van der Hoop Julie M, Fahlman Andreas, Hurst Thomas, Rocho-Levine Julie, Shorter K Alex, Petrov Victor, Moore Michael J
Massachusetts Institute of Technology-Woods Hole Oceanographic Institution Joint Program in Oceanography/Applied Ocean Science and Engineering, 77 Massachusetts Avenue, Cambridge, MA 02139, USA Woods Hole Oceanographic Institution, 266 Woods Hole Road, Woods Hole, MA 02543, USA
Texas A&M University Corpus Christi, 6300 Ocean Drive, Corpus Christi, TX 78412, USA.
J Exp Biol. 2014 Dec 1;217(Pt 23):4229-36. doi: 10.1242/jeb.108225. Epub 2014 Oct 16.
Attaching bio-telemetry or -logging devices ('tags') to marine animals for research and monitoring adds drag to streamlined bodies, thus affecting posture, swimming gaits and energy balance. These costs have never been measured in free-swimming cetaceans. To examine the effect of drag from a tag on metabolic rate, cost of transport and swimming behavior, four captive male dolphins (Tursiops truncatus) were trained to swim a set course, either non-tagged (n=7) or fitted with a tag (DTAG2; n=12), and surface exclusively in a flow-through respirometer in which oxygen consumption VO₂ and carbon dioxide production (VO₂; ml kg(-1) min(-1)) rates were measured and respiratory exchange ratio (VO₂/resting VO₂) was calculated. Tags did not significantly affect individual mass-specific oxygen consumption, physical activity ratios (exercise /resting ), total or net cost of transport (COT; J m(-1) kg(-1)) or locomotor costs during swimming or two-minute recovery phases. However, individuals swam significantly slower when tagged (by ~11%; mean ± s.d., 3.31±0.35 m s(-1)) than when non-tagged (3.73±0.41 m s(-1)). A combined theoretical and computational fluid dynamics model estimating drag forces and power exertion during swimming suggests that drag loading and energy consumption are reduced at lower swimming speeds. Bottlenose dolphins in the specific swimming task in this experiment slowed to the point where the tag yielded no increases in drag or power, while showing no difference in metabolic parameters when instrumented with a DTAG2. These results, and our observations, suggest that animals modify their behavior to maintain metabolic output and energy expenditure when faced with tag-induced drag.
将生物遥测或记录设备（“标签”）附着在海洋动物身上用于研究和监测，会给流线型身体增加阻力，从而影响姿势、游泳步态和能量平衡。这些代价从未在自由游动的鲸类动物身上测量过。为了研究标签产生的阻力对代谢率、运输成本和游泳行为的影响，对4只圈养雄性宽吻海豚（瓶鼻海豚）进行训练，使其游固定路线，一组不佩戴标签（n = 7），另一组佩戴标签（DTAG2；n = 12），并仅在流通式呼吸仪中浮出水面，在该呼吸仪中测量氧气消耗量（VO₂）和二氧化碳产生率（VCO₂；毫升·千克⁻¹·分钟⁻¹），并计算呼吸交换率（VO₂/静息VO₂）。标签对个体特定质量的氧气消耗量、身体活动比率（运动/静息）、总运输成本或净运输成本（COT；焦耳·米⁻¹·千克⁻¹）或游泳及两分钟恢复阶段的运动成本均无显著影响。然而，佩戴标签时个体游泳速度显著减慢（约11%；平均值±标准差，3.31±0.35米·秒⁻¹），而未佩戴标签时为（3.73±0.41米·秒⁻¹）。一个结合理论和计算流体动力学的模型，估计游泳过程中的阻力和功率消耗，表明在较低游泳速度下阻力负荷和能量消耗会降低。在本实验的特定游泳任务中，宽吻海豚减慢到标签不会增加阻力或功率的程度，同时在佩戴DTAG2时代谢参数没有差异。这些结果以及我们的观察表明，动物在面对标签引起的阻力时会改变行为以维持代谢输出和能量消耗。
