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Island hopping: a three-month field season off Hawai’i Island

Updated: 6 days ago

Written by MMRP MSc student Lewis Evans



Why Hawai’i Island?

If you have been following MMRP’s blogs and research, you may know that we conduct annual three-month field seasons studying humpback whales (HBWs) in Hawai’i. The 2024 season represented the sixth consecutive year of the project that started in 2019. Our winter research spans from January – March when the North Pacific population of HBWs arrive from a ~3,000 mile migration from high-latitude feeding areas to the Hawaiian Islands to reproduce, give birth and raise their young. Our project is in close collaboration with the Alaska Whale Foundation with which we have established a strategic partnership – and also with the Pacific Whale Foundation.  Up until this season, we have been conducting our research in the Au’ Au’ channel in Maui Nui, where most whales reside during this time. However, in August 2023, Lahaina experienced ferocious fires that devastated the community, town, harbor and the surrounding areas. Due to the fires, we did not feel it was right to use dock space on Maui, where these spots could be used to help rebuild and allow for employment opportunities. However, we still needed to continue our long-term drone-photogrammetry and photo identification (photo-ID) database of HBWs to help us assess the challenges they face, such as entanglements, vessel strikes, climate change and shifting prey availability. 


After the devastating loss of Lahaina Harbor, we transitioned our fieldwork to the Kona coast of Hawai’i Island out of Honokohau Harbour (Figure 1).


Figure 1: The orange lines represent our 53 survey tracks for our 2024 Hawai'i Island field season


Why are we conducting this research?

For those who don’t know about our HBW project, we use drones, photo-ID, biopsy sampling and non-invasive biologging tags to quantify “how much energy it costs to be a humpback whale”. Using drones mounted with 4k cameras and laser altimeters, we gather beautiful and data-rich images (Figure 2: bottom right) from which we can extrapolate metrics of HWB body condition. We use these images to assess how much volume whales lose and how their condition varies across years and within a season. We capture pictures of their unique ventral flukes using photo-ID methods and upload them to HappyWhale to resight individuals (Figure 2: top right image). HappyWhale is a website where anyone can upload these images to help inform HBW movements and life histories - you should try it!


Figure 2: Left picture (Left to right): Caroline Smith on photo-ID, Abigael Jacka driving the research vessel, Fiona Strasser flying the drone. Top right picture: Ventral fluke image ready for upload to HappyWhale. Bottom right image: Drone image of mum and calf ready to be measured for volume, length and body condition estimates.


Quantifying each individual’s change in body condition over time allows us to assess how much energy they are using. To date, our efforts have mainly focused on mother-calf bio-energetics, using repeated drone measurements of individual whales between Hawai’i and Alaska. Fun fact: From this data, Martin van Aswegen has calculated that lactating females in Hawai’i lose the equivalent of ~3,000 malasadas per day! These data are imperative when assessing threats to HBWs such as climate change, vessel collisions and entanglements, all of which can adversely affect HBW body condition.


Recapping our sixth season: how did it go?

Before beginning our work off the Kona coast, we spent one week operating from Ma’alaea Harbor, Maui, in collaboration with the Pacific Whale Foundation. Despite weather and flash flooding that limited us to two days on the water, we collected over 65 individual measurements - a strong start to the season.


Next, we transitioned our season to Hawai’i Island, encountering the highest abundance of HBWs since 2010 (HMMC). During 53 field days, we measured over 800 whales and identified more than 400 individuals. Despite three weeks of sustained Kona winds and 9-10 ft swells (not the Lake Kona we expected!), the subsequent good weather allowed us to conduct our research safely and effectively. 


On typical field days, we headed north or south of Honokohau Harbor. We found the highest number of HBWs, including most mother calf pairs, north of the harbor between Kawaihae and Makako Bay. However, strong winds often shortened our research days up north. Heading south towards Kealakekua Bay, the water was typically calm, but the continental shelf drops to ~800 meters deep within a mile offshore. As mother calf pairs typically rest in shallower water, we encountered fewer whales, which were mostly traveling adults. 


One notable encounter was a HBW calf in Kealakekua Bay with propeller wounds, estimated to be ~22 days old. We counted 17 lacerations from the eye to the dorsal fin. Encounters like this always hit the team hard – we anxiously waited to hear of a resighting from anyone and feared the worst. Almost six weeks went by with no news, and we feared this individual’s injuries were too severe to recover from.  Remarkably, this calf was sighted just over six weeks later! To our delight, the scars were healing, and it was swimming effortlessly, giving us new hope for its survival. We hope to encounter this individual in the future to confirm a full recovery. Unfortunately, due to increasing vessel traffic - vessel strikes remain a significant threat to cetaceans worldwide.


Figure 3: The left image, taken by Fiona Strasser on 01/30/2024, shows propeller wounds on the right side of the calf. The right image shows an aerial perspective taken by Lewis Evans of the same calf.


A season of firsts!

This season marked several firsts for our project. It was our inaugural HBW season off the Kona coast. We were eager to compare whale abundance, demography, and habitat use in this region to those around Maui. It was also the first field season for our new research vessel (acquired through a grant from ONR’s Defense University Research Instrumentation Program) that I had the pleasure of operating (Figure 4). The custom-built pulpit (Figure 4; metal frame on the bow) allowed us to capture higher-quality photo-ID images, safely deploy the drone, and enhance our ability to spot animals. Incoming MMRP PhD student Fiona Strasser joined us for her first HBW field season and learned to fly the drone to collect photogrammetry data in Alaska in collaboration with the Alaska Whale Foundation. Welcome to the lab, Fiona! 


Figure 4: Our research crew (Left to right: Liah Mcpherson, Lewis Evans, Abigael Jacka, Fiona Strasser and Sarah Perryman) on our research vessel.


Additionally, it was the first time our new research vessel was used to place non-invasive suction cup tags on HBWs, marking Gussie’s first tag deployment! Check out Gussie’s blog for more on our tagging season and the data we collect.


This season also marked our first time collecting blow samples. Nelmarie Giovanetti of the University of Hawaii Health and Stranding Lab is studying the presence of cetacean morbillivirus in the Northern Pacific HBW population. Morbillivirus is a disease posing a significant threat to cetaceans due to its high mortality and infection rates. We tested a method to collect HBW blow samples, using a large pole and an acrylic plate to pass through HBW blow clouds, and we successfully collected five samples. We eagerly anticipate contributing to the development of this project in future field seasons, aiming to increase the sample size and gather more effective data.


Not the usual suspects!

In the rich marine environment of Kona, where the bathymetry plunges dramatically close to shore, we encountered many remarkable marine species not commonly seen in previous field seasons. Among these extraordinary sightings were deep-diving marine mammals capable of reaching depths of 2,000 meters! This diverse list included sperm whales, pilot whales, rough-toothed dolphins, spotted dolphins, spinner dolphins, false killer whales and the elusive Blainville’s beaked whales! Although I had read about these animals, observing them in their natural habitat was truly unforgettable. The Blainville’s beaked whales were especially remarkable. These animals are typically boat-shy and elusive. However, eight were at the surface for around four minutes during our encounter, unperturbed by our presence. After diving down for seven minutes, they resurfaced right next to us for a second pass! It is unlikely we will have such an experience again. We were fortunate to capture photo-ID of this brief yet extraordinary encounter. See below for some images of this encounter. In addition, we had an incredible encounter with a group of sperm whales that Gussie has described in her blog.


Figure 5: Pictures captured from our unforgettable Blainville's beaked whale encounter. This individual was likely the male due to his coloration and his tusks protruding from his mouth. Pictures captured by Sarah Perryman.


One of the season's standout moments (excluding humpbacks - obviously!) was observing a pod of over ~25 pilot whales accompanied by three oceanic white-tip sharks and a rough-toothed dolphin. Witnessing pilot whales take breaks in between diving periods to rest and socialize was a first for me. They surrounded our boat, engaging in social behaviors such as spy hopping. While managing data collection in such a large and diverse group was challenging, the experience was truly incredible! Check out the short video below, showcasing the encounter!



Acknowledgments

We want to acknowledge the significance of koholā (humpback whale) and palaoa (sperm whale) within Hawaiian culture as ʻaumākua and manifestations of Kanaloa. We use minimally invasive techniques and undergo a rigorous permitting process to interact with whales. We are very grateful to be able to study them and contribute to their conservation and protection. 


We are grateful for the cooperative nature and support from the Hawai’i Island community. Tour companies like Captain Zodiac and Hawaiian Adventures directed us to humpbacks, facilitating our research. A big mahalo to Colin Cornforth of Captain Zodiac for going above and beyond to lend a helping hand whenever needed, including retrieving our tag 60 miles offshore. We would also like to thank the knowledgeable and passionate Hawai’i Marine Mammal Consortium for their invaluable support and expertise, which has been drawn from many years of experience studying the area. Additionally, we would like to thank the residents of Kukio for their continued interest and support of our research.


This project would not be possible without the help of many passionate and hardworking people. For their hard work, generosity and passion we would like to thank the following: Jens Currie, Stephanie Stack, Shannon Barber, Florence Sullivan, Grace Olson, Brian Sterling, Fiona Strasser, Abigael Jacka, Caroline Smith, Camron Nemeth, Sarah Perryman, Ella Samaha, Liah McPherson, Noah Harris, Elizabeth Beato, Martin van Aswegen, Kyleigh Fertitta, Suzanne Yin, Chris Gabriele, Adam Frankel, Susan Rickards, Colin Cornforth, Jason Laferty, Hawaii Kona Adventures, Judith Cunningham, Karen Harper, Steph Vlachos, Robin Baird, Sabre Mahaffy, Ed Lyman and Ted Cheesman. 


We would also like to thank all our funders who made this year possible. Mahalo to the Marine Mammal Commission, United States Pacific FLEET, Dolphin Quest, and NOAA. All research was conducted under NOAA permit 21476 and IACUC approvals.


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