Fig. 3
From: Assessing data bias in visual surveys from a cetacean monitoring programme
Fitted GAM for number of sightings. Results from the final Generalized Additive Model (GAM) to assess the bias on the number of sightings recorded per survey, fitted with variables related with the survey effort, the meteorological conditions, and the experience of observers. Tick marks above the x-axis indicate the distribution of observations. The area shadowed in green represents the 95% confidence interval of the spline functions. Cum – cumulative evaluation score (scale of 0 to 40); Effort – distance in kilometres sampled on effort per survey; Max_Wind – maximum wind state registered per survey (Beaufort scale); Min_Sea – minimum sea state registered per survey (Douglas scale); Min_Vis – minimum visibility state registered per survey (scale of 0 to 10); Max_Vis – maximum visibility state registered per survey (scale of 0 to 10); Min_Wind – minimum wind state registered per survey (Beaufort scale). For details on variables, see methods.
