A paper co-authored by Clark in the latest issue of the journal Science (July 22, 2005) urges emergency measures, such as reducing boat speeds, rerouting shipping lanes around the whales' migratory paths and modifying fishing techniques and gear.
Estimates indicate only 350 North Atlantic right whales remain, and deaths are exceeding births by less than 1 percent per year.
"We are not just at a precipice to extinction, in many ways we are actually over that precipice," said Clark, the I.P. Johnson Director of the Bioacoustics Research Program at Cornell.
North Atlantic right whales mostly live in heavily trafficked and fished coastal waters off the North American eastern seaboard, from Florida to Canada.
"There is really no place along the east coast of the United States free of humans, and shipping creates a lot of opportunities for whales to get hit," said Clark. "Swimming between ships and lobster pot lines, whales are constantly facing the gauntlets of traffic and snares. It's hard for a big animal like that to get through."
One thousand years of whaling brought the species close to extinction until the early 1900s when hunting bans were introduced. Nobody knows why the whales failed to rebound prior to the 1960s when shipping and fishing increased. Now, human influences have brought further declines in the whale's population.
In the last 16 months, scientists have recorded eight North Atlantic right whale deaths. Ships killed three, and one died after being tangled in fishing gear. Causes for the other deaths are unknown. Six of the dead whales were adult females. Four of these whales were just entering calf-bearing years, while three of them were actually carrying fetuses. Since females, on average, produce 5.25 calves in a lifetime, the researchers calculate that deaths of these females could represent a lost reproductive potential of as many as 21 animals.
Since 1986, 19 out of 50 reported dead right whales were killed by collisions with vessels, and at least six confirmed deaths were from fishing gear entanglements. There were also 61 confirmed cases of entangled whales dragging fishing gear, including the six confirmed entanglement deaths. Whales that become entangled over long periods of time lose weight and sink when they die; dead whales normally float. For this reason, there may be many more unreported deaths associated with fishing gear. Over the last 20 years, only 17 percent of deaths have been detected, the paper reports. If that detection rate has stayed constant, the authors suggest, then close to 47 right whales could have died in the last 16 months.
The Department of Commerce and the National Oceanic and Atmospheric Administration are promoting emergency measures that include reducing ship speeds and rerouting commercial and military traffic, Clark said.
"There is a collective effort to engage the shipping industry, which in some cases has agreed to change shipping lanes," said Clark. "But when economics get involved, it's more difficult for the industry to make changes just because of a large, black animal that's getting in the way."
The Bioacoustics Research Program at the Cornell Laboratory of Ornithology has deployed moored buoys fitted with underwater listening devices that automatically detect whales and relay the data back to Cornell. Soon the near to real-time data will appear on a Web site map. Since whales move slowly, a ship's captain approaching a whale migratory path will be able to check the Web site and avoid that area.
Both federal and state agencies are working with fishermen and engineers to create a rope that breaks at a tension point suitable for whales. The agencies will supply this rope free to fishermen and are instituting mandatory requirements for breakaway gear.
Efforts are also under way to reduce vertical lines from buoys on the surface to lobster pots on the sea floor by consolidating many pots on one line.