Rare whale vomit may have been found at Porth Dafarch An Anglesey man may have found a rare substance vomited by whales that could be worth "tens of thousands of US dollars" a kilo. Andrew Hughes found what he thinks is ambergris, produced in the intestines of sperm whales, at Porth Dafarch near Trearddur Bay. Chris Dearden reports. Beach find could be whale ambergris