But if we can think of them as massive cities in the sea, new research suggests we may also need something smaller in the future. Maybe closer to a string of Airbnb's.
"For conservation because species are moving from these areas. Larvae are drifting through ocean currents," says Dr. Nur Arafeh-Dalmau, Ph.D., a marine conservation scientist with Stanford's Doerr School of Sustainability.
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His work has included documenting a severe marine heat wave off the coast of Mexico. The kind of event that can both threaten marine habitats and push species to migrate.
"And you know, as climate change is happening, species are moving, they're kind of shifting a little bit their distribution," he said.
Researchers have noted examples of the changes in recent years, including the unexpected appearance of juvenile great white sharks in Monterey Bay, much further north that their normal nursery habitat off Southern California.
A similar northward migration by the predatory California Market Squid impacted salmon populations in the Gulf of Alaska. Fellow Stanford Doerr researcher Larry Crowder, Ph.D. studies marine food chains.
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"Well, one thing that's very clear, is that the data show that marine animals are moving poleward in the northern hemisphere, to the north, and in the southern hemisphere to the south. And that's thought to be related to long-term trends and climate," Dr. Crowder notes.
In this most recent study the Stanford team identified areas off the coast of California and Mexico that might act as safe zones, many containing healthy kelp forests or other habitats.
"We have this amazing data set in California, but also in Mexico, based on satellite that maps kelp forest in the past 40 years. So there are places that the satellite always detect that the kelp is there," says Arafeh-Dalmau.
The goal now is to possibly turn the areas into an international string of migration sanctuaries. A pathway, where species on the move could essentially check-in and check-out as they adjust to changes and fluctuations brought by climate change.
The Stanford team has now published their results. They've also included specific guidelines for world governments, to help them create protected migration stopovers along coastal corridors.