I am trying to test environmental variables against fish catch data to see how they impact the species composition. for environmental data, I have river discharge, temperature, rainfall, and salinity. I ran a ccf in R on my river discharge data and can see that there is a lag effect on several of my fish species. I would like to incorporate this lag into my analysis. My question is if I am lagging discharge, would I also need to lag my other environmental variables or can I just lag the discharge and leave the others alone?