1. Walrus: Large marine mammal Tusks Pinniped
Odobenus Rosmarus
Walrus:
Large marine mammal
Tusks
Pinniped

2. Ecology & Distribution
Arctic Regions
Two main populations:
Atlantic walrus
Pacific walrus
Migration

3. Mark-Recapture Most common method used in ecology. Set up traps.
Take samples of walrus population.
Analyze data and calculate mathematically.

4. LIDAR LIght Detection And Ranging
Advantages of the LIDAR
method.
Sends out harmless beams.
Easier and faster to
determine the population size.

5. There is no perfect method!
Conclusion
There is no perfect method!

6. References
Born, E. W., Gjertz, I. and Reeves, R. R. (1995). Population assessment of the Atlantic walrus (Odobenus rosmarus rosmarus L.). Norsk Polarinstitutt Meddelelser nr pp 100.
Microsoft Encarta Microsoft Corporation.
David G. B., Pierre R. R., Klaus P. H. and Jack O Walrus Population Assesment. Calibration of Aerial Thermal Infrared Imagery for Walrus Population Assessment. Arctic 44:56-65.

7. Odobenus Rosmarus

8. Age determination methods of the Odobenus Rosmarus
Three basic methods.
Method 1: Hard structured layers!
Dental material
Removing and counting
If canine teeth damaged? alternative teeth can be used.
Jaws of killed walruses are collected or capture-release technique used.

9. Method 2: Body characteristics
Life span +/-16-40
Mass adult(1700kg) newborns(38kg)
Figure feature changes
Hair colour (cinnamon)
Hair thinning

10. Method 3:behaviour Observations Atlantic and Pacific
Migration patterns

11. Cont. method 3: behaviour
Method possible by constant movement monitoring

12. References
Mammalian Species. No 238 pp.1-7. Odobenus Rosmarus by Francis H.Fay. Pub 25 May 1985 by the American Society of Mammologists
Comparison of tooth age estimate of Atlantic Walruses (Odobenus Rosmarus) Marine Mammal Science. Vol 21, issue 2, pp
www3.interscience.Wiley.com/journal