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Tangled up in blue, fishing lines imperil northern right whale populations


9th April 2004

Fishing lines imperil northern right whale populations, but can rescue efforts save them?

By Amanda Onion

Somewhere off the north-eastern coast of the United States, a 10-ton mammal known as Kingfisher is swimming against time.

Researchers say a mess of fishing lines and buoys wrapped 20 to 30 times around the juvenile northern right whale's fins and tail are likely to dig into its skin as he grows. The cuts could then become infected and lead to a slow, painful death.

Entangled whales are a human-made problem. More than half of the known deaths of the endangered northern right whale each year are due to entanglement with lines that are dragged by fishing boats or by a collision with the boats themselves. Human efforts to save right whales from entanglement remain spotty and expensive.

When crews of experts tried to free Kingfisher this spring, rough seas prevented them staying close to the whale long enough to cut the lines free. They did manage to attach a radio buoy that tracked the yearling for 15 days and 840 miles as it swam north. But when Kingfisher swam under a fishing boat last Sunday, the buoy, which was attached to the lines on the animal, snapped off and ended up in the boat.

"Without any means of systematically finding this whale, every aspect of planning for another disentanglement attempt on Kingfisher has now changed," researchers reported from the Center for Coastal Studies in Provincetown, Mass.

History of failed rescue attempts

Unfortunately, the failed efforts to save Kingfisher are common when it comes to disentangling northern right whales.

In 1991, researchers spent more than $250,000 trying to rescue a northern right whale tangled in rope, but couldn't save it. Despite massive rescue efforts to rescue a right whale in 1999, the animal died as the polypropylene line that was wrapped around both flippers and around the body gradually burned through its skin, blubber and muscle. In 2001, multiple attempts to save a 50-ton right whale named Churchill cost more than $250,000 and didn't work.

The record is troublesome, particularly for the northern right whale. While populations of species like the fin and humpback whales remain fairly healthy, scientists believe there may be only 350 northern right whales left in the ocean. That means every individual whale, particularly females, are vital for preserving the species. And records show about 60 percent of the entire right whale population becomes entangled in fishing lines.

What makes northern right whales so difficult to help is also what makes them unique, their size and strength. The massive mammals, which grow as old as 70 years, range in size from 45 to 60 feet as adults and weigh 30 to 80 tons.

When an entangled whale is spotted (usually by a fisherman), an alert is sent to a network of private, state and federal agencies, including the Center for Coastal Studies, NOAA, and the National Fish and Wildlife Foundation, that are spread out along the U.S. and Canadian coasts. The closest team sets out toward the animal to determine if the whale can free itself.

If they decide it's necessary to try and free the whale, the teams use an old whaling method known as kegging to disentangle the whale. Kegging involves attaching large floats -- or kegs -- to the gear entangling the animal (whalers would attach them to the animal, itself, using a harpoon). The added weight creates drag and eventually slows the massive animal and prevents it from diving under. People in rafts then try and cut the lines off the whale, using specially designed tools that feature hooked blades at the end of long poles.

Northern right whales have proven to be more resistant to the drag of attached floats and so more difficult to free. In the attempt to save Churchill in 2001, scientists injected the animal with sedatives to further slow it down so they might cut the ropes free. But the method was considered risky and the team later lost Churchill's tracking signal and believe the whale died.

Success is possible

Teri Frady of the National Oceanic and Atmospheric Administration is quick to point out that there have been some successful tries to save entangled right whales.

"It is true that we have more experience and success with humpback whales," she said. "But we have disentangled right whales and the whales sometimes free themselves on their own."

Some have turned to technology to try and improve the success of rescue efforts. Michael Moore, a research specialist at the Woods Hole Oceanographic Institute in Woods Hole, Mass., developed a device that could remotely deliver sedatives to an entangled whale and another that could rest atop a wounded whale and deliver antibiotics over time. The hope is the medicines could prevent deadly infections from setting in.

But the projects haven't yet been funded or tested. One certain way to help save more right whales is changing fishing gear to prevent entanglements from happening in the first place.

Big marine mammals usually become entangled in fixed lines extending from fishing equipment like nets or lobster pots on the ocean bottom to floats or buoys on the surface. Some ideas researchers are trying to address the problem include using weak links in the anchoring line that will give way if a whale is ensnarled, or using special lines that decompose when exposed to the sun.

But these changes are slow in coming. Still, new funding may help. In February, Congress approved $685,000 for research into developing fishing gear that's less likely to snag the animals.

In the meantime, rescue efforts will continue. And while some may question the value of rescue efforts that often fail, Moore suggests we don't have a choice.

"We have an industry that is putting these animals into substantial chronic pain that ends in death," he said. "I have a hard time just walking away from that."