Spatial Distance Sampling Modeling of Cetaceans Observed from Platforms of Opportunity

In this paper I outline the standard methods of distance sampling and how they are used to obtain estimates of density and abundance for species of interest. I then develop these methods following the approach of Hedley (2000) whereby waiting distances between detections are modelled to produce a density map of the area of interest. In doing so Standard distance sampling, multi-covariate distance sampling and generalized additive models are all discussed and combined together to achieve the density surface. The methods presented are then applied to a data set of fin whale provided by the Biscay Dolphin Research Programme (BDRP). Using the spatial model produced their a priori beliefs on the location of fin whale and trends in numbers are assessed. Both the density map produced (showing locations of high densities) and within season abundance estimates (together with 95% confidence intervals) support the claims set out by the BDRP.