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Life History Transmitters (LHX) in Steller sea lions: assessing the effects of health status, foraging ability, and environmental variability on juvenile survival and population trends.

Summary | Background | Concept | Objectives | Hypotheses | Update | Literature

A reduction in juvenile Steller sea lion (Eumetopias jubatus) survival, possibly linked to reduced foraging efficiency and increased nutritional stress, or high levels of predation by killer whales (Orcinus orca), has been hypothesized to contribute to the continuing decline of this mesopredator in the North Pacific and Bering Sea ecosystems. To date, this hypothesis has not been tested. As a central part of the Steller LHX Project, we will determine survival rates of juvenile Steller sea lions, using long-term, implanted satellite-linked life history transmitters. For the first time, this project will provide a direct measure of predation and deliver information on causes of individual animal mortality.

In addition, we are collecting 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. The LHX project is based on the development and application of a new generation of life-long archival satellite transmitters, the Life History Transmitter. LHX transmitters were developed in collaboration with Wildlife Computers, and are described in:

Horning, M. and R.D. Hill. 2005. Designing an archival satellite transmitter for life-long deployments on oceanic vertebrates: The Life History Transmitter. IEEE Journal of Oceanic Engineering. 30: 807-817.

The implantation of LHX transmitters is described in:

Horning, M., M. Haulena, P.A. Tuomi and J.E. Mellish. 2008. Intraperitoneal implantation of life-long telemetry transmitters in otariids. BMC Veterinary Research. 4:51. [pdf] 

For additional publications from this project, please check the update section of these pages.

This project is directed by the Pinniped Ecology Applied Research Laboratory in cooperation with the Alaska SeaLife Center, the National Marine Mammal Laboratory (NMFS), and the Alaska Department of Fish & Game.

The LHX Project has received support from:

North Pacific Marine Research Board                                                                                                        NOAA's National Marine Fisheries Service                                                                                                  Pollock Conservation Cooperative Research Center                                                                                   The Alaska SeaLife Center

This research is carried out under NMFS Permits #881-1668; 881-1890, 1034-1685 and 1034-1887.