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- Title
Biases in dolphin age structure due to age estimation technique
- Authors
Hohn, Aleta A.; Fernandez, Stephanie
- Abstract
The use of different tooth-preparation techniques resulted in widelydifferent estimates of age in a sample of bottlenose dolphins, Turriops truncatus. Teeth from 30 animals were prepared using the two mostprevalent techniques reported in the literature for this species, unstained sections and decalcified and stained thin sections, and the resulting paired counts of growth layers were compared. Estimates fromthe two methods were identical or at least placed the specimen in the same age class in only five cases, ranging in age from 2 to 22 yr. Otherwise, the results fell into one of two categories: when the estimates were close (=/<3-yr difference, n = 15), counts from unstained sections generally were higher (13 cases, age from unstained sections2-20 yr); when the counts were more disparate, estimates from stained sections always were higher (6-31 yr difference, n = 10, age from unstained sections 12-27 yr and corresponding ages from stained sections of 27-47). Previous studies of age estimation in known-age bottlenose dolphins indicate that stained sections allow accurate estimates of age and demonstrate that maximum lifespan approaches or exceeds 50yr. In contrast, the results herein suggest that using unstained sections for age estimation may result in imprecise or biased age-structure data.
- Subjects
ANIMALS; LONGEVITY; MARINE biology
- Publication
Marine Mammal Science, 1999, Vol 15, Issue 4, p1124
- ISSN
0824-0469
- Publication type
Article
- DOI
10.1111/j.1748-7692.1999.tb00881.x