Can we really save the whales?
For the endangered North Atlantic right whale, these are trying times. These leviathans who live and migrate in waters along the East Coast of North America teeter closer to the brink of extinction than perhaps any other whale species. Their population is tiny - less than 350 - and continues to shrink. By some estimates, if current population trends hold, the species will vanish within the next 200 years.
Yet for scientists and conservationists anxious about the future of these creatures, rays of hope are beginning to pierce an otherwise gloomy horizon. Thanks to a surge of scientific research and new tools for conducting it, they expect to learn far more about right whales, their interaction with the environment, and how to better protect them from their biggest threat: man. If they can save a population this small, then it could boost hopes of saving other species from the unintended impact of humans on the environment.
For the right whales, the leading causes of mortality are collisions with ships and encounters with fishing gear, researchers say. Females appear to have the toughest time surviving the range of human and natural threats. It's these challenges scientists hope to address with a growing momentum in right-whale research.
Later this month, for example, researchers are set to test new approaches to tracking the elusive whales in hopes of alerting ships to their presence. Meanwhile, chemists and engineers are developing whale-friendly commercial-fishing gear. Conservationists are working with governments and the shipping industry to move or control traffic on heavily used sea lanes that ships and whales share. And recent research is yielding potentially useful insights into the impact of factors ranging from water quality to shifts in climate.
"I'm not much of a Pollyanna; I can be very grumpy about the progress of right-whale biology and conservation," says Scott Kraus, director of research at the New England Aquarium in Boston. But "in the next couple of years we're going to see a tremendous burst of very creative scientific energy" applied to fundamental biological and ecological questions surrounding the whales.
"When those questions get answered, we're going to have very specific ideas about what management strategies will reduce mortality and perhaps enhance reproduction," he says.
To an outsider, the goal looks deceivingly within reach. The population is so small that it would take only modest gains in saving whales to help turn the situation around. In principle, preventing "two female deaths a year would have a major impact on the prospects for the population," says Hal Caswell, a marine zoologist at the Woods Hole Oceanographic Institution in Woods Hole, Mass.
Yet achieving that means untangling a web of intertwined human and environmental factors that contribute to the whales' plight. The one factor that weighs most heavily is human.
From 1500 to 1600, Basque whalers decimated right-whale populations in the eastern Atlantic, taking an estimated 25,000 to 40,000. In the late 1600s, by some accounts, it would have been possible to walk across Cape Cod Bay on the backs of whales. But by the mid-1700s, New Englanders had taken another 3,000, Mr. Kraus says. By the early 20th century, "only a few dozen whales survived in the western North Atlantic."
That population had slowly rebuilt. Over the past 20 years, researchers have built an impressive collection of 250,000 photos - a catalog of some 460 North Atlantic right whales. Each animal bears unique growths of hardened skin, or callosities, in places where hair would appear on humans. The callosity patterns act as visual tags, allowing researchers to follow the whales' life history.
"You get to know most of them on sight," Kraus says.
Surveys by boat and aircraft show that of the 460 whales in the catalog, fewer than 350 remain, despite three good calving years in the 1990s.
Researchers also have identified five critical habitats for the North Atlantic right whale along a stretch of coast running from Cape Canaveral, Fla., to Nova Scotia. As the whales migrate, they cross some of the most productive fisheries and most heavily traveled sea lanes, and pass by some of North America's busiest ports.
For conservationists working with the fishing and shipping industries, this presents a challenge.
"We're trying to deal with thousands and thousands of vessels calling at ports, and only 200 or 300 right whales. So the probability of any individual ship" hitting a whale "is very, very small," says Bruce Russell, a consultant who helped write a draft strategy now under federal review to cut the number of ship-whale collisions.
Yet for the population to survive, scientists say, the remaining group of North Atlantic right whales needs to hang on to every member it can. Thus, right-whale conservationists must design schemes that help the whales without breaking the bank for the industries involved. One approach: move shipping lanes. Last July, new lanes in Canada's heavily traveled Bay of Fundy were shifted to reduce the chances of whales being hit.
In addition, researchers are exploring a number of acoustic approaches to avoiding ship-whale collisions. One technique scientists hope to test later this month involves the use of moored buoys that use passive sonar systems to listen for whales.
A lot of progress has been made in developing a signal-processing capability that can tell a right-whale call from those of other species, notes Christopher Clark, a marine biologist at Cornell University, who conceived of the buoy.
The system he's devised would relay the data via cellphone from the buoy to a website at Cornell, giving users and the public at large virtually immediate information on whale locations.
Until now, researchers had been working with "pop-up" sonar sensors that had to be retrieved before the data could be analyzed. And shippers often had to rely on aircraft spotters to locate the presence of whale pods - an expensive, potentially dangerous approach that was of little value in bad weather.
If the technology proves successful, Dr. Clark says, a network of these "listen-only" buoys along the East Coast not only would provide the information shippers need to avoid whale pods, it also could help researchers answer some nagging questions about right-whale migration. For instance, only a small fraction of calving females shows up at the calving grounds off the southeastern coast. No one knows where the rest go.
Over the long term, he adds, it may be possible to use acoustic techniques to identify and track individual whales by their "voice prints," just as humans can be identified by subtle voice patterns.
The first buoy is slated for testing in Cape Cod Bay, where some right whales spend the winter, at the end of this month.
Researchers also say they are making progress on approaches for reducing the risk of entanglement in fishing gear. At a recent workshop on right-whale conservation at the Woods Hole Oceanographic Institution, for example, Norman Holy, a chemist with Atlantic Gillnet Supply in Gloucester, Mass., described netting he has designed to reflect sound, rendering them visible to marine mammals that use sound for navigation. If used in nets and buoy moorings, the new material could make it easier for whales to detect the lines and perhaps avoid entanglement.
Researchers also are trying to devise lines and netting that disintegrate after prolonged exposure to seawater in an attempt to reduce the threat from "ghost tackle" - lines and nets that are lost in storms or break free of ships.
Yet while these and other techniques hold out the promise of reducing risks to whales, much remains to be learned about fundamental right-whale behavior, biology, and ecology. Insights gained from research in these areas are expected to improve the population models that researchers use to try to gauge the whales' future.
A group led by Charles Greene, a Cornell University ecologist, recently suggested that swings in a climate pattern called the North Atlantic Oscillation could well be a harbinger of right-whale reproduction rates for a few years after the oscillation shifts from one phase to another. He and his colleagues found a strong correlation between shifts in the oscillation and the presence of tiny marine organisms in critical summertime feeding areas in the Gulf of Maine and off Nova Scotia. Those shifts in food supply shortly were manifested in higher or lower right-whale reproduction rates.
The link: Females need a hefty diet of these organisms as they recover from one pregnancy and store up energy for the next. If the organisms are in short supply, the females take longer to recover, lowering the birth rate for a period.
This relationship between climate and food also can affect migration patterns, as the whales search for new feeding grounds, he says. With further field work, it might become possible to forecast changes in near-term reproduction rates based on changes in the North Atlantic Oscillation, aiding conservation efforts.
These seven whale species are considered endangered by the US Fish and Wildlife Service. Their reasons for endangerment include environmental factors, excessive fishing, and collisions with boats on busy shipping routes.
• Blue whale: Lives off the coasts of California, Massachusetts.
• Bowhead whale: Lives near Alaska and in the northern oceans.
• Finback whale: Lives near Alaska, along most of the East Coast, Gulf of Mexico, Puerto Rico, and the Virgin Islands.
• Humpback whale: Lives near Alaska, Hawaii, along most of East and West coasts, and in the Gulf of Mexico.
• Right whale: Lives in northern oceans and along parts of the East Coast.
• Sei whale: Lives off the coast of Massachusetts.
• Sperm whale: Lives off the coasts near North Carolina, Puerto Rico, and the Virgin Islands.