Tipping is customary in many service industries, and float fishing expeditions are no exception. However, there is still a good bit of confusion among anglers as to how, when, and why guides should be tipped.
The amount of your tip should always reflect the quality of service. However, not tipping at all, in an industry where gratuities make up a considerable portion of the incomes of fishing guides and staff, is almost always insulting.
Discussing the source of a bad experience with the head guide while you are on-site, for example, is far better than leaving without tipping. As mentioned above, your tip should be based upon the total experience of the trip. There are days where the fish won't stop biting and days that you catch almost nothing (thankfully that does not happen too often on the waters we float here in Alaska). But the amount of gratuity should be based on how the guide controls all the variables, not on the number of fish caught. It is generally accepted that an appropriate tip is approximately 15% of your trip cost 20% is fair for an exceptional job.
Bring your tip as cash in your carry-on bag or in the form of personal checks or traveler's checks. Note that traveler's checks are probably the least-favored form of gratuity since banks will often charge significant fees to have them deposited.
More often than not, you are better off leaving a collective gratuity for your entire stay with the head guide at the end of the trip than you will tipping service staff and guides individually. The reasons for this are usually not readily apparent, but they include the fact that over-tipping to individuals makes it more difficult for the operations manager to control the expectations (and behavior) of the staff.