Combining Multiple Stable Isotope Methods Elucidates Diet, Trophic Position and Foraging Areas of Southern Ocean Humpback Whales Megaptera novaeangliae

aut.relation.journalMarine Ecology Progress Series
dc.contributor.authorBury, SJ
dc.contributor.authorPeters, KJ
dc.contributor.authorSabadel, AJM
dc.contributor.authorSt. John Glew, K
dc.contributor.authorTrueman, C
dc.contributor.authorWunder, MB
dc.contributor.authorCobain, MRD
dc.contributor.authorSchmitt, N
dc.contributor.authorDonnelly, D
dc.contributor.authorMagozzi, S
dc.contributor.authorOwen, K
dc.contributor.authorBrown, JCS
dc.contributor.authorEscobar-Flores, P
dc.contributor.authorConstantine, R
dc.contributor.authorO’Driscoll, RL
dc.contributor.authorDouble, M
dc.contributor.authorGales, N
dc.contributor.authorChilderhouse, S
dc.contributor.authorPinkerton, MH
dc.description.abstractSouthern Ocean humpback whales Megaptera novaeangliae are capital breeders, breeding in the warm tropics/subtropics in the winter and migrating to nutrient-rich Antarctic feeding grounds in the summer. The classic feeding model is for the species to fast while migrating and breeding, surviving on blubber energy stores. Whilst northern hemisphere humpback whales are generalists, southern hemisphere counterparts are perceived as krill specialists, but for many populations, uncertainties remain regarding their diet and preferred feeding locations. This study used bulk and compound-specific stable isotope analyses and isoscape-based feeding location assignments to assess the diet, trophic ecology and likely feeding areas of humpback whales sampled in the Ross Sea region and around the Balleny Islands. Sampled whales had a mixed diet of plankton, krill and fish, similar to the diet of northern hemisphere humpback whales. Proportions of fish consumed varied but were often high (2-60%), thus challenging the widely held paradigm of Southern Ocean humpback whales being exclusive krill feeders. These whales had lower 15N values and trophic position estimates than their northern hemisphere counterparts, likely due to lower Southern Ocean baseline 15N surface water values and a lower percentage consumption of fish, respectively. Most whales fed in the Ross Sea shelf/slope and Balleny Islands high-productivity regions, but some isotopically distinct whales (mostly males) fed at higher trophic levels either around the Balleny Islands and frontal upwelling areas to the north, or en route to Antarctica in temperate waters off southern Australia and New Zealand. These results support other observations of humpback whales feeding during migration, highlighting the species’ dietary plasticity, which may increase their foraging and breeding success and provide them with greater resilience to anthropogenically mediated ecological change. This study highlights the importance of combining in situ field data with regional-scale isoscapes to reliably assess trophic structure and animal feeding locations, and to better inform ecosystem conservation and management of marine protected areas.
dc.identifier.citationMarine Ecology Progress Series, ISSN: 0171-8630 (Print); 1616-1599 (Online), Inter-Research Science Center. doi: 10.3354/meps14532
dc.publisherInter-Research Science Center
dc.rights© The authors 2024. Open Access under Creative Commons by Attribution Licence. Use, distribution and reproduction are unrestricted. Authors and original publication must be credited.
dc.subject41 Environmental Sciences
dc.subject31 Biological Sciences
dc.subject3103 Ecology
dc.subject14 Life Below Water
dc.subject0405 Oceanography
dc.subject0602 Ecology
dc.subject0608 Zoology
dc.subjectMarine Biology & Hydrobiology
dc.subject3103 Ecology
dc.subject3109 Zoology
dc.subject4102 Ecological applications
dc.titleCombining Multiple Stable Isotope Methods Elucidates Diet, Trophic Position and Foraging Areas of Southern Ocean Humpback Whales Megaptera novaeangliae
dc.typeJournal Article
Original bundle
Now showing 1 - 3 of 3
Thumbnail Image
Bury et al._2024_Southern Ocean humpback whale trophic ecology.pdf
6.61 MB
Adobe Portable Document Format
Journal article
Thumbnail Image
1.92 MB
Adobe Portable Document Format
Supplement 1
Thumbnail Image
Suppl 2 table.pdf
590.38 KB
Adobe Portable Document Format
Supplement 2