Looking into the future of the North Atlantic fish stocks

In recent years it has become apparent that the marine climate of the North Atlantic, in addition to being variable, is also quite predictable on a 5-20 year time scale. In theory, it could therefore be possible to generate forecasts of the marine climate 20 or so years out into the future.

European and American scientists are meeting in Barcelona, Spain this month to launch a new European initiative for climate service observations and modelling to improve Europe's ability to effectively prepare for and manage climate-related risk on our society. DTU Aqua is part of the project "North Atlantic Climate" (NACLIM) that focuses on forecasts for the North Atlantic ocean, which plays a critical role in the weather and climate that we experience in Denmark and in Europe as a whole.

"This is a tremendously exciting prospect, because it opens up many applications, from improved preparations for extreme climate events, like heat waves or flooding, to sustainable management of marine resources, such as fish," says research scientist Mark Payne, DTU Aqua -- Institute for Aquatic Resources, Denmark, who is a work-package leader in NACLIM:

"The goals that we are trying to achieve with this project, making forecasts about biology 20 years into the future, are ambitious and extremely difficult. However, if this can be done, then the benefits to society are also tremendous. We don't expect that we will be able to solve all of these complex questions in all situations. But even if we can develop this type of forecast in a few specific cases, that will still be a major advance," Payne continues.

Avoid unpleasant surprises

As an example, Payne points to the rise and fall of the stock of blue whiting in the North Atlantic that took everybody by surprise and left a large fishing fleet and Faroese communities without income.

In 1996 the productivity of the North Atlantic Blue whiting stock suddenly increased five times, and remained high for the following 6-8 years. The fishing fleet expanded rapidly to take advantage of this new fishing potential, and in 2004 Blue Whiting was the third largest marine fishery in the world. However, the burst of productivity disappeared as suddenly as it arrived, leaving a large fishing fleet and very few fish. The resulting severe cuts in fish quota were felt particularly in the Faroe islands, where 80% of fish landed during this period were Blue Whiting.

"Research that we have performed at DTU Aqua together with others has showed that this high-productivity was associated with dramatic changes in the North Atlantic climate. If the type of forecast that we are trying to generate in NACLIM existed in the late 1990s, it could have been possible to avoid this situation, or at least minimize the impacts that it had on these communities," Payne says.

Fish stocks in the future

DTU and Mark Payne are leading a work package, where, together with the Faroe marine research institute, Havstovan, scientists try to translate the forecasts of the future physical conditions in the North Atlantic into biological outcomes. And Payne is not expecting an easy task.

"This is a tremendous challenge, as the biological understanding necessary to make such forecasts lags far behind the physics. Our work will focus in the first instance on identifying the "low-hanging fruit," that is the ecosystems and populations that show the tightest and most robust links to the physical environment -- and then making biological forecasts if, and as, appropriate. One possible outcome is that we may find that forecasting is simply not feasible with the precision required, in other words, that the biological, or physical, understanding is simply not good enough. But that's a result in itself, and one that can certainly tell us where we need to focus our efforts in the future," DTU Aqua-research scientist and NACLIM-leader Mark Payne concludes.

The project runs for 4 years. It was launched together with two other projects as part of a new European initiative for climate service observation and modelling (ECOMS), funded by the European Commission) on November 6th 2012 at a kick-off meeting in Barcelona with the participation of 150 researchers from Europa and USA.