1. Woods Hole Oceanographic Institution, 45 Water Street, Woods Hole, MA 02543-1050, USA
2. Large Whale Biology Program, Northeast Fisheries Science Centre, 166 Water Street, Woods Hole, MA 02543, USA
3. Department of Mechanical Engineering, University of Colorado, Boulder, CO 80309, USA
4. Department of Biological Sciences, University of North Carolina at Wilmington, 601 South College Road, Wilmington, NC 28403-3297, USA