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Pinniped Ecology Applied Research Lab (PEARL)

We investigate the ecology, behavior and physiology of pinnipeds (seals, sea lions, and walrus). Pinniped stocks and population trends are analyzed in relation to predator-prey interactions, anthropogenic (man made) and natural variations in environmental conditions.

We focus on pinniped diving and foraging behavior in relation to reproductive strategies. Of particular interest are the effects of physiological constraints on behavioral plasticity, and how these influence the ability of pinnipeds to respond to environmental changes.

Our research is carried out in many locations in Oregon, California and Alaska, and as far away as Antarctica.

A key aspect of our work involves the development and application of innovative research approaches and new technologies to study animals that spend the majority of their life outside of our sphere of direct observation. Examples include infrared and 3D remote imaging, as well as development of life-long satellite transmitters to monitor health, condition and vital rates in inaccessible species such as the Steller sea lion in Alaska.

We are affiliated with the Coastal Oregon Marine Experiment Station, and our faculty are part of the OSU Department of Fisheries & Wildlife.

News and Events

Markus Horning at Science on Tap

NEWPORT – Oregon State University marine mammal researcher Markus Horning  steps to the bar for this month’s Science on Tap lecture, with The secret lives or seals: Using high-tech marvels to pry into ocean depths.

In recent research, the high-tech tools have helped show that more juvenile Steller sea lions are falling to predators than had been thought, casting doubt on prospects for the animals’ ability to recover from recent population decline in Alaskan waters.

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Alaska Public Radio Network interview with Markus Horning

An Oregon State researcher is raising some new scientific doubts about the National Marine Fisheries Service Sea Lion biological opinion.  Markus Horning has been tagging Sea Lions in Prince William Sound and finding that predators like Killer Whales and Sharks are killing a larger proportion of their pups than expected.

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Predators may block recovery of Alaska sea lions, scientists say

Researchers at Oregon State University and the Alaska Sealife Center started tracking 36 juvenile Steller sea lions in 2005. By November, 12 had died, a death rate that's not exceptional, OSU marine mammal expert Markus Horning said Thursday.


Read more here: http://www.adn.com/2012/01/19/2272838/predators-may-block-alaska-sea.html#storylink=cpy

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PEARL Publications

In Press

Mathews, EA, Womble JN, Pendleton GW, Jemison LA, Maniscalco JM, Streveler G.  In Press.  Population growth and colonization of Steller sea lions in the Glacier Bay region of southeastern Alaska: 1970s-2009. Marine Mammal Science. :xx-xx.
Blundell, GM, Womble JN, Pendleton GW, Karpovich SA, Gende SM, Herreman JK.  In Press.  Use of glacial ice and terrestrial habitats by harbor seals in Glacier Bay. Marine Ecology Progress Series.

2012

Horning, M, Mellish JE.  2012.  Predation on an Upper Trophic Marine Predator, the Steller Sea Lion: Evaluating High Juvenile Mortality in a Density Dependent Conceptual Framework.. PLoS ONE . 7(1): e30173.

2011

Hindle, AJ, Mellish JE, Horning M.  2011.  Aerobic dive limit does not decline in an aging pinniped. J. Exp. Zoology. 315A :544-552.
Walker, KA, Horning M, Mellish JE, Weary DM.  2011.  The effects of two analgesic regimes on behavior after abdominal surgery in Steller sea lions. The Veterinary Journal. 190:160-164. Abstract
Mellish, JE, Hindle AJ, Horning M.  2011.  Health and condition in the adult Weddell seal of McMurdo Sound, Antarctica. Zoology. 114:177-183.

2010

Womble, JN, Conlon S.  2010.  Observation of Steller Sea Lion Eumetopias jubatus Predation on a Harbor Seal Phoca vitulina richardii in the Glacier Bay Region of Southeastern Alaska. Aquatic Mammals. 36(2):129-137. Abstract
Womble, JN, Pendleton GW, Mathews EA, Blundell GM, Bool NM, Gende SM.  2010.  Harbor seal ( Phoca vitulina richardii ) decline continues in the rapidly changing landscape of Glacier Bay National Park, Alaska 1992-2008. Marine Mammal Science. 26:686-697.
Nienaber, J, Thomton J, Horning M, Polasek L, Mellish JE.  2010.  Surface temperature patterns in seals and sea lions: A validation of temporal and spatial consistency. Journal of Thermal Biology. 35:435-440. Abstract
Mellish, JE, Tuomi PA, Hindle AJ, Jang S, Horning M.  2010.  Skin microbial flora and effectiveness of aseptic technique for deep muscle biopsies in Weddell seals (Leptonychotes weddellii ) in McMurdo Sound, Antarctica. Journal of Wildlife Diseases. 46(2):655-8. Abstract
Hindle, AJ, Horning M.  2010.  Energetics of breath-hold hunting: modeling the effects of aging on foraging success in the Weddell seal. Journal of Theoretical Biology. 264(3):673-82. Abstract
Mellish, JE, Tuomi PA, Hindle AJ, Horning M.  2010.  Chemical immobilization of Weddell seals (Leptonychotes weddellii) by ketamine/midazolam combination. Veterinary Anaesthesia and Analgesia. 37(2):123-31. Abstract
Mellish, JE, Hindle AJ, Horning M.  2010.  A preliminary assessment of the impact of disturbance and handling on Weddell seals of McMurdo Sound, Antarctica. Antarctic Science. 22(01):25. Abstract
Hindle, AJ, Lawler JM, Campbell KL, Horning M.  2010.  Muscle aging and oxidative stress in wild-caught shrews. Comparative Biochemistry and Physiology. Part B, Biochemistry & Molecular Biology. 155(4):427-34. Abstract

2009

Raum-Suryan, KL, Jemison LA, Pitcher KW.  2009.  Entanglement of Steller sea lions (Eumetopias jubatus) in marine debris: identifying causes and finding solutions. Marine Pollution Bulletin. 58(10):1487-95. Abstract
Horning, M, Mellish JE.  2009.  Spatially explicit detection of predation on individual pinnipeds from implanted post-mortem satellite data transmitters. Endangered Species Research. 10:135-143. Abstract
Walker, KA, Horning M, Mellish JE, Weary DM.  2009.  Behavioural responses of juvenile Steller sea lions to abdominal surgery: Developing an assessment of post-operative pain. Applied Animal Behaviour Science. 120:201-207. Abstract
Hindle, AJ, Lawler JM, Campbell KL, Horning M.  2009.  Muscle senescence in short-lived wild mammals, the soricine shrews Blarina brevicauda and Sorex palustris. Journal of Experimental Zoology. Part A, Ecological Genetics and Physiology. 311(5):358-67. Abstract
Sigler, MF, Tollit DJ, Vollenweider JJ, Thedinga JF, Csepp DJ, Womble JN, Wong MA, Rehberg MJ, Trites AW.  2009.  Foraging response of a marine predator, the Steller sea lion, to seasonal changes in prey availability. Marine Ecology Progress Series. 388:243-261.
Hindle, AJ, Horning M, Mellish JE, Lawler JM.  2009.  Diving into old age: muscular senescence in a large-bodied, long-lived mammal, the Weddell seal (Leptonychotes weddellii). The Journal of Experimental Biology. 212(Pt 6):790-6. Abstract