Abundance Estimation of Diving Animals by the Double‐Platform Line Transect Method

Summary . In conventional line transect theory, it is assumed that all animals on the line are detected. This article introduces an extended and generalized hazard probability model without the need for such an assumption. The proposed method needs a survey design with independent observers having t...

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Bibliographic Details
Published in:Biometrics
Main Authors: Okamura, Hiroshi, Kitakado, Toshihide, Hiramatsu, Kazuhiko, Mori, Mitsuyo
Format: Article in Journal/Newspaper
Language:English
Published: Wiley 2003
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Online Access:http://dx.doi.org/10.1111/1541-0420.00061
https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1111%2F1541-0420.00061
https://onlinelibrary.wiley.com/doi/pdf/10.1111/1541-0420.00061
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Summary:Summary . In conventional line transect theory, it is assumed that all animals on the line are detected. This article introduces an extended and generalized hazard probability model without the need for such an assumption. The proposed method needs a survey design with independent observers having the same visual region and assumes an explicit distinction of simultaneous and delayed duplicates. It can take account of random heterogeneity caused by surfacing behavior as well as systematic heterogeneity by covariate effects. Furthermore, it can be easily extended to cases in which data from incompletely independent observers are available. The abundance estimate is based on the Horvitz‐Thompson estimator in unequal detectability sampling scheme. Simulation studies suggest that the proposed method has good performance. The method is applied to a real data set on Antarctic minke whales in the illustration.