Jason Mays searches for tagged mussels in Stevens Creek, Mecklenburg County, NC

Biologist Jason Mays walks Stevens Creek, in Mecklenburg County, N.C., running a detector across the stream bottom to find previously stocked mussels. The mussels were fitted with a tag that has a unique, identifying letter/number combination, just like the chips used on pets. When the wand passes by one of the tagged mussels, the data logger logs the number of the mussel detected.