Parks that can move when the animals do

Already, scientists are observing shifts in species distribution around the world. After an 800,000-year absence, a species of Pacific diatom, a shell-encased alga, has recently appeared in the North Atlantic. Scientists are unsure of its impact, but they take its arrival as evidence that certain conditions absent for nearly a million years – lack of sea ice, prevailing winds – are reemerging.

Northern countries like Norway and Iceland have seen an influx of more southerly fish species. They’re not complaining, because they’re likely to catch more fish. Blue mussels, once found only as far north as Norway’s coast, meanwhile, have colonized the Svalbard archipelago, more than 400 miles from Scandinavia.

Salmon spawn in ever more northerly Alaskan rivers. And walleye pollock, the largest US fishery by volume, appear to be shifting into Russian waters. This development has implications for both US fishermen and stock health, says Daniel Pauly, a fisheries professor at the University of British Columbia, Vancouver. In US waters, pollock is carefully managed, he says – but not in Russian waters.

If a fish stock moves out of a particular area, he says, it takes much more time to work out new international fishing treaties than it does to fish down the stock.

Indeed, unsure about how much fishing newly accessible Arctic waters can sustain, in February, the US North Pacific Fishery Management Council approved a moratorium on fishing in the US Arctic pending more studies.

A recent study in the journal Fish and Fisheries concluded that, broadly speaking, these trends will continue during this century. Higher latitude waters will continue to see an influx of lower-latitude species, and, most likely, a corresponding increase in catches. Lower-latitude developing countries, on the other hand, where many people still subsist on fish, will lose species. Semienclosed oceans like the Mediterranean and the Gulf of Mexico are likely to see local extinctions.

“For people who are doing conservation or fishery management, they should not think of the ocean as static or unchanging,” says William Cheung, a researcher with the University of British Columbia and lead author on the Fish and Fisheries study. “They should think
of it as changing.”

But local changes due to a changing global climate can be unpredictable. Cornell University scientist Charles Greene has found that waters off the Northeastern US paradoxically cooled during the 1990s, for example. Melting permafrost, sea ice, and more precipitation at higher latitudes – all attributable to a warming climate – increased freshwater influx into the Arctic. That cold, low-salinity water then flowed south along the Eastern Seaboard, perhaps impeding the recovery of overfished cod stocks and affecting marine ecosystems as far south as North Carolina.

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