bad dataset, can it be salvaged

[lionmonkey]

Dear Fellows,

I have been asked to review a dataset with a view to exploring options for CMR analysis. However the dataset lacks many of the elements I would have thought important for succesful analysis.

Individuals of the the species were captured from 29 cells in a closed system. Capture effort was not the same in each cell and cells closer to research bases and with more evidence of the species given more effort. Subsequently camera traps were used to check for these animals who had been given obvious unique marks. Again capture effort was not the same in each cell and neither was it simultaneous. Two teams were operating in the North and South of the study area but again the effort is biased in terms of proximity to researcher habitation and conspicuousness of the species.

I would have thought these data would be significantly more useful if the capture and recapture efforts were standardised even if they were stratified. I can't really see how to divide the survey period up into sampling sessions when for any given session on a propotion of traps or camera traps may be open. Is there any scope to run MARK on data that has been gathered in the form described. I only ask because to reformat the data into something usable will also take some time and I am loathe to get involved if it will be for nought!

Best wishes,

Graham

[murray.efford]

Graham
They didn't make it easy, did they! I just composed a (too) thoughtful reply but phidot timed me out and threw it away before I could hit submit. Basically this sounds like a spatially explicit capture recapture problem (handling varying trap usage is straightforward in the Density and secr software) and you could try the Density/secr forum. I'd like to know What species? What trapping method? Was it an island? What do you/they want to measure? Are there enough data to be bothered?
Murray

[lionmonkey]

I will contact you outside the public forum Murray as the data is slightkly sensitive. Happy to provide an overview for anyone interested if we can resolve. Otherwise the names may have to be changed to protect the innocent and guilty!