Fig 1.
Examples of simulated datasets following a spatial capture-recapture model where density was uniform across the state space (top row) or a function of a spatial covariate in the state space (bottom row). Each individual was associated with an activity center, depicted by the points in the left column. Individuals were located around their respective activity centers on each sampling occasion, represented for one individual by the open circles in the middle column. The probability of an individual moving to a particular location during an occasion was a function of the distance from its activity center, with the individual being more likely to be located close to rather than far from the activity center. These locations were also distributed as a function of the spatial covariate in the spatial covariate scenario (bottom row). Line transect surveys, represented by the horizontal lines, were conducted during each sampling occasion. The probability that an individual was detected on an occasion was a function of the distance between its location on that occasion and the closest point on a transect line, with the probability being higher the closer an individual was to a line (right column). The locations of detections are depicted by the crossed-out circles in the right column.
Fig 2.
North Atlantic right whale density.
Expected North Atlantic right whale (NARW) density per 400 km2. NARW density was estimated as a quadratic function of depth within the state space using distance sampling (DS; bottom left panel and red in top panel) and spatial capture-recapture (SCR; bottom right panel and blue in top panel). Posterior mean expected density and 95% credible intervals across the range of depth in the state space is illustrated in the top panel for both DS (red) and SCR (blue) models. Bottom panels illustrate posterior mean expected density across the state space for DS (left) and SCR (right) models that included depth and depth2 as covariates on density.
Table 1.
Simulation summary.