Designing line transect surveys for complex survey regions

Line transect surveys are widely used to estimate the density and/or size of cetacean populations. Good survey design is essential for obtaining reliable results using standard (design-based) analysis methods. Even more complex (model-based) methods, a good valuable. A ‘good’ one (a) that employs randomisation in laying out transects; (b) stratified if known vary on large scale; (c) where each location within stratum has an equal probability being surveyed (uniform coverage probability); (d) produces even distribution transects throughout (e.g. systematic random designs); (e) at least 10-20 per stratum; (f) that, given previous points, gives maximum efficiency unit effort – example by minimising time spent travelling between lines (off-effort time). We discuss strategies creating designs constraints inherent many shipboard cetaceans: severely limited ship and topography. advocate use computer software, such as program Distance, create compare their properties simulation. provide link concepts implementation through concrete design: multi-species cetaceans coastal British Columbia. The uses equally spaced zig-zag configuration open strata combined with sub-stratification minimise off-effort time. In highly convex inshore we develop cluster sampling algorithm, selected clusters parallel line layout ensure long, narrow fjords. To aid those wishing learn automated Distance project files online.