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Aloha to Alaska: looking back on a successful winter of fieldwork

Following successful winter sampling in 2019, Marine Mammal Research Program (MMRP) Director Dr. Lars Bejder and I were keen to hit the ground running in 2020 alongside our collaborators. The humpback whale bioenergetics project aims to quantify the energetic demands of humpback whales migrating between the Alaskan foraging grounds and Hawaiian breeding grounds (for more info, please see the project page). This project has expanded since our last winter season off Maui with strong collaboration at the core of project success. Our collaborators include the Alaska Whale Foundation (AWF), Pacific Whale Foundation (PWF), Dr. Kristi West (MMRP), University of Hawaii at Hilo (UH Hilo), Oceanwide Science Institute (OSI), Hawaiian Islands Humpback Whale Sanctuary, Goldbogen Lab at Stanford University’s Hopkins Marine Station, and the Friedlaender Lab at University of California, Santa Cruz.

Early January: early breeding season off Maui, Hawaii

Over the first two weeks of January, myself and Dr. Adam Pack of UH Hilo joined the PWF team led by Jens Currie and Stephanie Stack. Being early in the season, most whales were just arriving off Maui from their high latitude feeding grounds. To investigate whale health, our aim was to collect multiple data streams including UAS measurements, biopsy samples and photo-identification. By linking UAS measurements with biopsy samples, I will determine how UAS-derived body condition estimates correlate with fat cell analyses like adipocyte area and index. Dr. Pack will investigate possible links between body condition/body length and steroid hormones, with an emphasis on how these metrics influence success within male competition groups.

Unfortunately, our field efforts were hampered by relentless gusty conditions with only five boat days possible during the two-week trip. However, the team was able to transform the trip into a winner with 63 UAS flights and over 100 whales measured including 16 mother-calf pairs and 71 adults. Importantly, Dr. Pack obtained 33 biopsy samples to link with body condition measurements and fluke identification images.

Fig. 1: A mother and calf in clear, shallow water off Maui Nui, Hawaii. Photo: Martin van Aswegen

Late February: tagging and peak breeding period off Maui, Hawaii

February was a busy but exciting month, with the commencement of a new project aiming to quantify the nursing behavior of humpback whale calves on their Maui breeding grounds. This project is a collaboration between MMRP, the Goldbogen Lab at Stanford University’s Hopkins Marine Station, and the Friedlaender Lab at University of California, Santa Cruz. Non-invasive suction cup CATS tags were deployed over a ten day period, by Lars Bejder, Will Gough (Goldbogen Lab at Stanford University’s Hopkins Marine Station), Marc Lammers (Hawaiian Islands Humpback Whale Sanctuary & Oceanwide Science Institute), the team from PWF and myself. With a built-in camera, pressure sensors and accelerometers, these CATS tags allow us to quantify fine-scale movement and breathing patterns while quantifying the frequency and duration of important nursing bouts. These data will be linked to UAS-derived body measurements to better understand the needs of mothers and calves on these important breeding grounds. For the full blog and video of this tagging expedition, please click here. In addition to the seven tagged calves, we flew 54 UAS flights and obtained measurements of over 100 whales including 40 mother-calf pairs and 20 adults.

Fig. 2: Forming great friendships during fieldwork – MMRP Director Lars Bejder celebrating a successful tag retrieval with Pete and Art of Molokai Ocean Tours. Photo: Lars Bejder

Early March: meeting up with hungry whales off Sitka, Alaska

Following our tagging expedition, I traded my flip flops and board shorts for gumboots and cold weather gear and travelled to Sitka, southeast Alaska. Early March represented an important period to sample, given whales were beginning to return to their temperate feeding grounds following several months of fasting. Alongside Dr. Andy Szabo (AWF), we braved the chilly, snowy conditions to sample 30 adult and juvenile whales over 24 UAS flights. We were fortunate to sample some familiar ‘faces’, allowing for repeated measurements of individual whales since 2018.

Mid-March: late breeding season rush for data off Maui, Hawaii

Upon returning from Alaska, a phone call from our diligent PWF collaborators indicated there was a limited window of good weather off Maui with further periods of wind and rain to come. In light of this news, I packed away my cold weather clothes and headed to Maui. Given windy conditions had hampered our field efforts previously, we wanted to maximize our sample size as much as possible over the preceding three days of good weather. With early starts and late finishes, the team was able to conduct 65 UAS flights and sampling 161 whales including 52 mother-calf pairs and 57 adults. The decision to maximize those three sampling days ultimately proved critical, with the ever-evolving COVID-19 situation ending our winter sampling prematurely.

Fig. 3: The characteristic blow of a humpback whale hanging in the cool Alaskan air. Photo: Martin van Aswegen

What’s next: summer in southeast Alaska

Unfortunately our spring sampling in southeast Alaska was cancelled due to the COVID-19 pandemic. Fast forward to June and we (MMRP and AWF) are hoping to salvage what is left of our summer data collection plans in remote southeast Alaska. Importantly, this summer will provide an exciting opportunity to collect a third consecutive year of body condition data, with many well-known whales repeatedly measured throughout multiple feeding seasons and across multiple years. In addition to UAS-derived measurements, we will also continue collecting biopsy samples for adipocyte, stable isotopes and steroid hormone analyses.

Stay tuned for our next update from remote southeast Alaska!

All research activities were conducted in accordance with NOAA permits 21476, 14585, 19655 and 19703. UAS activities were conducted in compliance with FAA Part 107 regulations.

If you have any questions about this project, please contact:

Lars Bejder:

Martin van Aswegen:


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