Blue whale (Balaenoptera musculus)

Stable isotope analysis in mysticete skin and baleen plates has been repeatedly used to assess diet and movement patterns. Accurate interpretation of isotope data depends on understanding isotopic incorporation rates for metabolically active tissues and growth rates for metabolically inert tissues. The aim of this research was to estimate isotopic incorporation rates in blue whale skin and baleen growth rates by using natural gradients in baseline isotope values between oceanic regions.

Characterization of multivariate time series of behaviour data from animal-borne sensors is challenging. Biologists require methods to objectively quantify baseline behaviour, and then assess behaviour changes in response to environmental stimuli. Here, we apply hidden Markov models (HMMs) to characterize blue whale movement and diving behaviour, identifying latent states corresponding to three main underlying behaviour states: shallow feeding, travelling, and deep feeding.

Baleen whales are gigantic obligate filter feeders that exploit aggregations of small-bodied prey in littoral, epipelagic, and mesopelagic ecosystems. At the extreme of maximum body size observed among mammals, baleen whales exhibit a unique combination of high overall energetic demands and low mass-specific metabolic rates. As a result, most baleen whale species have evolved filter-feeding mechanisms and foraging strategies that take advantage of seasonally abundant yet patchily and ephemerally distributed prey resources.

Blue whales in the eastern Pacific Ocean (EPO) migrate between habitats that exhibit contrasting baseline nitrogen (δ15N) and carbon (δ13C) isotope values. We hypothesized that blue whale tissues record these biogeochemical changes occurring at the base of the food webs, and thus provide insights into its foraging ecology and movement patterns. To test this we analyzed the δ15N and δ13C of blue whale skin biopsies (n=405) and baleen plates (n=4) collected in different regions across the EPO from 1980 to 2011.

Individual ID mark-recapture studies are critical to our understanding of marine mammals, yet gathering, processing and identifying individuals in images remains exceptionally labor and cost intensive.

Muscle serves a wide variety of mechanical functions during animal feeding and locomotion, but the performance of this tissue is limited by how far it can be extended. In rorqual whales, feeding and locomotion are integrated in a dynamic process called lunge feeding, where an enormous volume of prey-laden water is engulfed into a capacious ventral oropharyngeal cavity that is bounded superficially by skeletal muscle and ventral groove blubber (VGB).