Biologists search for displaying Winged Mapleleaft at the St Croix National Scenic Riverway. Photo Credit: Beth Glidewell/USFWS.

As early fall water temperatures begin to drop in the St Croix River, female Winged Mapleleaf mussels are ready to have their glochidia attach to host fish. They display a lure that helps to attract channel catfish closer to the female, where she can release glochidia into the water and -hopefully- onto the catfish’s gills. Individual females only display a lure for a short window of time (a day or 2) so mussel biologists have to time collection and propagation efforts to match the mussel’s and the river’s fluctuations. Biologists snorkel or scuba dive 2 to 3 times per week during the WML brooding season to visually check the population for females that are in ‘full display’.

A Winged Mapleleaf in full display. Photo Credit: Beth Glidewell/USFWS.