I have 7 different broken stock models and logistic regression models that represent size at maturities for male and female crab and I'm interested in adding the covariates temperature and depth to determine if these variables influence size at maturity estimates, but I am unsure how to add these in.

I'm using the package (SiZeR) for the broken stick model and the standard GLM model for logistic regression.  Any help would be greatly appreciated.