A mystery beaked whale trifecta

(This post was originally published October 6, 2021. Posts have been manually reordered for more logical storytelling. To go to the next post in the sequence, click “Previous Post” at bottom.)

Maps of beaked whale distribution are usually filled with question marks — often more question marks than confirmed sighting locations. These are not small animals (imagine a dolphin that weighs as much as a Clydesdale horse), so what is the problem?

Beaked whales are incredibly difficult to see. They spend mere minutes at the surface and then can disappear for an hour or more. They typically occur in small groups. They become almost invisible in rough seas. And the diagnostic characteristic used to visually identify them to species — the location, size, and shape of teeth in the lower jaw — can only be used for males.

Imagine if we could detect them in any sea conditions and identify them to species just by listening for their distinctive echolocation signals. Our expedition has brought us one step closer to making that hope a reality.

On September 22, Annamaria was monitoring the sounds coming in from our hydrophone towed behind Pacific Storm. Software was translating the inaudible, ultrasonic signals into visual representations, and her computer screen showed a type of beaked whale signal she had never seen before. When, after just three minutes, the mystery whales stopped vocalizing, she knew they would soon be surfacing, so she directed the vessel toward where she thought they were. Despite high winds and heavy seas, making for poor sighting conditions, all aboard were called to join the search with the faint hope of finding the whales before their next dive. After 80 minutes of searching, the two whales found us! They repeatedly approached our research vessel during the next 40 minutes, allowing us to take thousands of photographs and video recordings!

Amazingly, despite these close looks, we were unable to identify them to species (once again highlighting how little we know about this group of whales)! But our expedition team does not give up easily. Standing on the bow with crossbow in hand, Bob took aim and fired a two foot-long, lightweight dart at one of the whales. It bounced off the back and landed in the water, floating with the definitive prize: a pencil eraser–sized piece of skin and blubber of our mystery whale caught in the dart tip! This biopsy sample held the key to this species identification in the DNA the tissue contained!

But the tension would not be relieved until that sample was safely aboard. Two oranges offered up by our cook were thrown to help us keep the floating dart in view while we retrieved our hydrophone (requiring 20 minutes of hand-hauling in heavy seas with the vessel in full stop as the dart and oranges slowly drifted farther and farther away). Pressure mounted as Yogi expertly maneuvered our vessel alongside the bobbing dart. Craig dipped a salmon net into the water and landed our prize on the deck as we all cheered. We had achieved a mystery beaked whale trifecta: acoustic recordings, photographs, and a biopsy sample!

Watch this space for the DNA results!

~Jay Barlow