MER-CKMR

Context

Sustainable fisheries management requires estimating the abundance of each stock, which is challenging due to methodological limitations and dependence on fisheries that may provide inaccurate data. In addition, the lack of knowledge about connectivity between stocks may result in over- or underestimation of biomass. The traditional mark-recapture method is reliable both for biomass estimation and connectivity studies, but the large number of individuals that need to be marked, together with its logistical limitations, makes its application unfeasible.

This project aims to develop and apply the genetic close-kin mark-recapture method (CKMR – Close Kin Mark Recapture) to European hake (Merluccius merluccius) as a more precise and fisheries-independent alternative. Building on previous projects, key foundations have already been established, including the creation of a sampling network, the study of connectivity between stocks, the development of a genetic chip, and the estimation of the required sample size. This project will bring those advances to completion through the first application of CKMR to European hake.

Objectives

The overall objective of the project is to help improve the biomass estimate of European hake through the application of the CKMR method. To achieve this, 4 operational objectives are proposed:

• To develop a realistic sampling plan for applying CKMR that maximises the number of relatives identified while using the lowest possible number of samples.
• To optimise the method for detecting relatives based on genetic data and apply it to around 6,000 samples (4,000 to be genotyped in this project and 2,000 previously genotyped).
• To develop the CKMR model for hake, taking into account sample availability, the biological characteristics of the species, population connectivity, and uncertainty in age estimation.
• To communicate developments and results in relevant forums in order to maximise the project’s transfer and impact.

Expected impact

• Improved hake biomass estimation: this project is the first to seek the application of CKMR to estimate hake biomass, in a species of high commercial value whose assessment still presents some fitting issues.
• Method consolidation and capacity building: most initiatives using the CKMR method have focused on tuna, elasmobranchs and mammals, with only a few exceptions. Therefore, applying CKMR to European hake will also mark an important milestone in consolidating the method by extending it to other species, while also contributing to capacity building at European level, since most initiatives to date have been carried out outside the European Union.

Funding