Scientists may have found a way to predict blue whiting recruitment a full year in advance. This breakthrough could significantly improve one of the North Atlantic’s most important fish stock assessments.

Researchers from the Faroe Marine Research Institute (Havstovan) and the Technical University of Denmark (DTU Aqua) say results from the Blue Ocean project reveal a strong link between ocean climate conditions and the number of young blue whiting entering the stock.

The finding could reduce uncertainty in annual stock assessments carried out by the International Council for the Exploration of the Sea (ICES).

One-Year Warning Signal

The project examined how ocean climate in the North-East Atlantic affects the distribution of blue whiting and the recruitment of young fish into the stock.

Researchers found a close connection between recruitment and the strength of the subpolar gyre, a large ocean circulation system in the North Atlantic.

The key discovery is timing.

Changes in the gyre begin in the Labrador Sea but take about a year to influence waters west of the British Isles, where blue whiting spawn. That means scientists may be able to estimate future spawning conditions long before they occur.

According to the researchers, this creates an opportunity to forecast recruitment one year ahead.

Major Step for Stock Assessments

At present, stock assessments use an average recruitment value for the current year because the true level is unknown at the time of assessment.

Researchers say this increases uncertainty in forecasts of future stock size.

If environmental data can be used to estimate recruitment before it happens, stock projections could become more accurate and reliable.

The Blue Ocean team says the results may provide the foundation for a new environmental index that can be incorporated into stock assessment models.

Industry Significance

Blue whiting is one of the most economically important pelagic fish stocks in the North Atlantic.

Large swings in stock size have long challenged scientists and fisheries managers.

The researchers say they are now working with an ICES working group to explore how the project’s findings can be used to manage the highly variable stock.

The Blue Ocean project has now been completed. Still, its findings could help shape future assessments and management decisions for one of the region’s most valuable fisheries.