ACCURACY OF AGE DETERMINATION IN THE GREY SEALHALICHOERUS GRYPUSOF EASTERN CANADA
作者:
A. W. Mansfield,
期刊:
Marine Mammal Science
(WILEY Available online 1991)
卷期:
Volume 7,
issue 1
页码: 44-49
ISSN:0824-0469
年代: 1991
DOI:10.1111/j.1748-7692.1991.tb00549.x
出版商: Blackwell Publishing Ltd
关键词: Pinnipedia;Phocidae;grey seal;Halichoerus grypus;age determination;teeth;growth layers
数据来源: WILEY
摘要:
AbstractThe ages of 82 grey seals of known age from 1 to 10 yr were determined from growth layer groups in the cementum, readily seen in longitudinal sections 150 μm thick viewed under transmitted light. The sample of teeth was read five times in a series of blind replicates.With only one reading, an accuracy of 84% was achieved. This increased to 93% on the basis of three readings but improved only marginally to 94% when all five readings were considered. Accuracy was best in the middle range of ages (3–6 yr) which are the critical years for estimating age‐specific reproductive rates in population mo
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