Defining UoC Scope and Segregation for Multi-Site Operations

Understanding UoC scope and segregation rules under the ASC framework

The Aquaculture Stewardship Council establishes strict operational boundaries and chain-of-custody rules to ensure complete integrity from farm stocking through harvest and dispatch. Defining the Unit of Certification accurately prevents uncertified seafood, non-conforming inputs, or ineligible batches from entering certified supply chains under the ASC label. In complex aquaculture operations involving multiple grow-out locations, shared infrastructure, or fed-species culture, clear boundary definition and robust physical segregation form the cornerstone of compliance.

The Unit of Certification represents the primary scope of assessment audited by an accredited conformity assessment body. Under the ASC Farm Standard, the Unit of Certification applies to grow-out production sites and encompasses all cultured species, production units such as ponds, cages, tanks, or raceways, operational activities, on-site personnel, and associated facilities. Establishing this scope requires quality managers to map physical infrastructure, define legal boundaries, and implement physical controls that prevent product substitution or illegal mixing.

Defining legal boundaries and multi-site certification structures

Quality managers must establish clear spatial and legal limits for every site within the Unit of Certification. Under Requirements for Units of Certification Clause 5.1 and Certification and Accreditation Requirements Part B, the client must provide the conformity assessment body with legal licenses, operating permits, site addresses, and geographical polygon data following the ASC GIS Submission Procedure. Facilities located outside the main farm site, such as chemical storage units, feed warehouses, or worker accommodation, remain within the scope of the Unit of Certification if they support site operations.

Operations managing multiple grow-out sites must select an eligible certification structure under RUoC Clause 5.3 and CAR Table 1 and Table 2. Single-site certification covers one production location under direct legal control. Multi-site certification applies when a single client owns or contractually controls multiple sites operating within the same country under the same ASC species standard. Multi-site operations may operate without an Internal Management System under Option 1, requiring the conformity assessment body to audit every site annually, or with an Internal Management System under Option 2, where the central office manages compliance and external auditors evaluate a calculated sample of sites.

Processing and packing activities are generally excluded from the farm certification scope and require separate Chain of Custody certification under RUoC Clause 5.2. However, processing facilities may remain within the farm Unit of Certification if ownership does not change, only ASC-certified product from the Unit of Certification is handled, transport occurs entirely within farm premises, and the processing plant shares the physical address of the farm site.

Segregation controls and traceability protocols for mixed operations

Maintaining certified status requires rigorous identification and physical separation of certified and non-certified stock throughout the production lifecycle. Under Indicator 1.4.1, the Unit of Certification must conduct a comprehensive risk assessment to identify, evaluate, and mitigate risks of mixing or substituting ASC-certified products with non-certified products across all sites. Quality leads may utilize the risk assessment methodology in Appendix 3 of the ASC Farm Standard to map potential contamination points during stocking, live transfers, feeding, harvest, and transport.

Indicator 1.4.2 establishes mandatory traceability and segregation conditions that must be maintained at all times, including during live production. Farms must verify that all stocked animals originate from suppliers conforming with Criterion 1.5, maintain batch traceability back to specific production units and sites, and ensure accompanying transaction documents explicitly identify product certification status. Furthermore, RUoC Clause 15.2 mandates that quality managers execute input-output reconciliations for every production unit within 14 days of completing harvest, verifying survival rates, feed conversion ratios, and biomass yields.

When non-conforming products or prohibited chemical treatments occur, Indicator 1.4.5 and CAR Requirement 7.4 enforce mandatory scope exclusions. Crustaceans treated with antibiotics at the Unit of Certification, or any species treated with World Health Organisation Critically Important Antimicrobials at any lifecycle stage, are strictly ineligible for ASC certification. Quality leads must physically segregate these excluded batches, log them as Certificate Scope Exclusions, and block them from entering certified sales channels.

Verification matrix, worked example, and execution workflow

Compliance managers and internal auditors must evaluate traceability systems against explicit standard indicators, maintaining verifiable records across all operational phases.

Establishing robust Unit of Certification scope and segregation controls requires quality leads to follow a standardized four-step implementation process:

• Map all physical facilities, production units, and geographic coordinates using the ASC GIS Submission Procedure, confirming legal permit boundaries for every site.
• Draft a site-specific traceability risk assessment under Indicator 1.4.1, identifying all points where certified stock could mix with non-certified animals or non-conforming feed.
• Establish physical labeling, color-coded netting, or dedicated tank allocation to maintain batch identification and segregation during live culture, harvest, and transport.
• Implement a 14-day post-harvest input-output reconciliation workflow under RUoC Clause 15.2 to cross-check stocking numbers, feed usage, mortalities, and final harvested biomass.

Example

A compliance lead at a multi-site rainbow trout enterprise prepares for an annual ASC surveillance audit under Multi-Site Option 2. The operation consists of three freshwater raceway sites and an on-site primary processing shed located at Site A. Site B experienced a bacterial outbreak during the cycle, requiring a veterinary course of oxytetracycline that exceeded species treatment limits, while Site C cultured non-certified stock. To comply with Indicator 1.4.2 and Indicator 1.4.5, the compliance lead implements color-coded raceway tags, segregates Site B and Site C fish during harvest, and issues non-certified transport documentation. During the audit, the compliance lead presents input-output reconciliation sheets completed 10 days post-harvest, proving that product from Site B was processed separately, logged as a Certificate Scope Exclusion, and sold into conventional markets without ASC labeling.

Fed-species traceability and feed disclosure obligations

For operations culturing fed species, traceability requirements extend directly to compound feed inputs. Under Indicator 2.12.1 and Indicator 1.4.3, the Unit of Certification must exclusively use compound feed sourced from feed mills holding valid certification against the ASC Feed Standard. Quality managers must maintain documented verification showing that incoming feed is traceable as ASC-conforming throughout all supply chain steps between the feed mill and the farm site.

Indicator 1.4.3 mandates that formal documentation accompanying feed deliveries must explicitly identify the feed as ASC-conforming and specify the applied production model, distinguishing between Mass Balance and Segregation models. When feed is purchased under the Segregation Production Model, the product must be identifiable by a distinct feed name in delivery notes that matches the official schedule on the feed mill's ASC certificate. Using non-conforming feed invalidates the certified status of the affected biomass under Indicator 2.12.1.

In addition to feed sourcing verification, Indicator 1.4.4 enforces buyer disclosure obligations regarding genetically modified ingredients. The Unit of Certification must disclose to all buyers of certified seafood when the feed used contains greater than 0.9% Genetically Modified Organisms or macro-ingredients produced from GMOs. Compliance leads must collect technical specification sheets from feed manufacturers to calculate GMO thresholds and maintain written disclosure records issued to seafood buyers.

Before your audit

• Confirm that legal licenses, permits, and WGS 84 GIS polygon data cover all physical sites within the Unit of Certification.
• Verify that the multi-site certification structure complies with RUoC Clause 5.3 and CAR Table 1 or Table 2 rules.
• Review the traceability risk assessment to ensure all product mixing and substitution hazards are mapped and mitigated under Indicator 1.4.1.
• Check that physical segregation and batch identification are maintained across all live culture units, harvest systems, and transport tanks.
• Validate that input-output reconciliations are completed within 14 days of harvest completion for every production unit.
• Ensure batches treated with WHO Critically Important Antimicrobials or prohibited antibiotics are logged as scope exclusions under Indicator 1.4.5.
• Confirm that feed delivery notes explicitly verify ASC Feed Standard certification, production models, and distinct feed names under Indicator 1.4.3.

Questions people ask

Can processing facilities be included in a farm Unit of Certification scope?

Under RUoC Clause 5.2, processing facilities may be included in the farm Unit of Certification scope without separate Chain of Custody certification only if product ownership does not change, only ASC-certified product from the Unit of Certification is handled, transport occurs entirely within farm premises, and the facility shares the farm's physical location.

What happens if a farm uses compound feed from an uncertified feed mill?

Under Indicator 2.12.1 and Indicator 1.4.3, using compound feed from a mill that lacks valid certification against the ASC Feed Standard constitutes a non-conformity. The affected fish biomass cannot be sold or dispatched as ASC certified.

What is the deadline for completing input-output reconciliations after harvest?

Under RUoC Clause 15.2(f), the Unit of Certification must execute an input-output reconciliation for each production unit within 14 days after completing harvest, verifying stocking numbers, survival rates, feed conversion ratios, and harvested biomass.

How are multi-site operations without an Internal Management System audited?

Under CAR Part B Table 1 and RUoC Clause 5.3.2.1, multi-site operations without an Internal Management System fall under Option 1, requiring the conformity assessment body to audit every individual site during every routine CAB audit.

Reference documents

• ASC Farm Standard V1.0.1A2 - August 2026
• ASC Farm Standard Interpretation Manual V1.0.1 - September 2025
• ASC Farm and Feed CAR V1.0 - May 2025
• ASC Requirements for Units of Certification V1.0.1 - July 2023