When diving off monterey a few years ago, we found lots of the shell/skeletons of the big gumboots. Usually could find them all together in some hollow in the rocks. Really look cook put back together on a coffee table. unfortunately, I can't find the one I had.
I hear they taste a lot like abalone. The foot on the bottom of the Gumboot looks like the foot on an ab. I haven't tried them, just tried limpets, sushi stye...good!! Chewy, but Good!!
"Trust, but verify" - Russian Proverb, as used by Ronald Reagan