Research Document - 2014/017

Preliminary investigation of genetic capture-mark-recapture to census bowhead whales (Balaena mysticetus) in Nunavut, Canada

By Stephen D. Petersen, Lucy Johnson, Bernard LeBlanc, Jeff W. Higdon, Dave Yurkowski, Cory Matthews, Lianne Postma, and Steve H. Ferguson

Abstract

Cost effective and efficient methods to census marine mammals are needed to monitor and manage populations. In bowhead whales, aerial surveys are commonly used but can be cost prohibitive and may not be capable of tracking individual animals unless coupled with photographic identification. Genetic capture-mark-recapture (gCMR) techniques are being used more often and may be able to both estimate local population size and to track animals as they move throughout the population’s range. This research summarizes recent gCMR efforts on bowhead whales in the eastern Canadian Arctic and presents preliminary local abundance estimates. 714 skin samples have been collected sporadically over multiple years and locations. Collections were obtained during spring and summer from either boats or the floe edge and crossbow deployed 40- or 60mm biopsy darts. DNA was extracted and used to determine sex, mitochondrial haplotype, and to generate a microsatellite loci profile for all samples. Removing animals that were sampled multiple times resulted in samples from 642 individual whales sampled between 1995 and 2012. Although the long-term objective is to use the data to generate a population estimate, the current report summarizes recaptures among years and location and preliminary abundance estimates are limited to Foxe Basin (593 and 230 in 2009 and 2012, respectively) and Cumberland Sound (188 and 566 in 2011 and 2012, respectively). The simple local-annual estimates reported here are not useful for management purposes but serve to illustrate the utility of the proposed approach. Future research plans include conducting a more sophisticated capture-mark-recapture abundance analyses on these data to generate demographic models. Adding more recent samples, such as from 2013, and including data from west Greenland could lead to a robust abundance estimate for the eastern Canadian-west Greenland bowhead whale population.

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