Comparison of mandibular with cemental growth-layer counts for ageing Atlantic walrus (Odobenus rosmarus rosmarus)

Garlich‐Miller, Joel L.; Stewart, Robert E.; Stewart, Barbara E.; Hiltz, E. A.

doi:10.1139/z93-022

Cited by 38 publications

(25 citation statements)

References 3 publications

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“…Capture dates ranged from 1988 to 1996. Mandibular teeth were extracted at time of capture (or, in the case of Greenland samples, from mandibles in the laboratory) for later sectioning and ageing by enumeration of dental cementum growth layers (Garlich-Miller et al, 1993). Teeth were chosen as indicator tissues for isotope analysis because they grow incrementally through life and are not resorbed (Fay, 1982;Hillson, 1986).…”

Section: Methodsmentioning

confidence: 99%

Investigation of the Stock Structure of Atlantic Walrus (Odobenus rosmarus rosmarus) in Canada and Greenland Using Dental Pb Isotopes Derived from Local Geochemical Environments

Outridge¹,

Davis²,

Stewart³

et al. 2003

ARCTIC

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ABSTRACT. The chemical composition of animal tissues such as teeth appears to reflect an individual's exposure to its geochemical environment. In this study, the lead (Pb) isotope composition of dental cementum was used to investigate the stock structure of Atlantic walrus (Odobenus rosmarus rosmarus) in the Canadian Arctic and Greenland. The 12 communities providing walrus samples for this study represent most of the Canadian and Greenlandic villages where walrus still form an important part of the traditional Inuit diet. Significant differences between locations in mean Pb isotope ratios and the limited overlap of the ranges of values indicate that each village harvested walrus herds that exploited substantially different geological/geographical habitats. This geographic segregation based on isotopic signatures suggests that most walrus stocks (i.e., the groups of walrus that interact with hunters at each community) are more localized in their range than previously thought.208 Pb/ 207 Pb and 208 Pb/ 204 Pb were the most important stock discriminators, reflecting the influence of local geological Th/U composition (i.e., 208 Pb) on Pb isotope composition in walrus teeth.204 Pb-based isotope ratios in walrus were consistently higher (more radiogenic) and more homogeneous than those in regional terrestrial bedrock, a difference probably due to selective leaching of radiogenic Pb from mineral phases into seawater and mixing during weathering and transport. Dental Pb isotope signatures may have widespread application to stock discrimination of other coastal marine mammal species.Key words: walrus, Odobenus rosmarus rosmarus, teeth, lead isotopes, stock discrimination RÉSUMÉ. La composition chimique de tissus animaux tels que les dents semble refléter l'exposition d'un individu à son milieu géochimique. Pour la présente étude, on a utilisé la composition isotopique du plomb (Pb) contenu dans le cément pour examiner la structure du stock du morse de l'Atlantique (Odobenus rosmarus rosmarus) dans l'Arctique canadien et le Groenland. Les 12 communautés qui ont fourni les échantillons de morse pour ce projet représentent la majorité des villages canadiens et groenlandais où le morse constitue toujours une grande partie du régime alimentaire traditionnel des Inuits. Des différences marquées entre les sites dans la moyenne des rapports isotopiques du Pb et le faible recoupement des gammes de valeurs révèlent que chaque village prélevait des morses au sein de troupeaux qui exploitaient des habitats géologiques/géographiques bien distincts. Cette ségrégation géographique fondée sur des signatures isotopiques suggère que la plupart des stocks de morses (c.-à-d. le groupe de morses qui interagit avec les chasseurs dans chaque communauté) sont plus localisés dans leur territoire qu'on ne le pensait auparavant.208 Pb/ 207 Pb et 208 Pb/ 204 Pb étaient les grands caractères discriminants des stocks, reflétant l'influence de la composition géologique locale Th/U (c-à-d.208 Pb) sur la composition isotopique du Pb dans les dents ...

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Section: Methodsmentioning

confidence: 99%

Investigation of the Stock Structure of Atlantic Walrus (Odobenus rosmarus rosmarus) in Canada and Greenland Using Dental Pb Isotopes Derived from Local Geochemical Environments

Outridge¹,

Davis²,

Stewart³

et al. 2003

ARCTIC

View full text Add to dashboard Cite

show abstract

“…Females Ͻ 5-yr-old and males Ͻ 7-yr-old were considered juveniles (MacLaren, 1958). Ages of walrus were determined by counting dental annuli in the teeth (Garlich-Miller et al, 1993). Females Ͻ 6-yrold and males Ͻ 8-yr-old were considered to be juveniles (Fay, 1985).…”

Section: Pinnipedsmentioning

confidence: 99%

Serologic Survey of Brucella Spp. Antibodies in Some Marine Mammals of North America

Nielsen

Stewart

Nielsen

et al. 2001

Journal of Wildlife Diseases

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A serologic survey of anti-Brucella spp. antibodies was undertaken on 2,470 samples of 14 North American marine mammal species collected between 1984-97. Serum or blood from eight species of cetaceans and six species of pinnipeds was sampled from Pacific, Atlantic, and Arctic oceans. Two competitive enzyme-linked immunosorbent assays (C-ELISA's), using specific monoclonal antibodies to Brucella abortus cell wall components, were used to detect anti-Brucella spp. antibodies in the samples. Sera from 33 cetaceans and 61 pinnipeds gave inhibition values, in one or both of the tests, which exceeded the threshold that indicates Brucella spp. exposure in cattle. Seropositive animals were identified from Pacific, Atlantic, and Arctic oceans. While Brucella spp. was not isolated, differences in the response of seropositive cetacean and pinniped sera in the two assays suggest that two antigenically distinct species or biovars of Brucella spp. are present. No pathology consistent with clinical brucellosis was noted in any of the animals tested although detailed examination was not conducted on all carcasses.

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“…Generally, cementum in delphinids and phocoenids is not well developed and has inconspicuous layers so dentine is used for age estimation (Lockyer et al 1981, Myrick et al 1983, Hohn 2009). Cementum normally provides better clarity of GLGs for carnivores such as pinnipeds, sea otters and polar bears because the pulp cavity often becomes occluded (e.g., McLaren 1958a,b, Hewer 1964, Dietz et al 1991, Garlich-Miller et al 1993, Stewart et al 1996, Calvert and Ramsay 1998, Amano et al 2000 or dentine deposition is too irregular to resolve GLGs, especially last-deposited small layers (Myrick et al 1983, Bjørge et al 1995, Hohn 2009). …”

Section: Nammco Scientific Publications Volume 10 11mentioning

confidence: 99%

“…Thus, most studies have found significantly fewer GLGs than in other hard tissues, e.g., teeth, in the same animal, especially in older animals (Nishiwaki et al l961, Kleinenberg and Klevezal 1962, Petersen and Born 1982, Garlich-Miller et al 1993. Therefore, the use of most bones to obtain absolute age estimates is unsatisfactory when age can be obtained using other tissue or methods.…”

Section: Other Bonesmentioning

confidence: 99%

A review of age estimation methods in marine mammals with special reference to monodontids

2018

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This paper presents a critical review of methods for estimating absolute or relative age in marine mammals. Absolute age is achieved by counting growth layer groups (GLGs) in hard structures such as teeth, ear plugs, baleen, bones and claws. Relative age can be obtained by methods such as aspartic acid racemisation, genetic telomeres, bone mineral density, fatty acid signatures and other methods. Each method is discussed in detail. Accuracy and precision, including inter-reader calibration and anomalies, as well as methods of validating GLG deposition rates are also addressed. Each section concludes with methods of age estimation applicable to monodontids, and suggestions on the focus of future age-estimation research.

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Comparison of mandibular with cemental growth-layer counts for ageing Atlantic walrus (Odobenus rosmarus rosmarus)

Cited by 38 publications

References 3 publications

Investigation of the Stock Structure of Atlantic Walrus (<i>Odobenus rosmarus rosmarus</i>) in Canada and Greenland Using Dental Pb Isotopes Derived from Local Geochemical Environments

Investigation of the Stock Structure of Atlantic Walrus (<i>Odobenus rosmarus rosmarus</i>) in Canada and Greenland Using Dental Pb Isotopes Derived from Local Geochemical Environments

Serologic Survey of Brucella Spp. Antibodies in Some Marine Mammals of North America

A review of age estimation methods in marine mammals with special reference to monodontids

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