Are grey whales climate change’s big winners?

Marine biologist Greg McCormack spots what he’s been looking for about 100m off the port side. It is a grey whale surfacing, one of a species that migrates from the warm waters off Mexico to chilly Alaskan seas. It is lolling about, shooting spray into the air for tourists, about an hour outside Monterey in California.

Grey whales were once disparaged as “devil fish” by whalers who had had their ships charged, mostly by mothers after the whalers had killed their calves.

Having skirted annihilation last century, these whales are a conservation success story: the population is now estimated to be more than 20,000. Tourists aboard the 70ft Sea Wolf II are virtually guaranteed to spot these 40ft leviathans in springtime.

“They all have Mexican passports, being born in warm, shallow lagoons in Baja California,” McCormack says.

They migrate past Monterey, moving from winter breeding and calving lagoons to summer feeding grounds in the Arctic, between Russia and Alaska. They are also the only bottom-feeding whales.

Extinct off our coasts

The grey whale has been extinct off our coasts since the 17th century, the time of Shakespeare's Macbeth and the Battle of Kinsale. But it could come up trumps among the winners and losers of climate change.

In 2010, a grey whale turned up off the coast of Israel, and then the Balearic islands in the Mediterranean. In 2013, another was spotted off Namibia.

"There hasn't been a grey whale stranding reported [in Europe] for more than 500 years. This could be an example of global warming doing some whale populations a favour. As pack ice fragments, some species may be able to recolonise the Atlantic from the Pacific," says Pádraig Whooley of the Irish Whale and Dolphin Group. "We thought we had lost them. But if two turned up, that may be only the tip of the iceberg."

The grim decline of the Atlantic grey whale is instructive, according to fisheries historian Poul Holm of Trinity College Dublin. Evidence gathered during the 10-year History of Marine Animal Populations project shows that marine animals were hit hard even before the industrial revolution.

“Technology might have been simple, but the impact on marine populations could be great, because it all depended on fishing effort. The grey whale was depicted in [13th-century] Icelandic sagas as an easy source of meat because it forages inshore and was easily accessible,” Holm says.

Once grey whales were wiped out, hunters shifted to other species.

“We have records of Basques hunting whales since the 12th and 13th centuries, and already they were targeting [North Atlantic] right whales,” says fishery biologist and historian Cristina Brito, of the New University of Lisbon in Portugal, who was part of the epic project led by Holm. The right whale is another large, slow-moving species, and was deemed the right whale to kill, as the carcass stayed afloat.

Southern right whales are what most people see if they go whale-watching off New Zealand or South Africa, but not here.

“Even though they haven’t been hunted for 80 years, they are still on the brink of extinction,” says Whooley.

Humpback whales seem to be recovering better; there have been increased sightings.

Whalers later moved on to fast-moving species, such as fin and blue whales, which are found farther from shore and are harder to kill, and also deep-diving sperm whales. Scientists reckon that numbers of large whales in the north Atlantic have fallen to 10 per cent of what they once were. A great deal of damage was done by 20th-century commercial whaling.

But today too much focus goes on commercial whaling, which targets species such as the minke whale, says Whooley. "If you turned off every Norwegian, Japanese and Icelandic whaling boat, it would not make a difference. The damage was done hundreds of years ago and it was done by the nations that are so pro-conservation today: Americans and Europeans. We crashed the whole populations."

Today’s threats come from problems such as noise pollution, depletion of fish stocks, loss of habitat, and man-made chemicals. Nonetheless, Whooley is upbeat about Ireland’s waters. The Irish Whale and Dolphin Group has documented 24 species of whales and dolphins (called cetaceans by zoologists) from a total of 84 worldwide.

“Our waters have a high diversity of cetaceans,” he says. “We’ve good, suitable habitat, plenty of pelagic fish [such as sprat and herring] and plenty of clean water.”

Dr Conor Ryan, who recently completed a PhD at NUI Galway on the feeding habits of fin, humpback and minke whales, looked at skin and blubber samples from humpback whales biopsied on both sides of the Atlantic. “The toxic load from organic pollutants was orders of magnitude higher on the other side of the Atlantic, so our animals are probably swimming in much cleaner water,” says Whooley.

• All-Ireland Whale Watch Day will take place this year on Sunday, August 23rd

STRANDED: BEAKED WHALES WASHED UP IN IRELAND

An unlikely number of deepwater whales were stranded on Irish and Scottish coasts in December last year and early this year. The strandings happened over a short period of time and involved a single species: Cuvier’s beaked whales.

Whale conservationists say Ireland has not properly investigated the cause of these strandings, which may have been due to disorientation caused by human activities at sea.

“This is more than a blip. We recorded 10 strandings in Ireland, but those are only the ones we know about,” says Pádraig Whooley of the Irish Whale and Dolphin Group. “Nothing is known about the population of Cuvier’s beaked whales. To have a sample of 10 wash up on our beaches is extremely worrying. We could have seen in this recent episode a significant portion of the Cuvier’s beaked whales in Ireland wiped out. We don’t know.”

The Irish Whale and Dolphin Group is unhappy that no postmortems were carried out on these native marine mammals.

“We have obligations under all sorts of EU treaties, such as the EU habitats directive, to actually protect these animals, and as an NGO [that is] passionate about whales and dolphins, we cannot sit back,” says Whooley.

The National Parks and Wildlife Service needs to receive government support so that it can fund postmortems, he argues.

These beaked whales are known to be difficult to study, because they seem to prefer continental slopes and depths of 500m-3,000m. They feed mainly on deepwater squid, although they also catch fish such as whiting. They are sometimes seen from ferries crossing the Bay of Biscay. They are inquisitive and will surface close by the ships.