European hake (Merluccius merluccius) is one of the most important species in the Northeast Atlantic, both for its economic value and its ecological relevance. In recent years, however, significant problems had been identified in the assessment of the two main stocks—northern and southern—making it difficult to provide robust scientific advice for sustainable management.
In 2020, the International Council for the Exploration of the Sea (ICES) rejected the assessment model for the southern hake stock and based management advice solely on abundance indices, reducing the reliability of the process. At the same time, the northern hake assessment showed convergence issues and sensitivity to certain model assumptions, affecting estimates of individual growth.
With AZTI providing scientific leadership for the northern hake stock, and in collaboration with the Spanish Institute of Oceanography (IEO), a new population assessment model was developed that is more robust and better adapted to the biological and fishery characteristics of both hake populations.
During the formal review and update of the assessment methodology (the 2022 ICES benchmark process), existing models were revised and improved by integrating new biological data, updated growth parameters, and alternative population structures. This work made it possible to:
Resolve the technical problems identified in the southern hake assessment.
Develop a sex-structured model, improving the accuracy of biomass and mortality estimates.
Update biological reference points, strengthening the scientific basis for fisheries management advice.
In addition, the population genetic structure of the species was analysed to assess its implications for the coordinated management of both stocks.
International review and validation of the new assessment model within the ICES benchmark framework.
A significant increase in the southern hake TAC in 2023, better aligned with the biological status of the stock.
Improved precision in northern stock estimates, reducing uncertainty in management advice.
The incorporation of key scientific innovations—such as sex-structured modelling—representing a major methodological advance for sustainable fisheries management.
Sectors: Fisheries and aquaculture sector
Research lines: Blue Economy, Efficient, sustainable fisheries and aquaculture
Research sublines: Sustainable fishery management