Rejecting CJS

[brianz11]

Hi,

My data do not fit the standard time-dependent CJS model, but fit a two-age class structure fairly well. My question is can I still use the population estimate models found in Chapter 12 of your book, such as POPAN? The book says those models are dependent on the JS assumptions still, which my two-age class model does not fit into since recaptures vary over time.

I had a hard time finding what it actually meant when you rejected the standard CJS, in terms of doing follow up analysis with the data. Am I allowed to continue with the other analyses once I've fitted for the age-class model, even though the CJS model was rejected?

Thanks for your time and help.

[bacollier]

Hi,

My data do not fit the standard time-dependent CJS model, but fit a two-age class structure fairly well. My question is can I still use the population estimate models found in Chapter 12 of your book, such as POPAN? The book says those models are dependent on the JS assumptions still, which my two-age class model does not fit into since recaptures vary over time.

Can you be a bit more specific/provide more detail as to what question you are asking? The JS approach estimates parameters for apparent survival and recapture the same as in a CJS model (not withstanding the process associated with new animals are captured). In a JS you can have different age classes that vary over time in recapture probability, so I don't know what you are getting at here?

I had a hard time finding what it actually meant when you rejected the standard CJS, in terms of doing follow up analysis with the data. Am I allowed to continue with the other analyses once I've fitted for the age-class model, even though the CJS model was rejected?
Thanks for your time and help.

What are you asking here? How did you reject the standard CJS? What do you mean "follow up analysis"?

\bret

[brianz11]

I guess I was confused about the fact that my recapture probabilities were not the same for all the individuals in my data (e.g. age classes). I thought this was a violation of the assumption of equal catchability of all individuals in the study area.

If it's not a violation, then I think you have answered my question. I was worried that using age classes in my model would violate the JS assumptions and I would not be able to run any of the JS models.

Sorry for the confusion, and thank you for your help. I really do appreciate it.