Narwhal (Monodon monoceros) diet and dive behaviour as an assessment of foraging adaptability with changing climate
| dc.contributor.author | Watt, Cortney | |
| dc.contributor.examiningcommittee | Roth, Jim (Biological Sciences) Manseau, Micheline (Natural Resources Institute) Brigham, Mark (Biology, University of Regina) | en_US |
| dc.contributor.supervisor | Ferguson, Steve (Biological Sciences) | en_US |
| dc.date.accessioned | 2014-12-19T00:01:23Z | |
| dc.date.available | 2014-12-19T00:01:23Z | |
| dc.date.issued | 2013 | en_US |
| dc.date.issued | 2014 | en_US |
| dc.degree.discipline | Biological Sciences | en_US |
| dc.degree.level | Doctor of Philosophy (Ph.D.) | en_US |
| dc.description.abstract | Narwhals (Monodon monoceros) are sentinel species in the Arctic environment and are a vital component for Inuit culture and subsistence. The Arctic is undergoing rapid changes in temperature and sea ice cover and relatively little is known about how this has and will change narwhal foraging behaviour. There are three narwhal populations in the world, the Baffin Bay (BB), Northern Hudson Bay (NHB), and East Greenland (EG) populations; however, foraging behaviour, in terms of dive behaviour and primary dietary components, has really only been investigated in the BB population. Using a combination of stable isotopes, fatty acids, genetic techniques, and satellite tracking technologies I evaluated foraging behaviour in all three of the world’s narwhal populations. I also investigated social structure in the BB population to determine how adaptable narwhals are to a changing and dynamic Arctic environment. Stable isotopes (δ13C and δ15N) and fatty acids are chemical signatures in the tissues of an organism that can provide long-term information on their diet over varying temporal scales depending upon the tissue. Stable isotope analysis in the three narwhal populations found they forage on different primary prey, suggesting narwhal are adaptable in their preferred prey and that there is potential for them to adjust foraging behavior in the face of changing climate. Dietary changes were also assessed over three decades to determine how sea ice changes have affected narwhal foraging for the NHB and BB populations. Dietary changes were evident and can be attributed to changes in sea ice patterns and an altered migratory pathway for narwhals. An understanding of narwhal social structure is also needed to determine how behaviourally flexible narwhal are in diet and site fidelity. Genetic relatedness and dietary signatures from fatty acids were assessed for an entrapped group to determine if individuals that are closely related forage together, which would support a matrilineally driven social structure where females teach their young foraging strategies, and/or travel and forage together. I found no evidence that narwhals form a matrilineal social group, but they may display a fission-fusion structure, which may be an adaptation to patchy prey distribution in the Arctic. Finally, narwhal dive behaviour in all three populations was investigated to determine if dive behaviour could be used to predict diet. Dive differences among populations did correspond with differences in diet, suggesting that narwhals employ specialized foraging strategies. This has repercussions for their ability to adapt to ecosystem changes. Overall, narwhals may be more flexible in terms of their foraging behaviour than previously believed. However, an increased resilience to changing food webs will not be the only predictor of how narwhals will fare in the face of a changing climate; how they respond to increased industrial activities in their preferred habitats, increased predation from southern predators, and increased competition from southern cetaceans and humans alike, will play an equally large role in how they cope with the future. | en_US |
| dc.description.note | February 2015 | en_US |
| dc.identifier.citation | Watt, C. A., M. P. Heide-Jørgensen, and S. H. Ferguson. 2013. How adaptable are narwhal: a comparison of foraging patterns among the world’s three narwhal populations. Ecosphere 4(6):71. http://dx.doi.org/10.1890/ ES13-00137.1 | en_US |
| dc.identifier.citation | Watt, C. A., and Ferguson, S. H. 2014. Fatty acids and stable isotopes (δ13C and δ15N) reveal temporal changes in narwhal (Monodon monoceros) diet linked to migration patterns. Marine Mammal Science. doi: 10.1111/mms.12131 | en_US |
| dc.identifier.uri | http://hdl.handle.net/1993/30138 | |
| dc.language.iso | eng | en_US |
| dc.publisher | Ecosphere | en_US |
| dc.publisher | Marine Mammal Science | en_US |
| dc.rights | open access | en_US |
| dc.subject | narwhal | en_US |
| dc.subject | foraging | en_US |
| dc.subject | stable isotope | en_US |
| dc.subject | fatty acid | en_US |
| dc.subject | satellite tagging | en_US |
| dc.title | Narwhal (Monodon monoceros) diet and dive behaviour as an assessment of foraging adaptability with changing climate | en_US |
| dc.type | doctoral thesis | en_US |