Sustainable management of mackerel in the North Sea: Integration of new knowledge in stock assessment (113515)

Atlantic mackerel is a pelagic, migratory species widespread in the North Atlantic that sustains one of the most valuable fisheries with an annual catch of around 1 million tons, corresponding to an initial market value exceeding 1 billion EUR. One-third of the catch of the Northeast Atlantic (NEA) mackerel stock is realised in the North Sea, however, knowledge of the state and development of the mackerel in the North Sea is limited leaving its contribution to stock dynamics undefined.

Overall, the economic importance of NEA mackerel combined with an uncertain stock status and biology, including major changes in the distribution of the stock, have led to several years without international quota distribution agreements. The consequence has been significant overfishing resulting in a long-term suboptimal utilisation of mackerel as an important food source for human consumption. Moreover, in terms of stock development climate change in North Atlantic waters, i.e., rising sea temperatures, also appears to affect mackerel distribution and productivity. Thus, fisheries science and management face both, a challenging dynamic resource and an opportunity to implement an adequate monitoring and reliable assessment system leading to sustainable utilisation of this abundant and economically important fish stock.

The MAKE-IT project is designed to contribute to this management opportunity delivering knowledge and data for an adequate inclusion of the mackerel in the North Sea into the NEA mackerel stock assessment. This inclusion is supported by the recent, scientifically based accept that mackerel in the Northeast Atlantic constitutes one single stock. The project will not only increase knowledge about regional dynamics in the North Sea, it will also improve the quality and reliability of the entire NEA mackerel stock assessment and related management advice by the International Council for the Exploration of the Sea (ICES).

Furthermore, mackerel is an important predator of small pelagic fish as well as early and juvenile life stages of larger fish species. Knowledge about the predation pressure exceeded by mackerel is of utmost importance for the sustainable management of forage fish in the North Sea and the projection of reproductive success of larger fish, such as haddock, cod, and whiting. In this context, MAKE-IT will deliver input to ICES multispecies modelling of the North Sea fish stocks providing estimates of predation mortality of other species.

In response to these challenges, the project will i) implement the Daily Egg Production Method (DEPM) for the North Sea and inclusion in the DEPM for the entire NEA mackerel stock, ii) improve the North Sea component of the Ecosystem Summer Survey (IESSNS) in the Nordic Seas, iii) describe spatial and temporal spawning activity, location and importance of nursery areas and predatory impact of mackerel on other fish stocks in the North Sea and iv) improve NEA mackerel stock assessment and advice on fishing opportunities and fisheries management by implementing project results into stock assessments.

Funding
This project is co-funded by the European Union through the Danish Maritime, Fisheries and Aquaculture Programme (EMFAF).

Research area: Fish Biology
Research area: Marine Populations and Ecosystem Dynamics
Research area: Marine Living Resources