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Cited by 86Marine animal studies overviewWildlife Ecology and ConservationMarine and fisheries research

Intra‐ and inter‐annual variation in gray whale body condition on a foraging ground

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Soledade Lemos, Leila, Burnett, Jonathan D., Chandler, Todd E., Sumich, James L., Torres, Leigh G.·2020·Ecosphere
DOI 10.1002/ecs2.3094
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Abstract

Abstract Baleen whales store energy gained on foraging grounds to support reproduction and other metabolic needs while fasting for long periods during migration. Whale body condition can be used to monitor foraging success, and thus better understand and anticipate individual‐ and population‐level trends in reproduction and survival. We assessed the body condition of eastern North Pacific gray whales ( Eschrichtius robustus ) on their foraging grounds along the Oregon coast, USA, from June to October of three consecutive years (2016–2018). We used drone photogrammetry and applied the body area index (BAI) to measure and compare whale body condition, which is a continuous, unitless metric similar to the body mass index in humans. A total of 289 drone flights were carried out over 106 photo‐identified whales, which were grouped into demographic units by sex, maturity, and female reproductive status. Calves and pregnant females displayed the highest BAIs, followed by resting females, mature males, and, finally, lactating females, reflecting the significant energetic demands on reproductive females. In all three years, gray whale body condition improved with the progression of feeding seasons, demonstrating the accumulation of body energy reserves on the foraging grounds. Yet, body condition was significantly better in 2016 than in 2017 and 2018 when overall body depletion was observed, indicating a difference in prey availability and/or quality between years. We analyzed local upwelling patterns between 2013 and 2018 as an oceanographic proxy for prey and determined significantly greater upwelling between 2013 and 2015 than low upwelling years between 2016 and 2018. We hypothesize that these upwelling patterns created ecosystem shifts in primary productivity and zooplankton prey of gray whales, causing carry‐over effects between foraging success and body condition in subsequent years. This study demonstrates the value of monitoring whale body condition to better understand temporal variation in foraging success, and potentially detect and describe the causes of anomalous changes in whale population health, such as the 2019 gray whale mortality event.

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  • The conclusions of Lemos et al. (2020) and Torres et al. (2022) are somewhat conflicting regarding environmental conditions for gray whales prior to 2017.

    “The conclusions of Lemos et al. (2020) and Torres et al. (2022) are somewhat conflicting, with the latter implying that environmental conditions (namely the marine heat wave) were worse for gray whales prior to 2017, whereas the former reported that upwelling conditions were better for whales in the same area in 2016 than 2017-18.”

    From Update on the status of gray whales since the 2020 Implementation Review (2024) · cites this paper as Lemos et al., 2020

    The Upwelling index section (page unavailable) reports that 2016 had the poorest upwelling conditions of 2016–2018, contrary to the claim that conditions were better in 2016. The discussion reports better whale body condition in 2016, but distinguishes that observation from upwelling conditions and suggests a delayed effect. This verdict concerns only the conclusion attributed to Lemos et al., not Torres et al. (LLM, conf=0.93)

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  • Lemos et al. (2020) found that body condition of Pacific Coast Feeding Group whales improved through the feeding season and was variable by year.

    “Like Akmajian et al. (2021), they found that body condition improved through the feeding season and was variable by year.”

    From Update on the status of gray whales since the 2020 Implementation Review (2024) · cites this paper as Lemos et al., 2020

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Research works printed but not linked: 36

  1. Acevedo-Whitehouse, K., and A. L. J. Duffus. 2009. Effects of environmental change on wildlife health. Philosophical Transactions of the Royal Society B: Biological Sciences 364:3429-3438.
  2. Angell, C. M. 2006. Body fat condition of free-ranging right whales, Eubalaena glacialis and Eubalaena aus- tralis. Dissertation. Boston University, Boston, Mas- sachusetts, USA.
  3. Bates, D., M. Maechler, B. Bolker, and S. Walker. 2015. Fitting linear mixed-effects models using lme4. Journal of Statistical Software 67:1-48.
  4. Benoit-Bird, K. J., and M. A. McManus. 2012. Bottom- up regulation of a pelagic community through spa- tial aggregations. Biology Letters 8:813-816.
  5. Best, P. B., and H. Ruther. 1992. Aerial photogramme- try of southern right whales, Eubalaena australis. Journal of Zoology 228:595-614.
  6. Bograd, S. J., I. Schroeder, N. Sarkar, X. Qiu, W. J. Sydeman, and F. B. Schwing. 2009. Phenology of coastal upwelling in the California Current. Geo- physical Research Letters 36:1-5.
  7. Bradford, A. L., D. W. Weller, A. E. Punt, Y. V. Ivash- chenko, A. M. Burdin, G. R. VanBlaricom, and R. L. Brownell. 2012. Leaner leviathans: body condition variation in a critically endangered whale popula- tion. Journal of Mammalogy 93:251-266.
  8. Calambokidis, J., et al. 2002. Abundance, range and movements of a feeding aggregation of gray whales (Eschrichtius robustus) from California to southeastern Alaska in 1998. Journal of Cetacean Research and Management 4:267-276.
  9. Calambokidis, J., J. L. Laake, and A. Klimek. 2012. Updated analysis of abundance and population structure of seasonal gray whales in the Pacific Northwest, 1998-2010. International Whaling Commission, Cambridge, UK.
  10. Christiansen, F., G. A. Vikingsson, M. H. Rasmussen, and D. Lusseau. 2013. Minke whales maximise energy storage on their feeding grounds. Journal of Experimental Biology 216:427-436.
  11. Darling, J. D. 1984. Gray whales off Vancouver Island, British Columbia. Pages 267-287 in M. L. Jones, S. L. Swartz, and S. Leatherwood, editors. The gray whale Eschrichtius robustus. Academic Press, Orlando, Florida, USA.
  12. Di Lorenzo, E., et al. 2008. North Pacific Gyre Oscilla- tion links ocean climate and ecosystem change. Geophysical Research Letters 35:1-6.
  13. Hammond, P. S., S. A. Mizroch, and G. P. Donovan. 1990. Individual recognition of cetaceans: use of photo-identification and other techniques to esti- mate population parameters. International Whal- ing Commission, Cambridge, UK.
  14. Harrison, X. A., J. D. Blount, R. Inger, D. R. Norris, and S. Bearhop. 2011. Carry-over effects as drivers of fitness differences in animals. Journal of Animal Ecology 80:4-18.
  15. Jones, M. L., and S. L. Swartz. 2002. Gray Whale, Eschrichtius robustus. Pages 524-536 In Encyclope- dia of marine mammals. Academic Press, San Diego, California, USA.
  16. Kasuya, T. 1995. Overview of cetacean life histories: an essay in their evolution. Pages 481-498 in A. S. Blix, L. Walløe and Ø. Ulltang, editors. Whales, seals, fish and man. Elsevier Science, Amsterdam, The Netherlands.
  17. Koopman, H. N. 1998. Topographical distribution of the blubber of harbor porpoises (Phocoena pho- coena). Journal of Mammalogy 79:260-270.
  18. Le Boeuf, B. J., H. P erez-Cort es, J. Urb an, B. R. Mate, and F. Ollervides. 2000. High gray whale mortality and low recruitment in 1999: potential causes and implications. Journal of Cetacean Research and Management 2:85-99.
  19. Leaper, R., J. Cooke, P. Trathan, K. Reid, V. Rowntree, and R. Payne. 2006. Global climate drives southern right whale (Eubalaena australis) population dynamics. Biology Letters 2:289-292.
  20. Lockyer, C. 1986. Body fat condition in northeast at antic Fin whales, Balaenoptera physalus, and its rela- tionship with reproduction and food resource. Canadian Journal of Fisheries and Aquatic Sciences 43:142-147.
  21. Lockyer, C. 1987a. Evaluation of the role of fat reserves in relation to the ecology of North Atlantic fin and sei whales. Pages 183-203 in A. C. Huntley, D. P. Costa, G. A. J. Worthy and M. A. Castellini, editors. Approaches to marine mammal energetics. Society for Marine Mammalogy, Lawrence, Kansas, USA.
  22. Lockyer, C. 2007. All creatures great and smaller: a study in cetacean life history energetics. Journal of the Marine Biological Association of the United Kingdom 87:1035-1045.
  23. Machovsky-Capuska, G. E., and D. Raubenheimer. 2020. The nutritional ecology of marine apex predators. Annual Review of Marine Science 12:361-387.
  24. Mooers, C. N. K., C. A. Collins, and R. L. Smith. 1976. The dynamic structure of the frontal zone in the coastal upwelling region off Oregon. Journal of Physical Oceanography 6:3-21.
  25. National Academies of Sciences, Engineering, and Medicine. 2017. Approaches to understanding the cumulative effects of stressors on marine mam- mals. The National Academies Press, Washington, D.C., USA.
  26. Newell, C. L., and T. J. Cowles. 2006. Unusual gray whale Eschrichtius robustus feeding in the summer of 2005 off the central Oregon Coast. Geophysical Research Letters 33:1-5.
  27. Perryman, W. L., and M. S. Lynn. 2002. Evaluation of nutritive condition and reproductive status of migrating gray whales (Eschrichtius robustus) based on analysis of photogrammetric data. Journal of Cetacean Research and Management 4:155-164.
  28. Peterson, W. T., J. L. Fisher, P. T. Strub, X. Du, C. Risien, J. Peterson, and C. T. Shaw. 2017. The pelagic ecosystem in the Northern California current off Oregon during the 2014-2016 warm anomalies within the context of the past 20 years. Journal of Geophysical Research: Oceans 122:7267-7290.
  29. Pettis, H. M., R. M. Rolland, P. K. Hamilton, S. Brault, A. R. Knowlton, and S. D. Kraus. 2004. Visual health assessment of North Atlantic right whales (Eubalaena glacialis) using photographs. Canadian Journal of Zoology 82:8-19.
  30. Rugh, D. J., R. C. Hobbs, J. A. Lerczak, and J. M. Brei- wick. 2005. Estimates of abundance of the eastern North Pacific stock of gray whales (Eschrichtius robustus) 1997-2002. Journal of Cetacean Research and Management 7:1-12.
  31. Sinclair, A. R. E., and C. J. Krebs. 2002. Complex numerical responses to top-down and bottom-up processes in vertebrate populations. Philosophical Transactions of the Royal Society of London. Series B: Biological Sciences 357:1221-1231.
  32. Smith, C. E., S. T. Sykora-Bodie, B. Bloodworth, S. M. Pack, T. R. Spradlin, and N. R. LeBoeuf. 2016. Assessment of known impacts of unmanned aerial systems (UAS) on marine mammals: data gaps and recommendations for researchers in the United States. Journal of Unmanned Vehicle Systems 4:1- 14.
  33. Thomas, V. G. 1990. Control of reproduction in animal species with high and low body fat reserves. Pages 27-41 in R. E. Frisch, editor. Adipose tissue and reproduction (Progress in reproductive biology and medicine). S. Karger, Basel, Switzerland.
  34. Tollefson, T. N., L. A. Shipley, W. L. Myers, D. H. Keis- ler, and N. Dasgupta. 2010. Influence of summer and autumn nutrition on body condition and reproduction in lactating mule deer. Journal of Wildlife Management 74:974-986.
  35. Williams, R., G. A. Vikingsson, A. Gislason, C. Lock- yer, L. New, L. Thomas, and P. S. Hammond. 2013. Evidence for density-dependent changes in body condition and pregnancy rate of North Atlantic fin whales over four decades of varying environmen- tal conditions. ICES Journal of Marine Science 70:1273-1280.
  36. Zimushko, V. V. 1969. Some data on the biology of gray whales. Pages 93-97 in V. A. Arseniev, B. A. Zenkovich, and K. K. Chapskii editors. Marine Mammals. Akademii Nauk, Moscow, Russia.

Cited by

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Authors
Soledade Lemos, L., Burnett, J. D., Chandler, T. E., Sumich, J. L., & Torres, L. G.
Affiliations
  • Geospatial Ecology of Marine Megafauna Lab Marine Mammal Institute, Fisheries and Wildlife Department Oregon State University Corvallis Oregon 97331 USA
  • Oregon State University (US)
ORCID
Venue
Ecosphere
Publisher
Wiley
Published
2020-04
Volume
11
Issue
4
ISSN
2150-8925 (ISSN-L)
DOI
10.1002/ecs2.3094
OpenAlex
W3019434476
Cited by
86
References
3
Citations by year
2026: 13 · 2025: 13 · 2024: 19 · 2023: 13 · 2022: 19 · 2021: 7 · 2020: 2
FWCI
5.44
Type
journal article
Language
en
Open access
Licence
Locations
  • Ecosphere (publishedVersion, cc-by)
  • DOAJ (DOAJ: Directory of Open Access Journals) (submittedVersion, cc-by-sa)
  • NOAA Institutional Repository (submittedVersion, cc-by)
Funders
  • Oregon Sea Grant, Oregon State University
  • National Oceanic and Atmospheric Administration
  • Conselho Nacional de Desenvolvimento Científico e Tecnológico
Topics
  • Physical Sciences › Environmental Science › Ecology › Marine animal studies overview
  • Physical Sciences › Environmental Science › Ecology › Wildlife Ecology and Conservation
  • Physical Sciences › Environmental Science › Global and Planetary Change › Marine and fisheries research
Keywords
gray whale, body condition, foraging success, energy reserves, UAV photogrammetry, reproductive status, upwelling, prey availability, residual effects, Oregon coast, Northeast Pacific, photo-identification

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