North Sea Sandeel Recruitment

North Sea Sandeel Recruitment Forecast

Forecast sheet 03-20190920

Issued 20-09-2019. Valid through to 01-04-2020.

Prepared by Mark R. Payne and Christian Kiær, DTU Aqua, Copenhagen, Denmark.

This is the first forecast for the 2019 cohort strength for all North Sea sandeel stocks.

Forecast

The 2019 North Sea sandeel recruitment forecast covers the four assessed stocks (1r, 2r, 3r and 4) in the North Sea, together with the total recruitment across this portfolio of stocks. Forecasts for all individual stocks suggest a low probability (5% to 25%) of a strong year class, with a high probability (between 45% and 65%) of these year classes being in the lower third of the historically observed recruitment (Figure 1).

The portfolio forecast (for recruitment summed across all four stocks) indicates a low probability of a strong overall year class (15%). Probabilities of summed recruitment being at low or medium levels are approximately equal (40% and 45% respectively).

**Figure 1. Recruitment forecast for 2019 cohort for the individual management areas and for the aggregated recruitment across the portfolio of all four individual stocks.** *The probabilities of the 2019 year class falling in each of the three terciles (high, medium or low recruitment) are plotted as horizontal bars. Tercile thresholds are based on the values from the complete time series for a given forecast area and for the aggregated portfolio.*

Figure 1. Recruitment forecast for 2019 cohort for the individual management areas and for the aggregated recruitment across the portfolio of all four individual stocks. The probabilities of the 2019 year class falling in each of the three terciles (high, medium or low recruitment) are plotted as horizontal bars. Tercile thresholds are based on the values from the complete time series for a given forecast area and for the aggregated portfolio.

How to use this forecast

This forecast should be used as an indicator of the expected productivity (high, medium low) of the next sandeel cohort for each of the four stocks and for the species as a whole across the North Sea. The forecast can be used in planning commercial activities related to this species for the coming year. For activities that are dependent on North Sea sandeel as a whole, rather than on an individual stock, the “Portfolio” forecast should be consulted.

Background

Lesser sandeel (Ammodytes marinus) in the North Sea form the basis for a commercially important fishery, where they are used in the production of fishoil and fishmeal. The species lives on sandy banks distributed throughout the North Sea: while the adults are typically bound to a specific bank, larval sandeel are pelagic and drift between banks. Particle tracking studies (Christensen et al 2008) have characterised this connectivity pattern and form the basis for the definition of seven management units. Analytical stock assessments are performed annualy by ICES for four management areas (Figure 2).