CHATHAM – The North Atlantic right whale found dead on Monomoy Island last week most likely drowned after being entangled in fishing gear, according to the National Oceanographic and Atmospheric Administration.
Scientists from the Yarmouth-based International Fund for Animal Welfare performed a necropsy on the whale Aug. 30 and documented 11 lesions, including several linear depressions and bruises that are consistent with entanglement in line. That was particularly evident around the right flipper, according to a press release.
The whale was “moderately decomposed,” parts of the carcass were missing and significant shark predation was evident, the agency said.
The whale was a 30-foot male about a year and a half old. It was probably one of five North Atlantic right whale calves born over the 2016-2017 season, according to the release.
The carcass was first seen floating off Martha's Vineyard on Aug. 27 and reported washed up on the eastern shore of Monomoy early Aug. 31. IFAW performed the necropsy in the water with a shark spotter nearby to ensure safety.
The young whale's death is the latest in an increase in right whale mortalities that NOAA has dubbed an “unusual mortality event.” In 2017, NOAA confirmed 17 North Atlantic right whale deaths, which represents about 4 percent of the species' population of around 450. This year there have been two confirmed right whale deaths. The population currently has only about 100 females of breeding age, and there are more females dying than males, according to the agency. Births have also been in decline; no new calves were spotted in calving grounds off Florida this year.
The “unusual mortality event” designation helps NOAA direct additional scientific and financial resources to investigate, understand and reduce the mortalities, working in partnership with the Marine Mammal Stranding network, Canada's Department of Fisheries and Oceans and other outside experts in the scientific and research communities.