OA and Marine Spatial Planning

1. Outcome

This Circular provides guidance on using Ocean Accounts to inform marine spatial planning (MSP), including spatial data requirements, ecosystem service mapping, and trade-off analysis. The spatial architecture of Ocean Accounts--built on Basic Spatial Units (BSUs) and ecosystem extent accounts--provides a foundation for MSP processes. Practitioners will gain practical understanding of how standardised ocean accounting can strengthen evidence-based marine governance.

Specific applications include: delineating spatial zones based on ecosystem service supply and demand patterns; resolving conflicts between competing ocean uses (fisheries, aquaculture, shipping, offshore energy, tourism) by quantifying overlapping spatial footprints and ecosystem dependencies; prioritising areas for protection or restoration based on ecosystem condition and service flow accounts; and evaluating proposed spatial allocations through scenario analysis that projects changes in ecosystem extent, condition, economic outputs, and service flows.

2. Requirements

• TG-0.1 General Introduction to Ocean Accounts—provides foundational understanding of the Ocean Accounts Framework, including the spatial data framework and ecosystem asset concepts essential for marine spatial planning applications.
• TG-3.1 Asset Accounts—provides methods for compiling ecosystem extent and condition accounts, including the Ecosystem Condition Typology (ECT) framework, reference condition establishment, and composite condition index construction used throughout this Circular.
• TG-3.3 Economic Activity Relevant to the Ocean—provides methods for spatially allocating economic activity data to Basic Spatial Units, required for spatial conflict identification in Step 3. Practitioners should compile TG-3.3 accounts before undertaking spatial conflict analysis; where TG-3.3 accounts are not yet available, Step 3 may proceed using proxy activity data with appropriate caveats.
• TG-4.1 Remote Sensing and Geospatial Data—provides remote sensing resolution thresholds and spatial data methods for BSU delineation and ecosystem extent mapping used in Sections 3.3.1 and 3.3.2.

3. Guidance Material

3.1 What is marine spatial planning?

Marine Spatial Planning (MSP) is a public process of analysing and allocating the spatial and temporal distribution of human activities in marine areas to achieve ecological, economic, and social objectives that are usually specified through a political process^[1]. MSP emerged in the early 2000s, representing a shift from reactive, sector-by-sector management toward proactive, integrated, and spatially explicit governance of ocean space in response to growing conflicts between ocean uses and recognition that cumulative impacts require integrated responses. MSP serves as an 'implementation mechanism' through which high-level policy commitments--such as the Sustainable Development Goals and Convention on Biological Diversity targets--are translated into spatial management action within national marine jurisdictions^[2].

MSP is fundamentally a spatial process. It requires decisions about where different activities may occur, where they should be excluded, and how multiple uses can be accommodated within the same marine area. These decisions must account for the distribution of marine ecosystems, the spatial footprint of human activities, and the connections between adjacent areas--both marine and terrestrial. The United Nations Educational, Scientific and Cultural Organization (UNESCO) has been instrumental in promoting MSP globally, with the Intergovernmental Oceanographic Commission providing technical guidance on planning approaches^[3].

For UNCLOS maritime zone definitions (territorial sea, EEZ, continental shelf, ABNJ), see TG-0.6 Glossary (Exclusive Economic Zone entry). These zones define the geographic scope within which national MSP processes operate, with UNCLOS Articles 56 and 61-62 granting coastal states sovereign rights over natural resources and responsibility for conservation and management of living resources within their exclusive economic zone^[4].

The UN-GGIM Working Group on Marine Geospatial Information has identified MSP as a key application area requiring integrated marine geospatial information management^[5]. Effective MSP depends on the availability of consistent, interoperable spatial data across multiple domains--hydrographic, oceanographic, biological, and socioeconomic--that can be integrated to support evidence-based planning decisions.

3.2 Information needs for MSP

Marine spatial planners require comprehensive information to make informed decisions about the allocation of ocean space. The information needs of MSP can be organised into four broad categories: ecological, economic, social, and governance information.

Ecological information encompasses the distribution and condition of marine ecosystems, the habitats they provide, and the ecological processes that maintain ecosystem functioning. Planners need to know where different ecosystem types occur (coral reefs, seagrass meadows, mangroves, pelagic systems, benthic habitats), their current condition relative to reference states, and how they are connected through species movements, larval dispersal, and nutrient flows. The IUCN Global Ecosystem Typology provides a standardised classification of marine ecosystem functional groups that can support consistent spatial mapping across jurisdictions^[6].

Economic information includes the location and intensity of economic activities, their dependencies on marine ecosystem services, and their impacts on marine ecosystems. Key activities include fisheries (both commercial and artisanal), aquaculture, shipping and ports, offshore energy (oil, gas, wind, wave), mining, tourism and recreation, and coastal development.

Social information captures the distribution of benefits and costs across different community groups, including indigenous and traditional uses, subsistence activities, recreational values, and cultural connections to marine places. Equity considerations--who benefits and who bears costs from different spatial allocations--are increasingly recognised as central to legitimate MSP processes.

Governance information documents existing management arrangements, protected area designations, customary tenure systems, and regulatory frameworks that constrain or enable spatial planning decisions. This includes understanding jurisdictional boundaries, existing use rights, and the institutional arrangements through which planning decisions are made and implemented.

A critical challenge for MSP is integrating these diverse information types within a coherent spatial framework. Data often come from different sources, use inconsistent spatial units, and lack the temporal alignment needed for integrated analysis. Ocean Accounts, through their application of accounting principles and spatial frameworks, offer a structured approach to addressing this challenge.

Table 1 maps the typical phases of an MSP process to their core information needs and identifies which Ocean Account components can supply the required data. Planners can use this matrix to identify which accounts to prioritise for compilation given the current stage of their MSP process and to communicate data requirements to the statistical agencies responsible for account production^[7].

Table 1: MSP planning phases, information needs, and Ocean Account sources

The first five rows of Table 1 map sequential MSP planning phases to their core information needs; the final two rows capture cross-cutting integration dimensions that operate across all phases. Cross-border integration is supported because a standardised BSU framework and harmonised accounting classifications enable comparable spatial and ecological baselines between neighbouring jurisdictions sharing marine areas^[2:1]. Stakeholder and knowledge integration is supported because publishing accounts under common classifications reduces information asymmetry between government, industry, indigenous and local knowledge holders, and the wider public, providing a shared evidence base for deliberation. A fuller five-dimension integration framework (policy and sector, cross-border, stakeholder, knowledge, and temporal integration) is set out in Gacutan et al. (2022)^[2:2], to which practitioners are referred for the conceptual underpinning of these rows.

3.3 Ocean accounts data for spatial planning

The Ocean Accounts Framework provides several components essential for MSP. The spatial data framework, ecosystem extent accounts, ecosystem condition accounts, ecosystem services accounts, and governance accounts each contribute essential information for spatial planning decisions.

3.3.1 The spatial data framework

The spatial foundation of Ocean Accounts is built on Basic Spatial Units (BSUs)--the smallest units at which information is compiled and from which aggregations can be made^[8]. BSUs are defined to be exhaustive and mutually exclusive within the ecosystem accounting area (EAA), meaning that every location within the EAA is assigned to exactly one BSU. For marine applications, BSUs may be differentiated into coastal and marine units, with depth layers enabling three-dimensional representation of ocean systems.

In practice, BSU resolution for marine applications should follow the resolution of the best available data--both at the time of initial compilation and into the future as data infrastructure improves. The SEEA EA does not prescribe a single optimal resolution; instead, it advises that the resolution should be sufficient to distinguish the ecosystem types relevant to the analysis while remaining feasible given available data^[9]. For MSP, the guiding principle is that BSU resolution should be fine enough to differentiate between distinct use zones and ecosystem types within the planning area.

The decision table below provides indicative resolution ranges by context. These are starting points; the appropriate resolution in any national context depends on the spatial precision available from primary data sources.

BSU resolution decision table for marine applications

Where data resolution improves over time--for example through new high-resolution satellite imagery or expanded bathymetric surveys--the BSU grid may be refined. Any change in spatial resolution should be recorded as an accounting note (methodological revision) in the extent account for the relevant period, distinguishing genuine ecosystem change from reclassification due to improved measurement. Countries beginning marine ecosystem accounting are encouraged to start with the best available resolution and refine it as data infrastructure improves. See TG-4.1 Remote Sensing and Geospatial Data for remote sensing resolution thresholds that constrain minimum BSU size and for guidance on selecting spatial data sources for marine BSU delineation.

The delineation of marine BSUs presents specific challenges not encountered in terrestrial ecosystem accounting. Marine ecosystems are inherently three-dimensional, with distinct communities at different depth strata. Pelagic (water column) and benthic (seafloor) ecosystems may occupy the same horizontal location but represent distinct functional units. The BSU framework enables consistent spatial referencing across multiple data types: economic activities, ecosystem types, and condition indicators can all be assigned to BSUs, allowing planners to examine how different variables co-occur and interact within the same spatial framework.

3.3.2 Ecosystem extent accounts

Ecosystem extent accounts record the area of each ecosystem type within each BSU over time^[10]. For marine applications, extent accounts capture the spatial distribution of ecosystem types such as coral reefs, seagrass meadows, mangroves, kelp forests, coastal wetlands, and various pelagic and benthic marine ecosystems. The accounts track changes in extent through additions (ecosystem restoration, natural expansion) and reductions (ecosystem conversion, degradation).

Extent accounts provide MSP with baseline information on where different ecosystem types occur and how their distribution is changing. The ecosystem classification used in extent accounts should align with internationally recognised typologies--the IUCN Global Ecosystem Typology provides a hierarchical classification with realm (marine), biome (e.g., marine shelf), and ecosystem functional group (e.g., tropical coral reefs) levels that can be adapted to national contexts^[11]. See TG-3.1 Asset Accounts Section 3.4.1 for detailed guidance on ecosystem extent account compilation methods.

Ecosystem extent by designated use

A particularly useful analytical output for MSP is the cross-tabulation of ecosystem extent by designated use category. This approach overlays ecosystem extent data with the spatial footprint of designated marine use zones to reveal how different ecosystem types are distributed across management and activity areas. The resulting matrix shows, for each ecosystem type, how much of its extent falls within fishery zones, port areas, tourism zones, marine protected areas, and areas not currently designated for specific uses. This information is directly relevant to spatial planning because it makes explicit the relationship between ecological assets and human use allocations--a relationship that is often obscured when ecological and economic data are compiled separately.

Table 2 illustrates this approach using simplified example data from an ESCAP pilot exercise in the Pacific region^[12]. Values are recorded in hectares (ha), consistent with SEEA EA para 4.15, which requires ecosystem extent accounts to be compiled in area units.

Table 2: Example cross-tabulation of ecosystem extent by designated use category (ESCAP pilot exercise, hectares)

Countries beginning ocean accounting may initially compile this cross-tabulation in BSU counts when individual BSU area is not yet standardised--this is a valid first step that preserves spatial relationships and supports conflict identification. The operational target is area-based compilation consistent with SEEA EA para 4.15. Where earlier compilations used BSU counts, these can be converted to hectares by multiplying each count by the area of a single BSU; any such revision should be recorded as an accounting note (upward or downward area revision) in the extent account for the relevant period.^[13]

The cross-tabulation reveals patterns relevant to spatial planning. In this example, coral reefs are predominantly located within marine protected areas, suggesting existing protection measures are well targeted. Mangroves are more evenly distributed across use categories--including port and tourism zones--indicating greater exposure to development pressures. Seagrass ecosystems have substantial extent outside any designated use area, which may represent either a gap in spatial planning coverage or areas where formal designation has not yet occurred. The table can be expanded to include additional ecosystem types and use categories, extended over multiple accounting periods to reveal trends in spatial allocation, and supplemented with condition data to reveal how the quality of ecosystems varies across use zones.

3.3.3 Ecosystem condition accounts

Ecosystem condition accounts measure the quality or integrity of ecosystems relative to a reference condition^[14]. The SEEA EA Ecosystem Condition Typology (ECT) organises condition variables into six classes (physical state, chemical state, compositional state, structural state, functional state, and landscape/seascape characteristics); full class definitions are in TG-3.1 Asset Accounts Section 3.4.2. For MSP, condition accounts reveal not only where ecosystems are located but their ecological integrity--areas of high condition may be priorities for protection, while degraded areas may be candidates for restoration or may be appropriate for activities with lower ecological sensitivity. Understanding spatial patterns of condition also helps planners anticipate how ecosystems may respond to different management scenarios. See TG-3.1 Asset Accounts Section 3.4.2 for detailed guidance on compiling condition accounts using the ECT framework, including selection of condition variables, establishment of reference conditions, and aggregation methods for composite condition indices.

3.3.4 Ecosystem services accounts

Ecosystem services accounts record the contributions of ecosystems to human wellbeing and economic activity^[15]. Marine ecosystem services include:

• Provisioning services: wild fish and other aquatic biomass, genetic resources, water supply (for coastal desalination)
• Regulating and maintenance services: coastal protection from storms and erosion, global climate regulation through carbon sequestration and storage, water purification, nursery habitat for commercial species
• Cultural services: recreation, tourism, visual amenity, spiritual and symbolic values

Services accounts use a supply-use framework that identifies the ecosystem areas that generate services (service providing areas) and the locations where benefits are realised (service benefiting areas). This spatial articulation of services is applicable to MSP, which must consider how spatial allocations affect both service provision and benefit distribution.

For example, a mangrove ecosystem provides coastal protection services that benefit adjacent coastal communities. A spatial planning decision to permit aquaculture development in the mangrove area would reduce the ecosystem's extent, potentially diminishing its capacity to provide coastal protection. Ocean accounts quantify these relationships, enabling planners to assess trade-offs between economic development and ecosystem service maintenance.

3.3.5 Governance accounts

Governance accounts record spatially-explicit information on policies, legislation, jurisdictional boundaries, use rights, and management arrangements that apply within the ecosystem accounting area. They are a distinct OA component identified in the broader Ocean Accounts Framework as an emerging account type, and they directly address the 'governance information' need identified in Section 3.2^[2:3]. For MSP, governance accounts can support: (i) identification of jurisdictional and administrative boundaries relevant to the planning area, including overlapping authorities; (ii) documentation of existing use rights, designated zones, protected area designations, and customary tenure arrangements; (iii) mapping of which institutions hold regulatory authority for which uses and locations; and (iv) recording of cross-border or transboundary management instruments where the planning area abuts another jurisdiction.

Governance accounts are an emerging area of OA practice and compilation methodology continues to develop; the GOAP Technical Guidance materials on governance accounts should be consulted for current methods. Practitioners undertaking MSP are encouraged to compile, at minimum, a basic spatial layer of relevant policy and management designations that can be cross-tabulated against ecosystem extent (as in Table 2) to make the policy-ecology relationship explicit. This is particularly relevant in trans-boundary planning contexts under UNCLOS and in jurisdictions where customary or indigenous tenure systems coexist with statutory regimes.

3.4 Integrating accounts into MSP processes

The integration of Ocean Accounts into MSP processes can occur at multiple stages of the planning cycle: situation assessment, goal setting, spatial analysis, plan development, implementation, and monitoring. MSP aligns strategic targets across policies and manages human activities in ocean space, while OA provides a structured, standardised evidence base that informs each stage of that process^[2:4].

3.4.1 Situation assessment

In the initial assessment phase, MSP processes characterise the current state of the marine area--its ecosystems, uses, and governance arrangements. Ocean accounts provide a structured compilation of this information within a consistent spatial framework. Ecosystem extent accounts show what ecosystems are present and where; condition accounts indicate their integrity; economic accounts document current activities and their spatial footprint; and services accounts reveal how ecosystems contribute to human wellbeing.

3.4.2 Trade-off analysis

A central function of MSP is to navigate trade-offs between competing objectives--economic development versus environmental protection, one sector versus another, current uses versus future options. The SEEA AFF notes that "data that are in a common framework can be used to assess trade-offs between alternative scenarios using various modelling techniques"^[16]. In the MSP context, planners can examine how different spatial allocations would affect ecosystem extent, condition, and services, as well as economic outputs and social benefits. The accounting framework does not resolve trade-offs--these remain political decisions--but it provides a transparent evidence base for deliberation.

To illustrate, consider a simplified trade-off between designating a coastal area as an aquaculture zone versus maintaining it as an undesignated mangrove ecosystem. Using accounts data, planners can compare the economic output from aquaculture production (recorded in economic accounts) against the value of ecosystem services that the mangrove currently provides--including coastal storm protection (estimated via avoided damage costs), carbon sequestration (estimated via social cost of carbon), and nursery habitat supporting adjacent fisheries (estimated via the contribution of mangrove-dependent species to commercial catch). See TG-1.9 Safe Usage of Monetary Valuation for endorsed methods for avoided damage cost and social cost of carbon estimation and their appropriate use in ocean accounting contexts; both methods are illustrative approximations pending country-specific calibration^[17]. Even where the mangrove's annual service flows exceed the projected net returns from aquaculture, the allocation decision involves distributional effects, employment, food security, and other policy considerations. The accounts ensure that ecological costs of conversion are visible and quantified alongside economic benefits, enabling informed deliberation rather than prescribing an outcome.

It should be noted that OA trade-off analysis captures quantitative and instrumental values--physical measurements (hectares, tonnes, people protected) and monetary exchange values--and may not fully represent intrinsic, relational, or non-material values that are important to indigenous communities, coastal peoples, and other stakeholders for whom cultural, spiritual, or traditional use connections to marine places are significant. Where such values are relevant to the planning decision, OA trade-off analyses should be complemented by participatory valuation or deliberative assessment methods^[2:5]. The accounting structure also allows planners to examine partial conversion scenarios, where a portion of the mangrove is converted while the remainder is protected, and to assess how service flows change at different conversion thresholds.

3.4.3 Scenario development and evaluation

MSP typically involves developing and evaluating alternative spatial scenarios before selecting a preferred plan. For each scenario, planners can project:

• Changes in ecosystem extent (what areas would be converted or protected)
• Changes in ecosystem condition (how would ecosystem integrity be affected)
• Changes in ecosystem services (how would service flows be altered)
• Changes in economic outputs (how would production and employment be affected)
• Distribution of benefits and costs (who would gain and who would lose)

The accounting framework ensures that these projections are internally consistent--for example, that projected changes in ecosystem extent are reflected in projected changes in services. The use of OA to support scenario and trade-off analysis in MSP is a core integration use case identified in the peer-reviewed MSP-OA literature^[2:6]. Scenario projections should where possible be accompanied by uncertainty ranges for condition and service flow indicators. See SEEA EA Chapter 14 for guidance on communicating data quality and uncertainty in scenario contexts. A dedicated GOAP Technical Guidance circular on uncertainty characterisation in ocean account projections is planned; practitioners should refer to that circular once available.

3.4.4 Monitoring and evaluation

After plan adoption, ongoing monitoring is essential to assess whether the plan is achieving its objectives. Extent accounts show whether ecosystems are being maintained or lost; condition accounts indicate whether ecosystem integrity is improving or declining; services accounts reveal whether ecosystem contributions to wellbeing are being sustained. The temporal dimension of accounts--which record stocks and flows at regular intervals--aligns naturally with monitoring requirements. Annual or periodic account compilation creates time series that reveal trends and enable adaptive management responses.

3.5 Application procedure for MSP practitioners

The following procedure guides MSP practitioners in incorporating ocean accounts data into spatial planning decision-making. It assumes that extent, condition, and service flow accounts have been compiled (or are in the process of compilation) by the national statistical office or designated ocean accounting agency.

Step 1: Define the planning area and identify available accounts

Establish the geographic scope of the MSP process and identify which ocean accounts are available for that area. The planning area should align with jurisdictional boundaries (e.g., state or provincial waters, exclusive economic zone) and should be defined using the same coordinate reference system as the accounts. Contact the national statistical office or ocean accounting coordinator to determine:

• Which ecosystem types have been mapped within the planning area (extent accounts)
• What condition indicators have been compiled and at what spatial resolution (condition accounts)
• Which ecosystem services have been quantified, in physical or monetary terms (service flow accounts)
• What time periods are covered (annual accounts, multi-year series)
• What spatial resolution (BSU size and geometry) is used in the accounts

Where accounts cover only part of the planning area--for example, where extent accounts exist for coastal waters but not the full EEZ, or where condition accounts are available for coral reefs but not pelagic ecosystems--practitioners should document coverage gaps and use proxy or interim data for unaccounted areas where available, communicating data limitations transparently to planning stakeholders. See SEEA EA Chapter 14 for guidance on graduated account implementation and methods for progressing from partial to full coverage. If accounts are not yet available for the planning area, this step should identify priority accounts to compile based on the MSP information needs identified in Table 1.

Step 2: Compile extent-by-use cross-tabulation

Using the ecosystem extent accounts and a spatial layer of current or proposed use designations (fishery zones, aquaculture zones, shipping lanes, protected areas, etc.), compile a cross-tabulation table similar to Table 2. Record values in hectares consistent with SEEA EA para 4.15. This reveals the current spatial distribution of ecosystems across use categories and identifies:

• Ecosystem types with high exposure to extractive or development activities
• Ecosystem types with low representation in protected areas
• Areas where multiple uses overlap with high-value ecosystems
• Gaps where ecosystems are not currently subject to any designated use

This matrix forms the baseline for evaluating alternative spatial allocations.

Step 3: Identify spatial conflicts and opportunities

Overlay economic activity data from ocean accounts (fishing effort, aquaculture production, shipping traffic, tourism visitation) with ecosystem extent and condition data to identify spatial conflicts--locations where human activities and sensitive ecosystems co-occur--and spatial opportunities--locations where condition is high and activities are low, making them candidates for protection, or where condition is degraded and restoration efforts could yield co-benefits. For guidance on mapping economic activities to spatial units, see TG-3.3 Economic Activity Relevant to the Ocean, which provides methods for allocating supply-use table outputs to Basic Spatial Units. Note that this step depends on availability of TG-3.3 accounts; where these are not yet compiled, spatial conflict identification may proceed using proxy activity data (e.g., vessel monitoring records, permit data, site survey estimates) with appropriate documentation of data limitations.

Spatial conflicts may include:

• Fishing effort concentrated in areas with declining fish stocks (condition accounts show degradation)
• Aquaculture zones overlapping with mangrove or seagrass extent (extent accounts show habitat loss)
• Shipping lanes crossing marine protected areas or whale migration corridors (seascape connectivity variables from condition accounts)
• Offshore energy development in high-biodiversity areas (compositional state variables from condition accounts)

Step 4: Develop alternative spatial scenarios

Based on the conflict and opportunity analysis, develop two or more alternative spatial scenarios that differ in how ocean space is allocated. Each scenario should specify:

• Spatial boundaries of use zones (aquaculture, fishing, shipping, energy, tourism, protection)
• Management intensity within each zone (e.g., no-take protected area versus multi-use management)
• Areas designated for restoration or conservation priority

Scenarios should be designed to address identified conflicts while advancing planning objectives (e.g., protecting 30% of marine area, maintaining fisheries yield, supporting coastal livelihoods)^[18].

Step 5: Project scenario impacts using accounts

For each scenario, use the accounts to project changes in key variables. This requires translating spatial allocations into quantitative changes:

• Extent changes: If a scenario converts mangrove to aquaculture, estimate the hectares of mangrove extent lost and the corresponding increase in aquaculture area. Record these as reductions (conversions from mangrove) and additions (conversions to aquaculture).

• Condition changes: If a scenario establishes a no-take marine protected area, estimate the expected improvement in condition over time based on ecological recovery rates from the literature or from condition time series in similar protected areas. If a scenario permits increased fishing effort, estimate the expected decline in condition based on pressure-condition relationships. Note that ocean accounts do not record the immediate impact of a management action on ecosystem condition--instead, the efficacy of a management decision is traceable over successive accounting periods as condition variables in the ECT are updated. For example, MPA establishment reduces fishing pressure on compositional state variables (e.g., fish community diversity, coral cover); improvement in the composite condition index may take 3--5 years or more to be observable in the accounts depending on ecosystem recovery rates. Sub-step 5a below sets out a worked procedure. See TG-3.1 Asset Accounts Section 3.4.2 for ECT variable selection and condition index construction methods.

  Sub-step 5a: Linking a management action to condition change via TG-3.1

  1. Identify the primary pressure that the management action addresses (e.g., fishing pressure, sediment input, thermal stress).
  2. Select the ECT condition variable(s) most sensitive to that pressure (e.g., for fishing pressure: compositional state—fish community diversity; structural state—coral cover or seagrass canopy height).
  3. Consult ecological recovery literature or regional time-series to estimate the expected rate of change in the selected variable(s) per accounting period under the proposed management regime.
  4. Apply the per-period change rate to derive a projected condition variable trajectory across the scenario time horizon (e.g., 5 or 10 years).
  5. Use the aggregation method from TG-3.1 Section 3.4.2 to translate variable-level changes into a revised composite condition index value for each scenario period.
  6. Record the projected index values as the scenario condition trajectory in Table 3, noting that these are projections subject to uncertainty and that actual condition change will be verified through successive account compilations.

• Service flow changes: If mangrove extent declines, estimate the change in coastal protection services (beneficiaries at risk), carbon sequestration (tonnes CO2), and nursery habitat (change in juvenile fish recruitment). Use the supply-use framework from ecosystem services accounts to allocate changes in service supply to benefiting areas and sectors. See Annex A for a worked example showing which supply-use table rows and columns change under a 500 ha mangrove conversion scenario, and see TG-3.2 Flows from Environment to Economy for the full supply-use table structure and compilation methods.

• Economic output changes: Use economic accounts to estimate changes in production and employment from different spatial allocations. For example, if aquaculture zones expand, project increased aquaculture output; if fishing zones contract, project reduced catch (or, if condition improves, potentially increased sustainable yield over the medium term).

These projections need not be precise--MSP is inherently a forward-looking exercise with uncertainty--but they should be consistent within the accounting framework, ensuring that changes in one account are reflected in related accounts.

Step 6: Compare scenarios and present trade-offs

Present the projected impacts of each scenario in a summary table or dashboard that enables comparison across scenarios. Table 3 provides an illustrative template.

Table 3: Illustrative scenario comparison for MSP using ocean accounts data

This comparison reveals trade-offs across scenarios. Scenario A (Conservation Priority) achieves high protection coverage and improved ecosystem condition, supporting long-term service flows and tourism, but constrains aquaculture expansion. Scenario B (Development Priority) maximises aquaculture output but results in significant ecosystem extent loss, condition decline, and reduced service flows, with potential long-term costs to coastal protection and fisheries sustainability. Scenario C (Balanced Allocation) seeks a middle path, with moderate protection expansion, modest ecosystem improvements, and accommodation of some aquaculture growth. The choice among scenarios remains a policy decision informed by national priorities, stakeholder input, and international commitments.

Step 7: Select and implement a preferred scenario

Following stakeholder consultation and political decision-making, select a preferred scenario and translate it into spatial management regulations--zoning maps, use permits, protection designations, and monitoring requirements. The accounts compiled during the planning process establish the baseline against which future monitoring will measure progress.

Step 8: Monitor and revise using updated accounts

After plan implementation, continue compiling extent, condition, and service flow accounts at regular intervals (annually or biennially). Use the time-series data to assess whether the spatial plan is achieving its intended outcomes:

• Are protected ecosystems maintaining or improving condition?
• Are use zones delivering expected economic outputs without exceeding sustainable limits?
• Are service flows to beneficiaries being sustained or enhanced?

Where monitoring reveals deviations from expected trajectories, apply adaptive management--adjusting use intensity, expanding or contracting zones, or implementing restoration interventions--informed by updated accounts data. See TG-1.3 Marine Spatial Management (including MPAs) for detailed guidance on using accounts for MPA effectiveness monitoring and adaptive management.

3.6 Case examples

3.6.1 Ecosystem extent mapping for spatial zoning

Several countries have applied ecosystem extent mapping approaches consistent with SEEA EA principles to support marine spatial planning. Australia's National Marine Ecosystem Classification provides a hierarchical classification of marine ecosystems that can be mapped at national scales and used to ensure that MSP processes consider the full range of ecosystem types within their jurisdiction^[21]. Similarly, the European Union's MAES (Mapping and Assessment of Ecosystems and their Services) initiative has developed marine ecosystem maps that inform spatial planning under the EU Maritime Spatial Planning Directive^[22].

By establishing consistent ecosystem classifications and spatial representations, these mapping efforts enable planners to identify where particular ecosystem types occur, assess their representation within existing protected areas, and target spatial allocations to achieve conservation objectives.

3.6.2 Ecosystem services valuation for spatial allocation

The valuation component of Ocean Accounts--while acknowledged to have methodological challenges--can inform MSP decisions by making explicit the economic values at stake in different spatial allocations. Coral reef ecosystems, for example, provide coastal protection services whose value can be estimated using avoided damage cost methods, and tourism services whose value can be estimated from visitor expenditure data^[23].

When these values are mapped spatially, planners can identify high-value service areas and assess how different development scenarios would affect aggregate service values. Such analyses should not be the sole basis for planning decisions, but they provide useful information for deliberation, particularly in contexts where ecosystem service values might otherwise be overlooked.

3.6.3 Marine Protected Area planning

Marine Protected Areas (MPAs) represent a specific application of spatial planning where Ocean Accounts data are directly relevant. MPA network design requires information on:

• Ecosystem representation (are all ecosystem types included?)
• Ecosystem condition (are areas of high integrity prioritised?)
• Connectivity (are areas connected to allow species movement?)
• Threat exposure (are areas exposed to pressures that protection can address?)

Extent and condition accounts provide systematic data for addressing these questions. Several Pacific Island countries have used ecosystem accounting approaches to inform MPA network design, integrating ecological data with socioeconomic information on fishing effort and community dependence to identify areas where protection can achieve conservation benefits while minimising social costs^[24].

For detailed guidance on using accounts to monitor MPA effectiveness and track ecosystem recovery, see TG-1.3 Marine Spatial Management (including MPAs).

3.6.4 Resolving spatial conflicts between offshore energy and fisheries

Offshore renewable energy development creates spatial conflicts with existing ocean uses, particularly fisheries and shipping. In the North Sea, multiple countries have applied spatial analysis combining fisheries effort data (from vessel monitoring systems), wind farm footprints, and ecosystem condition indicators to identify areas where wind energy development would minimise displacement of fishing activity while avoiding high-biodiversity habitats^[25]. While not always framed explicitly as ocean accounts, these analyses apply accounting principles--spatially explicit activity data, ecosystem condition baselines, and trade-off assessment--to inform spatial allocation decisions. As offshore wind capacity expands globally, integrating fisheries accounts, energy accounts, and ecosystem condition accounts within a common spatial framework will become increasingly important for resolving use conflicts. For detailed guidance on accounting for offshore energy activities and their spatial interactions with marine ecosystems, see TG-6.9 Offshore Energy Thematic Methods.

Annex A: Supply-use table worked example for spatial scenario analysis

This annex provides a worked example showing which entries in the ecosystem services supply-use table change when a spatial scenario converts 500 ha of mangrove to aquaculture, and how the corresponding ecosystem asset stock entries in the extent account are adjusted.

Scenario: Conversion of 500 ha of mangrove to an aquaculture zone.

Step 1: Extent account adjustment

In the ecosystem extent account for the mangrove ecosystem type:

• Opening stock: [baseline mangrove area, ha]
• Reduction—conversion to aquaculture: --500 ha
• Closing stock: [opening stock minus 500 ha]

In the extent account for the aquaculture zone land use category:

• Opening stock: [baseline aquaculture area, ha]
• Addition—conversion from mangrove: +500 ha
• Closing stock: [opening stock plus 500 ha]

Step 2: Services supply-use table adjustments

The supply-use table for ecosystem services records, by ecosystem type and service, the physical quantity supplied (by ecosystem) and used (by economic sector or final beneficiary). The following rows change:

Step 3: Cross-account consistency check

Verify that the service flow changes in Step 2 are reflected in:

• The economic account: reduced fish provisioning from mangrove-dependent fisheries (nursery habitat loss); increased aquaculture output
• The condition account: if extent loss reduces structural state variables (e.g., shoreline habitat complexity), update the condition index accordingly following TG-3.1 Section 3.4.2

See TG-3.2 Flows from Environment to Economy for the full supply-use table structure, column definitions, and compilation guidance.

4. Acknowledgements

This Circular has been approved for public circulation and comment by the GOAP Technical Experts Group in accordance with the Circular Publication Procedure.

Authors: [To be confirmed]

Reviewers: [To be confirmed]

5. References