Research

My work focuses on connecting ocean conditions to the behavior and success of marine mammal populations. I am particularly interested in individual variability in behavior, what drives and maintains that variability, and what the ecological consequences are for a population.

I have had the privilege and opportunity to work with several different pinniped species on topics ranging from cellular-level physiology to species-level behavior and ecology. Currently, I am part of a collaborative effort to assess the consequences of multiple stressors on northern elephant seals. We are evaluating the interacting effects of acoustic disturbance, contaminant load, varying foraging conditions, and acute physiological stress responses on reproductive success.

Recent Publications

Effects of disease on foraging behaviour and success in a free-ranging marine mammal, the northern elephant seal

Holser, R.R., D.E. Crocker, A.B. Favilla, T. Adachi,

T. Keates, Y. Naito, D.P. Costa. (2023) Conservation Physiology

Northey, A., R.R. Holser, G. Shipway, D.P. Costa, D.E. Crocker (2023) AJP Regulatory Integrative and Comparative Physiology

Adrenal response to ACTH challenge alters thyroid and immune function and varies with body reserves in molting adult female northern elephant seals

Kendall-Bar, J.M., T.M. Willians, R. Mukherji, D.A. Lozano, J.K. Pitman, R.R. Holser, T.R. Keates, R.S. Beltran, P.W. Robinson, D.E. Crocker, T. Adachi, O.I. Lyamin, A.L. Vyssotski, D.P. Costa. (2023) Science

Foster-Dyer, R.T.N, K.T. Goetz, M.H. Pinkerton, T. Iwata, R.R. Holser, S.A. Michael, C. Pritchard, S. Childerhouse, J. Rotella, L. Federwisch, M. LaRue. (2023) Polar Biology

First observations of sponge foraging by Weddell seals in Erebus Bay, Antarctica

Other Publications

Peterson, S.E., J.T. Ackerman, R.R. Holser, B.I. McDonald, D.P. Costa, D.E. Crocker. 2023. Multiple stressors interact in a free-ranging marine mammal: mercury bioaccumulation and cortisol influence endocrine and immune biomarkers. Environmental Science and Technology

Adachi, T., P. Lovell, J. Turnbull, M. Fedak, B. Picard, C. Guinet, M. Biuw, T. Keates, R.R. Holser, D.P. Costa, D.E. Crocker, and P. Miller. 2023. Body condition changes at sea: onboard calculation and telemetry of body density in diving animals. Methods in Ecology and Evolutiom

Keates, T.R., E.L. Hazen, R.R. Holser, J. Fiechter, S.J. Bograd, P.W. Robinson and D.P. Costa. 2022. Foraging behavior of a mesopelagic predator in northeastern Pacific eddies. Deep Sea Research Part I: Oceanographic Research Papers

Holser, R.R., T.R. Keates, D.P. Costa, C.A. Edwards. 2022. Extent and Magnitude of Subsurface Anomalies During the Northeast Pacific Blob as Measured by Animal-Borne Sensors. J. Geophys. Res.: Oceans.

Costa, D.P., & R.R. Holser. 2022. Animal personality: Worn whiskers reveal resilience. Current Biology, 32(11), R528-R530

Adachi, T., Y. Naito, P.W. Robinson, D.P. Costa, L.A. Hückstädt, R.R. Holser, W. Iwasaki, & A. Takahashi. 2022. Whiskers as hydrodynamic prey sensors in foraging seals. Proc. Nat. Acad. Sci.

Kendall-Bar, JM; R Mukherji; J Nichols; C Lopez; DA Lozano; JK Pitman; RR Holser; RS Beltran;

M Schalles; CA Field; SP Johnson; AL Vyssotski; DP Costa; TM Williams. 2022. Eavesdropping on the brain at sea: development of a surface-mounted system to detect weak electrophysiological signals from wild animals. Animal Biotelemetry

Harcourt, R, MA Hindell, CR McMahon, KT Goetz, JB Charrassin, K Heerah, RR Holser, ID Jonsen, MR Shero, X Hoenner, R Foster, B Lenting, E Tarszisz, MH Pinkerton. 2021. Regional Variation in Winter Foraging Strategies by Weddell Seals in Eastern Antarctica and the Ross Sea. Front. Mar. Sci.

Adachi, T, A Takahashi, DP Costa, PW Robinson, LA Huckstadt, SH Peterson, RR Holser,

RS Beltran, TR Keates, Y Naito. 2021. Forced into an ecological corner: Round-the-clock deep foraging on small prey by elephant seals. Science Advances

Khudyakov, JI, RR Holser, CA Vierra, ST Ly, TK Niel, BM Hasan, DE Crocker, DP Costa. 2022. Changes in apolipoprotein abundance dominate proteome responses to prolonged fasting in the northern elephant seal. Journal of Experimental Biology, 225(4).

Holser, R.R., D.E. Crocker, R. Condit, P.W. Robinson, D.P. Costa. 2021. Density-dependent effects on reproductive output in a capital breeding carnivore, the northern elephant seal (Mirounga angustirostris). Proceedings of the Royal Society: B

Adamczak, SK, RR Holser, DP Costa, EB McCabe, & R. Wells. 2021. Body Composition of Common Bottlenose Dolphins in Sarasota Bay, Florida. Front. Mar. Sci. 8:615773.

Rzucidlo, CL, ES Sperou, RR Holser, JI Khudyakov, DP Costa, & DE Crocker. 2021. Changes in serum adipokines during natural extended fasts in female northern elephant seals. General and Comparative Endocrinology, 308

Wright, TJ, RW Davis, RR Holser, LA Hückstädt, CP Danesi, SG Widen, TM Williams, DP Costa, M. Sheffield-Moore. 2020. Changes in Northern Elephant Seal Skeletal Muscle Following Thirty Days of Fasting and Reduced Activity. Frontiers in physiology, 11.

Yoshino K., A Takahashi, T Adachi, DP Costa, PW Robinson, SH Peterson, LA Hückstädt, RR Holser, Y Naito. 2020. Acceleration-triggered animal-borne videos show a dominance of fish in the diet of female northern elephant seals. Journal of Experimental Biology, 223(5).

Keates TR, RM Kudela, RR Holser, LA Hückstädt, SE Simmons, DP Costa. 2020. Chlorophyll fluorescence as measured in situ by animal-borne instruments in the northeast Pacific Ocean. Journal of Marine Systems, 203, 103265.

Horning M, RD Andrews, AM Bishop, PL Boveng, DP Costa, DE Crocker, M Haulena, MA Hindell, AG Hindle, RR Holser, SH Hooker, LA Hückstädt, S Johnson, MA Lea, BI McDonald, CR McMahon, PW Robinson, RE Sattler, CR Shuert, SM Steingass, D Thompson, PA Tuomi, CL Williams, JN Womble. 2019. Best practice recommendations for the use of external telemetry devices on pinnipeds. Animal Biotelemetry, 7, 20.

McHuron EA, RR Holser, DP Costa. 2019. What's in a whisker? Disentangling ecological and physiological isotopic signals. Rapid Communications in Mass Spectrometry.

Hückstädt LA, RR Holser, MS Tift, DP Costa. 2018. The extra burden of motherhood: reduced dive duration associated with pregnancy status in a deep-diving mammal, the northern elephant seal. Biology letters, 14(2), p.20170722.