Archive for November, 2014

Living with Sea Otters

Wednesday, November 26th, 2014

A rare and famous success in conservation is the recovery of sea otters in the North Pacific. Of course it is also complicated.

Sea otter raft, floating among the fronds of kelp in a coastal kelp forest (otterproject.org)

Sea otter raft, floating among the fronds of kelp in a coastal kelp forest (otterproject.org)

Sea otters once lived along the kelp coasts from Hokkaido to Baja. Solid colors indicate where some recovery has occurred.(otterproject.org)

Sea otters once lived along the kelp coasts from Hokkaido to Baja. Solid colors indicate where some recovery has occurred.(otterproject.org)

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.

The sale of sea otter pelts (here measured in thousands) in London peaked in the 1880s, then crashed rapidly as the supply dwindled from  over-hunting. (en.wikipedia.com)

The sale of sea otter pelts (here measured in thousands) in London peaked in the 1880s, then crashed rapidly as the supply dwindled from over-hunting. (en.wikipedia.com)

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.

Hunted almost to extinction along the coast of BC, sea otters were reintroduced on the coast of Vancouver Island in 1989, and new colonies have re-established on the central BC coast (theglobeandmail.com)

Hunted almost to extinction along the coast of BC, sea otters were reintroduced on the coast of Vancouver Island in 1989, and new colonies have re-established on the central BC coast (theglobeandmail.com)

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.

A mature kelp forest results in far greater biodiversity than an 'urchin barrens' (aquariumofpacific.org)

A mature kelp forest results in far greater biodiversity than an ‘urchin barrens’ (aquariumofpacific.org)

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.

A sea otter rests on its back while ripping the legs off the crab it just caught.(seaotters.org)

A sea otter rests on its back while ripping the legs off the crab it just caught.(seaotters.org)

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.

Nuu-chah-nulth First Nations, traditionally  whale oriented cultures, live on the west coast of Vancouver Island (stoningtongallery.com)

Nuu-chah-nulth First Nations, traditionally whale oriented cultures, live on the west coast of Vancouver Island (stoningtongallery.com)

Logo for Nuu-chah-nulth First Nations (blogs.ubc.ca)

Logo for Nuu-chah-nulth First Nations (blogs.ubc.ca)

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?

Conserving Emperor Penguins

Friday, November 14th, 2014

A remote-controlled rover that looks like a pile of chick feathers with a chick’s head on top has successfully penetrated the defenses of a colony of Emperor Penguins on Antarctica, getting close to the penguins without stressing them.

A remote controlled chick-on-wheels meets the real thing, and provokes interest

A remote controlled chick-on-wheels meets the real thing, and provokes interest

We know a lot about Emperor Penguin breeding behavior from 5 decades of observations on the colony at Terre Adelie, one of the 45 breeding colonies that ring the continent. There adults have been electronically tagged for id and heart rate and other measurements. That colony gave us the movie March of the Penguins

Alone of all the penguins, the Emperor breeds on the sea ice during the Antarctic winter. As winter descends, each female lays her single egg, gives it to her mate, and leaves for a very long walk out to the edge of the sea ice, as much as 100 km away by then, where she forages for krill before walking back again, arriving two months later just in time for her egg to hatch. During those two months, each male brooded the egg his mate laid, stuffed into a feathery pouch just above his feet. When the female arrives she finds her now starving and very stiff mate in the huddle of males, and he transfers the egg to her and then in turn walks away to the distant ice edge to forage for krill, to return two months later.

It takes full time effort for a monogamous pair of Emperor Penguins to raise a single chick (guardian.com)

It takes full time effort for a monogamous pair of Emperor Penguins to raise a single chick (guardian.com)

Of course this has all occurred in weather as extreme as this planet offers – extreme cold, high winds, totally dark almost all the time. A single mistake – an egg unprotected for a minute, a parent lost or delayed, unexpected climate stress – and the breeding effort fails.

As the ice recedes with the spring melt, adults don’t have to walk so far to obtain krill, the chicks grow large enough to be left in huddling creches, and both parents forage for food for their growing chick. By the time fall arrives, the chick is large and agile enough to begin to forage on its own. If by chance it survives its first winter feeding at sea, it has a reasonable chance of making it to adulthood, breeding for the first time when it is about 15 years old.

Meanwhile, environmental stress plays its increasing role. In years with very cold conditions, the extent of the sea ice forces the adults to walk much further, and chick mortality is greater. In years with warmer winters the sea ice is less extensive, the krill feeding on the under-ice algae have less to feed on and the foraging penguins find less food, and again chick mortality is greater. In warm years, sea ice can also break up under the feet of the colony, and then most chicks are lost. Successful breeding is a delicate balance of sea-ice extent, size of krill schools, and parental condition.

So we know that Emperor Penguins grow large, live long, and breed late, with the lowest possible clutch size. Chick mortality is usually very high, around 50%, and the mortality of surviving fledged chicks through their first winter is often just as high.

Altogether a harsh and extraordinary existence.

The mean decrease in sea ice concentration around Antarctica by 2100 is expected to be as high as 20% in some areas. Of the 45 identified colonies, those depicted by red are expected to be 'quasi-extinct', by orange as  'endangered', by yellow as 'threatened', and by green as 'no threatened' (natture.com/natureclimatechange)

The mean decrease in sea ice concentration around Antarctica by 2100 is expected to be as high as 20% in some areas. Of the 45 identified colonies, those depicted by red are expected to be ‘quasi-extinct’, by orange as ‘endangered’, by yellow as ‘threatened’, and by green as ‘no threatened’ (natture.com/natureclimatechange)

What’s ahead? Winter sea ice will, over the next century, continue to recede around much of the Antarctic coast, in some places much more rapidly than others. Of the 45 colonies, probably ten will go extinct, seven on the ice of the Ross Sea will probably persist, and the rest will decline enough to be endangered, vulnerable to extinction. The models indicate 2/3 of the colonies will be less than 1/2 their current size.

Look ahead longer than a century, and few colonies remain. A bleak prospect. Clearly now is the time for enlightened conservation efforts.

Knowing how many birds there are is an essential first step. Colonies were photographed by satellite in 2009 using a variety of filters, identifying 45 – some never visited and others rarely seen. The current total population estimate is around 600,000 birds. Changes that occur in colony size and location will show up clearly in similar future surveys.

Satellite image of an Emperor Penguin colony, remarkable information to have for every colony (plosone.org)

Satellite image of an Emperor Penguin colony, remarkable information to have for every colony (plosone.org)

A penguin reserve – no fishing, no tourists – is the essential next step. The Ross Sea, where sea ice loss is expected to be least, is the obvious choice. It would provide a refuge, though even there colonies are expected to shrink. And of course there is resistance to protecting the Ross Sea from fishing, particularly from the Russians.

The third step? We’re back to the need to reduce global emissions of greenhouse gases, and this week the US and China have given us cause for at least some slim hope.

Now, adding even more detailed and reliable information to support effective conservation, the rover-chick has arrived. It has its own camera peeking out in the middle of its chest, and it can get close enough to adults to read their electronic ids and download physiological data. It creates little stress among the adults, unlike a human creeping into the colony to gather the data, and it can roll right into creches where it appears to be accepted. We’ll know more about the state of the penguins as global warming stresses increase.

The rover-chick has joined a creche, apparently successfully (ibtimes.co.uk)

The rover-chick has joined a creche, apparently successfully (ibtimes.co.uk)

Perhaps some of the colonies of Emperor Penguins will adapt to the loss of sea ice. Four colonies have apparently moved back onto the glacier ice shelf, well above sea level, as sea ice has receded. But they may not be able to adapt to diminishing schools of krill.

The other too-famous movie ostensibly about Emperor Penguins, ‘Happy Feet‘, includes concerns about the effects of global warming. Its solution? Humans and penguins dancing enthusiastically together as a call for action. Absurd and mindless fantasies are not helpful.

Emperor Penguins are a worthy icon for illustrating the stresses and effects of climate change and global warming. Their long-term survival is anything but certain, probably even unlikely, but they seem to intrigue us enough to care about them. Successfully conserving them conserves so much more of what we could lose.

The one colony we know most about is close to a research station. Most colonies remain remote. (whoi.edu/oceanus)

The one colony we know most about is close to a research station. Most colonies remain remote. (whoi.edu/oceanus)