New York Natural Heritage Program
Black Sandshell
Ligumia recta (Lamarck, 1819)
Bivalves

Threats [-]
The single most important cause of the decline of freshwater mussels during the last century is the destruction of their habitat by siltation, dredging, channelization, impoundments, and pollution. A healthy fish assemblage is critical to viable mussel populations and dams have resulted in heavy losses of mussels, mainly due to elimination of host fish species. Rarity and decline in New York of the primary host fish species (Sauger) is likely to account for the ongoing threats to this mussel (Khym and Layzer 2000). Erosion due to deforestation, poor agricultural practices and the destruction of riparian zones, causes an increase in siltation and shifting substrates that can smother mussels. Domestic sewage, effluents from paper mills, tanneries, chemical industries and steel mills, acid mine runoff, heavy metals, and pesticides have all been implicated in the destruction of the native mussel fauna.

Conservation Strategies and Management Practices [-]
The effects of PCBs and other toxic chemicals, and general water pollution, should be investigated for their potential role in the decline of this species. When feasible, the removal of impoundments in order to restore rivers to their natural flow would be beneficial since these structures negatively affect required fish host species as well as the mussels themselves. Khym and Layzer (2000) suggested that infecting any sportfish (especially Sauger/Walleye) with glochidia prior to release could be a good opportunity to augment populations.

Research Needs [-]
There is still much to learn about this species in New York, especially determination of the primary host fish species and whether the closely related Walleye and Sauger can serve equally well as primary hosts. Details about habitat requirements (current speed, water depth, substrate grain size, substrate stability, water temperature, and water quality factors) also need work. However, Strayer et al. (1994) found that the distribution of Unionids was not related to these typical physical habitat qualities, but instead was related to long term stability of the substrate (i.e., flow refuges) and other large-scale habitat variables such as riparian zone vegetation (i.e., grassy vs. forested). Both large and smaller scale forces promoting the patchy occurrence of Unionid mussel beds is an active area of research (Strayer et al. 2004).