title: Swimming and diving energetics in dolphins: a stroke-by-stroke analysis for predicting the cost of flight responses in wild odontocetes.
abstract: Exponential increases in hydrodynamic drag and physical exertion occur when swimmers move quickly through water, and underlie the preference for relatively slow routine speeds by marine mammals regardless of body size. Because of this and the need to balance limited oxygen stores when submerged, flight (escape) responses may be especially challenging for this group. To examine this, we used open-flow respirometry to measure the energetic cost of producing a swimming stroke during different levels of exercise in bottlenose dolphins (Tursiops truncatus). These data were then used to model the energetic cost of high-speed escape responses by other odontocetes ranging in mass from 42 to 2738 kg. The total cost per stroke during routine swimming by dolphins, 3.31±0.20 J kg-1stroke-1, was doubled during maximal aerobic performance. A comparative analysis of locomotor costs (LC; in J kg-1stroke-1), representing the cost of moving the flukes, revealed that LC during routine swimming increased with body mass (M) for odontocetes according to LC=1.46±0.0005M; a separate relationship described LC during high-speed stroking. Using these relationships, we found that continuous stroking coupled with reduced glide time in response to oceanic noise resulted in a 30.5% increase in metabolic rate in the beaked whale, a deep-diving odontocete considered especially sensitive to disturbance. By integrating energetics with swimming behavior and dive characteristics, this study demonstrates the physiological consequences of oceanic noise on diving mammals, and provides a powerful tool for predicting the biological significance of escape responses by cetaceans facing anthropogenic disturbances.
authors.affiliation: Center for Ocean Health, Long Marine Laboratory, University of California, Santa Cruz, 115 MacAlister Way, Santa Cruz, CA 95060, USA williams@biology.ucsc.edu.
authors.forename: Terrie M
authors.identifier: 0000-0001-8170-009X
authors.initials: TM
authors.lastname: Williams
authors.affiliation: Center for Ocean Health, Long Marine Laboratory, University of California, Santa Cruz, 115 MacAlister Way, Santa Cruz, CA 95060, USA.
authors.forename: Traci L
authors.initials: TL
authors.lastname: Kendall
authors.affiliation: Center for Ocean Health, Long Marine Laboratory, University of California, Santa Cruz, 115 MacAlister Way, Santa Cruz, CA 95060, USA.
authors.forename: Beau P
authors.initials: BP
authors.lastname: Richter
authors.affiliation: Center for Ocean Health, Long Marine Laboratory, University of California, Santa Cruz, 115 MacAlister Way, Santa Cruz, CA 95060, USA.
authors.forename: Courtney R
authors.initials: CR
authors.lastname: Ribeiro-French
authors.affiliation: Center for Ocean Health, Long Marine Laboratory, University of California, Santa Cruz, 115 MacAlister Way, Santa Cruz, CA 95060, USA.
authors.forename: Jason S
authors.initials: JS
authors.lastname: John
authors.affiliation: Epcot's The Seas, Walt Disney World Resorts™, Lake Buena Vista, FL 32830-1000, USA.
authors.forename: Kim L
authors.initials: KL
authors.lastname: Odell
authors.affiliation: Epcot's The Seas, Walt Disney World Resorts™, Lake Buena Vista, FL 32830-1000, USA.
authors.forename: Barbara A
authors.initials: BA
authors.lastname: Losch
authors.affiliation: Epcot's The Seas, Walt Disney World Resorts™, Lake Buena Vista, FL 32830-1000, USA.
authors.forename: David A
authors.initials: DA
authors.lastname: Feuerbach
authors.affiliation: Epcot's The Seas, Walt Disney World Resorts™, Lake Buena Vista, FL 32830-1000, USA.
authors.forename: M Andrew
authors.initials: MA
authors.lastname: Stamper
mesh_terms: D000818:Animals; D050681:Bottle-Nosed Dolphin / Q000502:physiology*; D004242:Diving; D004734:Energy Metabolism; D005260:Female; D008297:Male; D010100:Oxygen / Q000378:metabolism; D010101:Oxygen Consumption; D010805:Physical Conditioning, Animal; D013550:Swimming; D050685:Whale, Killer / Q000502:physiology*
chemical_list: D010100:Oxygen
keywords: Beaked whale; Diving; Dolphin; Energetics; Oceanic noise; Swimming