It isn't always about the sea slugs...
Anyway....
Eisenia arborea kelp with chiton Cyanoplax cryptica
Bluefish Cove, Point Lobos State Reserve, Monterey County, California
This weekend I went diving at Point Lobos, and was hoping to find both the kelp and the chiton in the above photo. Eisenia arborea is found more commonly in southern California, but there are isolated areas where it is found further north, all the way to British Columbia. Cyanoplax cryptica is a chiton (a type of mollusk) that lives exclusively on Eisenia, and until quite recently was only known as far north as Catalina Island... although also until recently, C. cryptica was thought to be a subspecies of another chiton which is quite abundant up here.
While the expanded range of the chiton might be an indicator of a climatic shift, it's just as likely (if not more so) an indicator of how little is known about the ranges of many marine invertebrates, and just what exists under the water along our coasts in general.
More photos from the dive are on my Flickr stream.