from Georges Bank
Teri Frady, NOAA
NMFS Northeast Fisheries Science Center
N E W S
Scientists Return with Samples from Georges Bank Dead Whales
Woods Hole, MA Working closely with Canadian counterparts, a U.S. team of marine mammal experts has returned from Georges Bank with samples taken from the carcasses of six dead whales. The whales are among those observed dead on Georges Bank between July 3 and July 30. It is hoped that the new data collected will help determine what caused these deaths.
The number of unique individuals and species documented as dead at sea between June 17 and July 30 has been estimated at 6-12 humpback whales, one pilot whale and one fin whale.
The sampling effort was organized by NOAA Fisheries, the federal agency charged with large whale protection and recovery. The U.S. agency worked closely with Canadian counterparts at the Department of Fisheries and Oceans who mounted a similar sighting and sampling effort. Carcasses have been sighted on both sides of the international boundary dividing waters on eastern Georges Bank between the two nations.
"When multiple mortalities occur, especially with an endangered species such as humpback whales, we need to know both what happened to individuals and how those removals will influence the population's recovery," said Dr. Teri Rowles, a marine veterinarian and chief of NOAA Fisheries' National Marine Mammal Health and Stranding Response Network. "These samples are extremely valuable, and may be our best chance at making those determinations," she said.
An international panel of experts established under the U.S. Marine Mammal Protection Act to advise the Federal government on marine mammal health concerns has determined that the situation meets criteria for an "unusual mortality event." This designation allows use of a contingency fund to further investigate the cause of the deaths, and makes it easier for the agency to call on a wider pool of experts for assistance. One critical sample yet to be collected is a freshly dead animal for a full shoreside examination. Should such an individual be sighted, it would have to be quickly retrieved and likely towed to land, requiring a powerful vessel.
On Wednesday, a U.S. whale response team aboard the U.S. Coast Guard cutter Tahoma and fishery officers aboard the Canadian Coast Guard vessel Sir William Alexander took a range of samples from four animals, and more limited samples from several others. Although most of the samples were taken from humpback whales, a single pilot whale that was discovered floating dead in the area was also sampled. At least two more large whale carcasses have since been sighted in Canadian waters by aerial survey. Samples obtained from these will be analyzed in Canada.
On Wednesday night, the Tahoma rendezvoused with the Canadian vessel to retrieve samples before returning to shore. The samples will be examined for biotoxins, or other findings relevant to determining the cause of death or the identity of individual animals. Data and samples collected include length estimates, sex determination, individual identifications, urine, feces, blubber, skin, and stomach contents.
Testing for a biotoxin produced naturally during harmful algal blooms (and known to have caused the deaths of at least 14 humpback whales during the fall and winter of 1986-87) will occur at NOAA's National Ocean Service Marine Biotoxin Laboratory in Charleston, S.C., and perhaps at the Woods Hole Oceanographic Institution. These results may be available by next week. Work will continue for the next few days to process other samples, debrief the scientific team, and attempt to identify the individual humpback whales observed dead at sea.
There are other potential sources of new information. Canadian fishermen working in the area have provided samples from their catch. U.S. fishery observers aboard fishing vessels on eastern Georges Bank have been asked to retain samples of fish preyed upon by humpback whales. The NOAA Ship Delaware II will be in the area beginning next week, as part of its previously scheduled humpback whale research cruise. The Center for Coastal Studies, a marine research organization based in Provincetown, Mass., will also be conducting a whale research project off Cape Cod and will alert NOAA Fisheries of any additional dead whales discovered.
Mariners in the region who encounter dead whales or dolphins at sea should note as much information as they can about the carcass and its location, and notify the U.S. Coast Guard or NOAA Fisheries Northeast Region's Marine Mammal Stranding Network.