Seasonal Abundance Estimate. Am I using the right model?

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Seasonal Abundance Estimate. Am I using the right model?

Postby MadalenaManta » Tue Apr 06, 2021 9:06 pm

Hello

I am studying Giant Mantas with photos collected by recreational divers over 4 seasons.
My seasons are 2015-2016(200 photos), 2016-2017(300 photos), 2017-2018(170 photos) and 2018-2019(150 photos). Each season is from November to June next year. I have many recaptures over the seasons (around 450) and around 550 identified individuals, just to give you a general idea of the database. I want to estimate seasonal abundances.

I have run a CJS with 4 basic models:
[Model 1] constant survival, constant recapture
[Model 2] constant survival, time-dependent recapture
[Model 3] time-dependent survival, constant recapture
[Model 4] time-dependent survival, time-dependent recapture

AICc:
[Model 1] 696.2403
[Model 2] 686.2462
[Model 3] 687.7077
[Model 4] 689.4508

I chose Model 2 (with lowest AICc) to estimate seasonal abundance.
My 3 resulting estimated seasonal abundances make sense compared to other populations of the same species. BUT....

My questions are:

1- Since the AICc values are so close, do I need to do model averaging?
2- Should I have used POPAN or Robust Design for this dataset??
3- Also, I would like to check if there is environmental variable influence on abundance such as Multivariate ENSO index, Sea surface temperature and others. For this, does it make more sense to use CJS, POPAN or Robust Design?

Thanking you in advance for your time and patience
MadalenaManta
 
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