Bay and the surrounding coral reef ecosystems. Specifically, the objective was to establish baseline values for the distribution of habitats, nutrients, contaminants, fi sh, and benthic communities. This baseline assessment is the first step in evaluating the effectiveness in changes in best management practices in the watershed. This baseline assessment is part of the Conservation Effects Assessment Project (CEAP), which is a multi-agency effort to quantify the environmental benefits of conservation practices used by agricultural producers participating in selected U.S. Department of Agriculture (USDA) conservation programs. Partners in the CEAP Jobos Bay Special Emphasis Watershed (SEW) included USDA’s Agricultural Research Service (ARS) and the Natural Resources Conservation Service (NRCS), National Oceanic and Atmospheric Administration (NOAA) and the Government of Puerto Rico. The project originated from an on-going collaboration between USDA and NOAA on the U.S. Coral Reef Task Force. The Jobos Bay watershed was chosen because the predominant land use is agriculture, including agricultural lands adjacent to the Jobos Bay National Estuarine Research Reserve (JBNERR or Reserve), one of NOAA’s 26 National Estuarine Research Reserves (NERR). This report is organized into six chapters that represent a suite of interrelated studies. Chapter 1 provides a short introduction to Jobos Bay, including the land use and hydrology of the watershed. Chapter 2 is focused on benthic mapping and provides the methods and results of newly created benthic maps for Jobos Bay and the surrounding coral reef ecosystem. Chapter 3 presents the results of new surveys of fish, marine debris, and reef communities of the system. Chapter 4 is focused on the distribution of chemical contaminants in sediments within the Bay and corals outside of the Bay. Chapter 5 focuses on quantifying nutrient and pesticide concentrations in the surface waters at the Reserve’s System-Wide Monitoring Program (SWMP) sites. Chapter 6 is a brief summary discussion that highlights key findings of the entire suite of studies.

A biogeographic assessment of the Samoan Archipelago

This report examines the marine biogeography of the Samoan Archipelago (~14º S latitude along the international date-line) with a focus on regional ocean climate, connectivity among islands due to larval transport, distributions of reef fish and coral communities, and the extent of existing marine protected areas. Management decisions and prior assessments in the archipelago have typically been split along the international political boundary between the islands of Samoa and those of American Samoa despite their close proximity and shared resources. A key goal in this assessment was to compile data from both jurisdictions and to conduct the characterization across the entire archipelago. The report builds upon earlier assessments by re-analyzing and interpreting many pre-existing datasets, adding more recent biogeographic data sources, and by combining earlier findings into a multidisciplinary summary of marine biogeography. The assessment is divided into 5 chapters and supporting appendices. Each chapter was written and reviewed in collaboration with subject matter specialists and local experts. In Chapter 1, a short introduction to the overall scope and approach of the report is provided. In Chapter 2, regional ocean climate is characterized using remote sensing datasets and discussed in the context of local observations. In Chapter 3, regional ocean currents and transport of coral and fish larvae are investigated among the islands of the archipelago and surrounding island nations. In Chapter 4, distinct reef fish and coral communities across the archipelago are quantified on the basis of overall biodiversity, abundance, and community structure. In Chapter 5, the existing network of MPAs in American Samoa is evaluated based on the habitats, reef fish, and coral communities that are encompassed. Appendices provide analytical details omitted from some chapters for brevity as well as supplemental datasets needed as inputs for the main chapters in the assessment. Appendices include an inventory of regional seamounts, a description of shore to shelf edge benthic maps produced for Tutuila, analytical details of reef fish and coral datasets, and supplemental information on the many marine protected areas in American Samoa.

Cruise report: regional assessment of ecosystem condition and stressor impacts along the northwestern Gulf of Mexico Shelf. NOAA Ship 'Nancy Foster' NF-11-07-RACOW (August 8-16, 2011)

This cruise report is a summary of a field survey conducted along a portion of the U.S. continental shelf in northwestern Gulf of Mexico (GOM), at navigable depths along the coastline seaward to the shelf break (~100m) from about 89°30' W to 95°28' W longitude, August 8 – 16, 2011 on NOAA Ship Nancy Foster Cruise NF-11-07-RACOW. Synoptic sampling of multiple ecological indicators was conducted at each of 34 stations throughout these waters using a random probabilistic sampling design. The original study design consisted of 50 stations extending from the Mississippi delta all the way to the U.S./Mexican border, but vessel failures precluded sampling at 16 stations within the western-most portion of the study area. At each station samples were collected for the analysis of benthic community structure and composition; concentrations of chemical contaminants in sediments and target demersal biota; sediment toxicity; nutrient and chlorophyll levels in the water column; and other basic habitat characteristics such as salinity, temperature, dissolved oxygen, turbidity, pH, sediment grain size, and organic carbon content. Other indicators, from a human-dimension perspective, were also recorded, including presence of vessels, oil rigs, surface trash, visual oil sheens in sediments or water, marine mammals, or noxious/oily sediment odors. The overall purpose of the survey was to collect data to assess the status of ecosystem condition and potential stressor impacts throughout the region, based on these various indicators and corresponding management thresholds, and to provide this information as a baseline for determining how such conditions may be changing with time. While sample analysis is still ongoing, some preliminary results and observations are reported here. A final report will be completed once all data have been processed.

Assessment of existing information on Atlantic coastal fish habitats: development of a web-based spatial bibliography, query tools, and data summaries

The primary objective of this project, “the Assessment of Existing Information on Atlantic Coastal Fish Habitat”, is to inform conservation planning for the Atlantic Coastal Fish Habitat Partnership (ACFHP). ACFHP is recognized as a Partnership by the National Fish Habitat Action Plan (NFHAP), whose overall mission is to protect, restore, and enhance the nation’s fish and aquatic communities through partnerships that foster fish habitat conservation. This project is a cooperative effort of NOAA/NOS Center for Coastal Monitoring and Assessment (CCMA) Biogeography Branch and ACFHP. The Assessment includes three components; 1. a representative bibliographic and assessment database, 2. a Geographical Information System (GIS) spatial framework, and 3. a summary document with description of methods, analyses of habitat assessment information, and recommendations for further work. The spatial bibliography was created by linking the bibliographic table developed in Microsoft Excel and exported to SQL Server, with the spatial framework developed in ArcGIS and exported to GoogleMaps. The bibliography is a comprehensive, searchable database of over 500 selected documents and data sources on Atlantic coastal fish species and habitats. Key information captured for each entry includes basic bibliographic data, spatial footprint (e.g. waterbody or watershed), species and habitats covered, and electronic availability. Information on habitat condition indicators, threats, and conservation recommendations are extracted from each entry and recorded in a separate linked table. The spatial framework is a functional digital map based on polygon layers of watersheds, estuarine and marine waterbodies derived from NOAA’s Coastal Assessment Framework, MMS/NOAA’s Multipurpose Marine Cadastre, and other sources, providing spatial reference for all of the documents cited in the bibliography. Together, the bibliography and assessment tables and their spatial framework provide a powerful tool to query and assess available information through a publicly available web interface. They were designed to support the development of priorities for ACFHP’s conservation efforts within a geographic area extending from Maine to Florida, and from coastal watersheds seaward to the edge of the continental shelf. The Atlantic Coastal Fish Habitat Partnership has made initial use of the Assessment of Existing Information. Though it has not yet applied the AEI in a systematic or structured manner, it expects to find further uses as the draft conservation strategic plan is refined, and as regional action plans are developed. It also provides a means to move beyond an “assessment of existing information” towards an “assessment of fish habitat”, and is being applied towards the National Fish Habitat Action Plan (NFHAP) 2010 Assessment. Beyond the scope of the current project, there may be application to broader initiatives such as Integrated Ecosystem Assessments (IEAs), Ecosystem Based Management (EBM), and Marine Spatial Planning (MSP).

Cruise report: regional assessment of ecosystem condition and stressor impacts along the northeastern Gulf of Mexico shelf; NOAA Ship Nancy Foster NF-10-09-RACOW (August 13-21, 2010)

This cruise report is a summary of a field survey conducted along the continental shelf of the northeastern Gulf of Mexico (GOM), encompassing 70,062 square kilometers of productive marine habitats located between the Mississippi Delta and Tampa Bay, August 13–21, 2010 on NOAA Ship Nancy Foster Cruise NF-10-09-RACOW. Synoptic sampling of multiple ecological indicators was conducted at each of 50 stations throughout these waters using a random probabilistic sampling design. At each station samples were collected for the analysis of benthic community structure and composition; concentrations of chemical contaminants (metals, pesticides, TPHs, PAHs, PCBs, PBDEs) in sediments and target demersal biota; sediment toxicity; nutrient and chlorophyll levels in the water column; and other basic habitat characteristics such as depth, salinity, temperature, dissolved oxygen, turbidity, pH, CDOM fluorescence, sediment grain size, and organic carbon content. Discrete water samples were collected just below the sea surface, in addition to any deeper subsurface depths where there was an occurrence of suspicious CDOM fluorescence signals, and analyzed for total BTEX/TPH and carcinogenic PAHs using immunoassay test kits. Other indicators of potential value from a human-dimension perspective were also recorded, including presence of any vessels, oil rigs, surface trash, visual oil sheens in sediments or water, marine mammals, or noxious/oily sediment odors. The overall purpose of the survey was to collect data to assess the status of ecosystem condition and potential stressor impacts throughout the region, based on these various indicators and corresponding management thresholds, and to provide this information as a baseline for determining how such conditions may be changing with time. In addition to the original project goals, both the scientific scope and general location of this project are relevant to addressing potential ecological impacts of the Deepwater Horizon oil spill. While sample analysis is still ongoing, a few preliminary results and observations are reported here. A final report will be completed once all data have been processed.

Scientific assessment of hypoxia in U.S. coastal waters

The occurrence of hypoxia, or low dissolved oxygen, is increasing in coastal waters worldwide and represents a significant threat to the health and economy of our Nation’s coasts and Great Lakes. This trend is exemplified most dramatically off the coast of Louisiana and Texas, where the second largest eutrophication-related hypoxic zone in the world is associated with the nutrient pollutant load discharged by the Mississippi and Atchafalaya Rivers. Aquatic organisms require adequate dissolved oxygen to survive. The term “dead zone” is often used in reference to the absence of life (other than bacteria) from habitats that are devoid of oxygen. The inability to escape low oxygen areas makes immobile species, such as oysters and mussels, particularly vulnerable to hypoxia. These organisms can become stressed and may die due to hypoxia, resulting in significant impacts on marine food webs and the economy. Mobile organisms can flee the affected area when dissolved oxygen becomes too low. Nevertheless, fish kills can result from hypoxia, especially when the concentration of dissolved oxygen drops rapidly. New research is clarifying when hypoxia will cause fish kills as opposed to triggering avoidance behavior by fish. Further, new studies are better illustrating how habitat loss associated with hypoxia avoidance can impose ecological and economic costs, such as reduced growth in commercially harvested species and loss of biodiversity, habitat, and biomass. Transient or “diel-cycling” hypoxia, where conditions cycle from supersaturation of oxygen late in the afternoon to hypoxia or anoxia near dawn, most often occurs in shallow, eutrophic systems (e.g., nursery ground habitats) and may have pervasive impacts on living resources because of both its location and frequency of occurrence.

Rapid assessment of stony coral richness and condition on Saba Bank, Netherlands Antilles

The benthic habitats of Saba Bank (17°25′N, 63°30′W) are at risk from maritime traffic, especially oil tankers (e.g., anchoring). To mitigate this risk, information is needed on the biodiversity and location of habitats to develop a zone use plan. A rapid survey to document the biodiversity of macro-algae, sponges, corals and fishes was conducted. Here we report on the richness and condition of stony coral species at 18 select sites, and we test for the effects of bottom type, depth, and distance from platform edge. Species richness was visually assessed by roving scuba diver with voucher specimens of each species collected. Coral tissue was examined for bleaching and diseases. Thirty-three coral species were documented. There were no significant differences in coral composition among bottom types or depth classes (ANOSIM, P>0.05). There was a significant difference between sites (ANOSIM, P<0.05) near and far from the platform edge. The number of coral species observed ranged from zero and one in algal dominated habitats to 23 at a reef habitat on the southern edge of the Bank. Five reef sites had stands of Acropora cervicornis, a critically endangered species on the IUCN redlist. Bleaching was evident at 82% of the sites assessed with 43 colonies bleached. Only three coral colonies were observed to have disease. Combining our findings with that of other studies, a total of 43 species have been documented from Saba Bank. The coral assemblage on the bank is representative and typical of those found elsewhere in the Caribbean. Although our findings will help develop effective protection, more information is needed on Saba Bank to create a comprehensive zone use plan. Nevertheless, immediate action is warranted to protect the diverse coral reef habitats documented here, especially those containing A. cervicornis.

Work plan for analytical support of an integrated ecosystem assessment of the California Current Large Marine Ecosystem, FY11 ‐ FY13

NOAA/NCCOS is conducting the following work for the NOAA California Current Integrated Ecosystem Assessment, in support of the NOAA/NMFS Northwest Fisheries Science Center.

An assessment of polybrominated diphenyl ethers (PBDEs) in sediments and bivalves of the U.S. coastal zone

NOAA’s Mussel Watch Program was designed to monitor the status and trends of chemical contamination of U.S. coastal waters, including the Great Lakes. The Program began in 1986 and is one of the longest running, continuous coastal monitoring programs that is national in scope. NOAA established Mussel Watch in response to a legislative mandate under Section 202 of Title II of the Marine Protection, Research and Sanctuaries Act (MPRSA) (33 USC 1442). In addition to monitoring contaminants throughout the Nation’s coastal shores, Mussel Watch stores samples in a specimen bank so that trends can be determined retrospectively for new and emerging contaminants of concern. In recent years, flame retardant chemicals, known as polybrominated diphenyl ethers (PBDEs), have generated international concern over their widespread distribution in the environment, their potential to bioaccumulate in humans and wildlife, and concern for suspected adverse human health effects. The Mussel Watch Program, with additional funding provided by NOAA’s Oceans and Human Health Initiative, conducted a study of PBDEs in bivalve tissues and sediments. This report, which represents the first national assessment of PBDEs in the U.S. coastal zone, shows that they are widely distributed. PBDE concentrations in both sediment and bivalve tissue correlate with human population density along the U.S. coastline. The national and watershed perspectives given in this report are intended to support research, local monitoring, resource management, and policy decisions concerning these contaminants.