Its unclear from your post exactly what stage of life you are planning to study (e.g., larval stage or juvenile). In any regard, a few things you should consider when developing your study are 1) The life history of the fish or fishes in question (e.g., for the stage you are interested in what is the site fidelity of the fish (i.e., are they highly mobile or do they tend to stick to one area; on what time scale is this behavior? This will help you figure out the appropriate time interval). Other aspects of life history should be important as well  2) the scale or scales of habitat you are interested in (regional, landscape, stream reach, mesohabitat, and microhabitat associations may be of interest to you). I assume you know the scale(s) of interest here but it is hard for me to offer advice without this information or more information about your objectives. 3) another thought is that if you think multiple time scales may be important (2-3 day, week, and 2 week scales) then you could design a study to look at habitat use on all three of those time scales with some kind of nested design. A lot of this depends on the details of your questions and objectives.

Hi David, thanks for your feedback!

So, my question involves only juvenile fishes at a regional scale from observations in natural reefs and a local scale in laboratorial experiments. Our objective is to identify how the phylogenetic signal acts on the assembly and dynamics of assemblages of young forms of tropical marine fish, in a positive, negative or nule correlation with the ontogenetic variation at ontogenetic proxies related to levels of the niche conservation x differentiation, considering the differences between environments at the levels of habitat heterogeneity and anthropogenenic pressure, by underwater observations and experimental simulations. Did you understand?  

My point is that the question of ideal or minimum observation time, is leaving me with doubts as to the support that the research can acquire, could you shed some light on this?

Regards,

Priscilla

@Priscilla, wow, that is an ambituous Project! Especially since the phylogenetic Signal is very likely to strongly affect morpholoy as well as the Speed of development.

If all your species are already in the juvenile stage I would suggest you sample every 2-3 weeks. You could do higher frequency sampling during the time of hatching/ early development of the most important/interesting taxa, as things Change rapidly during early development.

Good luck!

Irene

Thanks for that suggestions Irene, I'll really considerate your point of view in the experimental and amostral protocols.

And thank you also for the votes, we will need a lot of good luck, hehe

Cheers,

Priscilla