Like other mussels of the family Unionidae, the slippershell mussel requires a fish host to complete its unusual life cycle (7). Sperm is released into the water, usually around spring time (2), and is then taken in through the female’s siphon for fertilisation. Eggs develop into larvae within the female, where they are held internally for about a year. The larvae, called ‘glochidea’, are then released into the water and must attach to a suitable fish host to survive. The fish hosts for the slippershell mussel include the johnny darter (Etheostoma nigrum) and the mottled sculpin (Cottus bairdi) (7), which are probably infested from February to April (2). The larvae typically remain on the fish hosts for a couple of weeks to several months, when they transform into the adult form, before dropping from the host fish. This parasitic lifestyle is a unique feature of freshwater mussels, and helps these otherwise sedentary species to disperse (6). The slippershell mussel then spends the remainder of its life in the substrate (7).
Like all freshwater mussels, the slippershell mussel is a filter feeder, obtaining its nutrition by filtering particles, such as algae, zooplankton and debris, from the water column (7).