Science / Medicine : The Photogenic Prints of Whales : Researchers are using new techniques in photo identification to catalogue the distinctive markings of whales, learning more about the mammal’s migration and social habits.
Whale researchers, countering a tide of skepticism, have found ways to use photographs to identify and track the world’s most mysterious mammals individually and over decades.
Placed in burgeoning whale “photo albums,” the pictures are providing answers to questions about whale biology that in many cases could never be answered before. Births, deaths, social groupings and migration patterns are showing up in the thousands of photos that telephoto lenses snap every year.
Some species are difficult to study, and there is some question about the ability to track large whale populations. Nevertheless, the ability to recognize markings ranging from the shape and scarring of dorsal fins to subtle color variations have made many whales as recognizable as your next-door neighbor.
Furthermore, new computer and genetic analysis techniques are expected to make it possible to get faster and even more detailed answers from the photographs.
This not only opens up an oceanful of biological data but also makes it largely unnecessary to kill whales for research purposes, many scientists say.
Seen as Waste of Time
“When we all first started in this field, the general wisdom was that we were totally wasting time, and just hopelessly unrealistic that you could ever learn anything from whales in the wild,” said Roger Payne, a World Wildlife Fund senior scientist who pioneered photo identification techniques on southern right whales off the coast of Argentina.
Conventional wisdom had it that whales swam too far and too fast, were too dispersed in the ocean and did not have distinctive enough markings for successful tracking.
But in 1970 Payne began taking what would eventually total more than 50,000 photos of the whales. His group used patterns of light-colored head patches called callosities to identify 850 right whales and follow their lives over two decades.
Since then, scientists--with the help of photos by amateur whale-watchers--have found and tracked recognizable individual whales among most species of marine mammals, including some dolphins and porpoises.
“It’s developed to the point now where every large whale (type) in the world, with the exception of the pygmy right whale, has been looked at for individual identification,” said Steven K. Katona, a biology professor at the College of the Atlantic in Bar Harbor, Me. Katona is the driving force behind a catalogue of North Atlantic humpback whales that contains pictures of the distinctive tails of 3,700 humpbacks.
Benign Study Possible
Katona said photo identification means scientists can study whales benignly, as opposed to the traditional practice in the past of studying carcasses of animals killed by whalers.
“You don’t have to kill them anymore,” Katona said. “You can learn things a lot more efficiently and a lot more humanely and a lot better--because you don’t have to do it so indirectly as finding out how many scars there are on the ovary to indicate ovulation. You just watch the female have calves. And you can do it for her whole life as long as you find a little bit of money to do the work.”
Payne agreed, adding that this view is not merely a conservationist reaction to the emotional issue of killing whales.
“It’s not some tree-hugging sentimentality about how to learn about whales. It’s just that, hey, if you’re really interested in learning about them, don’t (kill them and) waste all that data you can get from years and years and years of study,” he said. For instance, Katona’s group identified a humpback recently seen in Icelandic waters as the same animal Payne had photographed in 1968 in the humpback breeding grounds, near the Dominican Republic. “Suppose my approach to that whale in ’68 had been to kill it. Then we wouldn’t have any idea of the connection between Iceland and the breeding grounds,” Payne said.
Whale Biologists Meet
Payne and Katona were among dozens of leading whale biologists who met in San Diego over the last two weeks under the auspices of the International Whaling Commission to discuss the state-of-the-art in non-lethal whale research.
Among their tasks was to fashion a report to the commission’s scientific committee, which began two weeks of meetings in San Diego Friday to develop recommendations for the commission.
Key among the committee’s deliberations will be consideration of the recently completed Japanese research expedition to kill up to 300 minke whales in the Antarctic this year despite the committee’s opposition. Critics call such “scientific whaling” a subterfuge to keep commercial whaling alive until the current worldwide moratorium comes up for review in 1990.
As the whaling commission wrestles with such issues, photo identification could give it a better way to comprehensively assess whale populations by then, said Gregory P. Donovan, a commission representative at the meetings.
“As part of the comprehensive assessment it’s very important that we look at the new techniques for the possibility of using them for the oceanic species, like minke whales and fin whales, where it’s been a lot harder to identify individuals,” Donovan said.
Needs Great Detail
The commission needs not only censuses but also myriad details about whale habits, reproduction and natural mortality, areas where the researchers say photo identification has already yielded unprecedented results. These include:
- Each bull sperm whale does not keep an exclusive harem, as once had been thought, said Hal Whitehead, assistant professor of biology at Dalhousie University in Halifax, Nova Scotia.
“There seem to be very few males taking part in the breeding,” Whitehead said. By individually identifying animals near the Galapagos Islands, he found that bulls instead rove from matriarchal group to group searching for a receptive female.
This indicates that, even though sperm whales number in the hundreds of thousands worldwide, killing off a single dominant bull could have more serious reproductive consequences for the species than had been previously thought.
Similarly, reducing the total numbers of females would diminish the wandering males’ chances of finding a female at the right time in her hormonal cycle, Whitehead said.
- The 30-foot-long minke ( “mink-ee” ) whales that hug the California shore near Monterey Bay are divided into two distinct groups, said Eleanor Dorsey of Payne’s Long-Term Research Institute in Lincoln, Mass. The steep underwater canyon of Carmel Bay seems to serve as an invisible barrier between the two, she said.
Elusive Species
But the minkes also illustrate the difficulties posed by some species. These “slinky minkes,” as they are called by harried scientists, are so elusive that only 17 have been individually identified off Monterey during three years of research.
- The composition of the group of humpback whales that summer near the Farallon Islands off San Francisco appears to change from year to year. Photo surveys identified 105 individual humpback whales there in 1986 and 1987, but most of the ones seen in 1987 had not been seen the previous year.
Among the few returnees in 1987 was Humphrey, the celebrated humpback that wandered up the Sacramento River in 1985. He was last seen last October, said Ken Balcomb, a whale researcher from Friday Harbor, Wash.
- The killer whales of the Pacific Northwest have been shown to live in tight matriarchal groups that have their own dialects and lose members only by death, said Michael Bigg, a British Columbia researcher who in 1972 began photo studies of them.
With their detailed genealogies of about 250 resident animals, the killer whale studies by Bigg, Balcomb and others are considered among the most elegant examples of what photo identification can do. But they covered a relatively small number of animals and the small geographic area in which they range.
Usefulness in Doubt
Donovan, of the whaling commission, said he wonders if the technique will be useful in estimating populations of more numerous species, such as the perhaps 300,000 minke whales in the Antarctic, or hard-to-find oceanic species.
Mathematicians also urge caution about deriving population figures for whales from photo identification. They suggest that whale researchers need to find ways to correct for biases in their sampling--for instance, to account for the possibility that some individuals or types of whales may be under-counted because they shun humans.
Greater numbers of animals also will intensify the tedium of comparing new photos with the catalogue of identified individuals. Although easy matches take only minutes, researchers tell tales of dizzying days trying to make a match.
“I can only do it for a few hours at a time, and then I’ve got to go do something else,” Balcomb said. “You look at one picture and then look at another--and you can’t remember what the first one looked like.”
Enter the computer. A National Marine Fisheries Service scientist, Sally Mizroch of Seattle, and a College of the Atlantic researcher, Judith A. Beard, have developed software that they are using to sort out 4,400 photos of humpback whales in the North Pacific. The system can rank a new photo against the entire catalogue within minutes, and eventually also will be used with the North Atlantic humpbacks, Mizroch said.
Digitized Images
At the University of Miami, Michael F. McGowan is at a more preliminary stage with a system that would use digitized images and sophisticated photo enhancement techniques to store, match and improve whale pictures.
A third computer system, also at a preliminary stage, is being developed by researcher Lex Hiby in Cambridge, England. It offers a way to correct for curvature that distorts photos of the subtle color patterns used to identify some species, such as blue whales. The curvature can make it difficult to compare one photo to another.
One of the most exciting prospects for photo identification proponents is the possibility to combine their photos with new “genetic fingerprinting.”
Using a small scrap of skin or other tissue, this form of genetic analysis compares sections of the hereditary chemical DNA against the same sections in another animal. Researchers hope it will be able to show whale paternity--the most difficult relationship to prove in far-flung, matriarchal whale societies.
To collect tissue samples, however, they would have to shoot whales with hollow darts, which in tests have caused extreme distress to a few animals. A proposal to dart some of Puget Sound’s killer whales in a genetic fingerprinting study has run into stiff public opposition.
Whatever the outcome of such controversies over methods, the scientists seem sure that biological data derived from photo identification work is critical to the future of whales in the Earth’s oceans.
