PROFILE:

• Director, Laboratory for Applied Biotelemetry & Biotechnology, Department of Marine Biology, Texas A&M University at Galveston

• Associate Graduate Faculty Member, Department of Wildlife & Fisheries Sciences, College of Agriculture & Life Sciences, Texas A&M University at College Station

• Associate Professor of Marine Sciences (Affiliate), School of Fisheries & Ocean Science, University of Alaska Fairbanks

• Ph.D. University of Bielefeld  & Max-Planck-Institute for Behavioral Physiology  (1992)

• Diplom degree, University of Freiburg (1988)

Specialty:

• Behavioral Physiology & Ecology of Diving, Airbreathing Vertebrates: physiological constraints & behavioral plasticity; development of diving, foraging & locomotion in divers; ontogenetic constraints & life history; scaling issues

• Development & Design of Electronic Research Instrumentation and Analytical Software Tools

Research Interests:

My research centers around the behavioral ecology and physiology of diving, airbreathing birds, reptiles and mammals. I am especially interested in continuing the study of foraging strategies, in conjunction with the analysis of physiological and ontogenetic constraints, as well as scaling issues related to temporal and spatial variability in prey accessibility.

I have devoted a considerable amount of my research time to the development of new tools that permit us to gather more information on how diving animals hunt. Physiological studies of free-ranging vertebrates, marine mammals in particular, are difficult to conduct. To address this problem, I have developed new methods for extrapolating physiological thresholds such as the aerobic dive limit from recorded dive behavior. In addition, I have developed data loggers capable of recording proxies of metabolic rate, such as heart rate and power output accelerometers. I am currently working on developing techniques to remotely monitor body condition, with the ultimate goal of assessing effects of natural or anthropogenic prey depletion on individual, free-ranging mammals. In addition, I am developing new approaches to permit long-term monitoring of foraging effort & survival of individual animals. To be able to coherently handle and analyze these large amounts of multi-variate and multi-scalar data, I am pursuing the development of a new generation of analytical software tools.

SELECTED PUBLICATIONS:

Williams TM, Davis RW, Fuiman LA, Francis J, Le Boeuf BJ, Horning M, Calambokidis J, Croll DA (2000) Sink or Swim: Strategies for Cost-Efficient Diving by Marine Mammals. Science 288: 133-136.

Horning M, Trillmich F (1999) Lunar cycles in diel prey migrations exert stronger effect on diving of juveniles than adult Galápagos fur seals. Proc. Royal Soc. Lond. B. 266 (1424): 1127-1132.

Ponganis PJ, Starke LN, Horning M, Kooyman GL (1999) Development of diving capacity in Emperor Penguins. J. Exp. Biol. 202(7): 781-786.

Davis RW, Fuiman LA, Williams TM, Collier SO, Hagey WP, Kanatous SB, Kohin S, Horning M (1999) Hunting Behavior of a Marine Mammal Beneath the Antarctic Fast Ice. Science 283: 993-996.

Horning M, Trillmich F (1997) Ontogeny of Diving Behaviour in the Galápagos Fur Seal. Behaviour 134: 1211-1257.

Ancel A, Horning M, Kooyman GL (1997) Prey ingestion revealed by oesophagus and stomach temperature recordings in cormorants. J.Exp.Biol. 200: 149-154.

Horning M, Trillmich F (1997) Development of Hemoglobin, Hematocrit and Erythrocyte Values in Galápagos Fur Seals. Marine Mammal Science 13 (1): 100-113.

Kooyman GL, Kooyman TG, Horning M, Kooyman CA (1996) Penguin dispersal after fledging. Nature 383: 397

CURRENT RESEARCH:

Determining survival & longterm foraging behavior in juvenile Steller sea lions through implanted, satellite-linked mortality transmitters (SMX) (9/1999 - 8/2001)
(http://www2.sfos.uaf.edu:8080/npmr/projects/mammals/33/abstract33.html)
A reduction in juvenile Steller sea lion survival, linked to reduced foraging efficiency and increased nutritional stress, possibly through depletion of primary prey stocks, has been hypothesized to contribute to the continuing decline of this apex predator in the North Pacific and Bering Sea Ecosystems. To date, this hypothesis has not been tested. As a central part of the Steller SMX project, we will determine survival rates of juvenile Steller sea lions, using long-term, implanted satellite-linked mortality transmitters. For the first time, this project will also deliver longitudinal, multi-year dive effort data from individual, free-ranging marine mammals. In a new experimental paradigm, we will directly assess the influences of proximate effects such as condition, health, pollutants and immuno-competence on survival of individual sea lions. This approach represents a departure from the classic regional comparison paradigm, comparing stable and declining populations.