Hello, I have a 5 year dataset on longline catches and I've fitted GAMs to standardize CPUE of target species. I would like to have a monthly mean of the standardized CPUE but I'm not sure which data should be used to predict the monthly mean. Should I find the median of my continuous variables and the most observed level of categorical variables for the whole dataset to predict for the effect of month? Should I calculate the median of my variables and most observed level of categorical variables per month and predict for the effect of month? I've seen examples of cpue data standardization that predict for each observation of the dataset and then average per month. I'm not sure which is the best choice and I'm struggling to find it on the literature. Thanks in advance!

Kind regards,

Hugo Parra