Tag-based estimates of bottlenose dolphin swimming behavior and energetics

Abstract

Current estimates of marine mammal hydrodynamic forces tend to be made using camera-based kinematic data for a limited number of fluke strokes during a prescribed swimming task. In contrast, biologging tag data yield kinematic measurements from thousands of strokes, enabling new insights into swimming behavior and mechanics. However, there have been limited tag-based estimates of mechanical work and power. In this work, we investigated bottlenose dolphin (Tursiops truncatus) swimming behavior using tag-measured kinematics and a hydrodynamic model to estimate propulsive power, work and cost of transport. Movement data were collected from six animals during prescribed straight-line swimming trials to investigate swimming mechanics over a range of sustained speeds (1.9ā€“6.1 m sāˆ’1). Propulsive power ranged from 66 W to 3.8 kW over 282 total trials. During the lap trials, the dolphins swam at depths that mitigated wave drag, reducing overall drag throughout these mid- to high-speed tasks. Data were also collected from four individuals during undirected daytime (08:30ā€“18:00 h) swimming to examine how self-selected movement strategies are used to modulate energetic efficiency and effort. Overall, self-selected swimming speeds (individual means ranging from 1.0 to 1.96 m sāˆ’1) tended to minimize cost of transport, and were on the lower range of animal-preferred speeds reported in literature. The results indicate that these dolphins moderate propulsive effort and efficiency through a combination of speed and depth regulation. This work provides new insights into dolphin swimming behavior in both prescribed tasks and self-selected swimming, and presents a path forward for continuous estimates of mechanical work and power from wild animals.

Document Details

Document Type
Pub Defense Publication
Publication Date
Nov 15, 2022
Source ID
10.1242/jeb.244599

Entities

People

  • Ding Zhang
  • Joaquin Gabaldon
  • Julie M van der Hoop
  • Julie Rocho-levine
  • Kenneth Shorter
  • Kira Barton
  • Michael J Moore

Organizations

  • Fisheries and Oceans Canada
  • National Science Foundation
  • Office of Naval Research
  • The Marine Mammal Center
  • University of Michigan

Tags

Readers

  • Aerodynamics.
  • Circadian Sleep-Wake Regulation and Chronobiology
  • Marine Mammal Biology