If you catch a tagged fish, re-tag and measure the fish. I would try to get the tag number off the existing tag and leave the fish and old tagalone. To date, we have one returned tag. It was a Sailfish caught by my youngest son Oct '00 out of Destin. It was "recaptured" early '02 off of south Florida. We estimated that the Sail was at best a 30 lbs fish and the re-tag results indicated 60 lbs. For what it is worth, I have trouble believing the fish grew from 30-6o lbs in 18 odd months. Good luck and release 'em in good shape if you can.