How big was your Tarpon?
Two key measurements are needed to estimate the weight of your tarpon. Fork length and dorsal girth length. The dorsal girth is the circumference around the fish, just in front of the dorsal fin. The fork length is from the tip of the snout to the fork in the tail. The Bonefish and Tarpon Trust has a Tarpon Weight Calculator, that will do the work once the measures are taken.