Abstract
Population estimates are important for the development of management plans of harvested species and thereby ultimately important for species sustainability. Aerial surveys are one of the methods used in preparing population estimates. For marine mammals, aerial population surveys require that animal biology is understood in order to account for availability bias. Availability bias in this case derives from animals that are invisible to the survey due to diving behavior. In order to understand diving behavior of the Northern Hudson Bay narwhal (Monodon monoceros), nine whales were tagged with satellite tracking devices in the Repulse Bay, Nunavut area in August 2006 (n = 5) and 2007 (n = 4). Of specific interest was time at depth of 0–2 m of water, the depth at which studies have shown that whales could be distinguished at the species level during an aerial survey. The proportion of time spent in 0–2 m of water can then be used to correct the population estimate from aerial survey. This research found that narwhals spent approximately 32 % of their time at the surface where they would be available to be seen by an aerial survey. This paper provides raw data that can be used to correct population survey estimates.
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References
Armitage DR (2005) Community-based narwhal management in Nunavut, Canada: change, uncertainty, and adaptation. Soc Nat Res 18:715–731
Asselin NC, Ferguson SH, Richard PR, Barber DG (2012) Results of narwhal (Monodon monoceros) aerial surveys in Northern Hudson Bay, August 2011. DFO Can Sci Advis Sec Res Doc 2012/037, iii + 23 p
Bourassa MN (2002) Inventaries de la population de narvals (Monodon monoceros) du nord de la Baie D’Hudson et analyse des changements demographiques depuis 1983. Dissertation, Universite du Quebec
Department of Fisheries and Oceans (1998a) Hudson Bay narwhal. Fisheries and Oceans Canada, Central and Arctic Region, DFO Science Stock Status Report E5–44
Department of Fisheries and Oceans (1998b) Baffin Bay narwhal. Fisheries and Oceans Canada, Central and Arctic Region, DFO Science Stock Status Report E5–43
Dueck LP (1989) The Abundance of narwhal (Monodon monoceros) in Admiralty Inlet, Northwest Territories, Canada, and implications of behaviour for survey estimates. Dissertation, University of Manitoba
Heide-Jørgensen MP, Dietz R (1995) Some characteristics of narwhal (Monodon monoceros) diving behaviour in Baffin Bay. Can J Zool 73:2120–2132
Heide-Jørgensen MP, Hammeken N, Dietz R, Orr J, Richard PR (2001) Surfacing times and dive rates for narwhals (Monodon monoceros) and beluga (Delphinapterus leucas). Arctic 54:284–298
Innes S, Heide-Jørgensen MP, Laake JL, Laidre KL, Cleator HJ, Richard P, Stewart REA (2002) Surveys of beluga and narwhal in the Canadian High Arctic in 1996. NAMMCO Sci Publ 4:69–190
Laidre KL, Heide-Jørgensen MP, Dietz R (2002) Diving behavior of narwhal (Monodon monoceros) at two costal localities in the Canadian High Arctic. Can J Zool 80:624–635
Legendre P (1993) Spatial autocorrelation: trouble or new paradigm? Ecology 74:1659–1673
Martin AR, Kingsley MCS, Ramsay MA (1994) Diving behavior of narwhals (Monodon monoceros) on their summer grounds. Can J Zool 72:118–125
Orr JR, Joe R, Evic D (2001) Capturing and handling of white whales (Delphinapterus leucas) in the Canadian Arctic for instrumentation and release. Arctic 54:299–304
Reeves RR, St. Aubin DJ (2001) Beluga and narwhals: application of new technology to whale science in the Arctic. Arctic 54:iii–vi
Richard PR (1991) Abundance and distribution of narwhals (Monodon monoceros) in Northern Hudson Bay. Can J Fish Aquat Sci 48:276–283
Richard P, Weaver P, Dueck L, Barber D (1994) Distribution and numbers of Canadian High Arctic narwhals (Monodon monoceros) in August 1984. Meddelelser om Grønland Bioscience 39:41–50
Richard PR, Laake JL, Hobbs RC, Heide-Jørgensen MP, Asselin NC, Cleator H (2010) Baffin Bay narwhal population distribution and numbers: aerial surveys in the Canadian High Arctic, 2002–04. Arctic 63:85–99
Westdal KH (2009) Movement and diving of Northern Hudson Bay narwhals (Monodonmonoceros): relevance to stock assessment and hunt co-management. Dissertation, University of Manitoba
Westdal KH, Richard PR, Orr JR (2010) Migration route and seasonal home range of the Northern Hudson Bay narwhal (Monodon monoceros). In: Ferguson SH, Loseto LL, Mallory ML (eds) A little less Arctic: top predators in the world’s largest Northern inland sea. Springer, London, pp 71–91
Acknowledgments
Funding for this research was provided by Fisheries and Oceans Canada, the University of Manitoba, ArcticNet, and the Northern Scientific Training Program. We gratefully acknowledge the assistance of Marius Tungilik, the project interpreter, and numerous field assistants. We would also like to thank the Hunters and Trapper Association and community of Repulse Bay, along with Drs. Rick Riewe and Nicola Koper for helpful discussion and review. The authors also thank three anonymous reviewers and the editors of Polar Biology for thoughtful and careful review that resulted in considerable improvements of this manuscript.
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Westdal, K.H., Richard, P.R. & Orr, J.R. Availability bias in population survey of Northern Hudson Bay narwhal (Monodon monoceros). Polar Biol 36, 1235–1241 (2013). https://doi.org/10.1007/s00300-013-1342-4
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DOI: https://doi.org/10.1007/s00300-013-1342-4