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. 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. Live animals have been recently documented in 2018 from the St. 1991), but by 1991 it had disappeared (Schloesser and Nalepa 1994). Between 1930 to 1982 this species was the second most common Unionid in western Lake Erie (Nalepa et al. Ligumia nasuta comprised about 5% of the pre-1960 Unionid records in the lower Great Lakes in Ontario, but dropped to 2.5% of the records post-1960. This species was once a major component of the lower Great lakes drainage basin, but is now virtually absent owing to the zebra mussel invasion.
Only 3 individuals of this species were found in a late 1980's survey of 52 sites in many watersheds in the Lake Erie and Ontario basins (Strayer et al. 1994), but densities were not reported post invasion. Average densities in the tidal Hudson River prior to the zebra mussel invasion were 0.08/sq. nasuta can still be encountered regularly, and is sometimes abundant (Strayer and Jirka 1997). Short-term TrendsĪlthough not widespread in the state, L. There is some evidence from recent survey effort that it may be rebounding in the St.
Lawrence River basin, lower Great Lakes and elsewhere throughout the state (Strayer and Jirka 1997). This species has been heavily impacted by the zebra mussel invasion in the Hudson River estuary, St. Because of its relatively thin shell, this species has suffered greatly from the zebra mussel (Dreissena polymorpha) invasion (Strayer and Jirka 1997).
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