A young Hawaiian monk seal, one of the world's most endangered species, was killed by a boat's propeller -- the first such accident in at least 20 years, according to the National Oceanic and Atmospheric Administration.
The year-old male was found dead last week on a beach on the Hawaiian island of Kauai, local news station KHON2 reported.
"It is perplexing that this animal died this way because they're rather agile in the wild," David Schofield, NOAA's health and response coordinator, told the Honolulu Star-Advertiser.
A necropsy of the 150-pound seal, identified as RF22, revealed head trauma and evenly spaced slashes across the right side of its face.
“There were slices across the front of the muzzle headed toward the eye," Schofield told local news station KITV4. There was a "lot of blood," he said, "which is indicative of a propeller wound."
Although this wasn't the first time a monk seal has been seen with wounds from a boat propeller, it's the first time in NOAA's 20 years of tracking marine mammals that one has been killed by such wounds, according to Schofield.
Rachel Sprague, NOAA's Hawaiian monk seal recovery coordinator, told KHON2 that the death appears to be purely accidental, "but it is a good reminder that Hawaiian monk seals are wild animals and we can help keep them wild by not feeding them or giving them any interest to approach people."
Hawaiian monk seals are endemic to Hawaii and, according to the Marine Mammal Center, are the rarest seals within U.S. waters. The species is protected under the Endangered Species Act, Marine Mammal Protection Act and Hawaii state law.
In late 2014, NOAA estimated the Hawaiian monk seal population to be around 1,200.