On behalf of my co-authors I am pleased to share two new papers that have recently been published on the behavioral ecology and anatomy of Antarctic minke whales and humpback whales.
Sympatry and resource partitioning between the largest krill consumers around the Antarctic Peninsula ABSTRACT: Understanding how closely related, sympatric species distribute themselves relative to their environment is critical to understanding ecosystem structure and function and predicting effects of environmental variation. The Antarctic Peninsula supports high densities of krill and krill consumers; however, the region is warming rapidly, with unknown consequences. Humpback whales Megaptera novaeangliae and Antarctic minke whales Balaenoptera bonaerensis are the largest krill consumers here, yet key data gaps remain about their distribution, behavior, and interactions and how these will be impacted by changing conditions. Using satellite telemetry and novel spatial point-process modeling techniques, we quantified habitat use of each species relative to dynamic environmental variables and determined overlap in core habitat areas during summer months when sea ice is at a minimum. We found that humpback whales ranged broadly over continental shelf waters, utilizing nearshore bays, while minke whales restricted their movements to sheltered bays and areas where ice is present. This presents a scenario where minke whale core habitat overlaps substantially with the broader home ranges of humpback whales. While there is no indication that prey is limiting in this ecosystem, increased overlap between these species may arise as climate-driven changes that affect the extent, timing, and duration of seasonal sea ice decrease the amount of preferred foraging habitat for minke whales while concurrently increasing it for humpback whales. Our results provide the first quantitative assessment of behaviorally based habitat use and sympatry between these 2 krill consumers and offers insight into the potential effects of a rapidly changing environment on the structure and function of a polar ecosystem. Ari S. Friedlaender, Trevor Joyce, David W. Johnston, Andrew J. Read, Douglas P. Nowacek, Jeremy A. Goldbogen, Nick Gales, John W. Durban This paper is provided with open access through Marine Ecology Progress Series and can be accessed at: https://doi.org/10.3354/meps13771 In-situ observations of the sensory hairs of Antarctic minke whales (Balaenoptera bonaerensis) Abstract The sense of touch in the largest marine mammals is poorly understood. While mysticetes possess specialized sensory hairs that are present through adulthood, descriptions of these structures are based almost entirely on examination of tissues in post-mortem individuals. Sensory hairs have rarely been observed and described in living whales. We photographed Antarctic minke whales Balaenoptera bonaerensis in the Western Antarctic Peninsula and used high-resolution images to describe the number, distribution, orientation, and relative size of sensory hairs in freely swimming individuals. Sensory hairs were well developed. They were distributed on the tip of the lower jaw, the margins of the upper and lower jaw, and near the blowhole. Far fewer hairs were observed than reported for other mysticete species, including the related species Balaenoptera acutorostrata. Placement and apparent stiffness of sensory hairs within living tissue combined with observations and images of moving whales suggest these structures aid in detecting air and ice interfaces, and possibly, the boundaries of submerged prey fields. Colleen Reichmuth <https://anatomypubs.onlinelibrary.wiley.com/action/doSearch?ContribAuthorStored=Reichmuth%2C+Colleen>, Caroline Casey <https://anatomypubs.onlinelibrary.wiley.com/action/doSearch?ContribAuthorStored=Casey%2C+Caroline>, Ari Friedlaender <https://anatomypubs.onlinelibrary.wiley.com/action/doSearch?ContribAuthorStored=Friedlaender%2C+Ari> The paper can be accessed through Anatomical Record at: https://doi.org/10.1002/ar.24720 <https://doi.org/10.1002/ar.24720> Thank you. Ari Friedlaender Ari S. Friedlaender, PhD (he/him/his) Associate Researcher, Institute of Marine Sciences Associate Adjunct Professor, Ocean Sciences & Ecology and Evolutionary Biology UC Santa Cruz 115 McAllister Way Santa Cruz, CA 95060 ari.friedlaen...@ucsc.edu https://btbel.pbsci.ucsc.edu/ http://www.caoceanalliance.org/
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