CueCountingExample: Cue counts of whale blows

In Distance: Distance Sampling Detection Function and Abundance Estimation

Cue counts of whale blows

Description

Cues are treated as an indirect count, requiring the use of multipliers.

Format

A data.frame with 109 rows and 15 variables.

• 'Region.Label stratum labels

• Area size (km^2) of each stratum

• Sample.Label transect labels

• Cue.rate rate of blows per animal per hour

• Cue.rate.SE variability in cue rate

• Cue.rate.df degrees of freedom (number of animals sampled for cues)

• object object ID

• distance perpendicular distance (km)

• Sample.Fraction proportion of full circle scanned (radians)

• Sample.Fraction.SE variability in sampling fraction (0)

• Search.time Duration of scanning effort (hr)

• bss Beaufort sea state

• sp Species detected (all observations W in these data)

• size Number of animals in group (all 1 in these data)

• Study.Area study area name

Details

Because whale blows disappear instantaneously, there is no need to measure a decay rate. However a cue production rate (blows per individual per unit time) is required, as is a measure of variability of that rate.

Note

There are two other nuances in this survey. Even though the survey is taking place on a moving ship, effort is measured as amount of time scanning for blows. In some instances, it is not possible for the observer to scan the sea all around them as view may be restricted by the ship's superstructure. Here a ⁠sampling fraction⁠ multiplier is employed to deal with restricted vision. Units of measure of cue.rate and Search.time must be equal.

Distance documentation built on Oct. 24, 2024, 5:08 p.m.