Do fishers follow fish displaced by climate warming?

Climate change is associated with altered oceanographic conditions that tend to shift the geographical distributions of fish. To assess the impact of climate change on fisheries, one must go beyond projections of catch potential and understand how fishers respond to moving target species. Many previous studies have explicitly or implicitly assumed that fishers follow fish that are displaced by climate warming. Here, we evaluate this assumption by analyzing a long-term, large-scale yet high-resolution dataset combined with a detailed oceanographic model. Our study case is the Atlantic cod (Gadus morhua) fishery in Norway, one of the largest whitefish fisheries in the world, with little technological or judicial constraints on the potential spatial response of fishers. An oceanographic model is used to predict the areas that have been suitable for Atlantic cod spawning over the two last decades. We compare whether these areas overlap with actually observed fishing locations. While the areas that are suitable for spawning clearly predict how much fish are caught per trip, the suitability of an area does not predict how many vessels fish in a given area at a given point in time. In contrast, the number of vessels in the previous week and the previous year explain both the number of vessels in the area. Hence, future projections of climate change effects should account for the rich and nuanced behavioral responses of humans to project climate change effects on fisheries.

Keita Abe, Florian Diekert, Arne Melsom, Øystein Langangen