A North Atlantic right whale found dead on the shore of Martha’s Vineyard in January died from “chronic entanglement,” according to a final determination by the National Oceanic and Atmospheric Administration Fisheries, released Wednesday.
After a necropsy performed on the Massachusetts island in February, NOAA Fisheries reported that rope was deeply embedded in the tail, the whale’s body was thin, and there was no evidence of blunt force trauma.
Purple markings on the rope indicated it came from trap/pot buoy lines used in Maine state water, the administration said.
The juvenile female right whale, identified by the number 5120 and the only known calf of a whale known as Squilla (3720), was born during the 2021 calving season.
Whale 5120 was first seen entangled on August 20, 2022, about 48 miles east of Shippagan, New Brunswick, with multiple wraps of line around her tail and flukes, two small buoys at the flukes, and roughly 200 feet of line trailing behind her, according to NOAA Fisheries.
“The entanglement was deemed serious because—at only 1 year old—the rope encircling her tail stock would likely tighten as she grew,” the administration said.
She was seen next in January 2023 in Cape Cod Bay where rescuers tried to disentangle her but were unsuccessful, in part because she was no longer trailing any fishing gear.
Her final live sighting was in June 2023, 60 miles northeast of Shippagan, New Brunswick, where she was feeding with other whales. The administration noted that her condition had declined and the wounds from the wraps of rope appeared to be more severe.
North Atlantic right whales are listed as an endangered species. NOAA Fisheries estimated that there were 356 individuals remaining in the population as of 2022.
Whale 5120 was added to the list of whales that have died in the ongoing Unusual Mortality Event, which started in 2017 and is determined to have resulted in 41 deaths, 37 serious injuries and 70 “sublethal” injuries or illnesses. The primary cause is entanglements in fishing gear and vessel strikes in U.S. and Canadian waters, according to NOAA Fisheries.
