Dead whale in Lubec points to hike in mortalities
A juvenile humpback whale that washed ashore on the beach at Boot Cove in Lubec on April 17 had been dead for some time, so researchers have not been able to determine a cause of death. They may let the whale continue to decompose on the beach, since it is currently not near any human presence.
A juvenile humpback whale that washed ashore on the beach at Boot Cove in Lubec on April 17 had been dead for some time, so researchers have not been able to determine a cause of death. They may let the whale continue to decompose on the beach, since it is currently not near any human presence. Unlike right whales, humpback whales in the North Atlantic are not endangered, but the number of mortalities has increased during the past two years, with a significant jump in deaths caused by ship strikes, and scientists are studying the reasons for the elevated number.
According to Rosemary Seton, marine mammal stranding coordinator with the Allied Whale program at the College of the Atlantic, the female humpback at Boot Cove is between 25 and 28 feet long and was one or two years old. The week before the whale came ashore in Lubec it had been seen off the Wolves and also off Grand Manan. "It's hard to tell how long it's been dead," Seton says, and because it is decomposing it also is not possible to see evidence of the cause of death.
Seton and a number of College of the Atlantic students have been to the site twice, on April 18 and 23, to try to examine the whale. In addition, Dr. Gayle Kraus, a professor of marine ecology at the University of Maine at Machias, and her students collected some skin samples and also baleen sections from the front of the whale's mouth, and Seton is hoping they can either get a genetic match or determine the whale's lineage. Because of where the whale is located a full necropsy isn't possible, although Seton was able to determine the blubber thickness.
During her second visit on April 23, Seton found that the whale had moved to the south side of Boot Cove, on the beach at the Boot Cove Preserve. She says the plan is to let it decay there, since it is "well away from any house" and is in "a tough place to dislodge it." She adds that the whale is now in a location that is very difficult to access on foot. However, it could be dislodged during a storm, and then might make its way down the coast.
On April 18 the Department of Marine Resources took the precaution of closing the cove to bivalve shellfish harvesting, because of the risk of contamination from the decomposing whale, but Marine Patrol Sgt. Russell Wright of Lubec notes that because of all the rock ledge in the cove it is not used for clamming.
Seton comments, "Local folks have been absolutely terrific -- and patient." David and Juanita Pressley, who live near where the whale was initially found, allowed the teams onto their land, a local lobsterman took Seton over to see the whale after it moved over to the south side of the cove, and other help has been received from Anne McGhie of Cutler and the COA students and Dr. Kraus and her students.
Causes of deaths examined
Although it's unusual to see whales in this area in April, Seton says, "It's not unheard of for them to be up here." Humpbacks are now in the southern Gulf of Maine around Stellwagen Bank, just north of Cape Cod, and she notes that some juvenile whales may over-winter without going much farther south.
As for whale movement patterns, Seton says they are food driven, and she notes that changes in the patterns are seen over time. In order to better understand whale movements, researchers have been studying how their food supply has been shifting.
Since January 2016 the number of humpback whale mortalities along the East Coast of the U.S. has been elevated, according to NOAA Fisheries, and NOAA has declared the number of deaths an Unusual Mortality Event (UME). There were 26 strandings in 2016, 33 in 2017 and 10 already this year. Necropsies were conducted on about half of the whales, and of those about 50% had evidence of either a ship strike or entanglement in fishing gear. According to NOAA Fisheries, of the 20 cases examined during the period from 2016 through April 2017, 10 whales had evidence of blunt force trauma or pre-mortem propeller wounds indicative of vessel strike, which is over six times the 16-year average in the region. NOAA considers all vessels in high-traffic areas to be risks for whales and has placed ship speed reduction rules into effect at certain times for specific areas. A team of scientists is working to review the data collected about the mortalities and will determine potential additional measures to reduce the number of deaths.
Seton notes that, in addition, at least two humpbacks have died in Canadian waters this year -- the one now at Boot Cove and one in the Gulf of St. Lawrence. Also, a finback whale died recently off Cape Breton.
The North Atlantic humpback population is "robust," says Seton, noting that it numbers at least 11,000 or more. They have been taken off the Endangered Species List and "can more readily absorb deaths" than the North Atlantic right whale, which is endangered, with a population estimated at around only 450. Deaths of right whales along the east coasts of the U.S. and Canada since 2017 also have been declared an Unusual Mortality Event by NOAA Fisheries, with 12 dead stranded whales in Canada and five in the U.S. that year, along with five live whale entanglements in Canada.
Because of the unprecedented number of right whale deaths in the Gulf of St. Lawrence last year, in March Fisheries and Oceans Canada announced a number of measures to be put in place this year, including imposing mandatory speed restrictions for larger vessels; closing the snow crab fishery season earlier; introducing fisheries closures where right whales are observed; reducing the number of traps in part of the fishery; and lifting the temporary moratorium on right whale disentanglements. Fisheries and Oceans Canada will also be increasing its financial support for marine mammal response groups.