کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
4396417 1618466 2010 8 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Dive response differs between shallow- and deep-diving Steller sea lions (Eumetopias jubatus)
موضوعات مرتبط
علوم زیستی و بیوفناوری علوم کشاورزی و بیولوژیک علوم آبزیان
پیش نمایش صفحه اول مقاله
Dive response differs between shallow- and deep-diving Steller sea lions (Eumetopias jubatus)
چکیده انگلیسی

Muscle exercise correlates with oxygen use, tissue perfusion and heart rate (fH) in terrestrial animals, but the relationship between these physiological processes is less clear in diving animals. We found the mean heart rate of Steller sea lions trained to voluntarily dive to depths up to 40 m dropped by 40% while diving, and noted that mean bradycardia was 9% greater during shallow (10 m) compared to deep (40 m) dives. Longer dives resulted in lower heart rates, but only when they were shallow; on the other hand, minimum instantaneous fH decreased consistently with dive duration. In general, instantaneous fH did not reflect activity over short timescales. Our data suggest that our sea lions invoked a different dive response depending on whether they dove to shallow or deep depths. During shallow (10 m) dives only, the correlation between activity and fH was indicative of vascular compromise between diving and exercise. However, during deep dives (40 m), there was no such correlation, suggesting that locomotory activity was uncoupled from dive bradycardia, which was possibly mediated by an absence of blood flow to active muscle. For both diving scenarios, surface fH correlated with dive activity, suggesting that some underwater locomotory costs were deferred to the post-dive surface interval. Ultimately, our data support the speculation that Steller sea lion locomotory muscles become hypoxic during diving, regardless of dive depth.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Journal of Experimental Marine Biology and Ecology - Volume 394, Issues 1–2, 30 October 2010, Pages 141–148
نویسندگان
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