Scientific Evidence Confirms Mixed Cod Populations Problem
The International Council for the Exploration of the Sea has confirmed that Northern Shelf cod is not a single stock, but a combination of distinct populations that overlap seasonally, complicating both assessment and management.
According to the latest scientific evidence, Northern Shelf cod consists of at least three biologically distinct substocks: the southern, northwestern and Viking components. These groups mix outside their spawning periods, creating a single fishery that cannot currently be managed separately due to the absence of real-time genetic data.
This limitation remains a central obstacle. Without the ability to distinguish between substocks during fishing activity, targeted management measures for individual components are not feasible under current systems.
Southern Substock Collapse Forces Zero Catch Advice
The southern component of the stock has now fallen below critical biological limits.
ICES advice for 2025 has called for zero catch on this substock in order to protect it and allow for recovery. However, given the mixing of stocks in shared fishing grounds, implementing such advice in practice presents clear operational challenges for the fishing sector.
The situation raises ongoing questions about how management can realistically protect the most vulnerable part of the stock without disproportionately impacting fishermen targeting mixed aggregations.
Tiger Team Established to Rebuild Scientific Basis
In response, ICES established a dedicated “tiger team” to address weaknesses in the current assessment model and improve the scientific basis for future advice.
The group began work in September 2025 and is expected to conclude in September 2026. Its findings will form the basis of draft advice for 2027.
The tiger team operates under the Working Group on the Assessment of Demersal Stocks in the North Sea and Skagerrak and follows ICES benchmark guidelines. The structure is designed to allow focused work on complex modelling and stock assessment issues.
Stakeholders Invited as Transparency Questions Remain
While ICES processes at this level do not permit stakeholder observers within technical review work, the organisation has scheduled an update meeting aimed at improving transparency.
Stakeholders have been invited to attend a session on 7 May to receive an update on progress and next steps.
Colm Lordan, Chair of the ICES Advisory Committee, said that “this meeting is an important milestone for the team that has been working hard to evolve the Northern shelf cod assessment”. He added that “it’s important to be transparent to stakeholders about the technical work they have been doing and the next steps in the process”.
The extent to which stakeholder input will influence outcomes remains unclear, given that core technical work is conducted without direct industry participation.
Management Challenges Remain Unresolved
The underlying issue remains unchanged: multiple cod populations are being exploited within a single mixed fishery, while management advice increasingly focuses on the most vulnerable component.
Until tools such as real-time genetic identification become operational, separating fishing pressure between substocks is not currently achievable.
The tiger team’s work is expected to address assessment methodology, but it does not in itself resolve the practical challenge facing managers and the fishing industry, how to apply stock-specific advice in a mixed-stock fishery.
