Instruction includes IGFA rules and fishing regulations, along with what observers are and aren't supposed to do (you're there to observe and report back to tournament directors - not be a judge or disqualify fish). There could be big money or just big egos at stake; either way, you don't want to get in the middle. In catch and release tournaments, observers may be required to identify billfish "on the fly" (literally) during a fight that may last only a few minutes and provides only quick glimpses of the fish. A good amount of instruction is dedicated to learning the subtle visual clues that, to the trained eye, clearly differentiate a black marlin from a blue from a striper - even if the fish does its best to hide. After learning these keys to the appearance and behavior of blues, blacks, stripers, white marlin, sailfish, swordfish and spearfish, we had to identify the species in quick video snippets shot during actual cockpit chaos.