January 26, 2015 — The gradual warming of the Arctic Ocean over the next century will weaken a natural barrier that has separated fish from the Atlantic and Pacific Oceans for millions of years, leading to a mixing of species that could make life difficult in fishing communities from Alaska to Norway.
A new study by scientists in Denmark combined current models of climate change, and the biological water temperature and food requirements for 520 fish species native to the two oceans. The report forecast changes in the range of these fish in five-year increments from now until 2100, when the world’s oceans are expected to heat up globally by an average 4 degrees Celsius (7 degrees Fahrenheit).
"There will be an interchange of the fish communities between those two seas," beginning as soon as 2050, said Mary Wisz, lead author on the report in Nature Climate Change and a senior ecosystem scientist at Aarhaus University in Denmark. "We know from historical examples that this kind of interchange, when biotas have been separated over long evolutionary time scales, can have huge consequences."
In this warmer future, fishermen based in Kodiak, Alaska, could be pulling up Atlantic cod, a prized species normally caught off New England and Northern Europe. A similar change has already started off the coast of Greenland, where fishermen in the last five years have been catching larger numbers of Atlantic mackerel, which prefers more temperate water.
Wisz and colleagues say that by 2100, up to 41 species could enter the Pacific and 44 species could enter the Atlantic, through Arctic water passages over Canada or Russia. This interchange will have ecological and economic consequences to ecosystems that at present contribute 39 percent to global marine fish landings.
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