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Introduction How Rivers Run Stories Value Of A River What We Can Do
Life of a River - Biology
Consequences (pg 3 of 3)

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Freshwater mussels are even more sensitive than fish to habitat degradation. Seventy species are currently federally listed as endangered or threatened.

The Mississippi River just downstream from the Twin Cities once harbored at least 42 species of mussels. By the 1970s, it supported as few as nine species, largely because untreated urban sewage depleted dissolved oxygen. In fact, no live mussels at all were found in the river between Minneapolis and St. Paul.

According to a U. S. Army Corps of Engineers report of a mussel survey in the 1970s, "The outlook for a mussel renaissance in this troubled reach is extremely poor" and would remain so "until radical improvement in water quality is accomplished."

Since then, substantial improvements in water quality have allowed mussel populations in the stretch to begin to recover. Moreover, biologists working for several state and federal agencies have succeeded in reestablishing species of mussels to stretches where they had disappeared.

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Introduction
Flow
Shape
Connections
Quality
Life
Description
Terrestrial plants
Terrestrial animals
Life cycles
Corridors
Refuges
Aquatic habitats
Adaptations
Continuum concept
Relationships
Consequences
Stories
Summary
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