Natural history of emperor penguins · project objectives. As part of our effort to specify the structural adaptations of antarctic fish tubulins, we employed reverse-phase high-performance

the MAPs of homeotherms. With respect to polymerization atcold temperatures, the major locus of adaptation appears tobe the tubulin dimer.

At Palmer Station we also made substantial progress in otherproject objectives. As part of our effort to specify the structuraladaptations of antarctic fish tubulins, we employed reverse-phase high-performance liquid chromatography to isolate pep-tides from chvmotryptic and cyanogen-bromide digests of thealpha and beta tubulins of N. coriiceps neglecta. The amino acidsequences of these peptides will be determined by automatedEdman degradation on a gas-liquid solid-phase protein se-quencer. In addition, we examined the assembly properties oftubulin purified from eggs of N. coriiceps neglecta. We also com-pared the domain structures of native brain tubulins from ant-arctic fishes and from the cow. The results of these studies arecurrently being analyzed.

To support our research, we obtained specimens of twonototheniids, N. coriiceps neglecta and N. gibberifrons, and oneice fish, Chaenocephalus aceratus, by bottom trawling from RIVPolar Duke near Low Island and in Dailman Bay near BrabantIsland. Additional specimens of N. coriiceps neglecta were caughtat Arthur Harbor by fishing with baited hook-and-line. Thefishes were transported to Palmer Station where they weremaintained in seawater aquaria at 0 to +2 °C.

Field studies were conducted at Palmer Station from midMarch to mid May 1990. I am deeply indebted to Sandra K.Parker and Marianne A. Farrington of Northeastern Univer-sity, to Silvio P. Marchese-Ragona of Pennsylvania State Uni-versity, and to Laurie B. Connell of the Massachusetts Instituteof Technology for their participation in the field research pro-

gram. I gratefully acknowledge the assistance provided to theproject by the captains and crews of RIV Polar Duke, by thepersonnel of ITT Antarctic Services, Inc., and of Antarctic Sup-port Associates, and by the scientists of Palmer Station. Thisresearch was supported by National Science Foundation grantDPP 86-14788.

References

Correia, J.J., and R.C. Williams, Jr.. 1983. Mechanisms of assemblyand disassembly of microtubules. Annual Review of Biophysics andBioengineering, 12, 211-235.

Detrich, H.W., III, K.A. Johnson, and S.P. Marchese-Ragona. 1989.Polymerization of antarctic fish tubulins at low temperatures: En-ergetic aspects. Biochemistry, 28(26), 10,085-10,093.

Detrich, H.W., III, B.W. Neighbors, R.D. Sloboda, and R.C. Williams,Jr. 1990. Microtubule-associated proteins from antarctic fishes. CellMotility and the Cytoskeleton, 17(3), 174-186.

Detrich, H.W., III, and S.A. Overton. 1986. Heterogeneity and struc-ture of brain tubulins from cold-adapted antarctic fishes: Compar-ison to brain tubulins from a temperate fish and a mammal. Journalof Biological Chemistry, 261(23), 10,922-10,930.

Detrich, H.W., III, V. Prasad, and R.F. Ludueña. 1987. Cold-stablemicrotubules from antarctic fishes contain unique alpha tubulins.Journal of Biological Chemistry, 262(17), 8,360-8,366.

DeWitt, H.H. 1971. Coastal and deep-water benthic fishes of the ant-arctic. In V.C. Bushnell (Ed.), Antarctic map folio series, (folio 15).New York: American Geographical Society.

Williams, R.C., Jr., J.J. Correia, and A.L. DeVries. 1985. Formation ofmicrotubules at low temperatures by tubulin from antarctic fish.Biochemistry, 24(11), 2,790-2,798.

Natural historyof emperor penguinsat Cape Washington

GERALD L. KOOYMAN, SCOTT E. ECKERT, and CARSTEN A.KOOYMAN

Physiological Research LaboratoryScripps Institution of Oceanography

University of CaliforniaLa Jolla, California 92093

MARKUS HORNING

Max-Planck-lnstitut fur VerhaltensphysiologieAbteilung Wickler

D-8131-Seewiesen, West Germany

The study at Cape Washington was a continuation of a pro-gram begun in 1986 (Kooyman and Croll 1987). It will continuethrough 1990 to obtain some measure of interannual variationin the breeding population, reproductive success, predationpressure, and ice conditions, to mention a few. In addition to

these major objectives, we also sought to determine foragingbehavior, fledging mass and time of fledging.

To conduct these studies, we established a remote camp atCape Washington which is 300 kilometers north of McMurdoStation. We were put in by LC-130 at Priestly Glacier, thenmen, machines, and science equipment were transferred toTerra Nova Bay by UHIN helicopters. The camp was estab-lished on 27 October. At this time and for the remainder ofthe season, there were six large icebergs trapped near the capein such a conformation that they protected the sea ice whichwas fast for 3 kilometers offshore from the cape.

Weather was monitored continuously with a Squirrel datalogger. Distribution of the birds was charted from the top ofthe cape. Group sizes and total colony size was done by aground count on 9 December. Mass determinations of chickswere obtained with a load-cell type of platform scale. Leopardseal predation behavior was assessed by many hours of ice-edge observations. Several aspects of foraging behavior weremonitored ranging from the general characteristics of cycleduration to the specifics of dive depths and duration. Cycledurations were determined from radio transmitters attachedto the birds. Dive behavior was recorded with attached mi-croprocessor units.

Similar to 1986, the weather was mild during the time ofour stay. The ice conditions showed no evidence of severewinter storms as they did in 1986. There were about the samenumber of groups, but the total chick count was larger by about

1990 REVIEW 219

2,000 birds from 1986 (Kooyman and Mullins 1990). There alsoseemed to be fewer dead chicks and fledging mass was greaterand the peak fledging date was earlier by about 1 week. Aboutthe same amount of leopard seal predation seemed to be oc-curring as in 1986.

Foraging cycle durations ranged from 3 days to about 14days during the month of November. About 12,000 dives wererecorded from 11 birds. Detailed analyses are in progress, butit appears that birds hunt through a considerable range of thewater column from near the surface to well below 400 meters.We have not determined yet whether there is a diurnal pattern.

This project was supported by the National Science Foun-dation grant DPP 87-15863. We thank Dave Bresnahan of PolarOperations who coordinated planning and execution of de-

ployment of the field camp. We appreciate the air support ofVXE-6, air and ship support of the Polar Star, and the ItalianAntarctic Program and New Zealand Helicopters for their sup-port while we were in the field.

References

Kooyman, CL., and D.A. Croll. 1987. Feeding patterns of emperorpenguins. Antarctic Journal of the U.S., 22(5), 221.

Kooyman, G.L., and J.L. Mullins. 1990. Emperor penguins breedingpopulations in the Ross Sea. In K.R. Kerry and C. Hempel (Eds.),Antarctic ecosystems, ecological change and conservation. Berlin and Hei-delberg: Springer-Verlag.

Demography andforaging behavior

of Pygoscelis penguins

W.Z. TRIVELPIECE, C. FRITZ, K.L. MONTGOMERY,S.C. TRIVELPIECE, and D.F. WALLACE

Point Reyes Bird ObservatoryStinson Beach, California 94970

We arrived in Admiralty Bay on 6 October 1989 and departedon 23 February 1990. Our field season encompassed two dis-crete research projects: a continued investigation of the pop-ulation demography of Adélie, gentoo, and chinstrap penguinsand a new study of the comparative foraging behaviors anddiving depths of these species.

Our demographic work included following the breeding cy-cle of all known-aged penguins from their arrival in Octoberuntil they departed or creched chicks in January or February.As predicted from our earlier work (Trivelpiece et al. 1990),the mild, light pack-ice winter of 1989 yielded low over-wintersurvival among the Adélie population. Furthermore, the num-ber of young Adélies that attempted to breed, a measure oftheir physiological fitness and the winter food resources avail-able to this species, was very low. Less than 5 percent of 3-year-old Adélies and 20 percent of 4-year-olds that returnedto the rookery in 1989 attempted to breed, compared to over20 percent and 50 percent of returning 3- and 4-year-old Chin-straps, respectively.

There were several indications that the summer food avail-able to the penguins may have been low, when compared toprevious seasons. The overall reproductive success for Adélieand chinstrap penguins was well below average, and the du-ration of incubation shifts following egg-laying was longer thanall preceding years except the 1982 season. The low percentageof pairs that successfully fledged two chicks also substantiatedthat food availability within the penguins' foraging range wasbelow average. Data from our foraging study may elucidatethis aspect of summer food resources when we analyze theforaging durations of transmitter-equipped penguins at a laterdate.

The telemetry study, our second area of emphasis in 1989,involved epoxying radio transmitters to the back feathers ofAdélie, gentoo, and chinstrap penguins feeding chicks be-tween mid-December 1989 and late January 1990. The foragingtrip durations of individual penguins were continuously re-corded for about 1 week using an automatic data logger. Fol-lowing this time, approximately one-half of the transmitter-equipped birds were recaptured, and time-depth recorders wereattached to their backs.

Penguins with a radio transmitter and a time-depth recorderwere then allowed to complete one more foraging trip. Uponreturning to the beach at the conclusion of this trip to sea, aprogrammable alarm alerted us to the return of our radio trans-mitter/time-depth recorder penguins, which were recapturedprior to their reaching their nest sites. These birds were stom-ach-pumped, the electronic equipment was removed, and theywere released unharmed. Concurrently, we recaptured andstomach-pumped penguins that had radio transmitters only.Additionally, we randomly captured other, unhandled pen-guins during these sampling periods and stomach-pumpedthem to serve as further controls.

Our foraging study results are largely unanalyzed at present;however, even a cursory look at the depth profile printoutshas confirmed our earlier hypotheses that the gentoo penguinis a much deeper diver than either congener. Furthermore, webelieve that the dive profiles may enable us to distinguishamong dives and assign functions to them such as commutingdives, searching dives, and feeding dives. Should this proveto be the case, we will be able to partition the foraging effortsof penguins into discrete behaviors and calculate detailed en-ergy budgets and prey capture rates for comparisons amongthe members of this important krill consuming genus.

Many thanks to the crew of the RIV Polar Duke and to theU.S. Antarctic Program for logistical support and to membersof the XIII and XIV Polish Expeditions for their hospitality andassistance. This research was supported by National ScienceFoundation grant DPP 88-15878.

Reference

Trivelpiece, W.Z., S.G. Trivelpiece, G.R. Geupel, J. Kjelmyr, and N.J.Volkman. 1990. Adélie and chinstrap penguins: Their potential asmonitors of the southern ocean marine ecosystem. In K. Kerry andG. Hempel (Eds.), Ecological change and the conservation of antarcticecosystems, (proceedings of the fifth SCAR symposium on AntarcticBiology). Berlin: Springer-Verlag.

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