From this release from Montana Fish, Wildlife and Parks (via Outdoor Pressroom):
According to Montana Fish, Wildlife & Parks Fisheries Biologist Mark Deleray, a local angler may have caught the oldest largemouth bass reported in Montana. Deleray said that 10-year-old Garrett Frost of Kalispell reported catching and releasing a 20-22" largemouth bass in Rose Creek Slough on July 16, 2011 weighing approximately 3.5 lbs. He pulled out the red floy tag numbered 5637 prior to releasing the fish. Fishery Worker Jon Cavigli checked the database and found that the bass had carried this floy tag for 14 years. According to Garret's father, Tyler, Garrett hooked the bass on a rubber worm while fishing from the front of their boat. Garrett landed the bass without assistance. When he had the fish in hand, he and his two brothers shouted, "It's a 5-pounder!" Tyler says that the bass appeared to be in good condition, and weighed 3-1/2 pounds on his scale.
_According to the tag information, this fish was caught and tagged by Phil Rivard in Fennon Slough on October 3, 1997. At that time the fish was 14.2" long and weighed 1.5 lbs. Cavigli, who keeps up the tag database, says that Rivard, a volunteer for FWP caught, tagged, and released many largemouth bass in the sloughs of the Flathead River, adding to the age-growth database. Based on the size of the largemouth bass in 1997 and the age-growth database, Deleray estimates that the fish was probably 5 years old when tagged. Adding that age with how long the tag was in the fish places its age at 19 years old. This may be the oldest confirmed largemouth bass reported in Montana. Most sources place the maximum age at 15 or 16 for largemouth bass in the northern United States.
Word has it Garrett used a prune-colored worm to catch the geriatric bass, and when they finally lifted it out of the water, his left-turn pectoral fin wouldn't stop blinking...