Gym workouts for swimmers?

I'm fairly new to master's swimming, doing it for the fitness and weight loss. I know I can lose weight swimming (my calorie burn is definitely greater than intake) however I've heard time & time again that you don't lose THAT much weight swimming (though, have you ever seen an overweight swimmer?) Anyway I am hoping to supplement that with gym workouts to help lose weight more, on days when I don't swim and when it gets too cold to ride my bike. Do competitive swimmers do gym workouts too? I can NOT run. Can anyone suggest specific exercises other than the usual? Thanks :)