A vessel strike was determined as the cause of death of a local humpback whale calf named Tango near Juneau in late August, according to National Marine Fisheries Service Alaska region officials on Thursday.
The conclusion followed a post-mortem exam that found “deep and large” lacerations on the body of Tango, a 2023-born calf of a well-known local humpback, Sasha, according to Suzie Teerlink, marine mammal specialist with NOAA Fisheries Alaska Region and Mandy Keogh, the Alaska region stranding coordinator.
The calf was originally discovered dead off the shore of Hump Island, a small island near Juneau, on Aug. 25. Preliminary examination showed some injuries on Tango’s body, but it was unclear at the time if Tango was involved in a strike and if that was the cause of its death.
“It looks as though there was an interaction with a large propeller,” Teerlink said in an interview Thursday.
Teerlink said during the exam, biologists and veterinarians found that one laceration went into its body cavity, and another nearly severed one of its pectoral fins.
Teerlink said Tango’s body had evidence of two or three other propeller scars, likely from smaller crafts, prior to the August strike. She said younger animals often partake in more human interaction, and the area in Juneau where the mom and calf spent most of their time is considered a “really high traffic area.”
“We see and have documented several forms of human interaction that weren’t lethal on lots of different animals,” she said. “These interactions, that we would consider sublethal, we can see them happening a lot more than is often thought to be happening. It does seem that during the short life of this animal there was a lot of vessel interaction.”
Keogh said in mid-September that NOAA’s Office of Law Enforcement was still investigating the death and strike. On Thursday she said it was unclear if the investigation was still ongoing in October.
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