rsos231462_si_001.pdf (57.65 kB)
Geographic stratification region boundaries as displayed in Figure 1 from Bellwethers of change: population modelling of North Pacific humpback whales from 2002 through 2021 reveals shift from recovery to climate response
journal contribution
posted on 2024-02-15, 05:37 authored by Ted Cheeseman, Jay Barlow, Jo Marie Acebes, Katherina Audley, Lars Bejder, Caitlin Birdsall, Olga Bracamontes, Amanda Bradford, Josie Byington, John Calambokidis, Rachel Cartwright, Jen Cedarleaf, Andrea Chavez, Jens Currie, Rouenne Camille De Castro, Joëlle De Weerdt, Nicole Doe, Thomas Doniol-Valcroze, Karina Dracott, Olga Filatova, Rachel Finn, Kiirsten Flynn, John Ford, Astrid Frisch-Jordán, Chris Gabriele, Beth Goodwin, Craig Hayslip, Jackie Hildering, Marie Hill, Jeff Jacobsen, M. Esther Jiménez-López, Meagan Jones, Kobayashi Nozomi, Marc Lammers, Edward Lyman, Mark Malleson, Evgeny Mamaev, Pamela Martínez Loustalot, Annie Masterman, Craig O. Matkin, Christie McMillan, Moore Jeff, John Moran, Janet L. Neilson, Hayley Newell, Haruna Okabe, Olio Marilia, Christian Ortega Ortiz, Adam Pack, Daniel Palacios, Heidi Pearson, Ester Quintana, Raul Ramírez Barragán, Nicola Ransome, Hiram Rosales-Nanduca, Fred Sharpe, Tasli Shaw, Ken Southerland, Stephanie Stack, Iain Staniland, Janice Straley, Andrew Szabo, Suzie Teerlink, Olga Titova, Jorge Urban-Ramirez, Martin van Aswegen, Marcel Vinicius, Olga von Ziegesar, Briana Witteveen, Janie Wray, Kymberly Yano, Igor Yegin, Denny Zwiefelhofer, Phil ClaphamFor the 40 years after the end of commercial whaling in 1976, humpback whale populations in the North Pacific Ocean exhibited a prolonged period of recovery. Using mark–recapture methods on the largest individual photo-identification dataset ever assembled for a cetacean, we estimated annual ocean-basin-wide abundance for the species from 2002 through 2021. Trends in annual estimates describe strong post-whaling era population recovery from 16 875 (± 5955) in 2002 to a peak abundance estimate of 33 488 (± 4455) in 2012. An apparent 20% decline from 2012 to 2021, 33 488 (± 4455) to 26 662 (± 4192), suggests the population abruptly reached carrying capacity due to loss of prey resources. This was particularly evident for humpback whales wintering in Hawaiʻi, where, by 2021, estimated abundance had declined by 34% from a peak in 2013, down to abundance levels previously seen in 2006, and contrasted to an absence of decline in Mainland Mexico breeding humpbacks. The strongest marine heatwave recorded globally to date during the 2014–2016 period appeared to have altered the course of species recovery, with enduring effects. Extending this time series will allow humpback whales to serve as an indicator species for the ecosystem in the face of a changing climate.
