Two dead whales were discovered last month in Southeast Alaska waters near Hoonah’s Icy Strait. Scientists believe at least one died after being struck by a vessel.
On July 3, NOAA Fisheries received a report of a floating yearling humpback whale, which later washed ashore near Elfin Cove. Mandy Keogh is NOAA’s marine mammal stranding coordinator in Alaska. She says they worked with their stranding partners to respond and perform a necropsy, or an animal autopsy, on the whale.
“A few days later, and that investigation found evidence of blunt force trauma, so there was bruising, there was some broken bones, and those are all indicative of a large blunt force trauma, which would really only be a vessel strike in that area,” Keogh said. “So we have determined that the cause of death for that yearling was of likely a vessel strike.”
She says the broken bones were larger, which is consistent with the whale being struck by a larger vessel.
A second humpback whale was reported floating near Point Adolphus on July 22. The whale was identified as a 23-year-old female. While they found some bruising on the whale that may have suggested a vessel strike, due to the whale’s size and position they weren’t able to fully examine the bones to confirm the cause of death.
“We also confirmed in that autopsy or necropsy that she was actually pregnant at her time of death, and so we found fetal bones in her uterus, which was very sad to hear,” Keogh said. “This female hadn’t been seen with a calf before, that we know of. So it was also a hard finding because of that.”
Keogh says a large number of whales are active in the area and they’ve received a number of reported whale interactions from boaters. Cruise ships, ferries and fishing boats all frequent Icy Strait.
Keogh says the best thing boaters can do to prevent vessel strikes across Alaska’s waters is slow down.
“Just try and reduce your speed, especially if you’re in an area like Point Adolphus and Icy Strait area, where we know this summer we’ve had a lot of whales, to just slow down your boat speed,” he said. “That allows you more time to observe a whale in the area. It also may help the whale not be surprised by vessels moving into the area, so that’s the safest thing you can do, and it’s also safer for the vessel operator.”
Alaska’s humpback whale approach regulations require that vessels stay over 100 yards away from humpback whales, not disrupt whale activity and operate vessels at slow, safe speeds when near whales. Boaters can report all dead, injured or entangled marine mammals to NOAA’s 24-hour stranding hotline, 1-877-925-7773.