[fishguy]

I think tips are divided evenly with the crew.
That 20% is the starting point for your fare and the fish cleaning and quality of service is where the adding or subtracting comes in. If the mate is a jerk, not helpful or absent all day than tip less. If he does a great job and is helpful than add some more to the tip. If you don't catch any keepers that is not the mates fault so don't stiff him.
If you come with a group, like the wife and kids tag along one day or something, the tip should still be based on the fare total for everyone. So many times I've seen a guy with a family and the mate takes care of him all day, untangling backlashes on their rental rods, helping his kids all day, being nice to them etc etc only to get 5 bucks (or less) in the end. The fare total for the group is like $150 or something and they tip 5 stinkin bucks? It should be more like $30.

I know that good tippers get remembered well by the mates as do the bad ones. It's very simple. You get what you pay for.

Don't be Mr. Pink...