“The top ocean predators in the North Pacific could lose as much as 35 percent of their habitat by the end of the century as a result of climate change, according to a study published Sunday in the journal Nature Climate Change.
The analysis, conducted by a team of 11 American and Canadian researchers, took data compiled from tracking 4,300 open-ocean animals over a decade and looked at how predicted temperature changes would alter the areas they depend on for food and shelter. Some habitats could shift by as much as 600 miles while others will remain largely unchanged, the scientists found, and these changes could affect species in different ways…
Some species with a relatively narrow temperature range — such as salmon, and blue and mako sharks — fared poorly as well.
At the same time, some highly mobile species such as tuna and seabirds may benefit from the changes because they will either be able to adjust more easily or have wider foraging opportunities.
The scientists identified key habitat areas by using satellite measurements of sea surface temperature and chlorophyll-a, which indicates an area’s productivity, along with migration patterns charted by the Tagging of Pacific Predators (TOPP) project. Using U.N. Intergovernmental Panel on Climate Change projections that global temperatures could rise between 1.8 to 10.8 degrees by 2100, the researchers modeled how these changes would affect habitat.
The North Pacific Transition Zone — which marks where cold, nutrient-rich polar water comes into contact with warmer, nutrient-poor water — will shift the most dramatically, by as much as 600 miles to the north during most seasons. According to the paper, this major migration corridor, which stretches from California to Japan, could lose as much as 20 percent of its species diversity.
By contrast, the California Current, which runs along North America’s west coast, will not be affected, because the upwelling of cold, nutrient-rich water will continue to occur and will stay largely in place.
“It will act like a buffer to climate change,” Hazen said in an interview. “That’s a kind of saving grace to the central California environment.””
WaPo