The National Oceanic and Atmospheric Administration (NOAA) has initiated a federal probe to investigate the unusually high number of dead humpback whales washing along the Atlantic coast, from Maine through North Carolina.
Due to these deaths, NOAA has declared an unusual mortality event (UME). The Marine Mammal Protection Act defines UME as "a stranding that is unexpected; involves a significant die-off of any marine mammal population, and demands immediate response."
"This begins the process of an investigation ... that could take months to years to complete," NOAA Stranding Coordinator Mendy Garron in a statement, as per Asbury Park Press. "It's a marked increase in the magnitude when compared with prior records."
A total of 41 dead humpback whales washed ashore since January 1, 2016. As of April 24, 2017, 15 dead whales were spotted along the Atlantic coast. This is higher than the 16-year average for the region from 2000 to 2015, which is 14 whales per year.
The investigators still don't know what causes UME. So far, NOAA can only identify whales that were killed by ship collision based on their injuries. Out of the 41 whales, 10 presented clear signs of injuries from vessel strike. Three of these whales were spotted in Virginia, three in New York, two in Delaware, one in Massachusetts and one in New Hampshire.
"Whales are big, but they are small compared to the size of the ships," explained Greg Silber, large whale recovery coordinator at NOAA Fisheries Office of Protected Resources, in a report from CNN. "Most operators are completely unaware they hit one, and we don't get a lot of calls because of it."
The Marine Mammal Protection Act's UME program was created in 1991. In the United States, there have been 63 formally recognized UME involving varieties of species. The last UME for humpback whales declared by NOAA was in 2006. Before that, two other UMEs were declared in 2005 and 2003.