Innumerable Whales

When the sun slipped north of the equator at the spring equinox, some of Alaska's seasonal residents began getting organized for their great trek northward. No, I don't mean birds, nor even construction workers. These travelers are the mightiest migrators of all, the great whales. And this year, we may be welcoming more whales than at any time since the whaling fleet left our coasts. At long last, it looks as if Alaska's biggest mammals are regaining their numbers.

Consider, for example, the gray whales. Often called California grays, particularly by denizens of that smaller state to the southeast of us, our gray whales spend the winter in Mexican lagoons and summer in the shallower reaches of the Bering Sea and points north. Once apparently on the brink of extinction, the eastern Pacific population of these big bottom feeders has now recovered so well that the U.S. National Marine Fisheries Service has requested gray whales' removal from the endangered species list.

Then there are the humpbacks. Like the gray whales, North Pacific humpbacks are no dumb bunnies. They spend the winter in the sunlit seas off Mexico or Hawaii, and return to gorge themselves all summer on the teeming life in Alaska's cold fjords and sounds. (Think of it as raiding the refrigerator on a leviathan scale.) University of Hawaii researcher Joseph Mobley asserted at a conference last November that 3400 humpback whales now spend the winter in Hawaii, compared to 1400 a decade ago.

Ah, but this heartening opinion is based on population estimates, extrapolations from numbers of whales seen. The presently accepted gray whale population of about 21,000 animals stems from actual sightings of perhaps 6000 animals---2900 pods, most of which contain only two whales.

Sometimes it's an extrapolation from animals heard; another of Alaska's resident great whales, the bowhead, is censused by acoustics. Based on hydrophone data that triangulated bowhead calls, scientists have concluded that the bowhead population is growing at about 3 percent a year. From an estimated 1500 animals in 1976, their numbers have now swelled to an estimated 7500.

That term "estimated" can fall somewhere between wishful thinking and hard fact; when it's applied to numbers of a kind of animal that spends much of its life hidden in the deep sea, we amateurs are especially tempted to think there's a higher proportion of pure guesswork involved. The professionals, however, have been gaining confidence in their methods.

For example, they've learned to tailor techniques to the peculiarities of the different great whale species. Many whales are individually identifiable by things like tail shape and location of callosities; photo inventories have been made for hundreds of whales. The probability of seeing a known whale from year to year in the same area is related to the size of the population, and scientists pore over these probability calculations with the enthusiasm of gamblers bound for Las Vegas. In some cases, just about every individual in a population may become known by its unique characteristics. Over the past 14 years, 325 individual North Atlantic right whales have been identified. Very few strangers are spotted any more, and the experts fear that there are no more right whales to be found over their entire range between Florida and Iceland.

The scientific whale watchers also have taken advantage of some new technology. In counting humpbacks off Hawaii, for example, Joseph Mobley's team was able to survey a larger area more precisely by using the global-positioning satellite system.

Critics point out that the better techniques may be at least partly responsible for the higher population estimates. In effect, they say, we don't have more whales; we're merely counting more of the whales we have.

Still, most scientific whale watchers hope that their estimates indicate a genuine change for the better in many whale populations, including the species most important to Alaskans' sense of how the seas should be.