Extending Fisheries Statistics for Ecosystem-Based Management

1. Outcome

This Circular provides guidance on extending conventional fisheries statistics to support ecosystem-based management (EBM)—the coordination of human uses of an ecosystem so that the combined effects do not compromise its function, structure, and capacity to sustain services over time. For ocean accounting purposes, this Circular is specifically concerned with the provisioning-service accounts defined in the SEEA Ecosystem Accounting (SEEA EA) framework^[1] and with the EBM indicators that are derivable from those accounts (such as catch composition indices, resource-rent-based effort proxies, and stock-extent linkages). Broader fisheries-stock-assessment EBM frameworks (e.g., fishing mortality relative to Fmsy, spawning stock biomass relative to SSBmsy) are not in scope here but are addressed in TG-1.5 OA and Fisheries Management.

Conventional fisheries statistical systems—built around FAO FishStat capture-production reporting, national logbook and landings registers, and stock-assessment models—are well established for tracking yield and effort but do not disaggregate catch to providing ecosystems, value the catch as an ecosystem service flow, or capture parallel provisioning flows such as gleaning and aquaculture. By following the candidate workflows in this Circular, statistical compilers may extend their existing systems to produce ecosystem-attributed physical supply tables and monetary supply tables based on resource rent, supporting EBM decision use cases including allocation of access rights across competing provisioning flows and ecosystem-aware coastal investment.

2. Requirements

This Circular requires familiarity with:

• TG-0.1 General Introduction to Ocean Accounts—for the conceptual framework
• TG-2.4 Environmental (including Ecosystem) Goods and Services—for ecosystem service definitions and the indicator context within which provisioning-service accounts are interpreted
• TG-4.3 Administrative Data Sources—for the use of agency landings, licensing, and logbook registers
• TG-4.5 Integrating Research Data into Official Statistics—for the integration of fishery-independent research data into accounting systems

Related Circulars:

• TG-3.9 Aquaculture Accounts—for the parallel cultivated-resource workflow; TG-4.10 provisioning-service supply tables feed into the broader accounts in TG-3.9
• TG-1.5 OA and Fisheries Management—for the fisheries-management decision context and stock-assessment EBM frameworks
• TG-4.1 Remote Sensing and Geospatial Data—for the upstream remote sensing methods that underpin habitat-extent data used in the §3.4 data matrix
• TG-6.7 Fisheries Accounting: Integrating Stock Assessment—for the thematic methods that link the provisioning-service supply tables compiled here to full fisheries asset accounts

3. Guidance Material

3.1 Conceptual Framework

Conventional fisheries statistics report what was landed—catch by species, gear, and reporting area—and, in more developed systems, what biomass remains through stock assessment models. EBM and ecosystem accounting require two additional dimensions: where the catch came from in ecological terms (which providing ecosystem) and what economic value the providing ecosystem contributed (the resource rent attributable to the natural resource itself, distinct from labour and capital). The SEEA EA framework (Chapter 6) sets out the provisioning-service account structure that organises these dimensions^[1:1].

Three related management frameworks use overlapping terminology that this Circular distinguishes as follows: the Ecosystem Approach to Fisheries (EAF), as defined by FAO, extends single-species management to consider interactions between target species, bycatch, and habitat^[2]; Ecosystem-Based Fisheries Management (EBFM), as practised under frameworks such as the US Magnuson-Stevens Act, further integrates multi-species dynamics and socio-economic considerations into harvest strategies; and Ecosystem-Based Management (EBM) is the broadest term, covering the full range of human uses of an ecosystem. This Circular adopts the EBM framing but focuses specifically on the provisioning-service account extensions that support all three approaches—the accounting infrastructure is the same regardless of which management framework a country employs.

The EBM indicators that are derivable from the extended accounts described in this Circular include: catch composition indices (the share of total provisioning supply attributable to each species group or providing ecosystem); resource-rent trends as a proxy for fishing pressure relative to ecosystem capacity; and cross-account consistency checks between provisioning-service use rates and ecosystem extent or condition accounts. FAO Code of Conduct for Responsible Fisheries principles on economic sustainability^[3] provide the normative context for interpreting these indicators.

The four workflows introduced in the Outcome section are detailed in Sections 3.3--3.6 respectively.

3.2 Extending Existing Statistical Systems

The starting point for most national compilers is an established FAO FishStat-aligned capture-production reporting system, supplemented by national landings registers, logbooks, port-sampling programmes, and (in better-resourced systems) stock-assessment models^[4]. The base system may be extended in three directions: ecological attribution (§3.3), economic attribution (§3.3.2), and coverage extension (§§3.6--3.7).

3.3 Wild-Capture Catch Accounting

The candidate workflow for wild-capture catch as a provisioning ecosystem service flow has three parts:

3.3.1 Physical measurement

a) Compile total annual landed catch (kg/yr) from the national fisheries authority landings register, FAO FishStat returns, and (where coverage is thin) structured fisher surveys.

b) Disaggregate by (i) species or species group; (ii) gear type—typical categories include pole-and-line, handline, gillnet, longline, trap, and trawl; and (iii) providing ecosystem, using species-habitat associations (standard sources include FishBase species-habitat associations^[5] and the FAO CWP Handbook of Fishery Statistical Standards habitat classifications^[6]).

c) Where landings surveys cover only a fraction of total fishing trips, practitioners may calibrate survey coverage against provincial or regional statistics to derive an extrapolation factor.

d) Map the spatial distribution of fishing effort using vessel monitoring data, logbooks, or structured fisher reporting.

The output is a physical supply table with rows for species groups and columns for providing ecosystems, totalled in kg/yr.

3.3.2 Monetary valuation—resource rent

The candidate primary monetary method is resource rent, computed as:

Resource rent = Gross revenue - Total fishing costs

where gross revenue is the sum across species groups of catch x first-sale price, and total fishing costs comprise labour, capital consumption, fuel, equipment, and maintenance. A positive residual represents the ecosystem's economic contribution; a negative residual indicates that fishing costs exceed revenue under prevailing conditions, in which case the entry may be reported as a zero ecosystem service value with the negative figure disclosed in metadata. The resource rent method aligns with the SEEA EA monetary valuation hierarchy for provisioning services^[7].

Where detailed cost decomposition is feasible, practitioners may consider:

• Operational expenses (consumables, fuel, maintenance, repairs)
• Labour costs, with the option of regional agricultural wages as a proxy where direct fisher wage data are unavailable
• Capital costs comprising vessel and gear depreciation plus a return on fixed capital computed at the national weighted-average cost of capital

3.3.3 Tiered implementation

Practitioners may begin at Tier 1 and progress as data systems mature. Value-transfer accuracy is limited; Tier 1 entries may be flagged in metadata as indicative.

3.4 Data Requirements and Sources

The following matrix sets out the minimum data items required for each workflow, with typical source agencies, recommended update frequencies, and alternatives for data-poor contexts.

Notes on data-poor contexts. Where national survey data are unavailable, practitioners should use the alternatives listed above as Tier 1 starting points, disclosing the source and any assumptions in metadata. The RAM Legacy Stock Assessment Database^[8] provides modelled reference points for a large number of assessed stocks; the Sea Around Us reconstruction methodology^[9] provides catch time series for countries with limited official reporting. FAO-modelled estimates are routinely used in official reporting contexts and are acceptable for Tier 1 compilation provided provenance is documented.

3.5 Aquaculture Production Accounting (Cross-Reference)

Aquaculture in the same accounting area is accounted as a cultivated provisioning flow following the produced-asset methodology in TG-3.9 Aquaculture Accounts, Sections 3.2--3.3. The fisheries statistical extension required here is primarily reconciliation: practitioners may consider cross-checking aquaculture output recorded in production accounts against FAO FishStatJ national aquaculture-production figures^[10], and recording cultivated and wild-capture provisioning flows in adjacent columns of the same supply table to enable trade-off analysis.

3.6 Gleaning (Intertidal Hand-Collection)

Gleaning—the hand-collection of molluscs, crustaceans, echinoderms, and seaweeds from intertidal mudflats, reef flats, and mangrove edges—is a provisioning flow frequently missed by both aquaculture and conventional fisheries statistics, despite its importance for coastal household food security and women's livelihoods. Practitioners may consider the following candidate workflow:

a) Physical measurement. Household survey instruments may be used to estimate per-collector annual harvest (kg/yr) by target species group, aggregated across the eligible population within accessible distance of the providing ecosystem. Spatial proxy models—collection modelled as a function of distance to the resource edge, accessible standing stock, and household demand parameters—may be used to extrapolate where survey coverage is incomplete.

b) Monetary valuation. Where gleaned products enter local markets, first-sale prices may be used to compute gross revenue and a resource rent analogous to wild-capture fisheries. Where collection is predominantly for subsistence with no observed market transaction, practitioners may consider a substitute-cost approach, valuing the catch against the market price of the nearest commercial equivalent, and recording the result as a non-market valuation using a cost-based approach, consistent with the SEEA EA monetary valuation hierarchy (Chapter 6, Section 6.3), in metadata.

c) Use table allocation. Gleaning output typically flows to subsistence households rather than the formal fisheries sector. The use table should record this allocation distinctly to preserve the distributional information needed for livelihood and food-security analysis.

3.7 Wood and NTFP Provisioning from Coastal Forests

Where the accounting area includes coastal forests—particularly mangroves—the forested area may continue to provide wood and NTFP provisioning services (fuel wood, building poles, charcoal feedstock, honey, dye, traditional medicine) alongside any fisheries or aquaculture present. While not a fisheries flow, this provisioning service typically shares the coastal accounting area with fisheries and may be compiled in the same supply table to support EBM trade-off analysis between mangrove conversion (for aquaculture ponds, for example) and retained provisioning value.

a) Physical measurement—spatial proxy. Where direct household survey data are unavailable, practitioners may consider a spatial proxy model estimating per-household extraction as a function of distance from household to mangrove edge, accessible deadwood stock, and a baseline household demand parameter drawn from peer-reviewed literature. Aggregation across eligible households within an accessible distance band yields total annual collection. Practitioners may consider flagging the implied use rate against a sustainable yield benchmark to check consistency with mangrove extent accounts.

b) Monetary valuation—substitute-cost. Where collected wood does not enter formal markets, the candidate primary method is substitute-cost: total annual collection converted to energy equivalent and valued at the market price of the displaced commercial fuel (typically LPG or kerosene). Air-dried biomass is converted to MJ using species-appropriate calorific values; bark and leaves are typically excluded.

c) Monetary valuation—resource rent (stumpage value). Where mangrove wood is marketed (sold as timber, poles, or firewood), practitioners may instead use the stumpage-value resource rent method: market price at point of sale less harvesting and transport costs. This yields a directly observed market-based exchange value consistent with the SEEA EA monetary valuation hierarchy^[11].

d) Cross-account consistency. The use rate implied by the physical account must be cross-checked against extent and condition accounts for the providing mangrove ecosystem. A use rate exceeding sustainable yield implies declining mangrove biomass and should be reflected in the extent or condition account and metadata.

3.8 Reporting and Integration

The extended fisheries statistical system may be integrated into a single provisioning-service supply and use table for the coastal accounting area, with rows for species groups and columns for providing ecosystems, and parallel sheets for the four workflows above. Monetary supply tables are compiled where cost and price data permit.

The physical and monetary supply tables produced by the workflows in Sections 3.3--3.7 are direct inputs to the cultivated-resource accounts in TG-3.9 Aquaculture Accounts and the fisheries asset accounts described in TG-6.7 Fisheries Accounting: Integrating Stock Assessment. The provisioning-service flows also contribute to ecosystem service indicator analysis described in TG-2.4 Environmental (including Ecosystem) Goods and Services. Compilers should document in metadata:

• Data sources, vintage, and coverage for each component
• Allocation parameters and their sources (species-habitat literature, distance elasticity values, use rates)
• Tier of implementation for each sub-procedure
• Components flagged as data-deficient or indicative
• Cross-account consistency checks performed

3.9 Data Quality and Limitations

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