[1] Duke Univ, Nicholas Sch Environm & Earth Sci, Levine Sci Res Ctr, Durham, NC 27708 USA
[2] Duke Univ, Marine Lab, Beaufort, NC 28516 USA
[3] Coastwise Consulting, Athens, GA 30601 USA
[4] New England Aquarium, Edgerton Res Lab, Boston, MA 02110 USA
[5] Oregon State Univ, Marine Mammal Inst, Newport, OR 97365 USA
[6] Woods Hole Oceanog Inst, Dept Biol, Woods Hole, MA 02543 USA
[7] Carnegie Inst Washington, Dept Global Ecol, Stanford, CA 94305 USA
[8] Duke Univ, Dept Biol, Durham, NC 27708 USA
[9] Duke Univ, Dept Stat Sci, Durham, NC 27708 USA