ST. PETERSBURG — Sarah Walters didn't think fish No. 14,401 was anything special. The red drum, one of several thousand caught by state biologists during a tagging study last fall, was big but certainly no record."It measured 39 inches and probably weighed about 18 pounds," said Walters, a biologist with the Florida Fish and Wildlife Research Institute in St. Petersburg. "It is pretty much average for the fish we see in those big schools that congregate offshore."Red drum, especially those caught off of Florida's east coast, can weigh up to 50 pounds. In case you're wondering, the largest red drum on record was caught in North Carolina on Nov. 7, 1984, and weighed 94 pounds, 2 ounces.That's a monster compared to the "slot limit" reds (18-27 inches) caught by most anglers in estuaries such as Tampa Bay and Charlotte Harbor."These are subadults," Walters explained. "They are usually just one or two years old."But as is the custom, Walters wanted to run the tag anyway, just to find out when and where the fish was captured. So she called the state's fish hatchery in Port Manatee."The problem was the tag was so old, there was no record of it in the files," Walters said.However, the colleague doing the checking knew a little bit about fish tags. "You might want to check with my dad," Josh Taylor told Walters. "He did a little tagging back in the 1980s."Taylor's father, the legendary snook biologist Ron "R.T" Taylor, and Mike Murphy, another well-known researcher, were among the first to conduct tagging studies in Florida. So Walters called the senior Taylor, who searched his cavernous files and produced some interesting data.Fish No. 14,401 was tagged in Boca Ciega Bay on Oct. 16, 1989, when Walters was in fifth grade at St. Stephens Episcopal School in Bradenton. The fish measured 29 inches long and was probably about 3 years old.Fast forward to Oct. 5, 2012, 2 miles west of John's Pass, where the 34-year-old Walters, who had since earned a master's degree in marine biology, was netting and releasing red drum as part of the state's decades-long redfish study."Starting in September, the redfish start to school up to spawn," she said. "There are literally tens of thousands of fish in these schools ranging in age from 3 to 35 years old."Biologists aren't certain how old No. 14,401 was when it was recaptured. The only sure way to determine the age of a fish is to kill it and remove the ear bone, which has growth rings like a tree. Redfish 14,401 was measured and released, but judging from its time at large, Taylor estimated it was probably at least 25 years old."They can get much older than that," Walters said. "We had one fish that was 35 years old."When captured, No. 14,401 measured 39 inches. So it grew less than a foot in its 22.97 years of freedom. "Redfish keep getting longer until they are 5 or 6 years old and then they just get wider and heavier," Walters said.But even more remarkable than the red drum's longevity has been the careers of the two marine biologists who started the tagging study."Here you have two guys who have devoted their whole lives to marine science," she said. "It must be neat for them to get to see it come back full circle."