Macro-economic Dependencies on Ocean Ecosystems

1. Outcome

This Circular provides guidance on compiling indicators of macro-economic dependencies on ocean ecosystems, enabling national accountants and ocean managers to quantify how national economies rely on marine and coastal natural capital. Understanding these dependencies is essential for assessing nature-related risks at the national and sectoral level, informing development finance decisions, and tracking progress toward sustainable ocean economies. The guidance addresses three decision use cases: quantifying GDP dependency on ocean ecosystem services to support national nature-related risk assessment; supporting national ocean economy reporting within medium-term expenditure frameworks as described in TG-1.1 Budget Processes; and tracking economic dependencies against SDG 14.7 on sustainable use of marine resources. The compilation approach integrates perspectives from the System of National Accounts and SEEA Ecosystem Accounting. Enterprise-level application of dependency indicators—including alignment with the Taskforce on Nature-related Financial Disclosures (TNFD), the LEAP process, IFRS S1, and CSRD—is addressed separately in TG-1.11 Private Sector and Ocean Accounts.

2. Requirements

This Circular requires familiarity with:

• TG-0.1 General Introduction to Ocean Accounts: conceptual framework and key components of Ocean Accounts
• TG-0.2 Overview of Relevant Statistical Standards: international statistical standards underpinning ocean accounting
• TG-3.1 Asset Accounts: physical and monetary accounts for marine environmental assets
• TG-3.2 Flows from Environment to Economy: physical supply and use tables for marine ecosystem services (required for Step 4)
• TG-3.3 Economic Activity Relevant to the Ocean: ocean economy sector classification and measurement

3. Guidance Material

Economic dependency on ocean ecosystems operates at multiple levels--from households relying on subsistence fisheries, to industries requiring clean water and healthy marine habitats, to national economies whose GDP depends significantly on ocean-related activities. This Circular provides the conceptual and methodological framework for measuring these dependencies at the macro-economic level, distinguishing between the direct contributions of ocean industries to national output and the broader dependencies of economic activity on marine ecosystem services. The guidance draws primarily on the ocean accounts framework in SEEA Ecosystem Accounting^[1] and the treatment of ecosystem services and economic activity in the 2025 SNA^[2]. Enterprise-level dependency assessment using the TNFD framework is covered in TG-1.11 Private Sector and Ocean Accounts. The dependency indicators compiled under this Circular feed directly into the structural analysis of ocean economies addressed in TG-2.5 Ocean Economy Structure, the investment analysis framework of TG-2.6 Ocean Investment, the private-sector application in TG-1.11 Private Sector and Ocean Accounts, and the evidence base for integrating nature-related considerations into national budget processes as described in TG-1.1 Budget Processes.

3.1 Conceptualizing Economic Dependencies

Economic dependencies on nature represent the reliance of economic actors on the flows of benefits from environmental assets and ecosystem services. The SEEA EA frames this as "the share of economy-wide value added that is dependent on ecosystem services" (SEEA EA 2021, para 11.4). In the context of ocean accounting, dependencies encompass the reliance of economic units--enterprises, industries, households, and governments--on the services provided by marine and coastal ecosystems. Enterprise-level dependency concepts—including the TNFD definition of dependencies and the "dependency pathway" construct—are addressed in TG-1.11 Private Sector and Ocean Accounts Section 3.1.

Dependency pathways

A dependency pathway describes the mechanism through which an economic activity relies on ecosystem services and the underlying environmental assets, and how observed or potential changes in those assets affect economic outcomes. At the macro level, pathways link changes in marine ecosystem condition (compiled following TG-2.1 Biophysical Indicators) to sectoral output through the channels summarised in Table 3.1.1 below.

For the relationship between the SNA production boundary and ecosystem service measurement, see TG-0.2 Standards and Frameworks. This complementarity is essential for understanding economic dependencies: the ocean economy as measured in conventional accounts captures only the direct production activities, while the full dependency on marine ecosystems extends to the regulating and cultural services that support but are not priced in market transactions.

Types of dependency

Dependencies may be categorized by their relationship to the economic unit, as summarised in Table 3.1.2 below.

Understanding these distinctions is important for interpreting dependency indicators: direct dependencies can be measured through the supply and use framework, while indirect and systemic dependencies require extended analysis such as input-output modelling.

3.2 Compilation Procedure for Ocean Economy Dependency Indicators

The compilation of macro-level dependency indicators follows a step-by-step procedure that extracts ocean economy sub-matrices from national supply and use tables and links them to ecosystem service accounts. The procedure adapts the methodology described in TG-2.5 Ocean Economy Structure Section 3.7 for the specific purpose of dependency measurement.

Step 1: Identify ocean economy industries

Using the industry classification concordance in TG-3.3 Economic Activity Relevant to the Ocean Section 3.3 (Table 2), identify all ISIC classes that constitute the ocean economy. For each class, determine whether it is wholly ocean-dependent (ocean ratio = 1.0) or partially ocean-related (ocean ratio < 1.0). Document the classification choices and ocean ratios applied. The list of ocean industries should include as a minimum:

• ISIC 0311 Marine fishing
• ISIC 0321 Marine aquaculture
• ISIC 5011, 5012 Sea and coastal water transport
• ISIC 0610, 0620 Offshore petroleum and natural gas extraction (ocean ratio: country-specific—onshore/offshore split required; consult national energy statistics or EITI data; see TG-3.10 Offshore Energy Accounts for split methodology)
• ISIC 3511 (partial) Electric power generation—offshore component
• ISIC 1020 Fish processing
• ISIC 3011, 3012 Shipbuilding
• ISIC 5222 Water transport support services
• ISIC 5510 (partial) Coastal accommodation

Step 2: Extract ocean economy sub-matrix from national SUTs

From the balanced national supply and use tables for the most recent complete accounting period, extract the columns corresponding to identified ocean economy industries. The extracted use table provides:

• Output by ocean industry
• Intermediate consumption by ocean industry
• Gross value added (GVA) by ocean industry
• Employment by ocean industry

For partially ocean-related industries, apply the ocean economy ratios determined in Step 1 to the extracted values.

Deriving ocean ratios for partially ocean-related industries. Where national data are available, compilers should derive ocean ratios using one of the following approaches in order of data availability:

1. Establishment-level survey data—if national statistical offices conduct establishment surveys that separately identify ocean-related and non-ocean-related activity within a mixed industry, use those establishment proportions directly.
2. Revenue or turnover splits from enterprise administrative data—where enterprise tax records or business registers record ocean-specific revenue (e.g., coastal accommodation revenue from beach-facing versus inland properties), use the revenue share as the ocean ratio.
3. Expert judgment with reference ranges—where no administrative data exist, apply expert judgment with documented reasoning. The SF-MST tourism ratio methodology provides an analogous approach: tourism supply tables use expert-derived attribution proportions for industries that partially serve tourists. For fish processing, a starting range of 0.70--0.90 (reflecting typical industry structures in small island and coastal states) is reasonable; for coastal accommodation, 0.30--0.50. Ratios outside these ranges require additional justification.

In all cases, ocean ratios must be documented in metadata and revisited when new business register or survey data become available.

Employment measure. Where the worked example and indicators in this Circular refer to "employment in persons", the primary measure is headcount (number of persons employed in the reference period), consistent with what is typically available from labour force surveys in most national statistical systems. Compilers should additionally report full-time equivalent (FTE) employment where source data permit, in line with the SNA 2025 recommendation that FTE is preferred for comparability where part-time and seasonal work is significant (SNA 2025, Chapter 16 on Labour). This is particularly relevant for coastal accommodation, tourism-related, and small-scale fisheries activity, where part-time and seasonal patterns are pronounced. The chosen measure must be applied consistently to both numerator (ocean-attributable employment) and denominator (total national employment) of the employment share indicator, and documented in metadata.

Step 3: Calculate ocean economy direct GVA

Sum the gross value added across all ocean industries, applying ocean economy ratios where appropriate:

$$\text{Ocean Economy Direct GVA} = \sum_i (\text{GVA}_i \times \text{Ocean ratio}_i)$$

This yields the total value added directly attributable to ocean economic activity. This figure represents the direct contribution of the ocean economy to GDP and serves as the baseline for contribution ratio calculations.

Note on double-counting. Summing GVA (rather than output) across ocean industries avoids double-counting of intermediate transactions by construction. The supply-use identity ensures that inter-industry purchases are already netted out of each industry's value added: fish processing (ISIC 1020) purchases raw fish catch as an intermediate input, and that purchase is deducted from fish processing output when GVA is computed. Both marine fishing (ISIC 0311) and fish processing (ISIC 1020) should therefore be included in the ocean economy sub-matrix; their combined GVA correctly captures the value added at each stage of the seafood supply chain without double-counting.

Step 4: Compile ecosystem service accounts

Following the methodology in TG-3.2 Flows from Environment to Economy Section 3.3, compile physical supply and use tables for marine ecosystem services. Table 3.2.1 below lists the minimum accounts that should be recorded.

The supply table attributes ecosystem service flows to marine ecosystem types (coral reefs, mangroves, seagrass, pelagic, other). The use table attributes ecosystem service flows to economic users (fisheries, aquaculture, tourism, coastal properties, households, rest of world).

Step 5: Link ocean industries to ecosystem service use

Map each ocean industry to the ecosystem services it uses. This mapping establishes which ecosystem service accounts provide inputs to which ocean economy production accounts. The sector-ecosystem dependency matrix in Section 3.3 (Table 2) provides the starting point for this mapping, which should be refined using national data.

Step 6: Derive contribution ratios

Calculate the ocean economy contribution ratio as:

$$\text{Ocean Economy Contribution Ratio} = \frac{\text{Ocean Economy Direct GVA}}{\text{National GVA at basic prices}} \times 100$$

This headline indicator expresses the percentage of national GVA at basic prices directly attributable to ocean economic activities.^[3] Note that this measures the output contribution of ocean industries rather than dependency in the strict sense; a true dependency measure would quantify how much economic output would be lost if ecosystem services were withdrawn (see Sections 3.4-3.6 for more comprehensive dependency analysis). For budget applications described in TG-1.1 Budget Processes Section 3.3 (Table 1), this ratio populates the "Ocean share" column for the GDP contribution indicator.

For sector-specific analysis, compute contribution ratios by industry:

$$\text{Industry Contribution Ratio}_i = \frac{\text{Ocean Industry GVA}_i}{\text{National GDP}} \times 100$$

3.3 Ocean Economy Share of GDP

The most widely used indicator of macro-economic dependence on the ocean is the share of Gross Domestic Product (GDP) attributable to ocean-related economic activities. The SEEA EA describes the ocean economy as measured "in terms of the contribution of the main ocean-related activities (e.g. marine transportation, coastal tourism, marine fishing, offshore mineral and gas extraction) to the national economy"^[4].

Measurement approach

Following the thematic and extended accounting principles described in TG-3.3 Economic Activity Relevant to the Ocean, ocean economy GDP is compiled by:

1. Identifying ocean industries using the International Standard Industrial Classification (ISIC), distinguishing between ocean-dependent industries (whose production is intrinsically linked to the ocean) and ocean-related industries (that provide goods and services to ocean-dependent activities)^[5]

2. Measuring gross value added (GVA) for each ocean industry, representing the value of output minus the value of intermediate consumption

3. Aggregating to ocean economy GVA, which represents the direct contribution of ocean activities to GDP

4. Calculating the ocean economy share as the ratio of ocean economy GVA to total national GDP

Table 3.3.1 below summarises the key indicators derived from this measurement approach.

For detailed guidance on industry classification and supply and use table compilation, see TG-3.3 Economic Activity Relevant to the Ocean.

Worked example: Ocean economy contribution ratio compilation

To illustrate the compilation of the ocean economy share of GDP using the step-by-step procedure, consider a country ("Country B") with national GVA at basic prices of 50,000 million currency units (used here as the denominator consistent with the Step 6 formula; for reporting against the commonly cited GDP figure, apply the bridge: GDP = GVA + taxes on products − subsidies on products, per SNA 2025 Chapter 6) and total employment of 10 million persons. Following Steps 1-6 above, the compiler has identified ocean industries, extracted data from national SUTs, and applied ocean ratios to partially ocean-related industries.

Table 1: Ocean economy sub-matrix extracted from national SUTs (Country B, million currency units)

Applying the ocean ratios to the partially ocean-related industries (fish processing, port services, coastal accommodation, other), the ocean-attributable GVA is:

• Fish processing: 120 x 0.80 = 96
• Port services: 250 x 0.90 = 225
• Coastal accommodation: 300 x 0.40 = 120
• Other ocean industries: 150 x 0.60 = 90

Total Ocean Economy Direct GVA = 300 + 150 + 400 + 96 + 225 + 120 + 90 = 1,381 million currency units.

Ocean Economy Contribution Ratio = 1,381 / 50,000 x 100 = 2.76% (of national GVA at basic prices).

Total ocean-attributable employment = 32,000 + 22,000 + 36,000 + (18,000 x 0.80) + (24,000 x 0.90) + (95,000 x 0.40) + (30,000 x 0.60) = 32,000 + 22,000 + 36,000 + 14,400 + 21,600 + 38,000 + 18,000 = 182,000 persons.

Ocean employment share = 182,000 / 10,000,000 x 100 = 1.82%.

This worked example demonstrates the full procedure from identifying industries through extracting SUTs to applying ocean ratios and computing contribution indicators. The results indicate that ocean-related activities directly contribute 2.76% of GDP and 1.82% of employment in Country B. As noted in Section 3.2 Step 6, this contribution ratio measures direct output, not the full extent of economic dependency on ocean ecosystem services.

Interpretation considerations

The ocean economy share of GDP measures the direct contribution of ocean industries to national production but does not capture the full economic dependency on ocean ecosystems. Several interpretive considerations apply:

The indicator measures production, not dependency. An economy where ocean industries contribute 5% of GDP may still have much larger dependencies on ocean ecosystem services if, for example, coastal protection services prevent flooding that would damage assets across multiple non-ocean sectors. The GDP share measures what is produced, not what depends on ecosystem condition.

Ecosystem services largely remain outside GDP. Following the SNA production boundary, many ecosystem services--including regulating services like coastal protection and waste treatment--are not recorded as economic output^[6]. The SEEA EA notes that "measurement of ecosystem services, in both physical and monetary terms, through ecosystem accounting complements the estimates of output based on the SNA production boundary"^[7]. Compilers should present ocean economy GDP alongside ecosystem service accounts to provide a complete picture of economic relationships with the ocean. For guidance on ecosystem service flow accounts, see TG-2.4 Ecosystem Goods and Services.

Structural change affects interpretation over time. As economies develop, the composition of GDP shifts--typically toward services and away from primary industries. A declining ocean economy share may reflect diversification rather than reduced absolute dependence. Presenting both absolute values (ocean economy GVA in currency units) and relative shares provides fuller context.

Comparison across countries requires adjustment. Countries differ in their ocean area (EEZ size), coastal population, and economic structure. Per capita or per square kilometre normalisations may support international comparison, though care is needed in interpretation.

SDG 14.7.1 Application

SDG Indicator 14.7.1 measures sustainable fisheries, aquaculture, and marine tourism as a proportion of GDP, with reporting obligations specifically for Small Island Developing States (SIDS) and Least Developed Countries (LDCs). The custodian agency is FAO; the methodology is documented in FAO SDG 14.7.1 metadata (FAO, 2023).^[8]

The ocean economy compilation described in this section supports SDG 14.7.1 reporting, but with an important scope difference: SDG 14.7.1 covers fisheries (ISIC 0311, 0321), fish processing (ISIC 1020), and marine tourism (relevant portions of ISIC 55, 79, 93)—not the full ocean economy. Compilers producing a full ocean economy GVA estimate following Steps 1--6 should extract the SDG 14.7.1 sub-total as follows:

1. From the ocean industry GVA compilation, identify the rows for marine fishing (ISIC 0311), marine aquaculture (ISIC 0321), fish processing (ISIC 1020, applying the same ocean ratio), and coastal/marine tourism (applicable ISIC sub-classes with ocean ratios applied).
2. Sum the ocean-attributable GVA for these rows only.
3. Divide by national GDP (not GVA at basic prices) as required by the FAO custodian-agency methodology, applying the GDP bridge (GDP = GVA + taxes on products − subsidies on products, per SNA 2025 Chapter 6) to the denominator.
4. Report the resulting percentage to FAO via the national SDG reporting mechanism.

Where full SUT data are not available, FAO accepts estimates based on national fisheries statistics (production value from SOFIA data) combined with available tourism satellite account data. Compilers in SIDS and LDCs should consult the FAO SDG 14.7.1 metadata for the simplified reporting template applicable where full SUT infrastructure is absent.

3.4 Ecosystem Service Dependencies

Beyond the ocean economy share of GDP, a fuller understanding of macro-economic dependencies requires analysis of how specific sectors depend on specific ecosystem services. The SEEA EA identifies the objective "to identify the share of economy-wide value added that is dependent on ecosystem services"^[9].

Sectoral dependency mapping

Sectoral dependency analysis identifies which ecosystem services each industry relies upon. For marine ecosystem services, the key dependencies by sector include:

Marine fishing (ISIC 0311): Depends directly on provisioning services (fish biomass, genetic diversity), regulating services (nursery habitat maintenance, water quality), and supporting services (primary production, nutrient cycling). Stock assessment accounts track the sustainable yield that represents the capacity of the ecosystem to maintain provisioning services over time^[10]. For detailed guidance on fish stock assessment and asset accounting, see TG-3.1 Asset Accounts, Section 3.3.1.

Marine aquaculture (ISIC 0321): Depends on water quality regulation (maintaining conditions suitable for cultured species), waste assimilation (capacity of surrounding waters to absorb aquaculture effluents), and provisioning services (wild-caught feed inputs, larval supply for some species). Condition accounts for coastal ecosystems provide indicators of the capacity to support aquaculture^[11]. See TG-3.9 Aquaculture Accounts for detailed methodology.

Coastal and marine tourism (portions of ISIC 55, 79, 93): Depends on cultural services (recreation, aesthetic values, spiritual and educational values) and regulating services (water quality for swimming and diving, beach stability from sediment regulation). Ecosystem condition variables such as water clarity, coral cover, and beach erosion rates indicate the capacity to support tourism services^[12].

Maritime transport (ISIC 50): Depends primarily on spatial access (the ocean as a medium for transport) but also on regulating services that maintain navigable conditions (sediment regulation in ports and channels, storm frequency affecting operations).

Offshore oil and gas (ISIC 06): Depends on mineral and energy resources rather than ecosystem services as such, though operations may be affected by marine conditions and weather extremes influenced by climate regulation services. See TG-3.10 Offshore Energy Accounts for specific guidance.

Coastal communities and households: Depend on multiple services including provisioning (subsistence fishing, aquaculture), regulating (coastal protection from storms, flood regulation, water purification), and cultural services (recreation, cultural identity, spiritual values).

Sector-Ecosystem Dependency Matrix

Table 2 provides a template dependency matrix summarising the principal relationships between ocean economic sectors and marine ecosystem services. The intensity ratings (high, medium, low) are qualitative and indicative; they should be adapted to national circumstances on the basis of available data and expert judgement. To support consistent application across compilers, the following descriptive anchors are used:

• High—the ecosystem service is a critical, effectively non-substitutable input to the sector's production process; sustained loss or degradation of the service would materially impair the sector's capacity to operate, and no close market substitute is available at comparable cost. Example: fish provisioning for marine capture fisheries.
• Medium—the sector relies on the service for normal operation but the service is partially substitutable (through engineered alternatives, alternative inputs, or relocation), or affects only part of the sector's output. Loss or degradation would raise costs or reduce productivity without eliminating the activity. Example: coastal protection for coastal tourism infrastructure.
• Low—the service has a marginal influence on the sector's production; degradation would have limited direct economic consequence for the sector, although it may affect impact pathways or other sectors.

These anchors are descriptive rather than quantitative thresholds; compilers with access to ecosystem service accounts compiled following TG-2.4 Ecosystem Goods and Services are encouraged to replace the qualitative ratings with measured service flows and dependency coefficients where data permit. Ratings should be documented in metadata, with the evidence base (literature, expert panel, or measured accounts) recorded for each cell. The matrix serves as a practical starting point for compilers undertaking sectoral dependency analysis; countries should refine the ratings using quantitative data from ecosystem service accounts compiled following TG-2.4 Ecosystem Goods and Services and condition accounts described in TG-2.1 Biophysical Indicators (which implements SEEA Ecosystem Accounting (2021), Chapter 5).

Table 2: Sector-Ecosystem Dependency Matrix

Note: Ratings reflect typical commercial-scale oceanic contexts and must be adapted to national circumstances, fishing methods, and geographic zones. In Pacific Island and coastal states, cultural dependencies for fisheries may be high.

The matrix highlights that primary industries (fisheries, aquaculture) exhibit the strongest direct dependencies on provisioning and regulating services, while tourism depends predominantly on cultural services and coastal protection. Sectors such as shipping and offshore energy have comparatively low direct dependencies on ecosystem services, though they may impose significant impacts on marine ecosystems--an asymmetry between dependency and impact that is important for policy analysis. The ecosystem types column supports spatial linking of dependency analysis with ecosystem extent and condition accounts, enabling identification of which specific marine areas underpin each sector's economic activity.

Quantifying dependencies

The quantification of ecosystem service dependencies in monetary terms remains methodologically challenging. The SEEA EA presents approaches for valuing ecosystem services but notes that valuation chapters are "internationally recognized recommendations" rather than full statistical standards, reflecting ongoing methodological development^[13]. The international methodological consensus—set out in the SEEA EA Monetary Valuation of Ecosystem Services and Assets for Ecosystem Accounting technical recommendations^[14]—ranks valuation methods by their proximity to observed market prices: directly observed values are preferred; resource-rent and productivity-change methods follow; revealed-expenditure (averting behaviour, travel cost, hedonic pricing) and expected/simulated-expenditure methods (replacement cost, avoided damage cost, simulated exchange value) sit below; stated-preference and opportunity-cost methods are not preferred for accounting. Compilers should not replicate the method-by-method, ecosystem-service-by-ecosystem-service guidance set out in that technical report and in TG-1.9 Valuation, but should use the same precedence order to select among methods.

Decision tree—selecting a valuation method for a dependency entry

For each ocean dependency to be valued, work through the following steps and stop at the first that applies:

1. Directly observable market price for the service?—e.g. individually transferable quota (ITQ) prices for wild fish access, voluntary carbon market prices for blue-carbon sequestration. If yes, use the directly observed value.
2. Service embodied in a marketed output with an extractable resource rent?—typical for provisioning services with commercial harvest (fisheries, aquaculture feed). Apply the resource-rent / residual-value method.
3. Service supports a marketed output through productivity?—e.g. mangrove nursery contribution to commercial fisheries yield, coral reef contribution to dive tourism throughput. Apply the productivity-change method.
4. Service substitutes for or avoids a market expenditure?
   • Revealed-expenditure data available (travel cost, hedonic property values, averting behaviour): preferred branch.
   • Otherwise: expected/simulated expenditure—replacement cost, avoided damage cost, simulated exchange value. Document the counterfactual.
5. None of the above applicable? Note that stated-preference and opportunity-cost methods are not preferred for accounting; if used, adjust to an exchange-value basis before recording.

Applied to the dependency categories already identified in this Circular, the precedence order maps as follows. Each example illustrates the dominant branch; alternative branches may apply in specific national settings.

The three method families retained from earlier versions of this Circular—resource-rent attribution, damage-avoided valuation, and factor/replacement cost—correspond to Steps 2, 4 (simulated-expenditure branch), and 4 (revealed-expenditure or simulated-expenditure branch) of the decision tree respectively. Worked examples for each step are in the SEEA EA monetary valuation technical recommendations^[14:1] and in TG-1.9 Valuation; this Circular does not reproduce them.

For comprehensive guidance on valuation methods for ocean ecosystem services and assets, see TG-1.9 Valuation.

3.5 Supply Chain Dependencies

The direct dependencies of ocean industries on ecosystem services represent only a portion of total economic dependency. Through supply chain linkages, industries that do not directly interact with marine ecosystems may nevertheless depend on ocean ecosystem services through their purchases of intermediate inputs.

Input-output analysis

Input-output analysis provides the framework for tracing dependencies through supply chains. Building on the supply and use tables described in TG-3.3 Economic Activity Relevant to the Ocean, symmetric input-output tables enable calculation of the linkages summarised in Table 3.5.1 below.

It is important to distinguish economic output multipliers from ecosystem service dependency coefficients. Output multipliers measure economic interdependence between industries—how a change in final demand for one industry's output propagates through the supply chain—but they do not directly measure ecosystem service dependency. To produce total-requirements-based ecosystem dependency estimates, ecosystem intensity factors from the dependency matrix (Section 3.4) should be applied to the columns of the Leontief inverse matrix: this yields the total ecosystem service content (direct and indirect) embodied in a unit of final demand for each product. The multiplier analysis retained in this section serves as supplementary economic impact context; it is not a primary dependency measure and should not be reported as such.

The Statistical Framework for Measuring the Sustainability of Tourism (SF-MST) notes that indirect effects "can be estimated, often using input-output modelling techniques" and that the entries in accounts "are organized to connect to entries for these other industries"^[16]. The same principle applies to ocean economy accounts: their integration with national supply and use tables enables tracing of supply chain dependencies.

Environmentally extended input-output analysis

Environmentally extended input-output tables (EE-IOT) add environmental data to economic input-output tables, enabling analysis of embodied environmental flows through supply chains^[17]. For ocean dependencies, this approach allows quantification of the measures summarised in Table 3.5.2 below.

The SEEA AFF notes that "environmentally extended input-output tables have been developed for individual countries, and are increasingly being developed to cover several countries; they are referred to as multiregional input-output tables, which also incorporate connections between countries through international trade in goods and services"^[18].

EE-IOT compilation is technically demanding and data-intensive, requiring integration of detailed environmental satellite data with balanced supply and use tables at a fine level of industry disaggregation. For most countries that are beginning ocean economy accounting, this represents an advanced application that is unlikely to be feasible in early implementation phases. Countries should consider the following progression: begin with the basic supply chain mapping described below, advance to partial quantification using available input-output data as the ocean economy thematic account matures, and pursue full EE-IOT compilation only when the requisite environmental and economic data infrastructure is in place. This phased approach aligns with the principle of building statistical capacity incrementally, as described in TG-0.1 General Introduction to Ocean Accounts. Compilers can use the following entry criteria to assess their current phase:

• Phase 1 entry—ocean industry list compiled following Section 3.2 Step 1; no balanced supply and use tables available at the national level.
• Phase 2 entry—balanced SUTs available at minimum ISIC section level, enabling extraction of the ocean economy sub-matrix per Section 3.2 Steps 2--3.
• Phase 3 entry—symmetric input-output tables available and environmental satellite data compiled for at least one marine ecosystem service (e.g., fish provisioning in physical units from TG-3.2 or TG-3.3 source data).

Countries that meet Phase 2 entry criteria can begin partial quantification of supply chain dependencies using available IO data. Countries at Phase 1 should focus on qualitative mapping and building the SUT infrastructure before pursuing EE-IOT.

Practical considerations

For countries beginning ocean economy accounting, practical approaches to supply chain dependency analysis include:

1. Qualitative mapping: Identify the principal industries that supply inputs to ocean industries, and the principal industries that purchase outputs from ocean industries, without full quantification
2. Partial quantification: Use available input-output data to estimate the share of selected industries' intermediate purchases that originate from ocean industries
3. Case-study analysis: Focus on specific supply chains of policy interest (e.g., the seafood supply chain from catch to consumption) rather than economy-wide analysis

3.6 Risk and Resilience Indicators

The practical importance of measuring economic dependencies lies in their implications for risk: economies that depend heavily on ocean ecosystems face economic risks when those ecosystems degrade. At the national and sectoral scale, the dependency indicators compiled under this Circular populate the macro inputs to nature-related risk assessment.

Nature-related risks (macro view)

At the macro level, the dependency-to-risk translation distinguishes three broad risk categories, mirroring the taxonomy used at enterprise level (see TG-1.11 Private Sector and Ocean Accounts Section 3.2 for the TNFD-aligned enterprise treatment):

• Physical risks to national output arising from ecosystem degradation—e.g. fishery collapse, loss of coastal protection from reef or mangrove degradation, decline in tourism attractiveness from water quality deterioration, aquaculture disruption from harmful algal blooms. These risks may be acute (short-term events such as oil spills or cyclones) or chronic (gradual changes such as ocean acidification or warming).
• Transition risks to national output arising from policy, market, technology, reputational, or liability shifts as economies adjust to nature pressures.
• Systemic risks arising from ecosystem tipping points, cascading service losses, and the simultaneous materialisation of physical and transition risks across coupled sectors.

For the conceptual definitions of these risk categories, their sub-types, and their application to enterprise-level disclosure, refer to TG-1.11 Private Sector and Ocean Accounts. The role of Ocean Accounts in this Circular is to provide the national/sectoral baseline data against which these risks are assessed.

Developing resilience indicators

Resilience indicators assess the capacity of economic systems to absorb shocks and adapt to changes in ecosystem service provision. Building on ocean accounts, relevant indicators include:

Ecosystem condition indicators from condition accounts provide early warning of capacity to maintain service provision. These indicators are addressed in detail in TG-2.1 Biophysical Indicators, following SEEA Ecosystem Accounting (2021), Chapter 5, and include:

• Coral reef condition indices indicating coastal protection and tourism support capacity
• Fish stock status relative to sustainable yield indicating provisioning service sustainability
• Water quality parameters indicating capacity to support multiple uses

A computable composite for this category is the ocean ecosystem condition index derived by applying the composite scoring methodology in TG-2.1 Biophysical Indicators to the marine ecosystem types relevant to each ocean sector. The index values from TG-2.1 can be used directly as condition-state inputs to resilience assessment.

Economic diversity indicators assess the extent to which economies depend on single ecosystem services or sectors. A computable indicator for sectoral concentration is the Herfindahl-Hirschman Index (HHI) for ocean economy GVA:

$$\text{HHI} = \sum_{i=1}^{n} s_i^2$$

where sᵢ is sector i's share of total ocean economy GVA (expressed as a proportion, 0 to 1) and n is the number of ocean industries. HHI ranges from 1/n (maximum diversification) to 1 (full concentration in a single sector). Values above 0.25 indicate high concentration. Additional diversity measures include:

• Geographic concentration of ocean-dependent activity (share of ocean GVA from a single coastal region or EEZ sub-zone)
• Diversity of export products from ocean industries

Adaptive capacity indicators assess the ability to respond to ecosystem changes. A computable indicator is the alternative livelihood investment ratio:

$$\text{ALI ratio} = \frac{\text{Public investment in alternative livelihoods for ocean-dependent communities}}{\text{Total public expenditure on ocean sectors}}$$

expressed as a percentage. Data sources are national budget classifications and expenditure reviews. Additional adaptive capacity indicators include:

• Technology and infrastructure for monitoring and response
• Governance capacity for adaptive management

These computable indicators are proposed as starting points for national implementation; they are not mandatory standards and should be adapted to national data availability and policy priorities.

Resilience indicator development for ocean accounts is an emerging area where specific indicator recommendations are expected to evolve as implementation experience accumulates. Countries currently piloting ocean accounts--including Thailand, Vietnam, and Fiji--are generating practical experience with resilience measurement that will inform future revisions of this guidance. In the interim, compilers are encouraged to draw on the condition indicator framework in TG-2.1 Biophysical Indicators as the primary basis for assessing ecosystem resilience, supplemented by economic diversity and adaptive capacity indicators where data permit.

Integration with financial disclosure

The increasing adoption of nature-related financial disclosure frameworks creates demand for dependency and risk indicators that can inform corporate and financial sector reporting. The 2025 SNA notes that "a related area of work is the assessment of enterprises' exposure to environmental risks, including climate risks and risks emerging from declines in nature and biodiversity"^[19].

National Ocean Accounts compiled following this Circular provide the population-level inputs that enterprise-level disclosure draws on:

• Baseline data on dependencies of industries and sectors on ocean ecosystem services
• Condition metrics against which physical risks can be assessed
• Geographic data linking economic activities to specific marine and coastal ecosystems
• Time series enabling tracking of changes in dependencies and risks

For private-sector application—including TNFD-aligned disclosure, the LEAP process, IFRS S1, and CSRD double-materiality reporting—see TG-1.11 Private Sector and Ocean Accounts. For development finance and multilateral appraisal contexts, see TG-1.7 OA and Multilateral Development Finance.

4. Acknowledgements

Authors: [To be confirmed]

Reviewers: [To be confirmed]

5. References