1. National Research Council Postdoctoral Fellow for Marine Mammal and Turtle Division, Southwest Fisheries Science Center, National Marine Fisheries Service, National Oceanic and Atmospheric Administration, La Jolla Shores Drive, La Jolla, CA 92037, USA
2. Marine Mammal Institute, Department of Fisheries, Wildlife, and Conservation Sciences, Hatfield Marine Science Center, Oregon State University, Newport, OR 97365, USA
3. Marine Mammal and Turtle Division, Southwest Fisheries Science Center, National Marine Fisheries Service, National Oceanic and Atmospheric Administration, La Jolla Shores Drive, La Jolla, CA 92037, USA
4. Southall Environmental Associates, Inc., Soquel Dr., Aptos, CA 95003, USA
5. Marine Mammal Research Program, SR3, SeaLife Response, Rehabilitation and Research, S 216th St., Des Moines, WA 98198, USA
6. Anderson Cabot Center for Ocean Life, New England Aquarium, Boston, MA 02110, USA
7. Department of Biology, Woods Hole Oceanographic Institution, Woods Hole Rd., Woods Hole, MA 02543, USA