WHALE TRUST MAUI

Conducting, Promoting and Supporting Whale Research and Education in Maui, Hawai‘i

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Autonomous (Robotic) Wave Glider Mission from Hawaii to Mexico Detects Humpback Whale Calls in Tropical Mid-Ocean and Questions Definition of Winter Breeding Assemblies

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Current NMFS humpback whale management policies assume Mexico and Hawaii winter assemblies are distinct with separate status and management warranted

BIG ISLAND, HAWAII – Jupiter Research Foundation and Whale Trust are pleased to announce the publication of the results of the first leg of their autonomous Wave Glider HUMPACS (Humpback Pacific Survey) acoustic survey in The Journal of the Acoustical Society of America – Express Letters. During a 100-day nearly 7,000 km (3,800 nm) round trip survey on a line between Hawaii and Mexico, during winter breeding season of 2018, humpback whale calls were heard in mid-ocean basin, halfway between the known near-shore assemblies. 

“They’re not ‘supposed’ to be there,” says Dr. Jim Darling, Whale Trust biologist and project partner. Humpbacks are known to assemble in specific near-shore, relatively shallow, breeding grounds in Mexico and Hawaii. “But then no one has looked in these more remote, offshore areas either.”

Mission control was from Puako, Hawaii where Beth Goodwin, Jupiter Research Foundation VP and HUMPACS Project Manager, and her team were in daily communication with the Wave Glider: monitoring status, downloading surface and underwater photographs, downloading short samples of recordings via satellite, and making course alterations if needed.

From January 16 to April 25, 2018, the Wave Glider, named Europa (after one of Jupiter’s moons), performed a 6,965.5 km, 100-day (RT) continual acoustic survey from Hawaii towards Mexico circa 20° N. The survey resulted in 2,272 hours of recordings and included over 4,000 cetacean calls.  Of these calls, 2,048 were identified as humpback whale calls.

The humpback calls were recorded up to 2,184 km (1179 nm) offshore spanning 30 days between January 20, when the Wave Glider left Hawaii, to February 23, 2018. On many days, multiple humpback call detections were recorded (up to 377 calls over 23 hours of a day). Actual numbers of whales cannot be determined, as one whale can make many calls.

“This was risky, we had no idea if humpbacks were even out there,” says Goodwin. “And then, even if they were, there were needle-in-haystack odds of intersecting them considering the size of the Wave Glider and the size of the ocean.”

Possible explanations, suggests Darling, include an undocumented migration route to Hawaii, a separate (from Hawaii and Mexico) offshore assembly of humpback whales, or travel between Mexico and Hawaii assemblies within the same season. At the very least, these results indicate an extension of winter distribution and habitat of humpbacks. It could also be that these offshore whales have not been included in current population estimates.

Since 2016, the model used by the U.S. National Marine Fisheries Service (NMFS) to manage humpback whale populations has treated the Mexico and Hawaii winter assemblies of humpback whales as distinct populations. As such, these populations have different status under the U.S. Endangered Species Act (ESA): Mexico humpback whales are considered threatened while Hawaii humpback whales have been delisted; that is, the Hawaii population has no protection under the ESA.

This assessment is further complicated by longstanding research showing shared song between the breeding assemblies and an interchange of photo-identified individual whales between these two winter breeding grounds.

Our findings question the independence of Mexico and Hawaii humpback whale populations and illustrate the huge potential for the use of autonomous vehicles in the study of whales across remote locations of the ocean.

“We feel certain our results will encourage more research, affect how humpback and other whales are monitored, and help with management,” says Goodwin.

The paper is online: https://doi.org/10.1121/1.5111970

BACKGROUND

Wave Glider

The Wave Glider (produced by Liquid Robotics, a Boeing Company) consists of a surfboard-sized surface platform (the float) tethered by an umbilical cable to a submerged glider (the sub) 8 m (26 ft.) below the surface. The float includes a command and control unit, three solar panels, an instrument package, surface and underwater cameras and communications systems. The sub is the propulsion unit, which transforms vertical wave movement into forward motion (https://www.liquid-robotics.com/wave-glider/how-it-works/). Time-lapse series of images from the two Europa cameras, surface and underwater, are accessible on the JRF blog:
http://jupiterfoundation.org/current/2018/5/22/f2l6bevguh177l21x42gi20pegicbv

About Jupiter Research Foundation

The Jupiter Research Foundation is a 501(c)(3) non-profit scientific research organization. Established in 2003, the Foundation is dedicated to conducting innovative scientific research and finding technological solutions to problems which are outside of mainstream science and technology. Our findings are shared with the public and academic community in hopes of better monitoring and understanding the natural world. Visit https://jupiterfoundation.org/ to learn more.

About Whale Trust

Whale Trust is a Maui-based 501(c)(3) non-profit organization whose mission is to promote, support and conduct scientific research on whales and the marine environment and broadly communicate the findings to the public. Whale Trust research programs focus on behavior, communication and social organization of whales. For more information, visit https://whaletrust.org/.

Mixing of Humpback Whale Populations Across the North Pacific

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FOR IMMEDIATE RELEASE:

Current NMFS humpback whale management policies assume four distinct populations in the North Pacific. Song studies suggest an alternate population model is warranted.

MAUI, HAWAII June 5, 2019 – Whale Trust researchers and international colleagues are pleased to announce the publication of a multi-year study involving song comparison between four locations spanning the North Pacific in Scientific Reports, an online open-access journal from the publishers of Nature. Shared song composition between humpback whales found in Philippines, Japan, Hawaii and Mexico in winter indicates ongoing mixing of ‘populations’ at some point during their annual cycles. Convergence of song over this three-year period recalls similar song transmission when humpback whales off east coast of Australia adopted a song from a western Australia population during a late 1990s’ study.

“Mixing may be the rule, not the exception and part of the biology of North Pacific humpback whales,” says project leader Dr. Jim Darling, who has spent his career studying humpback whale singers and their song.

Studies over at least 35 years (1977-2013) have shown humpback whales in these different winter assemblies have shared all, or portions of these ever-changing complex songs, as cited in a comparison included in this study. The common song across the North Pacific over the long-term indicates ocean-wide interaction and the composition’s fluid nature, annual variable mixing. While acoustic contact is necessary to song transmission, Darling cautions its mechanics, and the purpose of the song for the whales, are not fully understood.

For scientists, the song provides an acoustic identity, since each singer in a ‘population’ sings the same version of the ever-changing song. Singers, exclusively male, broadcast the song starting in fall, continuing through the winter migrations, and tapering off in spring before summer feeding. Recorded by hydrophone by teams of scientists across these four locations, the song’s composition was compared and analyzed by Darling.

“Song composition appears to reflect the recent interactions of populations of whales,” says Darling. Shared song suggests these populations may not be as independent of one another as outlined by management policies in effect. While Hawaiian humpbacks were delisted from endangered status in 2016, a reevaluation of their relationship with populations in Asia and Mexico may be warranted.

“Song should be considered when defining humpback whale populations across the North Pacific,” says Darling.

Currently, NOAA/NMFS (National Marine Fisheries Service) does not include song amongst the data determining populations.

“We may be making decisions around population management based on a model which doesn’t reflect humpback whale behavior in the North Pacific,” posits Darling.

The question must be posed, how can Mexico whales be ‘threatened’ and Asian whales “endangered” but Hawaii whales “warrant no protection” when it’s clear all three groups are integrated?

“We have been delighted to collaborate with Dr. Jo Marie Acebes in the Philippines, Manami Yamaguchi in Ogasawara, Japan, and Dr. Jorge Urbán and Oscar Frey in Baja and mainland Mexico,” says Whale Trust’s Executive Director, Dr. Meagan Jones. “This study would not have been possible without them. Thank you to all who supported this project and continue to support these independent studies across the Pacific.”

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BACKGROUND

CURRENT MANAGEMENT

The NOAA/NMFS (National Marine Fisheries Service) review of humpback whale populations that informed the decision to delist Hawaiian humpbacks from the endangered species list in 2016 divided the North Pacific population into four Distinct Population Segments and designations:

Central American – Endangered

Mexico – Threatened

Hawaii – No protection warranted

Western North Pacific – Endangered

For the sake of management, these groups are considered independent of one another. The conclusions were reached after a review of “genetic data, tagging and photographic-ID data, demographic information, geographic barriers, and stranding data.” Notably, songs were not considered in these deliberations. The songs suggest that, in fact, these populations are interactive − and potentially dependent on one another. The two views are so contradictory that implications to management going forward are significant.

The paper, published in Scientific Reports volume 9, can be viewed online and is available for download at https://www.nature.com/articles/s41598-019-42233-7.

ABOUT WHALE TRUST:

Whale Trust is a Maui-based non-profit organization whose mission is to promote, support, and conduct scientific research on whales and the marine environment, and broadly communicate the findings to the public. Whale Trust research programs focus on behavior, communication and social organization of whales. Results from Whale Trust field research are the basis for a broader program of outreach and education that involves the public, educators and students. For more information, visit www.whaletrust.org.

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