My research interests focus on the links between ecology, morphology, and physiological adaptation of marine vertebrates. In particular, I am interested to know how animals use and allocate energy for various activities and how the environment plays a role in shaping life history patterns that affect energy usage. I have found seabirds to be particularly interesting animals to study because they have evolved interesting life history patterns to overcome many challenges for life at sea. Overall, these life histories affect the way they allocate energy for themselves and their offspring. One pattern that is fundamental to all seabirds (and some marine mammal species) is the fact that they acquire food at sea, yet seabirds must breed on land. Pelagic seabirds like albatrosses and petrels are fascinating birds to study because they can exploit distant prey resources when breeding. Essentially, they integrate energy acquisition over vast areas of open ocean at relatively short time scales since albatrosses and petrels are adapted for fast and fuel-efficient flight. In essence, where they go, how they behave, and what it costs them are fundamental questions in my research. In addition to my research on seabirds, I have been involved in several studies related to the ecology, physiology, and behavior of marine mammals including cetaceans, fur seals, and true seals.

Environmental stochasticity plays a central part in affecting where seabirds and other marine predators go to find food. So, I am currently involved in a new and exciting research program called Tagging of Pacific Pelagics (TOPP) that aims to study the foraging ecology and distribution of top marine predators. As a whole, TOPP focuses on tracking tuna, sharks, squid and marine birds, reptiles, and mammals to study how all of these marine animal species behave with respect to the oceanography of the North Pacific Ocean. I manage research activities on seabirds for TOPP and am also a principal investigator studying the migratory behavior and habitat use of sooty shearwaters. TOPP seabird investigators are using a variety of electronic tags to track movement patterns and behavior of shearwaters and albatrosses in New Zealand, Chile, Mexico, and the Northwest Hawaiian Islands.

I have expertise in using doubly or singly labeled water, heart rate loggers, and respirometry to measure energy expenditure, effort, and body composition, and have extensive experience using state-of-the-art electronics such as satellite telemetry and activity data loggers to study foraging ecology and behavior.

Biology 20B - Physiology and Development of Animals and Plants
Biology 127 - Bioenergetics
Biology 139 - Biology and Ecology of Marine Mammals

Shaffer, S. A., Tremblay, Y., Weimerskirch, H., Scott, D., Thompson, D. R., Sagar, P. M., Moller, H., Taylor, G. A., Foley, D. G., Block, B. A., and Costa, D. P. (2006) Migratory shearwaters integrate oceanic resources across the Pacific Ocean in an endless summer. Proceedings of the National Academy of Sciences USA 103, 12799-12802. PDF

Angelier, F., Shaffer, S. A., Weimerskirch, H., and Chastel, O. (2006) Effect of age, breeding experience and senescence on corticosterone and prolactin levels in a long-lived seabird: the wandering albatross. General and Comparative Endocrinology 149, 1-9. PDF

Shaffer, S. A., Gabrielsen, G. W., Verreault, J. and Costa, D. P. (2006) Validation of water flux and body composition in Glaucous gulls (Larus hyperboreus). Physiological and Biochemical Zoology 79, 836-845. PDF

Shaffer, S. A. and Costa, D. P. (2006) A database for the study of marine mammal behavior: Gap analysis, data standardization, and future directions. IEEE Journal of Oceanic Engineering 31 (1), 82-86. PDF

Tremblay, Y., Shaffer, S. A. , Fowler, S. L., Kuhn, C. E., McDonald, B. I., Weise, M. J., Bost, C.-A., Weimerskirch, H., Crocker, D. E., Goebel, M. E., Costa, D. P. (2006) Interpolation of tracking data in a fluid environment. Journal of Experimental Biology 209: 128-140. PDF

Kuhn, C. E., McDonald, B. I., Shaffer, S. A. , Costa, D. P., Barnes, J., Crocker, D. E., and Burns, J. (2005) Diving physiology and winter foraging behavior of a juvenile leopard seal (Hydrurga leptonyx). Polar Biology (on line).

Shaffer, S. A. , Tremblay, Y., Awkerman, J., Henry, W. R., Teo, S. L. H., Anderson D. J., Croll, D. A., Block, B. A., and Costa, D. P. (2005) Comparison of light- and SST-based geolocation with satellite telemetry in free-ranging albatrosses. Marine Biology 147: 833-843. PDF

Costa, D. P., Kuhn, C. E., Weise, M. J., Shaffer, S. A. , and Arnould, J. P. Y. (2004) When does physiology limit the foraging behaviour of freely diving mammals? In: Animals and Environments (Morris S. and Vosloo A. eds). Proceedings of the Third International Conference of Comparative Physiology and Biochemistry 1275C: 359-366.

Shaffer, S. A. , Costa, D. P., and Weimerskirch, H. (2004) Field metabolic rates of black-browed albatrosses (Thalassarche melanophrys) during the incubation stage. Journal of Avian Biology 35: 551-558. PDF

Shaffer, S. A. (2004) Annual energy budget and food requirements of breeding Wandering Albatrosses (Diomedea exulans). Polar Biology 27:253-256. PDF

Mabille, G., Boutard, O., Shaffer, S. A. , Costa, D. P., and Weimerskirch H. (2004) Patterns of growth and energy expenditure in wandering albatross chicks. Ibis 146: 85-94.

Shaffer, S. A. and Costa, D. P. (2004) Bibliography: diving and tracking studies of marine mammals. Funded by Office of Naval Research.

Shaffer, S. A. (2003) Eye of the albatross: visions of hope and survival by Carl Safina - A review. Marine Ornithology 31: 92.

Arnould, J. P. Y., Luque, S. P., Guinet, C., Costa, D. P., Kingston, J., and Shaffer, S. A. (2003) The comparative energetics and growth strategies of sympatric Antarctic and sub Antarctic fur seal pups, at Iles Crozet. Journal of Experimental Biology 206: 4497-4506.

Shaffer, S. A. , Costa, D. P., and Weimerskirch, H. (2003) Foraging effort in relation to the constraints of reproduction of free-ranging albatrosses. Functional Ecology 17: 66-74. PDF

Weimerskirch, H., Shaffer , S.A. , Mabille, G., Martin, J., Boutard, O., Rouanet, J.-L. (2002) Heart rate and energy expenditure of incubating wandering albatrosses: basal levels, natural variation, and the effects of human disturbance. Journal of Experimental Biology 205: 475-483. (Including Cover Photo). (PDF)

Shaffer, S. A. , Costa, D. P., and Weimerskirch, H. (2001) A comparison of methods to evaluate energy expenditure of incubating wandering albatrosses. Physiological and Biochemical Zoology 74: 823-831. PDF

Shaffer, S. A. , Costa, D. P., and Weimerskirch, H. (2001) Behavioural factors affecting foraging effort in breeding wandering albatrosses. Journal of Animal Ecology 70: 864-874. (Elton Prize winner). PDF

Shaffer, S. A. , Weimerskirch, H., and Costa, D. P. (2001) Functional significance of sexual dimorphism in wandering albatrosses, Diomedea exulans. Functional Ecology 15: 203-210. (Including Cover Photo). (PDF)

Weimerskirch, H., Guionnet, T., Martin, J., Shaffer, S. A. , and Costa, D. P. (2000) Fast and fuel-efficient? Optimal use of wind by flying albatrosses. Proceedings of the Royal Society of London B 267: 1869-1874.

Shaffer, S. A. (2000) Foraging ecology of Wandering Albatrosses ( Diomedea exulans ): Impacts on reproduction and life history. Ph.D. dissertation. University of California , Santa Cruz , 113 pages. PDF

Shaffer, S. A. , Costa, D. P., Williams, T. M., and Ridgway, S. H. (1997) Diving and swimming performance of white whales, Delphinapterus leucas : An assessment of plasma lactate and blood gas levels and respiratory rates. Journal of Experimental Biology 200: 3091-3099. (Including Cover Photo). PDF