Overview
The green floater is a small freshwater mussel found in small streams and large rivers in the eastern United States. It is historically native to the District of Columbia and 10 states: Alabama, Georgia, Maryland, New Jersey, New York, North Carolina, Pennsylvania, Tennessee, Virginia, and West Virginia. Today, however, green floaters are considered extirpated in Alabama and Georgia, and there are no recent records from?New Jersey or the District of Columbia.
Scientific Name
Identification Numbers
Characteristics
Habitat
Green floaters prefer streams with slow to medium flows and good water quality. They are often found in sand or small gravel substrates where they establish a foothold and bury themselves as deep as 15 inches. They have limited mobility, and fast-flowing currents or high-water events can cause them to be washed downstream. When they occur in larger streams and rivers, they are found in quieter pools and eddies, away from strong currents.
Physical Characteristics
Green floaters are small freshwater mussels with ovate trapezoidal shaped shells. Adults rarely exceed 2.2 inches.
Green floater shells are yellowish brown to olive green with green rays.
Food
Like all freshwater mussels, the green floater is an omnivore that feeds on a wide variety of microscopic particulate matter, namely bacteria and algae.
Life Cycle
Green floaters are hermaphroditic and have the ability to self-fertilize, which increases the probability of fertilization. Spawning and reproduction occur during the late summer or early fall. In the winter, green floaters can directly metamorphose larvae, called glochidia, meaning that adults keep the glochidia in their gills until they mature into juveniles and then release them into the water column in the spring. For most freshwater mussels, glochidia are released into the water column and must attach to the gills of a host fish in order to undergo metamorphosis and transform into juveniles. Several weeks or months later, the juveniles detach from the fish and burrow into the substrate. Green floater adults have the ability to expel glochidia that use fish hosts, too, but it is not known what proportion of green floaters use this method of reproduction. The added ability to directly metamorphose glochidia without requiring an intermediate fish host is unique to the green floater. This life strategy may allow the green floater to occur in small streams with small populations and few fish, although the use of fish hosts is necessary for periodic upstream dispersal.
The green floater is a short-lived, fast-growing species compared to similar mussels. Green floaters typically live just three to four years.
Geography
The green floater is still found in seven of the 10 states within is native range: Maryland, New York, North Carolina, Pennsylvania, Tennessee, Virginia, and West Virginia. There are no recent records of green floater from New Jersey or Washington D.C., and it is considered extirpated from Alabama and Georgia and from some rivers in other parts of its range.
Timeline
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