Starving grey whales may be early sign of changes in the Pacific warns Earthwatch scientist
Oxford. 1 May 2007: Researchers with environmental charity Earthwatch have voiced their fears for grey whales arriving malnourished in their breeding grounds off the Mexican coast.
The scientists are not clear whether the current decline is climate related, or part of a natural predator-prey cycle, but stress the urgent need to find out why the grey whales are in trouble.
The latest discovery bears a worrying similarity to 1999, when large numbers of whales starved to death due to a drop in ocean productivity brought on by a strong El Niño event which increased water temperature. Warmer waters hold less oxygen and become less productive, resulting in less of the tiny crustaceans which constitute the whales' favoured diet.
Dr. William Megill, lead scientist on the Earthwatch supported research project Grey Whale Migrations, explained: "We're not really sure what is going on now. We certainly saw in Mexico this winter a very large number of starving whales. There is currently an El Niño building, and this is a worry."
Grey whales were the first great whales to be removed from the endangered species list, but their future is by no means certain. They are believed to spend their summers feeding in the plankton-rich waters of the Bering and Chuckchi Seas and winters in the warm lagoons off Baja California, where their calves are born, although recent evidence is challenging these assumptions. It is estimated there are now between 15,000 and 18,000 grey whales in the eastern Pacific, after pulling back from near extinction in the 1940s as a result of hunting.
In the last few years, Dr. Megill and his teams of Earthwatch volunteers have found the animals arriving exhausted off the Mexican coast.
"The animals are starving, their fat has just gone, and there's not a lot of breeding going on. They seem to spend their time looking around for food when they should be breeding."
One theory is that the whale population can no longer sustain itself.
"Around the year 2000, colleagues looked for mysids (tiny crustaceans) in kelp beds off the Canadian coast, and they found lots of them. The last two years, we've stuck cameras down there and seen nothing. It could just be the whales ate them all, and what we're seeing is the same thing that happens to wolf and lynx populations when they eat too much of their prey."
He is concerned that other factors, particularly the slow rise in the average temperature of the oceans, or the deepening annual Arctic melt, which would also deprive the whales of a rich source of food along the edge of the pack ice, could be involved.
"It may be a lot more serious than just grey whales - they may just be the early warning sign of changes for the whole Pacific, and we urgently need to know what's going on."
Since 2000, more than 500 Earthwatch volunteers have helped Dr. Megill in his study of grey whale migrations. Find out more about our Grey Whale Migrations research project.
For press information, images, and interviews contact:
Zoe Gamble, Earthwatch PR Manager
+44 (0)1865 318852 / + 44 (0) 7725690469
Photos© Dr William Megill