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Shrinking giants: The grey whales under threat from starvation

They survived the hunters - just - and their numbers surged. But now grey whales of the eastern Pacific are again under threat, this time from starvation.

Source:  Copyright 2007, Independent (UK)
Date:  May 3, 2007
Byline:  Julia Stuart
Original URL: Status DEAD

They were one of the triumphs of conservation worldwide. Grey whales were hunted to the brink of extinction in the 1850s after the discovery of calving lagoons, and again in the early 1900s with the introduction of floating whaling factories. In 1937, they were given partial protection by the International Whaling Commission (IWC), and full protection 10 years later.

From then on, the eastern North Pacific grey whale started its remarkable recovery. By 1993, the population had increased to around 25,000. The following year, grey whales were the first great whales to be removed from the endangered species list.

But now scientists are worried. Grey whales, whose numbers in the eastern Pacific have fallen to around 18,000 in recent years, have been arriving at their breeding grounds off the coast of Mexico looking decidedly slender. Experts have declared that they are suffering from what they term "skinny whale syndrome".

"I went down to Mexico this winter and my colleagues and I were finding whales that were starving," says Dr William Megill, whose work is funded by the Earthwatch charity. "You can tell because the fat has disappeared from the back of their heads. There are these big divots."

Nor do the whales appear to be breeding. Conception usually occurs between November and January. Grey whale females usually are pregnant over a two-year cycle, producing a single calf every other year. "It's pretty obvious when whales are breeding. The penis of a grey whale is about 9ft long and bright pink. You can't miss it. Usually when tourists come ashore in Mexico they are talking about having seen them. This year there was no talk of it, really. We have a feeling that the animals are looking for food," says Dr Megill.

In recent years, lack of food has killed thousands of grey whales. Between 1998 and 1999 an El Niño weather pattern reduced the population from around 25,000 to 18,000. It warmed up the water, which reduced oxygen levels, resulting in less of the tiny crustaceans that whales eat. "The result was that we had a lot of starving whales and it was a big enough crash in the population to have a lot of people worried," he says.

Eastern Pacific grey whales eat small shrimp called amphipods, which live at the bottom of the Bering Sea. In recent years, however, they appear to have vanished. "Now, when you look there is no mud or amphipods - there's just rock. Our whole ecosystem has disappeared from that part of the Bering Sea. We don't know why the amphipod beds disappeared. It might be to do with global warming or overfishing. It might also be that the whales have finished them off. What we may be seeing is a classic predator/prey cycle."

The grey whales have moved on, and now feed on mysids, a small type of shrimp that live in kelp beds along the shore, but which are a poorer food source. "These mysids may be able to tide them over for a while, but it may not be enough to keep the population indefinitely at its current level," he warned. "Some people are getting really worked up about it. Some whales will starve and some will die and we have to make sure there is enough resilience in the resource of the food they eat that it can recover and thereby the whales also recover."

This summer, Dr Megill will return to Mexico to monitor the mysids and the whale population. There are currently around 20 groups researching grey whales around the Pacific Rim. "All of us have the same concern in mind," he says. "All we can do is monitor it. Once we have figured out what is going on, if it is a man-made thing we can slow it down.

"We have really big threats in the Bering Sea in the form of oil exploration. Before they even do any drilling, they do seismic testing. They want to do that this summer, right in the middle of the grey whales' feeding time. And there are some real conflicts coming up in terms of the fisheries.

"Whether or not the grey whale numbers are linked to global warming, I couldn't make that claim. But there are a whole series of issues that we really seriously need to understand, so we can make these long-term management plans to make sure we don't lose the species. If I go up this summer and find mysids then I'll heave a sigh of relief. If I don't find any and no whales either, then I'm going to start rattling a lot of cages."

Steven Swartz, an expert in grey whales who monitors them in Baja California in Mexico with the Autonomous University of Baja California Sur, is another scientist who is concerned about the starving creatures. "It could be the early signs of something serious; we're not sure yet. We were able to photograph animals this year that appear to be either malnourished or suffering from disease or a combination of factors and we don't know what is contributing to it," said Dr Swartz, who also works for the fisheries service of America's National Oceanic & Atmospheric Administration.

"We know that the primary feeding ground is in the Bering Sea, north of the gulf of Alaska. We know that has been going through some severe changes associated with climate change, warming of the water and changing of the oceanography. Where the whales used to congregate in large numbers to feed, they don't any more. They may be suffering from not enough food, or they may have become vulnerable to parasites or diseases from having to switch to different food sources. They can survive this for a period of time, but not for ever. The biggest concern is if they are nutrition-stressed, the females may not be able to bring their calves to term or give birth to those that are hardy enough to survive."

Indeed, the counts of grey whales, particularly female-calf pairs, residing within Laguna San Ignacio, in Baja California Sur in Mexico during the past winter season were noticeably lower than in any previous year since 1978. According to Dr Swartz, the falling numbers could either be a reflection of the overall decline in the grey whale population since its peak in 1997-1998, or they have moved elsewhere. Certainly, the plight of the skinny whales needs to be watched closely. "It could be the early signs of something serious," says Dr Swartz.

Dr William Megill needs volunteers in Canada this summer. The expeditions last eight days and cost £695, which covers accommodation, food, training and carbon off-setting, but excludes flights. Teams are needed in Mexico from 19 January to 22 March next year. An eight-day trip costs £795. 01865 318 831;

The life of the grey whale

* Although skeletal remains and sightings of live animals indicate that the species occurred historically in both the north Pacific and the north Atlantic, grey whales are believed to have been extinct in the latter since the 18th century. Of the north Pacific populations, the western remains critically depleted (having only around 100 whales), although the eastern has recovered from exploitation.

* A small number of grey whales are still legally hunted. Currently, the IWC sets a quota allowing 169 whales to be caught annually from the eastern population for 'aboriginal subsistence'.

* Grey whales are sufficiently distinctive to other cetaceans to be placed in their own family: Eschrichtiidae. Recent molecular analysis, however, has provided conflicting views regarding this taxonomy.

* The migration route of the grey whale is often described as the longest known mammal migration. Beginning in the Bering and Chukchi seas and ending in the warm-water lagoons of Mexico's Baja peninsula, their round trip journey moves them through some 12,500 miles of coastline.

* Both female and male grey whales are promiscuous and copulate repeatedly with more than one mate.

* Grey whales are heavily infested with ectoparasites and epizoites, including a host-specific barnacle and three species of whale louse.

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