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"If gray whales have become food-limited, a high stranding rate and lowered reproduction would be expected to continue until an equilibrium is reached," the scientists predicted.
Le Boeuf and his colleagues' "starvation hypothesis" held that whales were going hungry for two related reasons. One, changes in the northern ecosystem were reducing the whales' principal prey, the amphipods. Moreover, they theorized, there were simply too many whales competing for the same meal.
This "carrying capacity hypothesis" has floated to the top of scientific debate over the future of the gray whales. Some researchers think the population has grown so large that the ocean environment simply cannot sustain 26,000 or more grays. The large number of strandings was simply nature's way of cutting the herd down to a sustainable size, they believe.
In New Times' special project "Shades of Gray," reporters from several of our papers have traveled from Siberia to Mexico to tell the complex tale of a creature whose annual migration -- at 12,000 miles round trip -- is the longest by any mammal. The trek joins the competing interests of Indians, scientists, environmentalists, and local residents. In this issue, Patti Epler explores the science, the money, and the politics behind gray whale research. With hundreds of whales mysteriously washing up dead and a plunging calf count coupled with reports of chemical contamination, scientific research has taken on a new urgency.
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A series documenting the perils, cultural conflicts and global and ecological warnings surrounding the gray whale.
Other scientists don't buy the carrying capacity theory. They think the strandings were a random event, a spike -- albeit a sharp one -- on the whales' biological timeline that shows an upturn in strandings every seven or eight years. The more likely culprit for the 1999 and 2000 strandings, they say, was a short-term warm water event, an El Niño effect that reduced the amphipods for a couple of years.
But some scientists like Le Boeuf and Mate, as well as many environmentalists, worry that the low birthrate on top of the high number of strandings means something more long-term is afoot.
"If the whales have come on hard times and their food supply is threatened, the first thing you would have is some starving in the first couple years," explains Le Boeuf. "So maybe that was kind of like the first cut and the weak ones have succumbed. So that perhaps explains why we have not had the same strandings rate."
Or perhaps not.
In July, two other leading gray whale scientists, Robert Brownell and David Weller, both on the staff of NMFS' Southwest Fisheries Science Center in La Jolla, Calif., submitted a paper to the IWC that argued against the carrying capacity theory. Both men have worked extensively with the Western Pacific gray whale population that is found mainly off Sakhalin Island in the Okhotsk Sea near Russia. That population has been deemed "critically endangered" and is down to fewer than 100 whales.
Brownell and Weller contend that by no stretch of the imagination could the Western gray whales be overgrazing their feeding grounds; there are simply too few of them. Yet they are dropping in numbers, too, almost to the point of extinction.
Instead, "more global or oceanwide changes may be influencing the availability of, or access to, primary prey for numerous large whale populations," Brownell and Weller say.
Again, Brownell and Weller don't have any recent data on the actual food supply. That's the work that won't be done until the coming year, perhaps by both NMFS and the National Science Foundation.
But the two scientists got together with 10 other whale experts at a meeting of the Society of Marine Mammalogy in Hawaii in December 1999. The group scrutinized photographs of skinny whales from both the Eastern and Western populations. Many of the features were the same: protruding shoulder blades, depressions behind the head, and a pronounced ridge or visible "bulge" along the lateral flank.
The scientists concluded that the starvation hypothesis proposed by Le Boeuf earlier in the year was indeed plausible. "However, we do not think that starvation is necessarily related to exceeding carrying capacity."
Evidence from throughout the world points to something much bigger at work, they say. Skinny blue whales have been observed in the Gulf of California and skinny right whales have been spotted in the North Atlantic. Changing global weather patterns may be affecting sea ice, which means the feeding grounds are not as accessible to the whales. Plankton production may be off in the North Atlantic because of long-term weather changes.
Brownell and Weller think that some sort of "large-scale ocean basin" climatic event has affected both sides of the North Pacific Ocean. They believe the shift took place in the late 1990s and changed the availability of food for both the Eastern and Western Pacific grays in the same way.
Brownell and Weller have no idea what that major environmental change might be or whether an end to industrial development, including oil drilling, or further cutbacks in aboriginal harvesting will, in fact, save the whales -- on either side of the ocean.
But it's important for scientists to figure out whether whales face a problem with abundance or the threat of scarcity. Marine mammal experts, especially the quasi-governmental IWC, will need the science to put in place species management plans. If there are too many whales (the carrying capacity theory), the IWC could decide to allow an increase in aboriginal quotas, for instance. If it looks like the food supply is being threatened by a larger environmental circumstance, officials may be forced to make tough political choices like limiting industrial development in whale territory.
Scientists agree there's only one way to solve the dilemma: study what's going on in the Bering Sea.
"What I think is most important for the gray whale now is to actually study the amphipods," says Le Boeuf. "You're probably saving the whales along with it."