Framework Overview

NOAA-TDC Dual-Flow ESG Attribution Framework

The NOAA-TDC Dual-Flow Framework is a science-based methodology for quantifying the ecosystem service value (ESV) of US oyster aquaculture leases. Developed by the NOAA Technology Development Center in collaboration with Oceanfarmr, it supports ESG reporting for oyster farmers, investors, and regulators. The framework is currently operational for two regions: Virginia (Chesapeake Bay) and Maine (Gulf of Maine).

The framework operates across two parallel analytical flows — Latent Potential and Realized Contribution — which together produce a lease-level ESV estimate that is both scientifically grounded and practically useful for ESG disclosure. Each flow draws on a distinct set of data inputs and produces outputs combined through a Data Adequacy Factor (DAF) derived from the REDQS scoring system.

Architecture

Dual-Flow Architecture

The two analytical flows address a fundamental challenge in aquaculture ESG accounting: the gap between what a lease could produce (its latent potential, based on area and biophysical context) and what it actually produces (its realized contribution, based on verified harvest and water quality data). Most leases have area data but limited harvest records, making Tier 1 the primary operational tier.

In the current platform, all leases are calculated at Tier 1 (Latent Potential) due to the absence of verified harvest records in the public cadastral datasets for both Virginia and Maine. The satellite growth data integration for Maine (Kiffney et al. 2026) provides a pathway toward Tier 2 estimates by supplying a modelled yield proxy derived from Dynamic Energy Budget (DEB) theory.

Service Vectors

ESV Service Vectors

The framework quantifies four ecosystem service vectors. Each has a distinct unit value, data source, and biophysical basis. Unit values are drawn from peer-reviewed literature and government valuation studies, and applied consistently across both regions.

Water filtration (Acres × 750k oysters × 50 gal/day) is reported as a co-benefit only — not included in the total ESV to avoid double-counting with nitrogen removal.

Data Quality

REDQS Scoring & Data Adequacy Factor

The REDQS (Reference Data Quality Score) system provides a standardised framework for assessing the confidence level of each ESV estimate. It is scored on a 1–5 scale and maps directly to a Data Adequacy Factor (DAF) that scales the raw ESV estimate to reflect data quality.

DAF = ((REDQS/5)² + REDQS/5) / 2

In the current platform, Virginia leases are assigned REDQS 3 (CBP water quality data available, no satellite growth data). Maine leases within the Kiffney et al. (2026) validated area are assigned REDQS 3 (satellite DEB model validated). Maine leases outside the validated area are assigned REDQS 2 (SST climatology available, no food proxy or DEB model).

Region

Virginia — Chesapeake Bay

Virginia is the largest oyster-producing state in the US by lease area, with 4,635 active polygon leases covering 131,614 acres across Chesapeake Bay and its tributaries. Lease data is sourced from the Virginia Marine Resources Commission (MRC) KMZ dataset, providing polygon geometry, lease ID, status, and primary species for all registered leases.

Water quality context for Virginia leases is derived from the Chesapeake Bay Program (CBP) DataHub, which provides total nitrogen (TN) loading estimates by tributary segment and growing area. Eight growing areas are defined: Lower Bay East, Lower Bay West, York River, Rappahannock River, Potomac River, Upper Bay, James River, and Eastern Shore. Each growing area receives a TN adjustment factor that scales the nitrogen removal ESV to reflect local nutrient loading conditions.

Region

Maine — Gulf of Maine

Maine has 158 active polygon leases covering 1,531 acres across the Gulf of Maine coast, from Casco Bay in the south to Washington County in the northeast. Lease data is sourced from the Maine Department of Marine Resources (DMR) ArcGIS REST service, providing polygon geometry, lease ID, status, species, and water classification for all registered leases.

Maine's Gulf of Maine environment differs substantially from Chesapeake Bay: colder water temperatures (mean annual SST 8–12°C vs. 14–18°C in Virginia), shorter growing seasons (130–170 days above 10°C threshold vs. 220 days in Virginia), and lower nutrient loading due to the absence of large agricultural watersheds. These differences are captured in the Activity Factor and TN adjustment applied to Maine leases.

Satellite Integration

Satellite Growth Data — Maine

A key innovation in the Maine implementation is the integration of satellite-derived growth data from Kiffney et al. (2026), published in Aquaculture (Vol. 612). This study used Landsat 8/9 imagery at 30-metre resolution to derive two biophysical variables across the Maine coast: sea surface temperature (SST) and a food availability proxy (chlorophyll-a / particulate organic matter). These variables were used to parameterise a Dynamic Energy Budget (DEB) model for Crassostrea virginica, producing lease-level estimates of growth rate and time to market.

The satellite data is accessible via the Landsat 8/9 Viewer for Aquaculture Site Selection (Google Earth Engine app), developed by the University of Maine.

Standards Alignment

Reporting Standards Alignment

The framework is designed to support ESG disclosure aligned with three international standards. The table below summarises the mapping between framework outputs and specific disclosure requirements.

Tool

ESV Calculator

The ESV Calculator allows users to estimate the ecosystem service value of an individual oyster lease using the Dual-Flow Framework. Enter the lease area, cultivation method, and water quality context to generate a Tier 1 ESV estimate across all four service vectors.

References

References