Once in the shallows, researchers place two tags in the fish. One is a brightly colored external tag. That lets fishermen and other researchers know that the fish is one on which data is being gathered. There's also an internal pit tag inserted beneath the fish's skin. That tag is numbered and researchers read the number by waving an electronic wand.
Researchers also clip a piece, about the size of a thumbnail, from one of the fish's fins.
DeHaan uses that for DNA research. By checking the DNA of adult fish against DNA from larvae fish, researchers can determine what percentage of adult fish are successfully reproducing. While they have the fish, researchers also measure the fish's length and girth and weigh it. As of Tuesday, researchers had tagged approximately 70 fish. It's difficult to say what percentage of the overall Black River system that number constitutes.