[MARMAM] New paper on dive heart rate in harbor porpoises

Gitte McDonald gitte.mcdonald at gmail.com
Tue Jan 23 09:00:05 PST 2018

We are pleased to announce the publication of the following paper in the
current issue of Journal of Experimental Biology:

McDonald, BI, M Johnson, and PT  Madsen. 2018. Dive heart rate in harbour
porpoises is influenced by exercise and expectations. *Journal of
Experimental Biology* 221: jeb168740

URL: http://jeb.biologists.org/content/221/1/jeb168740


The dive response, a decrease in heart rate (*ƒ*H) and peripheral
vasoconstriction, is the key mechanism allowing breath-hold divers to
perform long duration dives. This pronounced cardiovascular response to
diving has been investigated intensely in pinnipeds, but comparatively
little is known for cetaceans, in particular in ecologically relevant
settings. Here we studied the dive *ƒ*H response in one the smallest
cetaceans, the harbour porpoise (*Phocoena phocoena*). We used a novel
multi-sensor data logger to record dive behaviour, *ƒ*H, ventilations and
feeding events in three trained porpoises, providing the first evaluation
of cetacean *ƒ*H regulation while performing a variety of natural
behaviours, including prey capture. We predicted that tagged harbour
porpoises would exhibit a decrease in *ƒ*H in all dives, but the degree of
bradycardia would be influenced by dive duration and activity, i.e., the
dive *ƒ*H response will be exercise modulated. In all dives, *ƒ*H decreased
compared to surface rates by at least 50% (mean maximum surface=173 beats
min−1, mean minimum dive=50 beats min−1); however, dive *ƒ*H was
approximately 10 beats min−1 higher in active dives due to a slower
decrease in *ƒ*H and more variable *ƒ*Hduring pursuit of prey. We show that
porpoises exhibit the typical breath-hold diver bradycardia during aerobic
dives and that the heart rate response is modulated by exercise and dive
duration; however, other variables such as expectations and individual
differences are equally important in determining diving heart rate.

Please email me (gmcdonald at mlml.calstate.edu) if you would like a PDF copy
of the paper.




Birgitte I. McDonald

Assistant professor

Moss Landing Marine Laboratories


gmcdonald at mlml.calstate.edu

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