Abstract
We use line transect detection functions together with generalized linear and additive models to estimate detection probability when detection on the line (“g(0)”) may not be certain. The methods provide a flexible way of modeling detection probability for independent observer surveys, and for investigating the effects of explanatory variables. Analysis of data from an aerial survey of pack-ice seals produced g(0) estimates substantially below 1 for some observers (it varied from 0.80 to 0.98), demonstrated a fairly complex dependence of detection probability on covariates, and showed negative correlation between observers’ search width and their g(0). In addition to illustrating the utility of generalized additive models for capturing the effect of covariates on detection probability, the analysis suggests that detection functions may be sufficiently variable that use of g(0) correction factors obtained from other surveys would be inadvisable. We recommend that estimation of g(0) be considered for all aerial surveys; if g(0) is found to be very close to 1, estimation from subsequent surveys under the assumption that it is 1 may be reasonable, but without any estimation of g(0), the assumption that it is 1 is a matter of faith.
Similar content being viewed by others
References
Borchers, D. L. (1996), “Line Transect Abundance Estimation with Uncertain Detection on the Trackline,” unpublished Ph.D. dissertation, University of Cape Town.
Borchers, D. L., Buckland, S. T., Goedhart, P. W., Clarke, E. D., and Hedley S. L. (1998a), “Horvitz-Thompson Estimators for Double-Platform Line Transect Surveys,” Biometrics, 54, 1221–1237.
Borchers, D. L., Zucchini, W., and Fewster, R. M. (1998b), “Mark-Recapture Models for Line Transect Surveys,” Biometrics, 54, 1207–1220.
Borchers, D. L., Laake, J. L., Southwell, C., and Paxton, C. G. M. (2006), “Accommodating Unmodelled Heterogeneity in Double-Observer Distance Sampling Surveys,” Biometrics, 62, 372–378.
Buckland, S. T., Anderson, D. R., Burnham, K. P., Laake, J. L., Borchers, D. L., and Thomas, L. (2001), Introduction to Distance Sampling: Estimating Abundance of Biological Populations, Oxford: Oxford University Press.
Buckland, S. T., Breiwick, J. M., Cattanach, K. L., and Laake, J. L. (1993), “Estimated Population Size of the Californian Gray Whale,” Marine Mammal Science, 9, 235–249.
Burnham, K. P., Buckland, S. T., Laake, J. L., Borchers, D. L., Marques, T. A., Bishop, J. R. B., and Thomas, L. (2004), “Further Topics in Distance Sampling,” in Advanced Distance Sampling, eds. S. T. Buckland, D. R. Anderson, K. P. Burnham, J. L. Laake, D. L. Borchers, and L. Thomas, Oxford: Oxford University Press.
Butterworth, D. S., and Borchers, D. L. (1988), “Estimates of g(0) for Minke Schools from the Results of the Independent Observer Experiment on the 1985/86 and 1986/87 IWC/IDCR Antarctic Assessment Cruises,” Report to the International Whaling Commission, 38, 301–313.
Chen, S. X. (1999), “Estimation in Independent Observer Line Transect Surveys for Clustered Populations,” Biometrics, 55, 754–759.
— (2000), “A nimal Abundance Estimation in Independent Observer Line Transect Surveys,” Environmental and Ecological Statistics, 7, 285–299.
Chen, S. X., and Lloyd, C. J. (2000), “A Nonparametric Approach to the Analysis of Two-Stage Mark-Recapture Experiments,” Biometrika, 87, 633–649.
Drummer, T. D., and McDonald, L. L. (1987), “Size Bias in Line Transect Sampling,” Biometrics, 43, 13–21.
Evans-Mack, D., Raphael, M. G., and Laake, J. L. (2002), “Probability of Detecting Marbled Murrelets at Sea: Effects of Single Versus Paired Observers,” Journal of Wildlife Management, 66, 865–873.
Hastie, T. J., and Tibshirani, R. J. (1990), Generalized Additive Models, London: Chapman and Hall.
Hiby, L., and Lovell, P. (1998), “Using Aircraft in Tandem Formation to Estimate Abundance of Harbour Porpoise,” Biometrics, 54, 1280–1289.
Johnson, B. K., Lindzey, F. G., and Guenzel, R. J. (1991), “Use of Aerial Line Transect Surveys to Estimate Pronghorn Populations in Wyoming,” Wildlife Society Bulletin, 19, 315–321.
Laake, J. (1999), “Distance Sampling with Independent Observers: Reducing Bias from Heterogeneity by Weakening the Conditional Independence Assumption,” in Marine Mammal Survey and Assessment Methods, eds. G. W. Garner, S. C. Amstrup, J. L. Laake, B. F. J. Manly, L. L. McDonald, and D. G. Robertson, Rotterdam: Balkema.
Manly, B. F. J., McDonald, L. L., and Garner, G. W. (1996), “Maximum Likelihood Estimation for the Double-Count Method with Independent Observers,” Journal of Agricultural, Biological, and Environmental Statistics, 1, 170–189.
Marques, F. F. C., and Buckland, S. T. (2003), “Incorporating Covariates into Standard Line Transect Analyses,” Biometrics, 59, 924–935.
Polacheck, T., and Smith, T. D. (1989), “A Proposed Methodology for Field Testing Line Transect Theory for Shipboard Surveys of Cetaceans,” Report to the International Whaling Commission, 39, 341–345.
Quang, P. X., and Becker, E. F. (1997), “Combining Line Transect and Double Count Sampling Techniques for Aerial Surveys,” Journal of Agricultural, Biological, and Environmental Statistics, 2, 230–242.
R Development Core Team (2006), R: A Language and Environment for Statistical Computing, R Foundation for Statistical Computing, Vienna, Austria, http://www.R-project.org.
Ruppert, D., Wand, M.P., and Carroll, R. J. (2003), Semiparametric Regression, Cambridge: Cambridge University Press.
S-plus (1988–1999), Mathsoft Inc.
Southwell, C., de la Mare, W., Underwood, M., Quartararo, F., and Cope, K. (2002), “An Automated System to Log and Process Distance Sight-Resight Aerial Survey Data,” Wildlife Society Bulletin, 30, 394–404.
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Southwell, C., Borchers, D., Paxton, C.G.M. et al. Estimation of detection probability in aerial surveys of antarctic pack-ice seals. JABES 12, 41–54 (2007). https://doi.org/10.1198/108571107X162920
Received:
Revised:
Issue Date:
DOI: https://doi.org/10.1198/108571107X162920