Thesis (Ph. D.)--University of Washington, 2003. / Vita. Includes bibliographical references (leaves 144-164).

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The life history of the narwhal Monodon monoceros was studied utilizing animals captured by the Inuit in northern Baffin Island. Segregation by age and sex within this population is evident, with summering groups consisting of mature females with calves, immature and maturing males, and large mature males. The diet consists of arctic cod, shrimp, and squid during June and July, but feeding activity declines markedly during the open-water months of August and September. Growth layers in the unerupted teeth and periosteal zone of the mandible were found to be related to age but absolute rates of accumulation of these layers are uncertain. The maximum life span is estimated to be 40 to 50 years. Male narwhals, which mature sexually at lengths exceeding 390 cm and at 16-17 growth layers, display protracted maturation and a possible annual cycle of spermatogenesis. Females, which mature sexually at lengths exceeding 340 cm and at 12 growth layers, are seasonally polyoestrous, experiencing up to four consecutive ovulations during the breeding season. The gestation period is estimated to be 15.3 months. The season of conceptions is March to May and calving occurs during July and August. Since the lactation period exceeds 12 months, the interval between successive conceptions is usually three years, but about 20% of females conceive at the first breeding season following birth of their calves. The annual population birth rate is calculated to be about 0.07. The basic life history features of the narwhal are similar to those of other medium-sized toothed whales.

Graduation date: 1982

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The hunting of narwhals (Monodon monoceros) has been an important element in the cultural and economic life of indigenous people in the eastern Canadian Arctic and Greenland for centuries. This dissertation explores factors that have motivated the hunters and ways that non-indigenous forces have intervened to restrict hunting activities. Particular attention is paid to commercial (trade) aspects of the hunt and to how these have developed and changed through time. Concern about narwhal conservation first arose during the late 1960s and early 1970s. This concern has focused on a presumed positive correlation between the monetary value of tusk ivory for export and the intensity of hunting by the Inuit. An idealized model of conflict development and resolution is used to facilitate comparisons among six cases, including bowhead whale (Balaena mysticetus) hunting in Alaska, beluga (Delphinapterus leucas) hunting in southeastern Baffin Island and northern Quebec, dugong (Dugong dugon) hunting in Australia and Papua New Guinea, and narwhal hunting in Canada. These comparisons suggest that the conflict surrounding narwhal-hunt management is in a middle to late phase of development. Also, its commercial dimensions and geographically dispersed markets for products (ivory and maktaq) distinguish the narwhal hunt from the other marine-mammal hunts considered here. The continuing demand for narwhal products necessitates a hunt-management regime that is rooted in scientific knowledge, has legitimacy in Inuit communities, and keeps the kill rate within sustainable bounds.

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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.

This thesis considers the environmental, economic, social, and cultural effects of increasing shipping activities around Sirmilik National Park of Canada, in order to develop possible scoping questions for future environmental assessments. Using a qualitative approach, 25 semi-structured interviews, two focus groups, observation, and field notes were used to collect data which are then analyzed for linkages between valued environmental and social components and the potential effects from shipping and associated activities. The most prominent concern that emerged regarded the potential impacts to migrating and breeding narwhal in the area. Many respondents also discussed economic and social issues because they perceive increasing shipping as a signal of economic growth. In total, 124 scoping questions were developed in 17 direct environmental impact areas identified by participants, as well as 53 scoping questions relating to cumulative effects and strategic issues. The thesis concludes with some broader management implications that flow from the analysis.