Searchin' for urchin: SoCal divers face warming waters that drive urchins to deep waters

For more than 30 years, Matt Pressly has been diving off the coast of California for sea urchins, sold in sushi restaurants as a delicacy called "uni."

In that time, he's seen urchins move to deeper water in search of the kelp they feed off ‒ kelp that, in many cases, no longer grows as it used to. Scientists say hotter water is rapidly changing the ecosystems of California coastal areas. Among the changes: less kelp in shallower areas.