CLEVELAND, Ohio — It takes a lot to faze crews from the Alpena Fish and Wildlife Conservation Office. They crisscross the Great Lakes from Superior to Erie helping to reintroduce native fish and standing guard against invasive species in places where aquatic hitchhikers with ill intent are most likely to turn up. But on one routine mission in Cleveland Harbor last month, they found a link to a prehistoric past they weren’t expecting: three healthy juvenile lake sturgeon, all a year old.
The crews knew the fish’s ages and more, including when and where they were raised, because each had been implanted with a Passive Integrated Transponder (PIT) tag before being released the year before. The tiny tags work like the chips that identify lost cats and dogs. The fish came from a class of 2,000 reared at Genoa National Fish Hatchery in Wisconsin that had been stocked the previous fall. Two had been released into the Cuyahoga River in downtown Cleveland, and the third was from Cuyahoga Valley National Park about 20 miles south.
“To some of us, it was a bit of a surprise how fast they grew,” said Jason Fischer, a fisheries biologist with the U.S. Fish and Wildlife Service…