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Simulated Likelihood Methods for Complex Double‐Platform Line Transect Surveys
Author(s) -
Schweder Tore,
Skaug Hans J.,
Langaas Mette,
Dimakos Xeni K.
Publication year - 1999
Publication title -
biometrics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.298
H-Index - 130
eISSN - 1541-0420
pISSN - 0006-341X
DOI - 10.1111/j.0006-341x.1999.00678.x
Subject(s) - covariate , statistics , maximum likelihood , transect , abundance estimation , likelihood function , observational error , line (geometry) , computer science , mathematics , econometrics , geology , ecology , abundance (ecology) , biology , oceanography , geometry
Summary. The conventional line transect approach of estimating effective search width from the perpendicular distance distribution is inappropriate in certain types of surveys, e.g., when an unknown fraction of the animals on the track line is detected, the animals can be observed only at discrete points in time, there are errors in positional measurements, and covariate heterogeneity exists in detectability. For such situations a hazard probability framework for independent observer surveys is developed. The likelihood of the data, including observed positions of both initial and subsequent observations of animals, is established under the assumption of no measurement errors. To account for measurement errors and possibly other complexities, this likelihood is modified by a function estimated from extensive simulations. This general method of simulated likelihood is explained and the methodology applied to data from a double‐platform survey of minke whales in the northeastern Atlantic in 1995.