Fine-scale spatial differences in humpback whale diet composition near Kodiak, Alaska

Journal Article (Journal Article)

On the North Pacific feeding grounds, humpback whales (Megaptera novaeangliae) are recovering from commercial whaling at a rapid rate (6.8%). The potential effect that this recovery will have on trophic dynamics involving these predators is currently unknown. To better elucidate complex trophic dynamics, variability in diet composition of apex predators on their respective feeding grounds needs to be understood. Thus, we explored the diet composition of two defined subaggregations of humpback whales of the Kodiak Archipelago population (“North,” “South”) using stable carbon (δ13C) and nitrogen (δ15N) isotope ratios of humpback whale skin and regional prey samples in Bayesian dietary mixing models. Humpback whales in the “North” region consumed proportionally more fish, dominated by capelin (Mallotus villosus), whereas, whales in the “South” region consumed predominantly krill. The difference in diet composition appears to reflect regional differences in prey availability. Thus, regional variability in diet composition by humpback whales may have disproportionate impacts on prey resources of sympatric predators depending on available prey biomass. As a result, we suggest fine-scale studies of apex predator diets are needed to better model trophic dynamics with accuracy.

Full Text

Duke Authors

Cited Authors

  • Wright, DL; Witteveen, B; Wynne, K; Horstmann-Dehn, L

Published Date

  • July 1, 2016

Published In

Volume / Issue

  • 32 / 3

Start / End Page

  • 1099 - 1114

Electronic International Standard Serial Number (EISSN)

  • 1748-7692

International Standard Serial Number (ISSN)

  • 0824-0469

Digital Object Identifier (DOI)

  • 10.1111/mms.12311

Citation Source

  • Scopus