State biologists say a lake trout caught this month is the oldest they've found in northern Wisconsin in recent history.
The fish caught near the Apostle Islands of Lake Superior is at least 46 years old, or nearly 100 in human years, Wisconsin Public Radio reported .
The fish was tagged as part of the Department of Natural Resources' fall trout assessment, said Brad Ray, a senior fisheries biologist at Lake Superior. The fish has been tagged eight times in the past four decades, he said.
"It's been out at large for 36 years since we originally tagged it. At that time, it was at least 10 or 12," he said. "It could have been much older than that . That makes it at least 46, if not 48, and it could even be over 50."
The trout was 35.5 inches (about 900 millimeters) long, Ray said. It was tagged and released back into the water in the Gull Island Refuge on Nov. 2.
"It's definitely a rarity to see an old fish, and it just really shows the importance of the refuge system to protect those fish to limit the harvest," he said. "That fish probably lived most of its life in the refuge, because in 36 years it only grew 8 inches, which is pretty slow growth."
Officials with the U.S. Fish and Wildlife Service say the oldest lake trout ever recorded was 70 years old.
