The effect of line-transect placement in a coastal distance sampling survey

Distance sampling surveys are commonly used to estimate animal abundance (N). The choice of survey design has only recently received attention in the line-transect research literature, which tended focus more on violation assumptions. In this study, simulation methods were assess effect line placement accuracy and precision a for estimating dolphin abundance. 1998, vessel-based Hector’s (Cephalorhynchus hectori) was carried out around Banks Peninsula (New Zealand). These data generate spatially realistic distribution onto different designs overlaid. Eight types considered, consisting four stratification two allocating lines: random or systematic. None showed any evidence significant bias N(Nˆ). Systematic lines generally provided precise estimates N, with an average reduction (over all designs) 14% coefficient variation Nˆ, [CV(Nˆ)]. results correspond well those expected from classical theory case population mean. However, these also overestimated CV(Nˆ) by 10-28% (mean=22%). line-placement several practical advantages over placement, including uniform spatial coverage. For coastal cetacean populations dynamics similar one considered here, we recommend use systematic line-placement, proviso that is likely be 10-28%.