Southern elephant seals: A top predator of the southernocean and a useful vehicle to study its environmentSusan Gallon
Southern elephant seals               (Mirounga leonina)Largest pinniped species (♂ 1500-3000 Kg, ♀ 400-600 Kg)Extremely s...
1- INVESTIGATING FORAGING STRATEGIES  Study site:  Elephant Island (61°S 55°W)  29 southern elephant seals (5 PM SA  ♂, 20...
1- INVESTIGATING FORAGING STRATEGIES
1- INVESTIGATING FORAGING STRATEGIES                      Satellite tracked animals and kernel density of foraging area
1- INVESTIGATING FORAGING STRATEGIES                  13C                                         15N                     ...
1- INVESTIGATING FORAGING STRATEGIES                  13C                                          15N                    ...
1- INVESTIGATING FORAGING STRATEGIES                                                         13C                          ...
1- INVESTIGATING FORAGING STRATEGIES                                                         13C                          ...
1- INVESTIGATING FORAGING STRATEGIES                                                         13C                          ...
1- INVESTIGATING FORAGING STRATEGIES                                                         13C                          ...
2- IDENTIFYING FORAGING EVENT  Translocation study:  Kerguelen Island (49°S 69°E)  3 adult female southern elephant seals ...
2- IDENTIFYING FORAGING EVENT                                                                              Heave          ...
2- IDENTIFYING FORAGING EVENT                                                                                 Heave       ...
2- IDENTIFYING FORAGING EVENT
Climate                             Ocean resources                             Demography        Oceanographers          ...
3- FUTURE WORK
4- Merging expertise          It may be possible to use seal tracking data to locate deep-sea coral habitats          and ...
Thank you
Southern Elephant Seals - Susan Gallon
Southern Elephant Seals - Susan Gallon
Southern Elephant Seals - Susan Gallon
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Southern Elephant Seals - Susan Gallon

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Centre for Marine Biodiversity and Biotechnology Away Day 2012. Presentation by Susan Gallon on Southern elephant seals: A top predator of the southern ocean and a useful vehicle to study its environment

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  • Southern elephant seals (Mirounga leonina) range widely throughout the Southern Ocean and are associated with important habitats (e.g., ice edges, shelf) where they accumulate energy (prey) to fuel their reproductive efforts on land.
  • Why do we use southern elephant seals? They are a great study species because:Large size means can carry tagsLong migration throughout the southern ocean during summer and winter at great depthAccessible on land during breeding and moulting season. Top of the food chain in Southern Ocean.
  • Several studies using accelerometer show the accurate detection of feeding event.Easy to do with captive animals or species that are central place foragers. More problematic with animals that spend months travelling through the southern ocean.
  • Studying the foraging behaviour of top marine predators by establishing when and where they forage in relation to the oceanographic context is critical to understand how the natural variability of the marine environment and longer term changes induced by human activity could impact the foraging efficiency and consequently the demographic trajectories of these apex predators.
  • Accelerometry might help determine at a finer scale if they use any clues in the vertical dimension: it could be water temperature, salinity, chlorophyll or bio-luminescence
  • Southern Elephant Seals - Susan Gallon

    1. 1. Southern elephant seals: A top predator of the southernocean and a useful vehicle to study its environmentSusan Gallon
    2. 2. Southern elephant seals (Mirounga leonina)Largest pinniped species (♂ 1500-3000 Kg, ♀ 400-600 Kg)Extremely sexually dimorphic: male up to 10 times largerthan adult femaleLong (up to 2 hours), deep (up to 2500 m) and nearly continuousdiving at sea (90 % diving)2 annual migrations from their breeding and molting sitesMajor consumers of Southern Ocean biomass
    3. 3. 1- INVESTIGATING FORAGING STRATEGIES Study site: Elephant Island (61°S 55°W) 29 southern elephant seals (5 PM SA ♂, 20 PM ♀ and 4 PR ♀) Whisker SI analyses 15N a proxy for the trophic position of predator 13C a proxy for foraging habitat Satellite tags (SMRU, St Andrews, UK) To track individual seals at sea and monitor their diving behaviour State Space Models (SSM) were used to infer foraging areas during seals’ migration. In these foraging areas we calculated: dive duration, dive depth, diel migration, shelf foraging and benthic foraging
    4. 4. 1- INVESTIGATING FORAGING STRATEGIES
    5. 5. 1- INVESTIGATING FORAGING STRATEGIES Satellite tracked animals and kernel density of foraging area
    6. 6. 1- INVESTIGATING FORAGING STRATEGIES 13C 15N 13C 15N F203-262 F203-262 F255-263 F255-263-18 14 -18 14 0 2 4 6 8 10 12 0 2 4 6 8 10 12 13.5 13.5-19 13 -19 13 12.5 12.5-20 -20 12 12 11.5 11.5-21 -21 11 11-22 10.5 -22 10.5 10 10-23 9.5 -23 9.5 9 9-24 0 2 4 6 8 10 12 -24 0 2 4 6 8 10 12 F255-263 F255-263 F203-262 F203-262 -18 14 0 2 4 6 8 10 12-18 14 13.5 0 2 4 6 8 10 12 -19 13 13.5-19 13 12.5 -20 12.5 12-20 11.5 12 -21 11 11.5-21 -22 10.5 11 10-22 10.5 -23 9.5 10-23 9 9.5 -24 0 2 4 6 8 10 12 9-24 0 2 4 6 8 10 12 F203-262 F203-262-18 14 13C 15N 0 2 4 6 8 10 12 13.5-19 13 12.5-20 F229-265 F229-265 12 -18 14 11.5-21 0 2 4 6 8 10 12 13.5 11 -19 13-22 10.5 12.5 10 -20-23 12 9.5 11.5 9 -21-24 0 2 4 6 8 10 12 11 -22 10.5 10Samples taken in November 2008 and 2009 and January 2009 for -23 9.5 9F203-262 -24 0 2 4 6 8 10 12Samples taken in January 2008 and 2009 for F255-263 and F229-265 F229-265 F229-265 -18 14 0 2 4 6 8 10 12 13.5 -19 13 12.5 -20 12 -21 11.5 11 -22 10.5 10 -23 9.5 9 -24 0 2 4 6 8 10 12
    7. 7. 1- INVESTIGATING FORAGING STRATEGIES 13C 15N 13C 15N F203-262 F203-262 F255-263 F255-263-18 14 -18 14 0 2 4 6 8 10 12 0 2 4 6 8 10 12 13.5 13.5-19 13 -19 13 12.5 12.5-20 -20 12 12 11.5 11.5-21 -21 11 11-22 10.5 -22 10.5 10 10-23 9.5 -23 9.5 9 9-24 0 2 4 6 8 10 12 -24 0 2 4 6 8 10 12 F255-263 F255-263 F203-262 F203-262 -18 14 0 2 4 6 8 10 12-18 14 13.5 0 2 4 6 8 10 12 -19 13 13.5-19 13 12.5 -20 12 Similar profiles in consecutive years 12.5-20 11.5 12 -21 11 11.5-21 -22 10.5 11 10  fidelity to foraging area and prey-22 10.5 -23 9.5 10-23 9 9.5 -24 0 2 4 6 8 10 12 9-24 0 2 4 6 8 10 12 F203-262 F203-262-18 14 13C 15N 0 2 4 6 8 10 12 13.5-19 13 12.5-20 F229-265 F229-265 12 -18 14 11.5-21 0 2 4 6 8 10 12 13.5 11 -19 13-22 10.5 12.5 10 -20-23 12 9.5 11.5 9 -21-24 0 2 4 6 8 10 12 11 -22 10.5 10Samples taken in November 2008 and 2009 and January 2009 for -23 9.5 9F203-262 -24 0 2 4 6 8 10 12Samples taken in January 2008 and 2009 for F255-263 and F229-265 F229-265 F229-265 -18 14 0 2 4 6 8 10 12 13.5 -19 13 12.5 -20 12 -21 11.5 11 -22 10.5 10 -23 9.5 9 -24 0 2 4 6 8 10 12
    8. 8. 1- INVESTIGATING FORAGING STRATEGIES 13C 15N F256 F256 -18 14 0 2 4 6 8 10 12 13.5 -19 13 12.5 -20 12 11.5 -21 11 -22 10.5 10 -23 9.5 9 -24 0 2 4 6 8 10 12 WAP: Feed on the shelf, some benthic dives, lower 13C and higher 15N F292-293 F292-293 -18 14 0 2 4 6 8 10 12 13.5 -19 13 12.5 -20 12 11.5 -21 11 -22 10.5 10 -23 9.5 9 -24 0 2 4 6 8 10 12 OPEN WATER: No shelf, no benthic dives, higher 13C and lower 15N F209 F209 -18 14 0 2 4 6 8 10 12 13.5 -19 13 12.5 -20 12 11.5 -21 11 -22 10.5 10 -23 9.5 9 -24 0 2 4 6 8 10 12 MIXED: Shelf, benthic dives, open water, mixed 13C and 15N values
    9. 9. 1- INVESTIGATING FORAGING STRATEGIES 13C 15N F256 F256 -18 14 0 2 4 6 8 10 12 13.5 -19 13 12.5 -20 12 11.5 -21 11 -22 10.5 10 -23 9.5 9 -24 0 2 4 6 8 10 12 WAP: Feed on the shelf, some benthic dives, lower 13C and higher 15N F292-293 F292-293 Different C and N profiles -18 14 0 2 4 6 8 10 12 13.5 -19 13 12.5 -20  Different isotopic signature for seals 12 11.5 -21 11 -22 10.5 10 feeding in different geographic areas -23 9.5 9 -24 0 2 4 6 8 10 12 OPEN WATER: No shelf, no benthic dives, higher 13C and lower 15N F209 F209 -18 14 0 2 4 6 8 10 12 13.5 -19 13 12.5 -20 12 11.5 -21 11 -22 10.5 10 -23 9.5 9 -24 0 2 4 6 8 10 12 MIXED: Shelf, benthic dives, open water, mixed 13C and 15N values
    10. 10. 1- INVESTIGATING FORAGING STRATEGIES 13C 15N 13C 15N F252 F252 -18 14 0 2 4 6 8 10 12 13.5 -19 13 12.5 -20 12 11.5 -21 11 -22 10.5 10 -23 9.5 9 -24 0 2 4 6 8 10 12
    11. 11. 1- INVESTIGATING FORAGING STRATEGIES 13C 15N F261 F261 -18 14 0 2 4 6 8 10 12 13.5 -19 13 12.5 -20 12 11.5 -21 11 -22 10.5 10 -23 9.5 9 -24 0 2 4 6 8 10 12 Similar C profile but different N profile 15 13C N Seals (from same gender and age class) F252 F252 that forage in same habitat feed on prey -18 -19 0 2 4 6 8 10 12 14 13.5 13 12.5 from different trophic level -20 12 11.5 -21 11 -22 10.5 10 Why? How? -23 -24 9.5 9 0 2 4 6 8 10 12
    12. 12. 2- IDENTIFYING FORAGING EVENT Translocation study: Kerguelen Island (49°S 69°E) 3 adult female southern elephant seals (T3, T4 and T5) Satellite tags (SMRU, St Andrews, UK): Provided an estimate of the location of the animal at sea and on land Accelerometer tags (Loggend, CNRS, France): Placed on neck of the animal to detect feeding event 2-D accelerations (heave and surge) at 8 Hz (T4 and T5) and 16 Hz (T3) Depth sensor at 1 Hz
    13. 13. 2- IDENTIFYING FORAGING EVENT Heave Surge 400 m Static acceleration gravity or pitch Dynamic acceleration movements of the seals resulting from either stroking and/or rapid head movements
    14. 14. 2- IDENTIFYING FORAGING EVENT Heave Surge Threshold 400 m Matlab (version 7.0.1) Low pass filter to extract static (gravitational) acceleration Feeding event acceleration spikes over the threshold Feeding dive acceleration profiles with more than one spike present in both the surge and heave axes
    15. 15. 2- IDENTIFYING FORAGING EVENT
    16. 16. Climate Ocean resources Demography Oceanographers Biologists Oceanographic Distribution and conditions availability of prey- Temperature - Prey species- Salinity - Prey encounter- Fluorescence - Foraging efficiency- Dissolve oxygen - Life history
    17. 17. 3- FUTURE WORK
    18. 18. 4- Merging expertise It may be possible to use seal tracking data to locate deep-sea coral habitats and furthermore to use bio-logging equipment attached to seals as platforms for ocean sensors to relay physical ocean data (e.g. salinity, temperature) from the areas they frequent. These physical data may be in turn be used to better identify and protect cold water coral habitats.
    19. 19. Thank you

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