Good Morning Folks. The two answers above are basically right. A little clarification is necessary. Tips (more commonly called gratuity) are a very personal thing. You have to look at the Mates service as similar to a Restaurant Server X 2. As mentioned a good Mate will Make your Day. On Offshore Trips a Mates day is 12 Hours Plus. Try having a mate who is not experienced rigging Ballyhoo, or doesn't know the technique for Billfish, or slow with multiple hook ups and on and on. 15 to 20% is recommended. Captain, basically no except in winning Tournaments or as said a small Inshore "Mateless" boat where the Captain does everything. Now I know some people from the Northeast will say why tip a Mate generously, they don't clean my fish! Charter Boat mates in many Northern ports clean your catch. Please understand that Mates do not clean fish HERE because of several reasons. Governmental Size regulations (you have to have evidence of size at the dock), most boats do not have suitable cleaning tables and on a rocky, fast moving boat no way. Also some Marina Contracts prohibit Boats cleaning fish, especially in the Marina. There is a lot to say about this but that is another discussion. Occasionally Captains will get tips from generous "Regulars" or for exceptional catches, but as a rule a big No. Keeping/Selling your catch. In this area all fish belong to the charter. Yes, Charter Boats can not LEGALLY sell your catch, neither can you. Can you offer fish to the crew, sure you can. Dockside Fish cleaning can get quite expensive with a large catch. Just so you know, there are very few fish cleaners who clean a fish ready for the pan. Trimming of some sort is always necessary, especially on Tiles, Triggers, Sea Bass and Tuna. However you may want to consider Catch and Release if you know you don't want a lot of fish. Unfortunately, many fish do not lend themselves to Catch and Release, especially Deepwater Bottom Fish. Discuss this with your Captain. You may find out the Captain (well some) have real big "Egos" and want to throw up huge catches on the dock for publicity. Oh well.