A rare and famous success in conservation is the recovery of sea otters in the North Pacific. Of course it is also complicated.
Their story is familiar. Once two to three hundred thousand sea otters lived in inshore kelp beds around the North Pacific from Baja California to Hokkaido in Northern Japan. A market in China for their pelts opened in the early 1700s nourished by Russian hunters, and it later expanded to Europe. By the early 1800s, few sea otters remained on the Alaskan coast, so the hunt continued down the British Columbia coast to Washington, Oregon and finally California until few if any remained there as well. A belated international treaty in 1911 stopped all hunting leaving perhaps 2000 left alive in scattered colonies. Extinction seemed the likely outcome.
It didn’t happen. Instead, natural recovery, a few re-introductions, and a hundred years later sea otters have re-established colonies throughout most of their range, in some places even to pre-hunt numbers.
Sea otters are keystone predators. If they are not present, sea urchins thrive, eat all the young kelp shoots, destroy the kelp forests, and create urchin barrens – virtually nothing there but sea urchins. If they are present, they eat the urchins, the kelp forests regrow and biodiversity increases: more fish, more sea birds, more marine mammals, and on the BC and Alaskan coasts, more eagles.
But much of the world that the sea otters have recovered into is radically different from the one from which they were almost completely eliminated. In Alaska, after recovering to pre-hunt levels, they crashed once again to about 30,000 animals – probably due to Orca shifting their predatory focus to them from seals which had greatly declined in numbers. Where the Exxon Valdez foundered near Prince William Sound in 1989, about half the newly re-established sea otter population there of 5000 died from the oiling. On the central coast of California, diseases from coastal pollution appear to have kept the recovering population from growing very large.
As well, conflicts with humans increasingly occur, for both species hunt the inshore rocky subtidal for the same shellfish. In California they compete for abalones. There the sea otters have refused to remain in selected regions set aside for them along the coast, and now they roam freely – and are certainly not appreciated by abalone fishermen. In Alaska they are resented, if not hated, by inshore crab fishermen.
Yet on the west coast of Vancouver Island their reception is different. Along 300km of this coast live the Indigenous peoples of the Nuu-chuh-nulth First Nations. They speak of having shared the sea’s resources with other species, including sea otters, for thousands of years, and they are intent on continuing to live in harmony with them now. They need recognition of their rights as First Nation’s and despite resistance from the Harper Government they are slowly winning them through the courts, including the Supreme Court of Canada. They present a model for successful conservation, as they act to ensure the well-being of this and future generations.
The Nuu-chah-nulth fishermen also ask how many sea otters are enough. Enough to keep the ecosystem a kelp forest rather than an urchin barrens, certainly. But then? Not so many that few shellfish are left for them to gather. They know they will need to be able to shoot sea otters when they become too numerous.
Not surprisingly, this raises strong reactions from non-fishing humans, for sea otters are considered cute. Cuteness of course is a purely human construct. Though sea otters do look harmless living in the coastal kelp, cracking shellfish on their bellies as they float on their backs, sometimes playing together, they can also be hostile and aggressive. Our coexistence is essential with communities of species whether we like them or not. We just can’t let them deplete the resources we have agreed to share with them.
So the questions remain everywhere along the kelp coasts: How many sea otters are enough? How will we control their numbers? And do the Nuu-chah-nulth First Nations provide a model that will work elsewhere?