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Dead whale in First State part of spike in humpback mortality along East Coast

Katie Peikes
Delaware Public Media
A photo of the dead whale at Port Mahon, taken Wednesday morning.

A whale that washed up at a Delaware port is the 42nd humpback whale death in the region over the last year, and federal officials want to know why there seems to be a growing trend.




Locals near Port Mahon spotted a dead whale floating in the water and called the sighting into the Marine Education Research and Rehabilitation Institute over the weekend. MERR executive director Suzanne Thurman said it appeared to be a juvenile humpback whale, but bad weather and how the carcass was stuck on the rocks prevented her from examining it thoroughly.


Thurman confirmed the whale to be a humpback Thursday evening, making Delaware's humpback whale death the 42nd.


“It’s common for whales to be up in the Delaware Bay and feeding,” Thurman said. “Local fishermen and others at Port Mahon often describe seeing whales out in the water and swimming.”


But although this is first humpback whale death in the state for 2017, this is the fourth humpback whale death in Delaware in a year-span, from 2016 to the present, which Thurman said is alarming. 


Delaware’s four humpback whale deaths are part of a larger trend along the east coast. The National Oceanic and Atmospheric Administration declared during a press call Thursday that the 41 humpback whale deaths in the last year stretch from Maine to North Carolina, and is an unusual amount. It’s roughly a 240 percent increase since 2000, when 12 humpback whales were found dead in the region. If confirmed, Delaware's humpback whale death will be the 42nd.


NOAA is calling the increase an “unusual mortality event” and declaring an investigation into the reason why whale mortalities are rising in the area is necessary.


Under the Marine Animal Protection Act, an unusual mortality event is declared when a significant number of a marine mammal population dies, calling for an urgent response. 


And scientists say they don’t know why all these whales are dying. Of the 41 dead whales, 20 have been examined. Ten seem to have been hit by ships. 


Gregory Silber, a coordinator of recovery activities for large whales with NOAA’s Office of Protected Resources, said ships of any size can harm these whales.


“Smaller vessels - they tend to be propeller strikes,” Silber said. “And then larger vessels, they appear to be in the form of blunt trauma - hemorrhaging or broken bones.”


Silber said humpback whales tend to follow their prey - one possible reason accounting for why they might get hit by a boat. But researchers don’t know enough about the  behavior in whales that would make them more susceptible to a ship strike, he said.


“Most large whales, when they’re feeding, they’re engaged in feeding and probably relatively oblivious to things around them, including large ships coming towards them,” Silber said.


Whales that have had interactions with a vessel often show evidence of blunt force trauma or propeller cuts, said Deborah Fauquier, a veterinary medical officer with NOAA Fisheries Office of Protected Resources.


“And those were all acute events, so they were the proximate cause of death,” she said. 


In Delaware, one of the humpback whale deaths in the last year is believed to have resulted from a ship strike. Another one was fisheries related. MERR does not know the two other causes, Thurman said. The strandings took place at the Port of Wilmington, Bethany Beach and The Point at Cape Henlopen.


And Thurman said she thinks it's helpful that NOAA officially declared an "unusual mortality event".


"We already had a good sense that this is a real spike in humpback whale mortality and when that starts to happen, that’s sort of a red flag that says 'I wonder if there’s something going on'," Thurman said.


NOAA has declared three other unusual mortality events, or UMEs in the past involving humpback whales on the east coast, Fauquier said. The last was in 2006, when the region saw 23 humpback whale mortalities. In 2005, a UME was declared involving humpbacks and other large whales, but humpback whale deaths reached only six during that year. NOAA also declared a UME in 2003, when 21 humpback whales died from Maine to North Carolina. 


The cause of those three UMEs was undetermined, Fauquier said. Depending on how the investigation proceeds, NOAA hopes to find out if the reason behind the rise in humpback whale mortalities is related to natural or human causes.


All humpback whales were listed as endangered in 1970, according to NOAA. Officials then announced in September 2016 that many of the endangered population segments had recovered enough, and their classification as endangered was removed. Four populations are still endangered and one is threatened.


Updated at 9:30 p.m. April 27 to include MERR confirmed the dead Delaware whale to be the 42nd humpback whale death and include their reaction to NOAA's announcement.

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