Pinctada Margaritifera is a salt water species. It sounds like a bogus entry from a confused contributor to wikipedia. There are many, many species of freshwater mussel, many of which can produce pearls. The greatest concentration of and diversity of species is to be found in the Mississippi river drainage system in the USA. Unfortunately, a combination of problems, among them being pollution and over-harvest has reduced their numbers greatly and a good number of them are threatened, endangered or possibly even extinct. However, one simply cannot justify the sweeping generality that "...the freshwater mussel is an endangered specie." Some of the many freshwater species are and some are not. Before their habitat was degraded and their numbers were reduced, great numbers of very valuable pearls were harvested from these waters.
J Marcus
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