Fish Guidance Systems

Climate change projected to drive species northward

Anticipated changes in climate will push marine species from sharks to salmon northward an average of 30 kilometres per decade. A new study suggests that shifting species will likely move into the habitats of other marine life to the north as the climate warms, and species will follow the conditions they're adapted to" said Richard Brodeur, a NOAA Fisheries senior scientist.

The study was led by William Cheung of the University of British Columbia and the researchers used established global climate models to project how the distribution of fish would shift by 2050 as greenhouse gases warm the atmosphere and, in turn, the ocean surface. Brodeur cautioned that like any models, climate models carry some uncertainty. "Nothing is certain," he said, "but we think we have a picture of the most likely changes." In the US, Some species shifts are already being documented as West Coast waters are warming: predatory Humboldt squid from Central and South America have invaded the West Coast of North America in recent years, albacore have shifted to more northerly waters and eulachon have disappeared from warming waters at the southern end of their range.

An intrusion of warm-water species into cooler areas could lead to significant changes in marine communities and ecosystems. The diversity of northern fish communities may increase as southern species enter the region, leading to new food web and species interactions.

"Thinking more broadly, this re-shuffling of marine species across the whole biological community may lead to declines in the beneficial functions of marine and coastal ecosystems" said Tom Okey, a Pew Fellow in Marine Conservation at the University of Victoria and a co-author of the study. "These declines may occur much more rapidly and in more surprising ways than our expected changes in species alone".