Bellwethers of change: population modelling of North Pacific humpback whales from 2002 through 2021 reveals shift from recovery to climate response

• DOI: 10.1098/rsos.231462
• Publication Date: 2024-02-28T00:05:58Z
• Authors: Ted Cheeseman; Jay Barlow; Jo Marie Acebes; Katherina Audley; Lars Bejder; Caitlin Birdsall; Olga Solis Bracam...; Amanda L. Bradford; Josie Byington; John Calambokidis; Rachel Cartwright; Jen Cedarleaf; Andrea Jacqueline...; Jens Currie; Rouenne Camille D...; Joëlle De Weerdt; Nicole Doe; Thomas Doniol-Val...; Karina Dracott; Olga Filatova; Rachel Finn; Kiirsten R. Flynn; John Ford; Astrid Frisch-Jordán; Chris Gabriele; Beth Goodwin; Craig Hayslip; Jackie Hildering; Marie C. Hill; Jeff K. Jacobsen; M. Esther Jiménez...; Meagan Jones; Nozomi Kobayashi; Marc Lammers; Edward Lyman; Mark Malleson; Evgeny Mamaev; Pamela Martínez L...; Annie Masterman; Craig O. Matkin; Christie McMillan; Jeff Moore; John Moran; Janet L. Neilson; Hayley Newell; Haruna Okabe; Marilia Olio; Christian D. Orte...; Adam A. Pack; Daniel M. Palacios; Heidi Pearson; Ester Quintana-Rizzo; Raul Ramírez Barr...; Nicola Ransome; Hiram Rosales-Nan...; 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 Clapham
• Keywords: 0106 biological sciences; 570; Atmospheric Science; Period (music); Science; Population; 590; Abundance (ecology); Whale; marine heatwave; Ecology, Conservation and Global Change Biology; Whaling; Oceanography; Sociology; abundance estimation; carrying capacity; Marine ecosystem; Climate change; mark-recapture modelling; Fish Population Dynamics; Biology; Ecosystem; Demography; Global and Planetary Change; Ecology; Geography; Physics; Q; Geology; FOS: Earth and related environmental sciences; Acoustics; mark–recapture modelling; FOS: Sociology; Earth and Planetary Sciences; Humpback whale; climate change; Fishery; FOS: Biological sciences; Impacts of Climate Change on Marine Fisheries; Habitat Change; Environmental Science; Physical Sciences; Arctic Sea Ice Variability and Decline; Ecology and Conservation of Marine Mammals; environmental variables

For 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 Hawai‘i, 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.