High diving metabolic rate indicated by high-speed transit to depth in negatively buoyant long-finned pilot whales
High diving metabolic rate indicated by high-speed transit to depth in negatively buoyant long-finned pilot whales
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DOI：
10.1242/jeb.158287
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发表时间：
2017-10-15
影响因子：
2.8
通讯作者：
Miller, Patrick J. O.
中科院分区：
文献类型：
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作者：
Aoki, Kagari;Sato, Katsufumi;Miller, Patrick J. O.
为了最大限度地提高觅食时间的深度，潜水哺乳动物预计将使用最低成本的最佳速度在下降和上升过境，并尽量减少运输成本，实现中性浮力。在这里，我们为18头深潜长鳍领航鲸配备了多传感器数据记录器，并发现有迹象表明，它们的潜水策略与其他深潜齿鲸的成本更高有关。理论模型预测，最佳速度与（基础代谢率/阻力）（1/3）成比例，因此与体重（0.05）成比例。标记动物的通过速度（2.7 +/- 0.3 m s（-1））明显高于根据体重预测的最佳速度（1.4-1.7 m s（-1））。根据理论模型，这种选择的高运输速度，给出了类似的阻力系数（中位数，0.0035），在其他鲸目动物，表示更大的基础代谢成本在潜水过程中比其他鲸目动物。这可以解释它们深潜（最大深度444 +/- 85米）的持续时间相对较短（8.9 +/- 1.5分钟）的原因。流体动力学滑翔模型表明，与其他深潜齿鲸相比，其组织体密度为负浮力（1038.8 +/- 1.6 kg m（-3），+/- 95%可信区间，CI），潜水气体体积为34.6 +/- 0.6 ml kg（-1），+/- 95% CI）。高潜水代谢率和昂贵的负浮力意味着长鳍领航鲸的“花费更多，获得更多”策略，与其他深潜齿鲸不同，这限制了觅食期间的运动成本。我们还发现，净浮力影响的最佳速度：高过境速度逐渐下降，在上升过程中，由于气体膨胀的鲸鱼接近中性浮力。
To maximize foraging duration at depth, diving mammals are expected to use the lowest cost optimal speed during descent and ascent transit and to minimize the cost of transport by achieving neutral buoyancy. Here, we outfitted 18 deep-diving long-finned pilot whales with multi-sensor data loggers and found indications that their diving strategy is associated with higher costs than those of other deep-diving toothed whales. Theoretical models predict that optimal speed is proportional to (basal metabolic rate/drag)(1/3) and therefore to body mass(0.05). The transit speed of tagged animals (2.7 +/- 0.3 m s(-1)) was substantially higher than the optimal speed predicted from body mass (1.4-1.7 m s(-1)). According to the theoretical models, this choice of high transit speed, given a similar drag coefficient (median, 0.0035) to that in other cetaceans, indicated greater basal metabolic costs during diving than for other cetaceans. This could explain the comparatively short duration (8.9 +/- 1.5 min) of their deep dives (maximum depth, 444 +/- 85 m). Hydrodynamic gliding models indicated negative buoyancy of tissue body density (1038.8 +/- 1.6 kg m(-3), +/- 95% credible interval, CI) and similar diving gas volume (34.6 +/- 0.6 ml kg(-1), +/- 95% CI) to those in other deep-diving toothed whales. High diving metabolic rate and costly negative buoyancy imply a 'spend more, gain more' strategy of long-finned pilot whales, differing from that in other deep-diving toothed whales, which limits the costs of locomotion during foraging. We also found that net buoyancy affected the optimal speed: high transit speeds gradually decreased during ascent as the whales approached neutral buoyancy owing to gas expansion.