AN ABSTRACT OF THE THESIS OF Stephen Vale Shabica for the degree of Doctor of Philosophy in Oceanography presented on 22 July 1976 Title: The Natural History of the Antarctic Limpet Patinigera Redacted for Privacy Abstract approved: I Professor Patinigera polaris is tie only large invertebrate commonly found in the littoral zone of Arthur Harbor, Anvers Island, Antarctica. From January 1970 through March 1971 the general ecology and physio- logical ecology of this large patellid limpet was studied. Patinigera polaris is found in the littoral zone at Palmer Station throughout the year during both high and low tides. The largest live limpet collected was slightly over 58 mm in length. The largest limpet shell found in the Arthur Harbor vicinity was 61 mm in length. Its population density is lower during the austral winter than during the austra]. summer. Patinigera polaris responds to the tide by moving with it up and down the littoral zone. By moving into crevices and cracks in the granitic littoral zone, P. polaris may be protected from thermal stress and the crushing effects of sea-borne ice. Littoral and upper-sublittoral limpets in exposed situations have thicker, more robust shells than do sublittoral limpets.The morphological variations in the shell of P. polaris may be due to the selective pressures of ice. The development of the thick shells appears to be in response to the environment in which the animal occurs rather than a strictly inherited trait. Respiration rates I or ni era polaris arehigh. For the median size class (21-35 mm) an oxygen consumption rate of22.2 l O/hr/g was determined. Patinigera polaris is a non-selective herbivore. Major predators of P. polaris include the Dominican Gull Larusdominicanus, and the Sheath Bill, Chionis alba, the asteroids Diplasteriasbrucel, Odontaster validus, and Perkuaster sp., and toa less extent, the fish Notothenia coriiceps, the echinoid Sterechinusneumayeri, and the pycnogcnids Colossendeis robusta, C. megalonyx andPentanymphon sp. Larus dominicanus appears to take the greatest numbersof limpets of all the identifiedpredators. Patinigera polaris exhibits a positive phototacticresponse which is augmented by very low water pressure gradientsor currents. The chemical oceanographic conditions of both littoralrock poois and surface water of Arthur Harbor showed very markedseasonal vari- ation in dissolved oxygen, pH, temperature, and salinity. These variations are related to intense seasonal primaryproduction, ices and fresh waterrun off The tides in Arthur Harborare of the mixed, dominant semi- diurnal type. The mean tide level is +0.73m above mean lower low water, The maximum range observed during 1970 was 1.89m. The minimum range of 0.02 m. The principal tidal harmonicconstants were determined for ArthurHarbor. During the austral winter, shore ice forms protectivebarriers between the fauna and flora of littoral rock pools andthe low air temperatures and crushing forces ofsea and swell transported ice. Littoral rock pools which occur below this ice foot are oftenlinked to the subtidal by ice-free corridors. These corridors allow fresh sea water to circulate in the poolson the return of the tide. Estimates of growth rates andabsolute growth were made by marking and releasing over 600 limpets from different depths.After almost a year, 31% were recaptured and remeasured. Up to a length of approxi- mately 25 mm, growth rates are relatively high (2-5 mmper year) and approximately linear. For larger individuals therate of growth declines sharply up to a length ofabout 38 mm. Individuals above 38 mm exhibited changes in length which were generally less thanthe accuracy of the vernier calipers. It is suggested that Patinigera polaris can live to be inexcess of 60 years old, Linpets 60 mm in length may be older than 100years. Reproductive maturity occurs atan age of four years and there is no upper age or size limiton fecundity. The parental stock of Patinigerapolaris is probably the southern South American limpet Nacellamytilina which has been found in deposits of the Eocene Age. The break-up of Gondawanalandin the vicinity of South America andAntarctica during the Late Cretaceous- Early Tertiary, and consequent interruption of gene flow ledto the separation of the N. j4jna population along theScotia Ridge region. Selection for species tolerantto the Antarctic environment probably contributed to the evolutionof Patinigera polaris. The most striking aspect, not onlyof the life history of Patinigera polaris, but also of its ecologyand physiology, is that this limpet is not greatly differentfrom limpet species inhabiting warmer climates. Patinigera polaris differs from those species intwo major aspects: its extremely slow growth rate and itsextended ion- gevity. The range of this species' tolerance to a variety ofthermal and osmotic stresses is similar to that of otherlimpet species throughout the world. The life history features of P. polarissuggest that it is a K-strategist associated with densitydependent population regulation. The Natural History of the Antarctic Limpet Patinigera polaris (Hombron andJacquinot) by Stephen Vale Shabica A THESIS submitted to Oregon State University in partial fulfillment of the requirements for the degree of Doctor of Philosophy completedAugust 1976 Commencement June 1977 APPROVED: Redacted for Privacy Profes44r Emeritus c4VOceanography J in charge bf major Redacted for Privacy Acting Deap{, Soo1 ofOceanography Redacted for Privacy Dean of the Graduate School Thesis presented 22 July 1976 Typed by Rebecca Rakish for Stephen Vale Shabica To my mother and father ACKNOWLEDGEMENTS I wish to thankthose individuals who helped duringthe field study and in thepreparation of this dissertation: Professor Joel W. Hedgpeth, my teacherand critic, Professor Arthur Boucot forsome valuable discussionsand use of his reprint collection,Dr. John Byrne for his advice,Professor P. Kilho Park for hisinterest and assistance, Dr. Saul Berkmanof the National Oceanic and AtmosphericAdministra- tion for thereduction of tide marigrams, the officersand crew of the Chilean shipPiloth Pardo, the officers andcrew of the U. S. Coast Guard CutterGlacier, the crew of the NSF ship R/VHero, Becky Rakish for deciphering and typing the first and finaldrafts, Judy Brenneman for typingthe last chapter one hour before itwas due at the Graduate School,Naomi Narvich for editorial assistance,Ronald Hill and DavidReinart for their assistance in thepreparation of the figures, Dr. MichaelNeushul for the identification ofalgae, Professor Harry Phinney andWendy Moore for identifications of algaeand diatoms, Dr. Larry Hunterand the Oregon State UniversityCcmputer Science Center for threegrants of computer time, Mr. DavidNiess for assis- tance in estimatingcomputing time, Kenneth Keeling andLouis Grothaus for programmingand computing assistance, WilliamStout and Michael Richardson (USARP),Paul Finnigan of the BritishAntarctic Survey, and WilliamCurtsinger of the National GeographicMagazine for diving assistance while inAntarctica, and Ehrenrich Photo-Optical Industries and Nikon Inc. forsurface and underwater photographic equipment. Special thanks toMichael Bergin of Marine AcousticalServices, Inc., without whose assistance many of these studies couldnot have been performed, and HarveyHigh, Jay Klinck, and Dennis Patton ofthe U. S. Navy Deep Freeze 1970 winter-over crew. I would also liketo thank Drs. ChristopherBayne, Andrew Carey, and Henry van Dyke ofmy disser- tation committee fora useful final exam. Financial and logistic support is acknowledged fromthe National Science Foundation (grant GA-18348) and the U.S. Naval Support Forces, Antarctica, duringthe field study. Finally, I am grateful to my wife, Dr. FrancisK. Shabica (n(e Korolenko) for key punching over 4000 computer cardsand for seven- tenths of the financial support which enabledme to complete this dissertation. TABLE OF CONTENTS I. INTRODUCTION 1 II. OCEANOGRAPHIC CONDITIONS, 1970-1971 9 III. THE TIDES 31 IV. SEA ICE, ANCHOR ICE, AND THE LITTORAL ZONE 36 V. PHYSICAL-CHEMICAL CHARACTERISTICS OF LITTORAL ROCK POOLS IN ARTHUR HARBOR, 1970-1971 49 VI. ACTIVITY PATTERNS OF PATINIGERA POLARIS INTHE LITTORAL ZONE 16 VII. SALINITY TOLERANCES OF PATINIGERA POLARIS 98 VIII. VOLUME REGULATION AND OSMOTIC BEHAVIOR OF PATINIGERA POLARIS 104 IX. DESICCATION 113 X. RESPONSES TO THERMAL STRESS BY PATINIGERAPOLARIS 117 Thermal Preferenda 117 Thermal Stress from High Temperature 127 Resistance to High Thermal Stress 139 Thermal Stress from Low Temperature 156 Resistance to Freezing 175 XI. COMPENSATION FOR TEMPERATURE IN PATINIGERAPOLARIS 180 XII. FEEDING BEHAVIOR OF PATINIGERA POLARIS 201 XIII. PREDATION PRESSURES ON PATINIGERA POLARIS 207 XIV. AVIAN FAUNA IN THE ARTHUR HARBOR VICINITY,1970-1971 222 XV. PHOTOTACTIC BEHAVIOR IN PATINIGERA POLARIS 227 XVI. GROWTH OF PATINIGERA POLARIS 237 XVII. THE GENERAL REPRODUCTIVE HABITS OF PATINIGERAPOLARIS 251 XVIII. THE DISTRIBUTION AND EVOLUTION OF PATINIGERAPOLARIS 253 XIX. SUMMARY 270 BIBLIOGRAPHY 276 LIST OF FIGURES Figure Page 1 Aerial photograph of Palmer Station andArthur Harbor showing study areas (to the southeast) inFebruary 1970. 8 2 Arthur Harbor, Antarctica. 10 3 Daily mean wind velocity anddirection at Palmer Station. Vertical lines indicate therange in wind velocity. Each date line refers to the middle of the month. 15 4 Mean weekly air temperaturesat Palmer Station. Each date line refers to the middle ofthe month. Vertical lines denote the range for thepreceding seven days. 16 S Sea ice cover