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NCER Grantee Research Project Results

An integrative approach to understanding foraging behavior of southern elephant seals using novel methods of oceanographic data collection

EPA Grant Number: F5E11031
Title: An integrative approach to understanding foraging behavior of southern elephant seals using novel methods of oceanographic data collection
Investigators: McDonald, Birgitte
Institution: University of California - Santa Cruz
EPA Project Officer: Cobbs-Green, Gladys M.
Project Period: September 1, 2005 through August 31, 2008
Project Amount: $111,344
RFA: STAR Graduate Fellowships (2005)
Research Category: Academic Fellowships

Description:

Objective:

The goal of this study is to investigate, in southern elephant seals (Mirounga leonina) off the Antarctic Peninsula, the relationship of specific diving behavior and animal movements to oceanographic and bathymetric features, develop and test models of these features’ role in defining habitat use, and predict how these animals might respond to oceanographic variations that are coupled with climate change.

Approach:

Seals will be instrumented with Satellite Relay Data Loggers (SRDLs – Sea Mammal Research Unit). The SRDLs collect, summarize, and transmit data on the animal’s behavior (location, dive depth, and dive duration) and environment (temperature, salinity, and light) via the ARGOS satellite system. This allows for near real-time tracking and accurate geopositioning.

I will use the animal derived temperature and salinity data to place behavior in the context of water masses by defining habitat types using hierarchical agglomerative cluster analysis on the temperature and salinity profiles. Each dive's combined temperature and salinity profile can then be assigned to a cluster that will be examined for a relationship to known water types in the Southern Ocean. I will then examine the diving behavior in the different clusters. Habitat usage will be modeled based on individual seal utilization. Animals show preference for a habitat when it uses an area more than would be expected on the basis of relative availability of the habitat. I will then use a Generalized Additive model approach to relate the spatial utilization of the seals to the environmental variables defining the habitats. These data will be used to investigate foraging behavior and see how the seals change their behavior to deal with seasonal and annual variation.

Expected Results:

This study will provide information on the foraging behavior of one of the Southern Oceans prominent apex predators. Global warming will likely affect oceanographic features such as currents, eddies, and ice edge characteristics. This three-year study will most likely not demonstrate affects of global warming on elephant seals but it can provide data that can be used as a baseline in the future. With the information obtained from this study on the mechanisms seals are using to find prey, I will be able to model what affects global warming will have on this species.

Supplemental Keywords:

Southern elephant seal, Mirounga leonina, habitat usage, foraging, Antarctic peninsula, Livingston Island, AMLR, global warming, oceanographic features, CTD, satellite tags,, RFA, Scientific Discipline, Air, Ecosystem Protection/Environmental Exposure & Risk, climate change, Air Pollution Effects, Habitat, Environmental Monitoring, Atmosphere, remote sensing, habitat dynamics, habitat use, animal responses, habitat disturbance, elephant seals, ecological consequences, environmental stress, bathymetric models, habitat population structure, foraging behavior

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The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Conclusions drawn by the principal investigators have not been reviewed by the Agency.

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