(S.M-WHOI / 04-10-09) Scientists successfully used a new sedative delivery system on a large whale in the wild. It calmed the 40-foot, 40,000-pound whale so that rescuers could approach safely by boat and cut away fishing gear wrapped around its head.

Over the past 10 years, Michael Moore, a biologist at Woods Hole Oceanographic Institution, has collaborated with the NOAA National Marine Fisheries Service and veterinary schools at the University of Florida and the University of Wisconsin to develop a sedation system to make it easier—on both whales and rescue teams— to extricate whales entangled dangerously in fishing lines.

Entanglement in commercial fishing gear can cause show, painful death, and it is a particular concern for endangered North Atlantic right whales. Fewer than 400 remain, and 70 percent of their population exhibits scars from fishing gear.

“The typical success rate for freeing right whales from fishing gear is about 50 percent, due largely to the difficulties in getting close enough to cut the entangling gear,” said Jamison Smith, NOAA’s East Coast project leader for whale disentanglement. “We hope this new technique can improve the overall safety of the operations, as well improve the chances of the whales’ survival.”

The new sedation delivery system, built by Trevor Austin of Paxarms New Zealand, comprises a 12-inch needle and a syringe that uses compressed air to inject drugs into whales’ muscles. The researchers had to calculate a dosage for large whales, based on experience sedating animals in captivity, starting at a low dose until they found a safe and effective level.

The entangled whale was first sighted off Georgia on Jan. 14, 2009, by an aerial survey team, which noted multiple lengths of heavy line cutting into the whale’s upper jaw and left lip and trailing behind the animal. The whale evaded all attempts by rescuers to cut the lines on Jan. 22. They tried again the next day, using a sedation dose, but the whale was not sedated enough to be more approachable. Another disentanglement attempt failed on Feb. 1.

On March 5, the disentanglement team tried again, increasing the dosage used on Jan. 23. The sedative appeared to cause the whale to take shallower, more frequent breaths, but the animal continued to evade the boat’s attempts to approach it. On March 6, the team increased the dose further. An hour after the sedatives were injected, the animal no longer evaded the boat and tolerated close approaches, allowing the team to remove 90 percent of the remaining rope. The whale has not been sighted since, Moore said, “so I don’t know the outcome of this case.”

Moore welcomed “this novel and exciting new tool in the large whale disentanglement toolbox.” But, he noted, “it does not address the underlying problem of how to enable fisheries to pursue a profitable business without jeopardizing the survival of endangered species such as the North Atlantic right whale.”