I called a fish place on the commercial wharf that sometimes has it. No luck.
So, our last resort was Monterey Abalone. I thought: we'll just clean two fresh ones and change the menu to "sea urchin-flecked soup."
D was so, so sad and very disappointed. But, always my sunny boy, he concluded, "it's okay, Mom, we just have to change the menu for tonight, but I'll make urchin soup for my friends in January."