Statistical modeling of baleen and body length at age in bowhead whales ( Balaena mysticetus )

• Published in: Canadian Journal of Zoology
• Main Authors: Lubetkin, S.C., Zeh, J.E., George, J.C.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Canadian Science Publishing 2012
• Subjects: Animal Science and Zoology; Ecology, Evolution, Behavior and Systematics; Balaena mysticetus
• Online Access: http://dx.doi.org/10.1139/z2012-057; http://www.nrcresearchpress.com/doi/full-xml/10.1139/z2012-057; http://www.nrcresearchpress.com/doi/pdf/10.1139/z2012-057

We used baleen lengths and age estimates from 175 whales and body lengths and age estimates from 205 whales to test which of several single- and multi-stage growth models best characterized age-specific baleen and body lengths for bowhead whales ( Balaena mysticetus L., 1758) with the goal of determining which would be best for predicting whale age based on baleen or body length. Previous age estimates were compiled from several techniques, each of which is valid over a relatively limited set of physical characteristics. The best fitting single-stage growth model was a variation of the von Bertalanffy growth model for both baleen and body length data. Based on Bayesian information criterion, the two- and three-stage versions of the von Bertalanffy model fit the data better than did the single-stage models for both baleen and body length. The best baleen length models can be used to estimate expected ages for bowhead whales with up to 300–325 cm baleen, depending on sex, which correspond to age estimates approaching 60 years. The best body length models can be used to estimate expected ages for male bowhead whales up to 14 m, and female bowheads up to 15.5 m or ages up to approximately 40 years.