Friday, June 17, 2011

{Press} Looking for Admiral

North Atlantic right whales are in trouble, but it’s hard to know what to do about it

Scienceline | Rose Eveleth | June 7, 2011

When Admiral surfaces, she looks like a submarine breaking the water, her giant girth pushing the deep blue ocean out of the way, almost bouncing out of the depths. That’s how Phillip Hamilton describes her, at least.

Admiral is a North Atlantic right whale. She was first sighted in 1979, the year before the New England Aquarium started cataloging every remaining whale in the population off the Northeastern coast of the United States. She is also one of the researchers’ favorites. “She’s just an amazing whale,” says Hamilton, who runs the right whale catalog. “She really is iconic,” agrees Amy Knowlton, a fellow researcher at the aquarium. Sadly, she’s iconic in another way too: After a bad entanglement with fishing lines, she hasn’t been seen since 2007. If she’s dead, her fate is representative of many of her species, which must contend with the dangers of boats and fishing gear.

Admiral and her fellow right whales are a remnant population, one decimated by whaling and struggling to overcome constant, often deadly human interactions. Today, there are only around 500 North Atlantic right whales left. That’s an uptick from a few decades ago, when there may have been as few as forty right whales in the North Atlantic, but it’s still too soon to celebrate. As the National Marine Fisheries Service tries to regulate ships and fishing gear — the two main causes of right whale mortality — the population is in a state of limbo that is both hard to study and hard to change. Each birth and death can alter the species’ chances of survival.

North Atlantic right whales were once hunted nearly to extinction. From the early 1600s to the 1800s, between 5,000 and 11,000 whales were taken out of the water. They were hunted for their fat and meat, and their namesake comes from being the “right” whale to kill because their bodies float to the surface rather than sinking. It helped that they were big, too; right whales can be up to seventy feet long and weigh seventy tons.

Genetic analysis of the remaining whales suggests that there are only five unrelated female lineages left. That could mean that the population at one point dwindled to just five living females, but it’s more likely that there were around 40, and that the whales in the current population happen to all be descendants of five of those 40 female whales.

That means that the surviving whales are not very diverse genetically. But no one really knows how this will affect the species’ chance of survival. Some experts think the smaller gene pool will make it harder for the whales to adapt to environmental changes. Others studies have suggested that the population had a tiny gene pool even before whaling ships arrived, which could explain their struggle to repopulate.

Finding out when this genetic bottleneck happened, and how it might affect right whales, is just one of the many questions researchers still have about these whales. Despite over thirty years of constant monitoring, there is still a huge amount scientists don’t know about them. They seem to disappear in the winter, and a third of the mothers are missing during the summer. Researchers don’t know how social they are, how important vocal communication is to them, or whether they’re getting enough food.

Answering those questions is difficult because the whales are hard to study. Researchers can’t out a right whale in a lab, so all their work has to be at sea. “We’re working on something that doesn’t want to be found, swims really fast and has a wide-ranging habitat,” says Aaron Rice, who studies animal acoustics at Cornell University.

New developments in technology have helped, by allowing researchers to study these whales without ever seeing them. Genetic testing can be done on free-floating feces, for example, that scientists find with the help of a deck-side, scat-sniffing dog. Whales can be jabbed with GPS tracking units that record their location and speed. The Boston Harbor is equipped with underwater recording devices that listen for right whales all day and night. Researchers hope that those, combined with a yearly aerial survey and constant boat trips to right whale habitats, will help them chip away at the secrets behind the species, and find out how it might be pulled from the brink of extinction.

Of course, right whales weren’t the only species targeted by the whaling industry. But while sperm whales and bowhead whales have steadily recovered, right whales have not. Unlike sperm and bowhead whales, right whales are still dying in large numbers from human interactions.

That’s because right whales’ lifestyle puts them at an increased risk. They tend to live within the top ten to twenty feet of the water column, says Leila Hatch, a marine ecologist who works for the National Oceanic and Atmospheric Agency. “That means that they are within the strike zone of vessels for almost 100 percent of their life history. They basically evolved to do something that puts them in direct conflict with us all the time.” Boat captains often don’t know the whales are there until it’s too late, and boat strikes account for up to 40 percent of right whale deaths. While boats may only kill a few whales each year, the small right whale population makes each premature death dangerous for the survival of the species.

The same surface-swimming tendencies that put whales at risk of boat strikes can get them into trouble with commercial fishing lines, too. From scarring, researchers can tell that around 80 percent of the right whales alive right now have been stuck in fishing gear at some point in their lives, and the entanglements seem to have been getting worse over time.

Knowlton thinks this has something to do with new fishing products. In the early 1990s, rope manufacturers developed a new process to make their lines stronger than ever before. With the old ropes, the seventy-ton whales could break free. These new ropes might simply be too strong. Knowlton is using the right whale database to try to figure out if the uptick in entanglements does indeed correspond with the use of the new ropes. “In the eighties, when I started this project, we didn’t see the sort of complex entanglement” seen today, she says.

Recent regulations in the United States have helped. The National Oceanic and Atmospheric Administration adopted a rule in 2008 that slowed ships down to ten knots – about twelve miles per hour – in right whale habitats like Boston Harbor and Cape Cod Bay. Fishermen are now required to switch from floating ground lines — the ropes that hold strings of traps together — to sinking ones, which float below the right whale’s preferred swimming space. But those rules are only in effect in United States waters, and they only apply until 2013. Then, researchers will have to convince policy makers to extend the regulations. In Canada, where the whales spend much of the summer, there are no speed restrictions at all.

Boat collisions and net entanglement are the pressures we know the most about, but they’re not the only things that can kill right whales. In the 1990s, right whale mothers nearly stopped having calves. Only one calf was born in 2000. Whales started showing up with lesions all over their bodies. They were getting skinny. No one really knows why. It could have been a lack of food, or an outbreak of a disease, or some other stressor from the environment — or a combination of the three. Slowly, the whales got better, and started having more calves, but the cause of the sudden deterioration is still a mystery. For the best-studied whale species in the world, there are still plenty of unknowns.

One of those unknowns is Admiral’s fate. Since her first sighting, she has been seen 232 times. But since her entanglement in fishing gear, sightings dropped off. When researchers did see her, she looked pretty beat up. No one has seen her at all since 2007, and many are worried she may have died from her injuries.

When any whale dies, it’s not just a number in a catalog. Most of the people who have been studying right whales have been at it for 25 to 30 years. They know every whale by sight, from Admiral to Millipede to Zipper. “I’ve spent half my life studying this population,” says Knowlton. “You get to know their families and who’s related to who, and you see them in all these different activities.”

Every winter, during calving season, the researchers have a pool to try to guess how many calves will be born that year. For the past few years, the population has been increasing slowly. Nineteen calves were born last year. Researchers are hoping that the combination of slower boats and new fishing techniques will help this trend continue. “This past decade was the first decade of good news of three decades of doing this work,” says Hamilton. “It’s the first little bit of hope, frankly.”

But while the numbers are improving, it’s not quite time to let the whales fend for themselves. “I don’t think we can celebrate yet,” says Knowlton. Ships are still striking and killing whales. Fishing gear is still entangling them. “I think we have to keep our guard up, stay very vigilant,” she says, “because if we drop our vigilance, then our population could still fail to survive.”

No comments: