Sea otters and shellfish lovers have always had an uneasy relationship.
People who like to gather clams at low tide, or dive for abalone -- or who make their gleaning sea urchins and abalone -- resent the presence of furry predators that can eat a quarter of their weight in shellfish each day.
On the other hand, sea otters are the charismatic stars of coastal waters wherever they live. And they're they're the linchpin of ecosystem health and abundance, too.
So there's tension, sometimes conflict, when sea otters and fishermen intersect.
That's what's happening now in Japan, where the tiny sea otter population off Nemuro, in eastern Hokkaido Island, is drawing oohs and aahs from tourists -- and grumbles from urchin fishermen.
"We can't remain calm, wondering whether sea otters are eating sea urchins," complained one.
Sound familiar? The same story has played out in California waters south of Point Conception, where commercial and sport fishermen want sea otters excluded from their historic range for fear hungry otters won't leave enough urchins and abs for people.
The federal government has dropped that approach, though the no-otter zone remains on the books. That's why some conservation groups are suing, so that sea otters can continue to re-colonize waters from which they were hunted to near-extinction by 19th century fur traders.
Dr. Steve Palumbi, director of Stanford University's Hopkins Marine Station, has chronicled the recovery of Monterey Bay's coastal marine ecosystems and gives the lion's share of the credit to sea otters.
"In the early 1900s you’d see all these beautiful rocks but you wouldn’t see any kelp and you wouldn’t see very many of these birds and you wouldn’t see a lot of the other life that's really here because the kelp forest was gone," he said in a PBS documentary.
That's because the kelp had been devoured by sea urchins and abalones that flourished in the absence of their chief predator. When otters returned, so did the kelp forests -- and all the other marine life supported by those healthy forests.
The same story has played out in Alaska, where kelp forests wax and wane depending on how many otters are in the same waters.
Sea otters also bring tourists, who are happy snapping photos before eating (sustainably) farmed abalone at seaside restaurants.