Behavioral impacts of disentanglement of a right whale under sedation and the energetic cost of entanglement |
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| Authors: | Julie van der Hoop Michael Moore Andreas Fahlman Alessandro Bocconcelli Clay George Katharine Jackson Carolyn Miller David Morin Thomas Pitchford Teri Rowles Jamison Smith Barb Zoodsma |
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| Affiliation: | 1. Biology Department, Woods Hole Oceanographic Institution, , Massachusetts, 02543 U.S.A;2. Life Sciences Department, Texas A&M Corpus Christi, , Corpus Christi, Texas, 78412 U.S.A;3. Marine Operations Department, Woods Hole Oceanographic Institution, , Woods Hole, Massachusetts, 02543 U.S.A;4. Georgia Department of Natural Resources, One Conservation Way, , Brunswick, Georgia, 31520 U.S.A;5. Florida Fish and Wildlife Conservation Commission, Fish and Wildlife Research Institute, , Florida, 33701 U.S.A;6. NOAA Fisheries, , Gloucester, Massachusetts, 01930‐2276 U.S.A;7. NOAA Fisheries, , Silver Spring, Maryland, 20910 U.S.A;8. NOAA Fisheries, , Fernandina Beach, Florida, 32034 U.S.A |
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| Abstract: | Protracted entanglement in fishing gear often leads to emaciation through reduced mobility and foraging ability, and energy budget depletion from the added drag of towing gear for months or years. We examined changes in kinematics of a tagged entangled North Atlantic right whale (Eg 3911), before, during, and after disentanglement on 15 January 2011. To calculate the additional drag forces and energetic demand associated with various gear configurations, we towed three sets of gear attached to a load‐cell tensiometer at multiple speeds. Tag analyses revealed significant increases in dive depth and duration; ascent, descent and fluke stroke rates; and decreases in root mean square fluke amplitude (a proxy for thrust) following disentanglement. Conservative drag coefficients while entangled in all gear configurations (mean ± SD Cd,e,go = 3.4 × 10?3 ± 0.0003, Cd,e,gb = 3.7 × 10?3 ± 0.0003, Cd,e,sl = 3.8 × 10?3 ± 0.0004) were significantly greater than in the nonentangled case (Cd,n = 3.2 × 10?3 ± 0.0003; P = 0.0156, 0.0312, 0.0078, respectively). Increases in total power input (including standard metabolism) over the nonentangled condition ranged from 1.6% to 120.9% for all gear configurations tested; locomotory power requirements increased 60.0%–164.6%. These results highlight significant alteration to swimming patterns, and the magnitude of energy depletion in a chronically entangled whale. |
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| Keywords: | disentanglement Dtag drag energetics entanglement sedation right whale
Eubalaena glacialis
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