Ocean health in the Northeast United States from 2005 to 2017

1. People in the Northeast United States have a long history of benefitting from the ocean in many ways, exemplified by the region's important cod and lobster fisher -ies, coastal tourism and recent expansion of offshore energy. Over the past few decades, the region has become one of the fastest warming spots on the planet, has seen significant growth in coastal populations, and expansion of new sectors into the marine environment, resulting in ecosystem shifts and changes to the supply and distribution of these benefits. With these changes comes a need for measuring ocean health to understand how engagement with the ocean may be affected, and how regional management may need to adapt. To this need, we tailored the Ocean Health Index framework to the U.S. Northeast region, scoring eight distinct goals for ocean health on a scale of 0 to 100 for 11 sub- regions over 13 years 2017). All Health of 1 point


| INTRODUC TI ON
Continued growth of the human population, expansion of ocean uses, and acceleration of climate change all play a role in impacting ocean health at local and global scales. Effective management requires understanding, assessing and planning for these changes while simultaneously protecting ocean resources and allowing for continued access to and use of those resources. Typically, planning efforts bring diverse stakeholders together to identify complementary and conflicting ocean activities and to develop regulatory frameworks and pathways for management of resources and activities. Plan development also allows the setting of social, economic and environmental goals (Fairbanks et al., 2019). Yet, planning processes rarely incorporate monitoring and evaluation mechanisms to track changes after time of implementation (Ferraro & Pattanayak, 2006). Long-term assessments can be used to understand whether a management decision was a success or failure (Sullivan et al., 2018) and guide responsive decision-making for adaptive management (Vugteveen et al., 2015). While plan development is important, tracking changes before, during and after implementation is equally essential for ensuring effective management.
The benefits people derive from ocean systems involve economic, cultural and natural aspects of the ecosystem, and thus assessments of ocean health should integrate social, economic and environmental information. The Ocean Health Index (OHI) was designed to do this, defining a healthy ocean as one that 'sustainably delivers a range of benefits to people now and in the future'  and drawing on diverse data to holistically assess the status of a range of goals people have for healthy oceans. The framework can be applied at any scale, from local to global, and indeed to date, OHI assessments have been conducted at local (US West Coast-Halpern et al., 2014;British Columbia-O'Hara et al., 2020), national (Elfes et al., 2014;Selig et al., 2015), multi-national (Baltic sea states- Blenckner et al., 2021, Arctic-Burgass et al., 2019 and global scales . Here we focus on applying the OHI framework to the Northeast region of the United States, where regional coordination around integrating social, economic and environmental information has been occurring in support of ocean planning for over a decade through the Northeast Regional Ocean Council (NROC). NROC, established in 2005, is a state and federal partnership from Maine to Connecticut-one of several Regional Ocean Partnerships in the U.S. that are voluntarily convened by state governors, in collaboration with other governments and stakeholders, to address ocean and coastal issues of common concern. Other regional partners, such as the New England Fishery Management Council and federally recognized tribes, and bordering jurisdictions, such as the State of New York and Provinces of Canada, also participate in NROC ocean planning activities. In 2016, the US Northeast Ocean Plan was completed and established regional priorities for enhancing planning and coordination within existing mandates in ultimate support of the goals of healthy ocean and coastal ecosystems, effective decision-making, and compatibility among ocean uses (Northeast Regional Planning Body, 2016). Examples of priorities identified in the plan include aquaculture, energy and infrastructure, commercial and recreational fishing, marine life and habitat, marine transportation, recreation and cultural resources.
In addition to identifying these areas for regional coordination, the plan identified potential monitoring and evaluation tools that could be developed to support and inform decision-making, including this initial OHI assessment.
Recent ecosystem and socio-economic changes in the region make the US Northeast an interesting place to study changes in ocean health. The Gulf of Maine is warming faster than 99% of the global ocean (Pershing et al., 2015), leading to observed changes in the regions iconic lobster fishery as the population shifts northward (Goode et al., 2019;Pinsky et al., 2013). The endangered Northern Right Whale population has gained significant attention in the area due to increased conflicts with humans through ship strikes (Davies & Brillant, 2019). Meanwhile there is expansion in the shellfish (Lapointe et al., 2013;Rickard et al., 2018) and seaweed (Yarish et al., 2017) aquaculture industries, and increasing interest in harnessing offshore wind as an alternative energy source (Firestone et al., 2012;Klain et al., 2017). All of these changes in the US Northeast offer an important opportunity to use OHI to better understand how ocean health has been changing, and plan for how it will continue to change. Through the regional application of the OHI, we aimed to develop an assessment that helps inform regional planning by addressing the following questions: (a) how has ocean health changed over time in the region? (b) what environmental or management changes may explain those shifts? and (c) where can focused efforts result in significant increases to Ocean Health? In addressing these questions, we hope to inform NROC and other regional decision-makers in their efforts to plan for and manage ocean uses to support and maintain regional ocean health. 8. As managers plan for the future in a changing Northeast marine region, the ability to track annual changes in ocean health and its respective components is key to making decisions that benefit the entire social-ecological system.

K E Y W O R D S
aquaculture, fisheries, Gulf of Maine, marine conservation, ocean health, ocean planning 2 | ME THODS

| Region
The US Northeast assessment was divided into 11 sub-regions, including seven nearshore and four offshore areas that extend out to the United States Exclusive Economic Zone (Figure 1). Nearshore sub-region boundaries extend from the shoreline out three nautical miles, the boundary between state and federal waters.
Massachusetts' state waters were additionally split into North and South sub-regions at the southern end of Cape Cod, a well-recognized biogeographic break between George's Bank region and the Gulf of Maine (Wilkinson et al., 2009). Sub-regions within Long Island Sound follow state waters boundaries between Connecticut and New York.
The offshore sub-regions represent Ecological Production Units (EPUs), which are large, defined bioregions that correspond with important groundfish stocks in the region and support distinct community structures (Gamble et al., 2016). The National Marine Fisheries Service and Northwest Atlantic Fisheries Office use these EPUs in ecosystem planning (Koen-Alonso et al., 2019). In addition to these 11 sub-regions, the entire region was also assessed separately as a single 12th region.

| Stakeholder engagement
Discussions with stakeholders in the Northeast were held in partnership with NROC, both alongside other NROC meetings and separate from NROC events. Over 100 people across 50 organizations were engaged throughout the assessment process to inform decision-making around selection of sub-regional boundaries, ocean health goals, models and indicators for those goals, and datasets to include to measure the indicators (Table S1) Tribe of Indians of Connecticut), academics, and non-governmental organizations (e.g. Surfrider, Conservation Law Foundation). In addition to stakeholder engagement activities and discussions during and associated with NROC meetings, 12 webinars were held across 2 years as the project progressed to provide updates, present draft results for discussion, and to generally allow as much stakeholder input as possible. Seven webinars held in 2018 focused on drafting the goal models, identifying available datasets, and determining what regional priorities should or should not be included. Five additional webinars held in spring 2019 were used to present draft results to stakeholders and receive feedback on the data used and models implemented. These webinars were informal discussions and made publicly available. Primary data for our study were not collected through this process and therefore we did not require ethical approval for working with human participants.

| Ocean Health Index model
Ocean Health Index assessments are designed to measure how close or far a region is from meeting targets for ocean-specific benefits.
These discrete benefits are categorized as goals within the Ocean Health Index model and are scored for every region on a scale from 0 to 100. All Ocean Health Index assessments follow the same structure, briefly outlined below, and detailed in Halpern et al. (2012 The likely future status of each goal projects the expected status of the goal 5 years into the future in an effort to account for the sustainable delivery of goal benefits into the future. This is calculated by applying a weighted average between the trend in present status over the past five years (T, ranging from −1 to 1), and the balance between pressures (p) and resilience (r) measures that are specific to each goal. The recent status trend is given a higher weight (twothirds) as it is assumed to be a stronger predictor of future status.

| Goal score
The goal score for each region is a simple average of present status and likely future state.

| Index score
Each region in the Northeast receives an Index score which is equal to the unweighted average of all goal scores assessed for that region.
By working with local partners and consulting key marine planning and management documents, OHI assessments are tailored to incorporate locally meaningful information, data, priorities and perspectives . The process involves first establishing goal definitions to ensure that all benefits and services provided by the ocean and important to the region are being represented, and then identifying and using locally available data to measure the status of these goals on a scale of 0-100. Data used in each goal ideally met each of the following criteria; (a) be spatially comprehensive of entire region, (b) of high enough resolution to capture variation throughout space, (c) provide multiple years of data and (d) publicly accessible for free. The OHI US Northeast assessment incorporated over 50 unique regional datasets that met the majority of these criteria from a diversity of sources and represent social, economic and ecological metrics.
Some datasets did not meet all of these criteria but were still the best available information for the goal. We qualitatively assessed each data layer across three dimensions that affect the ability to calculate meaningful goal scores (spatial, temporal and fit dimensions).
For each dimension we measured how well the extent and resolution of the data match the assessment. Each dataset was scored across all dimensions and given a 0.0 (poor), 0.5 (fair) or 1.0 (good) as applicable (see Supporting Information for full details).

| Goals & sub-goals
Goals from the global Ocean Health Index were cross-walked with ocean planning priorities highlighted in the Northeast Ocean Plan.
Stakeholders in the Northeast identified at least two priorities in the Northeast Ocean Plan that did not fit within the approach and philosophy of the Ocean Health Index to measure attributes of the ocean system either because they do not depend on the health of the ecosystem (National Security) or are not currently occurring (Offshore Sand Resources). For this reason, these Plan priorities were not assessed in the Northeast OHI. A total of eight goals were assessed in the OHI Northeast assessment, four of which contain two sub-goals, one that contains three and three which do not contain sub-goals (Table 1). Sub-goals are generally used to either measure distinct aspects of a goal that contribute unequally to the overall scoring of that goal or communicate components of a goal directly that were not appropriate as stand-alone goals. Sub-goals were scored on a scale from 0 to 100 and are then combined either through an equal or weighted average to get the final goal score. Sub-goals for four goals were equally weighted, but for one goal, Food Provision, were weighted unequally because they contribute differently to the overall goal. Each goal and sub-goal was made up of data layer(s) that are scaled between 0 and 1 before being combined either using a simple mean, geometric mean or weighted mean, depending on how the layers depend on each other (see supplement for more details).

| Setting reference targets
Reference points, or targets, can be set in one of several possible ways

| Calculating goal scores
Below are descriptions of how we calculated each goal and subgoal. For more detailed methods and equations see Supporting

Information.
The Biodiversity goal measures the conservation status of all ocean-dependent species and habitats in each region and contains two sub-goals, Species and Habitats. For the species sub-goal we used species risk assessments for 691 species that have been Likely future status = (1 + 0.67T + 0.33 (r − p)) × Present status.
Goal score = Present status + Likely future status 2 .
TA B L E 1 Goals, relevant sub-goals and associated reference targets. Goals were either assessed for all 12 regions, or only for nearshore regions ( assessed to provide a geographic snapshot of how total marine biodiversity is faring, recognizing that these species are a very small sample of overall species diversity (Fautin et al., 2010). The target was to have all species categorized as of Least Concern using the IUCN Red List criteria. Following previous approaches O'Hara et al., 2020), we scaled the lower end of the score to be 0 when 75% of species are extinct, a level comparable to each of the five documented mass extinctions that would constitute a catastrophic loss of biodiversity (Barnosky et al., 2011).
We included the habitat sub-goal as a measure of both ecosystem integrity and a proxy for condition of the broad suite of species that have not been mapped and assessed that depend on the habitats. We assessed the status of three key foundational habitat groups in the region: salt marsh, eelgrass and unvegetated seabed habitat. Each of the habitats had different data availability and required different reference point targets. Salt marsh coverage was compared to a historical reference point pre-1920s. Eelgrass condition was calculated using EPA water quality sampling data from within a 10-km radius of known locations of past and present eel- The status of this goal is calculated as the geometric mean of the four data layers included, as described elsewhere .  Spatial landings data for all 53 assessed stocks across 42 species were used to weight the contribution of each stock's score to the overall sub-goal score. Although only 42 out of the 137 commercially fished species are assessed, this represents more than 90% of total reported landings for each year in the assessment.
The Aquaculture sub-goal measures annual production of farmed species (clams, mussels, oysters, scallops, Atlantic salmon and trout) and incorporates sustainability weights, on a scale from 0 (least sustainable) to 1 (most sustainable), derived from Seafood Watch criteria for aquaculture (Monterey Bay Aquarium Seafood Watch Program, 2019). Species-specific annual production (pounds produced) was multiplied by sustainability scores so that a more sustainably grown species (e.g. oysters) would contribute more to total aggregate production than the same annual production of a less sustainable species (e.g. Atlantic salmon). Total annual production across all species was compared to the previous year's production to calculate annual growth rates. With limited information about regional targets for aquaculture production in the Northeast, a total annual aquaculture production growth rate of 4% was used.
This target was informed by historical growth trends across all species throughout the United States. Although the region also houses a few seaweed farms, they are not yet producing at a commercial level, so we did not include them. However, the industry as a whole is expected to grow and we foresee inclusion of many more farms and higher levels of production in the future, in which case seaweed grown for human consumption can and should be incorporated into the Food Provision score. The Food Provision score was calculated using a production weighted average of the Fisheries and the assumption that there is room to increase fishing engagement for both of these layers. The Sense of Place goal scored highest when marine species valued by the community had a conservation status of least concern, when there were areas identified as special that were protected, and when there was engagement in fishing.
These three sub-goals were equally weighted to calculate the final Sense of Place goal score. Recreation goal was assessed separately from its economic benefits, which are reported in the Livelihoods & Economies goal. We included three components for this goal: tourism growth (measured by job growth in the tourism sector), the proportion of the swim season with beach closures, and access points along the coast. Job growth in the tourism sector is used as a proxy measure, one that mirrors tourism participation trends in the region. If tourism jobs grow, we assume that is a direct result of increased participation in tourism.
Annual growth was compared to the average of the previous 3 years.
Any increase was awarded a score of 100, while a decrease, indicating a decline in tourism, resulted in a lower score, with a 25% loss as the lowest possible score (0). The beach closure layer was  and (f) social pressures. In total there were sixteen pressure layers across these six categories. Each layer was scaled from 0 (no impact) to 1 (highest impact) and assigned an impact sensitivity rank between 1 and 3 specific to each relevant goal. (Tables S1 and S2).

| Resilience
The resilience dimension measures an ecosystem's ability to cope with and return to a stable state following acute or chronic pressures and is comprised of three components: ecological integrity, social resilience and regulatory resilience. There are a total of seven resilience layers: one ecological, one societal and five regulatory.
Resilience metrics were selected to directly counter pressure metrics outlined above, representing how the human and natural system act to counter the negative impacts caused by stressors.
Resilience layers were only included in calculating goal or sub-goal scores when the pressure they counteract is present for that goal or sub-goal. For example, the water pollution pressure pathogen layer only affected the Resource Access Opportunities, Clean Waters, Lasting Special Places and Tourism & Recreation goals, and so the water pollution resilience layer only applied to those goals and subgoals. Ecological integrity is measured by species' statuses used in the Biodiversity goal's Species sub-goal.
Social resilience represents a region's ability to implement measures safeguarding ocean health. We used data from national assessments aimed at estimating various aspects of societal health. These assessments include measurements of regional opportunities based on health, education, economy and communities, coastal fishing vulnerability and resilience, whether or not states have certain policies in place for sustained economic growth, and if voting for environmentally driven politicians is a priority for regional communities.
These four data layers were averaged with an equal weighting for the social resilience layer.
We were able to account for additional aspects of regulatory resilience compared to past OHI assessments by accounting for three components of regulatory resilience (presence of regulations, enforcement and compliance). This was uniquely possible for this regional assessment because of the breadth and quality of data available in the Northeast region that meet the Index's requirements. We used 17 different data sources to measure the three components of each of the five regulatory resilience layers (see Supporting Information for details). The components were then averaged resulting in one score for each of the five layers. This new method enabled us to equally weight each of the three components of regulatory resilience, and give a region a higher resilience score if it not only implements policies to combat stressors but also follows through with enforcing and ensuring compliance with those policies.

| US Northeast overall
The US Northeast region received an Ocean Health Index score

| Trends by sub-regions
By evaluating annual goal scores over time ( Figure 4)  Tourism & Recreation also demonstrated low volatility over time but had a larger spread in regional scores than the previously discussed goals (21 points between the lowest and highest scores).
Tourism & Recreation scores were based on growth in tourism jobs, beach closures and coastal access. Every region had increasing jobs in the tourism sector and relatively low proportions of beach closures throughout the 13 years. The primary driver in varied scores for this goal was coastal access. Maine, the lowest scoring region for Tourism & Recreation, has only 39% of their coast with an access point every mile, followed by Massachusetts North (43%) and South (44%). On the other hand, Rhode Island has 90% of its coastline accessible. These regional differences in coastal access, combined with Fishing Engagement. All sub-goals showed variation, but the largest score spread in sub-goals is from Lasting Special Places ( Figure S2).
The high scoring regions have all met their targets for Lasting Special Places, meaning they have at least 10% of offshore marine area protected and 17% of coastal area within 1 km of the shore protected.

The rest of the regions have Lasting Special Places scores below 70
and Connecticut is much lower at 40, indicating these regions are much further from reaching this target. All three sub-goals showed little change over 13 years. The amount of area protected did not change at all over the 13 years for marine areas, and only increased by 3% at most for inland areas. The conservation status of Iconic Species was also unchanged but the third sub-goal, levels of Fishing Engagement, did show interannual variation across most regions.

The large difference in Habitat Services goal scores between
Maine on the upper end (99) and New York on the lower end (59) can be explained by examining the underlying data for each of the marine habitats in these regions. Maine's habitats are meeting the goal targets with no loss of salt marsh, high water quality near eelgrass beds, and improving seabed habitats under reduced fishing  Figure S3). On the other hand, New York has lost 50% of historical salt marsh habitat and experienced high, but decreasing, impacts to seabed habitats from fishing. Water quality sampling in and around Long Island Sound shows low and unchanging water quality, negatively impacting the health of existing eelgrass habitat. Massachusetts fishing communities during this period (Brinson & Thunberg, 2013 One of the greatest needs is to refine targets for all aspects of ocean health throughout the region. In this assessment, targets for each goal were developed under the constraints of currently available data. Although appropriate for the region, the targets could be improved by formally bringing together regional experts to evaluate and form targets. By establishing more focused targets, specific goals for ocean health would be better represented in the OHI. We recognize there is inherent difficulty in achieving this task across a large region, such as the US Northeast, which is made up of diverse stakeholders and policy makers from local to federal government levels, but there currently exists a regional planning process that could be leveraged to achieve such a task.

| Low scores, high volatility
Even with agreed-upon targets, if consistent data collection and monitoring are missing, then any progress towards targets will be difficult to measure.
Many of the underlying datasets used in this assessment were of appropriate spatial and temporal resolution to allow a year-to-year picture of ocean health, but not all. Most notably, health and locations of past and present eelgrass beds, coastal access and marine debris pollution are key data gaps for the US Northeast. Rather than removing these layers from the Index, we relied on the best available data to act as proxies. For example, a high resolution assessment of eelgrass condition does not exist for the Northeast. Some locations in the Northeast, such as New Hampshire's Great Bay National Estuarine Research Reserve, have been monitoring eelgrass health consistently for multiple years. But these data could not appropriately be extrapolated to the entire region. We ultimately chose to use the NCCA's Water Quality Index (WQI) data as a proxy of eelgrass health since it monitors water clarity and nutrient pollution, both of which are drivers of eelgrass condition (Short & Wyllie-Echeverria, 1996;Waycott et al., 2009). This data layer also required temporal gap filling since it contained multi-year gaps due to the nature of the assessment, which is done every 5 years by the EPA. The fact that it is a proxy dataset that required significant temporal gap filling begs careful consideration of the goals where this data layer is used (Clean Waters, Habitat Services and Habitats Sub-goal). The data quality analysis ( Figure 6) can be used to quickly identify goal layers which are of lesser quality.
The inclusion of proxy and gap filled data are necessary steps towards a more complete and immediate understanding of ocean health. Data availability, accuracy and appropriateness is a spectrum and any useful Index should be able to include imperfect data in the absence of perfect data. Utilizing the best data available, while acknowledging the shortcomings of any data product is crucial to making timely and informed management decisions. The results of both the OHI assessment and the data quality analysis can help users understand and evaluate the potential trade-offs when including imperfect data, as well as guide future data collection and monitoring efforts in the Northeast.
When developing an Ocean Health Index assessment, it is important to prioritize datasets that have high geographic and temporal resolution that allow for quick response to changes. When selecting datasets for an assessment, the focus should be on quality over quantity. Each goal needs at least one dataset but if the F I G U R E 6 Data quality analysis. Data layers associated with each goal listed on the left-hand side were assessed across seven criteria to indicate how good (green) or bad (red) the data source used met the criteria. Each data layer was scored by taking the average (good = 1, fair = 0.5, bad = 0) across all criteria to give an overall indication of data quality for each data layer used in the Ocean Health Index assessment for the US Northeast quality of that dataset is low, often times multiple datasets will be combined to develop a comprehensive view of the goal. One of the biggest challenges for indicators is that the best-available science and the underlying data to inform indicators often changes over time. The Ocean Health Index is designed to be flexible and updatable with improved information, such that new data can be incorporated when available and the Index can be expanded to incorporate new ocean uses or priorities into the assessment as they become relevant. In the Northeast, this could include new activities such as offshore wind and offshore aquaculture. Indeed, this repeatability also significantly lowers the bar to repeat assessments even when no changes in underlying science or data have occurred (Lowndes et al., 2017).
Moving forward, the US Northeast Ocean Health Index assessment can be used to not only examine historical changes, but can also be used to evaluate how ocean health might change in the fu- in the Northeast by 5% (22% to 17%). This effect would be seen within the Index by decreasing resilience for several goals and ultimately decreasing goal scores. One might also expect the Lasting Special Places sub-goal status to decline, but because the target is already achieved and exceeded by a lot (target is 10% protection) it would not impact the goal status unless further protections are removed. This further supports the need for explicit, agreed-upon regional targets for goals that people in the Northeast value, such as the protection of Lasting Special Places. Additionally, the opening of this area for commercial fishing could impact Food Provision goal scores in either direction depending on what stocks are fished, and increased fishing activity could potentially negatively impact seabed habitats and marine biodiversity in the region. The impact of this decision can be measured across many different components of the Index. If the US Northeast Ocean Health Index assessment continues in the future, it has substantial potential to support and guide decision-making, and ultimately to help the US Northeast achieve ocean health goals. We also like to thank the Gordon & Betty Moore Foundation for funding this project.

CO N FLI C T O F I NTE R E S T
The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

AUTH O R S ' CO NTR I B UTI O N S
B.H., C.S. and J.M. conceptualized and designed the study; J.M. and C.S. led and coordinated the data collection and analysis; J.M. and J.V. analysed the data; E.S. and N.N. provided guidance on data collection, analysis and stakeholder engagement. All authors contributed to the writing and editing of the manuscript and approved its submission.

DATA AVA I L A B I L I T Y S TAT E M E N T
The full US Northeast Ocean Health Index assessment data are archived and publicly available on Zenodo https://zenodo.org/recor d/ 4721453 . The results are also displayed on an interactive dashboard: https://ohi-north east.shiny apps.io/nedashb oard/.