Climate Change & the Arctic Ocean Fish Population

By: Daniel Zummo

The seas around the Arctic Ocean are estimated to host at least 20 percent of all the fish in the world’s seas.[1]  Like many land-based species, fish are on the move as they try to adapt to a changing climate.  One place this is happening is the seas surrounding the Arctic Ocean. But precisely how fast, in what direction, and to what effect the fish will migrate from their home territories is unknown.

Predicting future patterns of fish distribution and migration is difficult, in part, because the surface water temperatures in the Arctic waters are as warm as they have ever been, leaving no historical comparison points.[2] What is clear is that fish will only travel to where they can find enough food.

Additionally, scientific models used to estimate marine primary productivity–namely the availability of phytoplankton that are the key ingredient in the diet of zooplankton and fish–are still quite crude and lack data.[3]  That is why many marine scientists are trying to better understand current and future primary productivity there. The primary productivity of an area is the chemical and biological conditions. The species composition of both phytoplankton and zooplankton is critical for possible migration of pelagic species into the Arctic Ocean. It is therefore important to follow the development in these plant and animal communities so it is easier to document possible feeding migration of fish into the area.

Primary production relies on a wide range of elements, including sunlight, water and air temperature, currents, wind patterns, salinity, and sea ice cover and extent.[4] All of these are moving targets in the Arctic under climate change. Average surface air temperatures in the Arctic are expected to increase by 3 to 6 degrees Celsius by the end of the century, according to estimates from the Intergovernmental Panel on Climate Change[5] and the Arctic Council[6]. Furthermore, over the last 30 years the ice volume in Arctic has shrunk by at least 70 percent.

The impact on fisheries of changes in the biological productivity of marine ecosystems will vary between fisheries and will depend of the specific environmental changes that occur and the particular biological characteristics of each species. Changes in a particular marine environment may become conducive to a rapid growth of a high-priced species found in that environment, while the reverse may be true in other instances. Climate change will also result in modifications of the area of distribution of marine resources. Consequences for the fishing industry could be significant.

Unlike most other oceans, commercial fisheries do not exist in the high Arctic, while they are extensive in the sub-Arctic southern Barents and southeastern Bering Seas. The lack of high-Arctic fisheries catch and by-catch data yields a void of even basic knowledge.

As the arctic sea ice continues to melt and further exploration is possible in previously inaccessible regions, the profitability of a high Arctic fishery will continue to draw interest from many nations.  The migration of various fish species to these northern regions is currently being studied and may provide clues to the future of the Arctic Ocean fish population