Age determination and age related factors in the teeth of Western North Atlantic bottlenose dolphins.

Hohn, Aleta A. (1980) Age determination and age related factors in the teeth of Western North Atlantic bottlenose dolphins. Scientific Reports of the Whales Research Institute(32), pp. 39-66.

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Official URL: http://swfsc.noaa.gov/publications/CR//1980/8026.P...

Abstract

Teeth were taken from 120 bottlenose dolphins, Tursiops truncatus, which had stranded on the mid-Atlantic coast of the United States. The number of annual growth layer groups (GLGs) for each animal was used to construct a growth curve. The growth rate of coastal North Atlantic Ocean Tursiops is similar to other cetaceans in having a high initial rate of growth, with no differences in growth between females and males. In females, the first dentinal GLG is thickest and is followed by GLGs which become progressively narrower. In males, the second GLG is thicker than the first; GLGs beyond number two become progressively smaller but at a slower rate than in females. In males and females, the translucent layer makes up proportionally larger parts of the GLG as the animal ages, but in males the percent translucent layer remains constant at about 50% while in females it continues to increase up to about 70% of the GLG. These two factors, GLGs width and translucent layer width, indicate that the sex and age of the animal influence the deposition of GLGs. Incremental layers are also present, averaging 12 per GLG, and seem similar to incremental layers described in other marine mammals. A plot of the relationship of percent growth of the last GLG to time of death suggests that the deposition of GLGs is relatively constant, at least during the first half of the year, and that North Atlantic Ocean Tursiops give birth in the fall as well as in the spring. (PDF contains 31 pages.)

Item Type: Article
Title: Age determination and age related factors in the teeth of Western North Atlantic bottlenose dolphins.
Personal Creator/Author:
CreatorsEmail
Hohn, Aleta A.
Refereed: Yes
Journal or Publication Title: Scientific Reports of the Whales Research Institute
Number: 32
Page Range: pp. 39-66
Date: 1980
Issuing Agency: United States National Marine Fisheries Service
Subjects: Ecology
Conservation
Fisheries
Item ID: 2457
Depositing User: Patti M. Marraro
Date Deposited: 20 Jul 2009 18:08
Last Modified: 29 Sep 2011 19:05
URI: http://aquaticcommons.org/id/eprint/2457

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