The International Seafood Sustainability Foundation (ISSF) has approved a series of updates to its conservation measures aimed at strengthening oversight of tuna supply chains, tightening rules on at-sea transhipment, and reinforcing best practices for bycatch mitigation and fish aggregating device (FAD) management.
Adopted on 20 November 2025, the amendments apply to all ISSF Participating Companies and, in most cases, to vessels listed on the organisation’s ProActive Vessel Register (PVR), a public database used widely by seafood buyers to verify vessel-level compliance.
Tony Lazazzara, ISSF Board Chair and Thai Union’s Global Fish Procurement Chief, said the changes further embed transparency and accountability in global tuna sourcing.
“These amendments strengthen oversight of at-sea transshipment and set clearer expectations for longline vessels to implement best practices that reduce bycatch,” he said. “Together with improved guidance on FAD management, these updates help ensure that science-driven practices translate into measurable improvements on the water.”
Tougher rules for transhipment at sea
Two measures — CM 1.2 (RFMO participation) and CM 4.4(c) (transshipment observer coverage) — have been revised to close gaps in the governance of at-sea transhipment, a crucial node in tuna supply-chain traceability.
Under the amendments:
- Any vessel engaged in at-sea transshipment must be flagged to a nation that is a member of the relevant regional fisheries management organisation (RFMO)
- Transshipment vessels must also appear on the RFMO’s authorised vessel list — ensuring that only vessels under RFMO oversight are allowed to participate
By aligning ISSF rules with RFMO best practice, the updates are intended to limit the use of poorly regulated carrier vessels and strengthen monitoring of tuna movements between fishing grounds and ports.
Clearer expectations on bycatch mitigation
ISSF has updated Conservation Measure 3.6 to clarify that seafood companies may only source from longline vessels implementing specific, science-backed bycatch-reduction techniques.
These include the mandatory use of circle hooks, monofilament branch lines where wire traces are banned, and whole finfish bait where required. In southern temperate zones, vessels must deploy at least two seabird-deterrent measures — such as weighted branch lines, tori lines, or night-setting — unless using hook-shielding devices.
The changes mirror recommendations in ISSF’s Skippers’ Guidebook for sustainable longline practices and are aimed at driving wider adoption of proven shark, seabird and turtle mitigation tools.
FAD management rules broadened
ISSF also amended Conservation Measure 3.7 to clarify that its vessel-based FAD management policy applies to anchored as well as drifting FADs. The expansion is expected to support more consistent auditing, reporting and compliance across both FAD types.
Science-led, independently audited approach
ISSF President Susan Jackson said the updates reflect ISSF’s adaptive approach to improving tuna fisheries management. “By refining measures as conditions evolve, we help companies lead and continue to raise the bar on verified, effective practices that protect tuna stocks and ocean ecosystems,” she said.
ISSF measures are developed with input from scientists, NGOs and industry, then independently audited by MRAG Americas, with results published publicly — a level of transparency seen as a benchmark within the global tuna sector.
