Research report: Compiling preliminary SEEA Ecosystem Accounts for the OSPAR regional sea: experimental findings and lessons learned

Researchers have compiled the first set of ecosystem accounts for an entire regional sea, providing an experimental snapshot of marine and coastal natural capital across the OSPAR area of the North-East Atlantic. The preliminary accounts cover ecosystem extent, the physical and monetary supply of selected services, and estimated asset values for habitats associated with wild fisheries, aquaculture, carbon sequestration and outdoor recreation. They are not a complete valuation of the ocean: condition accounts could not be produced, several estimates omit important habitats or countries, and available observations cover different years.

Nevertheless, the exercise demonstrates how data already collected for marine monitoring can be organized within the United Nations System of Environmental-Economic Accounting, known as SEEA Ecosystem Accounts. The work responds to a measurement problem in economic and environmental policy. Ocean ecosystems provide goods and services that support livelihoods, including fisheries, aquaculture, climate regulation, coastal protection and recreation.

Many of these contributions do not arise through direct extraction or use, making them difficult to represent in conventional economic accounts. The resulting omission has contributed to decisions that prioritize economic values over ecosystem degradation. International strategies for sustainable ocean development have therefore promoted integrated assessments framed in terms of natural capital and ecosystem services.

SEEA was developed as a complementary accounting standard to the System of National Accounts, using regular, objective and internationally comparable data to recognize nature’s contribution to economic and social activity. SEEA Ecosystem Accounts organize information into linked components. Extent accounts measure the area occupied by different ecosystem types, while condition accounts describe selected characteristics of those ecosystems at particular times.

Service accounts quantify flows of ecosystem services in physical or monetary terms and identify the households, businesses and government bodies that use them. Asset accounts estimate the monetary value of ecosystem stocks and their additions or reductions over time. The standard is endorsed for use in more than 90 countries, and 41 countries had compiled ecosystem accounts by 2023, but most existing work concerns terrestrial environments.

Marine accounts pose additional difficulties because habitats extend through the seabed and water column, their boundaries are not always concentrated at the surface, and resources and pressures cross national jurisdictions. The OSPAR Convention for the Protection of the Marine Environment of the North-East Atlantic provides a regional setting for testing these methods. It has 15 Contracting Parties and includes the European Union.

Its maritime area covers more than 13.5 million square kilometres, encompassing the internal waters, territorial waters and exclusive economic zones of Contracting Parties, adjacent high seas, and areas extending into the Wider Atlantic and Arctic Waters. Researchers assessed existing accounts, consulted technical experts and worked through OSPAR’s Intersessional Correspondence Group on Economic and Social Analyses. They combined guidance from SEEA and the Global Ocean Account Partnership with data from OSPAR’s Data and Information Management System, European seabed maps, European Environment Agency extent estimates, and marine natural capital accounts from the Netherlands and United Kingdom.

The resulting extent account covered more than 9.2 million square kilometres, approximately 68% of the OSPAR area. Deep-sea sedimentary habitats were the most extensive mapped class, representing 46% of the accounted area. Infralittoral and circalittoral rocky habitats together accounted for only 0.006%, or 5,281 square kilometres.

The researchers represented seabed habitats in two dimensions rather than attempting a full account of the water column and seabed as three-dimensional systems. EUSeaMap 2019 data provided the principal habitat classification through the EUNIS system, while separate European Environment Agency data supplied estimates for intertidal ecosystems and coastal estuaries. The available data were not aligned with the IUCN Global Ecosystem Typology endorsed by SEEA, illustrating a tension between international classification standards and the marine datasets that can currently be assembled.

A central limitation prevented the compilation of ecosystem condition accounts. OSPAR already reports indicators including acidity, eutrophication, species diversity, sea-surface temperature, coral condition, seagrass cover and the state of fish stocks, but many are aggregated across the entire North-East Atlantic or broad subregions. These regional measurements cannot be assigned to the specific habitat classes used in the extent account without spatially disaggregated data.

The researchers recommend shifting future collection toward ecosystem-based reporting so that condition indicators can be linked directly to mapped assets. They also note that the revised EUNIS classification, which distinguishes benthic and pelagic components, could support future work on biotic habitats such as kelp forests and oyster reefs, as well as assets and services in the water column. The physical service accounts selected for OSPAR priorities and data availability had markedly different temporal coverage.

Wild fish provisioning was estimated for 2012 through 2019 and fluctuated between about 8.1 and 9.3 million tonnes, reaching its highest reported level in 2018 and its lowest in 2019. Aquaculture provisioning was available for 2012 through 2015 and remained close to 2.12 to 2.15 million tonnes. Carbon sequestration and capture could be estimated only for 2019, while outdoor recreation was available only for 2012.

The fish figures were based on reported landings, which may omit commercially caught species and could not be assigned to the ecosystems that supplied them. Carbon estimates omitted seagrass and excluded major habitats containing significant carbon sinks, making the regional total an underestimate. Recreation used potential annual visits as a proxy and could not be extended to the whole OSPAR area.

Monetary values were derived mainly through benefit transfer, a method that applies estimates from a study site to another location with similar characteristics. United Kingdom resource-rent values informed the wild-fish estimate, a Norwegian aquaculture study supplied values for aquaculture products, an efficient carbon price from a low-reduction scenario was applied to sequestration, and the INCA project provided recreation values for European Union members that were also OSPAR Contracting Parties. Fish provisioning was valued between €1.7 billion and €2.8 billion, with no clear relationship between changes in physical and monetary values.

Aquaculture’s monetary value increased from €1.3 billion to €3.7 billion between 2012 and 2015 despite a nearly stable physical flow. Carbon sequestration and capture was valued at €1.6 million in 2019, while outdoor recreation in OSPAR countries with available data was estimated at €253 million in 2012. Using the net present value of expected future service income, the researchers estimated the value of ecosystem assets across the OSPAR region at €125.75 billion.

Carbon sequestration represented €48.15 billion of this preliminary total, and outdoor recreation represented €7.56 billion; together, they contributed more than 40%. These are modelled asset values, not market prices for the North-East Atlantic, and the incomplete carbon and recreation estimates imply that the asset totals are also underestimated. The study further cautions that absolute monetary values depend strongly on the valuation method and may be less informative than changes over time.

For example, lower landings in 2016 received a higher resource-rent value than higher landings in 2015 because the method is connected to factors such as fuel prices rather than directly representing fish abundance or ecosystem health. Beyond the numerical estimates, the exercise exposed a set of practical requirements for regional ocean accounts. Future data should align more closely with international ecosystem and service classifications; condition indicators should be spatially linked to named habitats; and OSPAR Contracting Parties should use common methods, tools and reporting practices.

The convention’s existing data platform could support more systematic collection and collation, while repeated and coherent reporting would permit future accounts to track changes rather than provide isolated snapshots. Higher-resolution ecosystem mapping and remote sensing could improve estimates of extent change, and three-dimensional accounting could clarify flows involving dynamic stocks such as fisheries. The study’s principal contribution is therefore a tested blueprint for assembling SEEA-aligned accounts for a regional sea, accompanied by a clear inventory of the data, harmonization and valuation work still required.

Subject of Research: Preliminary SEEA ecosystem accounting for marine and coastal ecosystems in the OSPAR North-East Atlantic region

Article Title: Compiling preliminary SEEA Ecosystem Accounts for the OSPAR regional sea: experimental findings and lessons learned

Article References: Alarcon Blazquez, M., van der Veeren, R., Gacutan, J., & James, P. (2023). Compiling preliminary SEEA Ecosystem Accounts for the OSPAR regional sea: experimental findings and lessons learned. One Ecosystem, 8, Article e108030. https://doi.org/10.3897/oneeco.8.e108030

Image Credits: AI Generated

DOI: 10.3897/oneeco.8.e108030

Keywords: SEEA Ecosystem Accounts, OSPAR, North-East Atlantic, marine natural capital, ecosystem services, environmental accounting, fisheries, carbon sequestration, outdoor recreation, Compiling, preliminary, SEEA