This paper is dedicated to Joshua Spillane who provided
excellent technical and logistical support during the
GLOBEC cruises. Additionally, he has been a great friend
over the years and he will be missed. This work would not have been possible without the technical and logistical
support provided by Raytheon Polar Services staff and the
Captain and crew of the R.V. Lawrence M. Gould. We
would also like to thank N. Gales, M. Hindell, S. Trumble,
J. Barnes, M. Gray, C. Kuhn, and S. Shaffer for valuable
field assistance. In addition, we would like to thank the
British Antarctic Survey and the winter-over staff at
Rothera Base for hosting us for a week. Comments from
Michael Castellini and one anonymous reviewer improved
this manuscript. This research was funded under NSF grants
#OPP-9981683 to D.P. Costa and D. Crocker and #OPP-
0003956 to J.M. Burns. B.I. McDonald was supported
under a NSF graduate fellowship. All animal handling
protocols were authorized under National Marine Fisheries
Service permit #87-1593 and approved by Institutional
Animal Care and Use committees at University of
California, Santa Cruz, and the University of Alaska,
Anchorage. This is US GLOBEC contribution number 511.