Re: [distance-sampling] Distance with presence/absence data?

[Eric Rexstad]

Ana

The key to distance sampling is measuring animal-to-transect distances.  Those distances are fundamental in estimating detection probability.  Detection probability adjusts the number detected to produce an estimate of the number of animals in the area covered by your survey.

It does not appear that the methodology you describe has a way to estimate detection probability if distances are not records.  I would not think distance sampling methodology could be applied to these data.

On 24/02/2021 18:12, Ana Carolina França wrote:

Hi all,

I am trying to estimate population size and density using the Spotlight Survey methodology, where the animals search is made in boats and the animals are identified through the use of flashlights. The number is recorded by a manual counter at every 10 animals counted and the distance traveled noted.  The distance between the "transect"  and the animal is not well accurate and not always noted (in fact, hardly ever noted). 

So, my question is: could i use distance sampling analysis for these methodology? I am not getting it, because for me, the data is like presence/absence and i don't know if i can use for example the 'unmarked' package for analyse this data.

Could anyone help me, please?

Best regards

Ana

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Eric Rexstad
Centre for Ecological and Environmental Modelling
University of St Andrews
St Andrews is a charity registered in Scotland SC013532