A mussel survey was conducted in the Black River State Forest portion of the Black River in 1997. Several tributaries within the state forest were also surveyed. Preliminary results reflect different species composition above and below the dam at Black River Falls. This may be a reflection of different fish communities above and below the dam, which acts as a barrier to migration. Prior to existence of the dams, natural barriers, such as a waterfall, may have also played a role.
Fish play an important role in the mussel reproduction as hosts for larval mussels.
Good water quality, stable substrate in which to anchor, and specific fish species are crucial to mussel survival and reproduction. The Black River and several tributaries within the state forest contain the proper conditions for diverse mussel populations. This curious discovery has not yet been explained. Downstream of the Black River Falls dam, a mussel bed was discovered on the Black. The threatened species was found near an eroding sand bank.