Abundance of walruses in Eastern Baffin Bay and Davis Strait

Authors

  • Mads Peter Heide-Jørgensen Greenland Institute of Natural Resources
  • Kristin Laidre Polar Science Center, Applied Physics Laboratory
  • Sabrina Fossette
  • Marianne H Rasmussen
  • Nynne Hjort Nielsen
  • Rikke G Hansen

DOI:

https://doi.org/10.7557/3.2606

Keywords:

walrus, Odobenus rosmarus, abundance, aerial survey, West Greenland

Abstract

Walruses (Odobenus rosmarus) are exploited for subsistence purposes in West Greenland. However, current information about the abundance of walruses subject to harvest in eastern Baffin Bay subject to harvest has been unavailable despite being critical for maintaining sustainable catch levels. Three visual aerial surveys were conducted in 2006 (21 March to 19 April 2006), 2008 (3 to 12 April) and 2012 (24 March to 14 April) to estimate the number of walruses on the wintering grounds in eastern Baffin Bay and Davis Strait. Data on the fraction of walruses that were submerged below a 2m detection threshold during the surveys were obtained from 24 walruses instrumented with satellite-linked-time-depth-recorders in northern Baffin Bay in May-June 2010-2012. An availability correction factor was estimated at 36.5% (cv=0.08) after filtering of data for an observed drift of the pressure transducer of more than 2.5 m. The surveys resulted in walrus abundance estimates that were corrected for walruses submerged below a detection threshold and for walruses that were missed by the observers. The estimates of abundance were 1,105 (cv=0.31, 95% CI 610-2,002) in 2006, 1,137 (0.48, 468-2,758) in 2008 and 1,408 (0.22, 922-2,150) in 2012. 

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Published

2014-12-15

How to Cite

Heide-Jørgensen, M. P., Laidre, K., Fossette, S., Rasmussen, M. H., Nielsen, N. H., & Hansen, R. G. (2014). Abundance of walruses in Eastern Baffin Bay and Davis Strait. NAMMCO Scientific Publications, 9, 159–171. https://doi.org/10.7557/3.2606