Hi there,
I have a gander who is now a year and nine months old, and he is going through his second breeding season. I'd just like to second what the previous posters have been saying - don't let him get away with biting you! He is testing the group hierarchy and aiming to be top goose, and you really don't want that! It's rather like training a puppy - you need to be sure that he knows you are in charge. Remember also that geese are pretty 'hands-on' with each other; you may need to be forceful with him to get your point across, although I wouldn't recommend hitting him, since that can just heighten his aggression.
My personal tactic for putting the gander in his place (when he is being particularly bad) is to grab him by the neck with one hand, then press down between his shoulders/wings with the other until he lies flat on the ground. Once he submits, I let him up, and he usually runs away. If he is just being a bit obnoxious, I've tried hissing at him, and that worked. During the breeding season, I usually use a stick if I need to move him and the geese, it's much less stressful for everyone.
Just a word of warning - my gander was particularly aggressive last year, during his first breeding season - I suspect that it was largely because it was all very new to him. It was rather upsetting, honestly, because a couple of months before, he had been very sweet and friendly. The good news is that this year, he isn't anywhere near as bad.
Good luck and I hope all goes well!
G