Metabolic trade-offs in tropical and subtropical marine mammals: unique maintenance and locomotion costs in West Indian manatees and Hawaiian monk seals
Abstract
Unlike the majority of marine mammal species, Hawaiian monk seals (Neomonachus schauinslandi) and West Indian manatees (Trichechus manatus latirostris) reside exclusively in tropical or subtropical waters. Although potentially providing an energetic benefit through reduced maintenance and thermal costs, little is known about the cascading effects that may alter energy expenditure during activity, dive responses and overall energy budgets for these warm-water species. To examine this, we used open-flow respirometry to measure the energy expended during resting and swimming in both species. We found that the average resting metabolic rates (RMRs) for both the adult monk seal (753.8±26.1 kJ h−1, mean±s.e.m.) and manatees (887.7±19.5 kJ h−1) were lower than predicted for cold-water marine mammal species of similar body mass. Despite these relatively low RMRs, both total cost per stroke and total cost of transport (COTTOT) during submerged swimming were similar to predictions for comparably sized marine mammals (adult monk seal: cost per stroke=5.0±0.2 J kg−1 stroke−1, COTTOT=1.7±0.1 J kg−1 m−1; manatees: cost per stroke=2.0±0.4 J kg−1 stroke−1, COTTOT=0.87±0.17 J kg−1 m−1). These lower maintenance costs result in less variability in adjustable metabolic costs that occur during submergence for warm-water species. However, these reduced maintenance costs do not appear to confer an advantage in overall energetic costs during activity, potentially limiting the capacity of warm-water species to respond to anthropogenic or environmental threats that require increased energy expenditure.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- Aug 01, 2021
- Source ID
- 10.1242/jeb.237628
Entities
People
- Beau Richter
- Jason S. John
- Joseph C. Gaspard
- Katharine Boerner
- Laura Denum
- Nicole M Thometz
- Terrie M. Williams
- Traci L. Kendall
Organizations
- Mote Marine Laboratory
- National Oceanic and Atmospheric Administration
- Office of Naval Research
- Pittsburgh Zoo & Aquarium
- Society for Integrative and Comparative Biology
- University of California, Santa Cruz
- University of San Francisco