Trace element and stable isotope analysis elucidate stock structure in a narwhal ( Monodon monoceros ) population with no genetic substructure

• Published in: Canadian Journal of Zoology
• Main Authors: Watt, Cortney A., Hornby, Claire, Ferguson, Steven H.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Canadian Science Publishing 2019
• Subjects: Animal Science and Zoology; Ecology, Evolution, Behavior and Systematics; Arctic; Baffin Bay; Canada; Somerset Island; Jones Sound; Eclipse Sound; Admiralty Inlet; Baffin; Monodon monoceros; narwhal*
• Online Access: http://dx.doi.org/10.1139/cjz-2018-0307; http://www.nrcresearchpress.com/doi/full-xml/10.1139/cjz-2018-0307; http://www.nrcresearchpress.com/doi/pdf/10.1139/cjz-2018-0307

Chemical composition of tissues can act as a biological tag to discriminate among groups of animals that inhabit different areas. In Canada, subsistence hunting of the Baffin Bay narwhal (Monodon monoceros Linnaeus, 1758) population is managed as stocks represented by summer aggregations. However, narwhals are highly mobile and are hunted during the migration while stocks mix. Thus, information that can help managers decipher the stock origin of hunted individuals to prevent overexploitation of animals adapted to particular summering grounds is needed. Stable isotope and trace element analyses were conducted on narwhal skin tissues from five stocks in the eastern Canadian Arctic from 1990 to 2015. Discriminant analysis showed a significant difference between Admiralty Inlet and Eclipse Sound stocks in the summer residency period and both differed from Jones Sound and Somerset Island. During the migration season, there was more overlap and less distinction among stocks, but 75% of animals were classified correctly to their defined stocks in both periods. Together stable isotope and trace element analyses are useful for delineating stocks and could be used to complement other stock discrimination approaches.