New Humpback Whale Research Findings

By Jean Souza

Dr. Marc Lammers, Research Coordinator at the Hawaiian Islands Humpback Whale National Marine Sanctuary. Contributed photo

As the humpback whale breeding season for 2020-21 begins, here is a summary of new humpback whale research findings.

In October, the first humpback whales of the season were observed off Maui. They represent the first arrivals that, by the end of the season in May/June, may total up to 12,000 seasonally present humpback whales in Hawai‘i. It is estimated that approximately half of the humpback whales in the North Pacific Ocean come to Hawai‘i to breed, calve and nurse their young before migrating back to their feeding areas in northern latitudes. Hawai‘i has one of the largest seasonal gatherings of humpback whales on the planet and is the only state that is their breeding grounds.

Dr. Marc Lammers, Research Coordinator at the Hawaiian Islands Humpback Whale National Marine Sanctuary, is deeply immersed in understanding these charismatic critters and their habitat in Hawai‘i. He is an expert in marine acoustics and specializes in the analysis of soundscapes to monitor biological trends in the marine habitat.

Lammers received his bachelor and doctoral degrees in zoology at the University of Hawai‘i, and is also an affiliate faculty member at UH Hawai‘i Institute of Marine Biology. He is also the co-founder and president of Oceanwide Science Institute. At the sanctuary, he leads research activities focused on understanding the population, ecology and behavior of Hawai‘i’s humpback whales.

Humpback whales are difficult subjects to study in the field because they spend about 90 percent of the time beneath the ocean surface. And when they are visible at the surface, most of us usually only see about 10 percent of their bodies, while the rest remains submerged.

However, humpback whales are ideally suited to be monitored acoustically because males sing. Using underwater acoustic recorders, they can be tracked for their arrival, peak populations, density, distribution and departures. New kinds of acoustic recorders are giving us improved insight into their lives, their habitat, and the impacts we may have on them.

Humpback whale. HIHWNMS/NMFS ESA Permit #782-1719

Lammers shares these highlights of new humpback whale findings especially through the use of acoustics and by studying the sounds the whales generate:

• Acoustic monitoring has expanded beyond the Maui Nui area through the SanctSound project in which buoys with recorders are deployed during the breeding season. The acoustic energy contributed by singing male humpback whales are recorded and help to confirm the numbers of whales throughout the season and the variations from season to season.

The acoustic energy levels corresponded with whale counts from several sources. Recorded acoustic levels have given us a better calculation of the reduced number of humpback whales in Hawai‘i during the 2015-2018 seasons, when even shore observers remarked about the reduced number of whale sightings.

Lammers indicates the acoustic levels at one of the sites off Maui recorded an estimated 46 percent reduction in whale presence between the 2014/2015 and 2017/2018 seasons. Similar reductions were reported in other locations, including Glacier Bay, Alaska.

The cause of reduced whale abundance was likely the 2013-2016 marine heat wave in the Northeast Pacific Ocean, combined with the El Nino and the Pacific Decadal Oscillation. These conditions caused changes in ocean circulation, disrupted the flow of nutrients, reduced productivity, and caused a collapse of the food chain that fish, seabirds and whales depend on.

Between 2015-2018, humpback whales were affected in various ways, as some of the whales that normally migrate to Hawaii to breed likely skipped the breeding migration and remained in their northern feeding grounds. Some whales may have also shifted their feeding grounds and used different winter breeding grounds as a result, such as off Mexico.

• Temporary suction cup tags equipped with magnetometers and accelerometers help to visually recreate the whale’s movements in three-dimension. This is especially helpful in understanding what they are doing beneath the ocean surface.
• Another type of temporary suction cup tag equipped with video cameras is being used to study mothers and calves, including nursing behavior. Video of nursing calves will allow the frequency and nursing pattern to be quantified. Disturbances of the mom and calf pairs will also be identified. The University of Hawai‘i, Stanford University and the University of California at Santa Cruz have been leading these efforts with support from the sanctuary staff.
• Another kind of acoustic buoy that was deployed off Maui last season in collaboration with Scripps Institution of Oceanography and Greenridge Sciences, Inc. can help determine sound direction for more accurate determination of the locations and numbers of singing whales in an area.
• An autonomous surface vehicle known as the Wave Glider was outfitted with acoustic monitors. The Wave Glider is powered by the sun and waves and is controlled using a satellite link. During a two-month period last spring, the Wave Glider traveled more than 2,600 nautical miles from Puako on the Big Island to beyond Lisianski Island in the Northwestern Hawaiian Islands and back. The Wave Glider recorded sounds continuously as it visited the shoals, atolls and seamounts in the monument. The purpose of the project was to determine how widespread humpback whales are in the Papahanaumokuakea Marine National Monument and to identify hotspots of whale presence.

More than 92,400 one-minute recordings were made during the mission. The Wave Glider mission was a partnership between the Office of National Marine Sanctuaries and the Jupiter Research Foundation, based in Puakō, Big Island.

Humpback whales were heard throughout the Papahanaumokuakea Marine National Monument, high abundance of whale song was observed between Middle Bank and French Frigate Shoals, and also between Raita Bank and Lisianski Island.

• Another Wave Glider mission in 2018 traveling between in the eastern North Pacific and Hawai‘i recorded whale song in open waters between Mexico and Hawai‘ Could humpback whales visit more than one breeding area in the same season?

HappyWhale App

HappyWhale is an app used by researchers and others to digitally catalog whale fluke photos. Algorithms employing artificial intelligence are used to analyze the fluke patterns to aid in establishing a sighting record, life history, and migration patterns for individual whales.

Whale Song Documentary

In recent weeks, webinars and presentations by Lammers and others have been recorded and are available free for viewing. On Nov. 18, Lammers and Dr. Adam Pack of the University of Hawai‘i at Hilo participated in the screening of a Florida PBS Changing Seas documentary of humpback whale songs filmed in Hawai‘i. The live question and answer period was also recorded. The entire video can be viewed on the sanctuary’s Facebook page at www.facebook.com/watch/?v=821566305301898

Webinars

In coming weeks, recordings of Hawaii webinars on humpback whales will be posted on the National Marine Sanctuaries webinar archive at: sanctuaries.noaa.gov/education/teachers/webinar-series-archives.html

Visit hawaiihumpbackwhale.noaa.gov/ for more information about humpback whales.

• Jean Souza serves as the on-site manager of Kaua‘i Ocean Discovery at Kukui Grove Center and is a Program Specialist with the Hawaiian Islands Humpback Whale National Marine Sanctuary. She can be contacted at Jean.Souza@noaa.gov