Ptychobranchus fasciolaris 

Scope: Global
Language: English

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Taxonomy [top]

Kingdom Phylum Class Order Family
Animalia Mollusca Bivalvia Unionoida Unionidae

Scientific Name: Ptychobranchus fasciolaris Rafinesque, 1820
Common Name(s):
English Kidneyshell

Assessment Information [top]

Red List Category & Criteria: Near Threatened ver 3.1
Year Published: 2017
Date Assessed: 2015-06-19
Assessor(s): Bogan, A.E. & Woolnough, D.
Reviewer(s): Seddon, M.B. & Ormes, M.
Contributor(s): Cordeiro, J., Cummings, K. & Seddon, M.B.
The Kidneyshell occurs widely throughout the Ohio, Tennessee, and Cumberland River systems, and in Lake Erie, Lake St. Clair, and some of their tributaries.

The species is listed as Near Threatened, as the most significant declines have occurred in the northern part of the range where the Zebra Mussel has invaded where in Great Lakes basin, a 70% decline in Canadian populations has been recorded (COSEWIC 2003, 2013) with losses from three out of five river systems in eastern Illinois (Cummings and Mayer 1997).

Further south the species meets the status of Least Concern, as it is considered stable in the Ohio, Tennessee, and Cumberland River systems.

The species was originally listed as Least Concern (IUCN 1996) based on wide range and lack of threats operating across the range,  However the impact of the Zebra Mussel has impacted northern populations since 1994, and as such the species has become a candidate for listing under the Near Threatened on basis of population declines, loss of area of occupancy (AOO) and subpopulations due to pollution and invasive species (A2c,e).
Previously published Red List assessments:

Geographic Range [top]

Range Description:This species is found in eastern North America. The Kidneyshell has a very wide range and is found throughout Mississippi River system, including the Ohio, Tennessee, and Cumberland Rivers, but it has declined somewhat in some places although many sites still report large populations (NatureServe 2008). In particular, significant declines have occurred in Canada, while U.S. occurrences have been more stable (NatureServe 2008). The Kidneyshell occurs in Lake Erie, Lake St. Clair, and some of their tributaries. In Canada, it is only known from southern Ontario, where it is extant in south in the Sydenham and Ausable rivers and Lake St. Clair, with historical occurrences in the Grand, Thames, Niagara and Detroit rivers (COSEWIC 2003).
Countries occurrence:
Canada (Ontario); United States (Alabama, Georgia - Possibly Extinct, Illinois, Indiana, Kentucky, Michigan, Mississippi, New York, North Carolina - Possibly Extinct, Ohio, Pennsylvania, Tennessee, Virginia, West Virginia)
Additional data:
Range Map:Click here to open the map viewer and explore range.

Population [top]

Population:Recent information suggests that the current distribution and abundance of the Kidneyshell in the U.S. remains much the same as it was historically and is locally abundant at many locations across its range, including sites in Indiana, Ohio, Pennsylvania, New York, Michigan,West Virginia (Cordeiro 2009). It has declined in abundance and range in Tennessee (Parmalee and Bogan 1998) and is considered historic in North Carolina and Georgia. The most significant declines have occurred in the Great Lakes basin, with a 70% decline in Canada (COSEWIC 2003, status reconfirmed in 2013) and from three out of five river systems in eastern Illinois (Cummings and Mayer 1997).
Current Population Trend:Decreasing
Additional data:
Continuing decline of mature individuals:Yes
Extreme fluctuations:Yes

Habitat and Ecology [top]

Habitat and Ecology:The Kidneyshell is most often found in small to medium-sized rivers and streams, where it prefers shallow areas with clear, swift-flowing water and substrates of firmly-packed coarse gravel and sand.It is rarely found in either large rivers or headwater creeks, but has been found on gravel shoals in Lake Erie and Lake St. Clair. It is often found near beds of water willow, an aquatic plant. It is usually found deeply buried in the substrate (COSEWIC 2003).
Generation Length (years):10

Use and Trade [top]

Use and Trade:

Historically unionids were use for pearl and button industry.  Ptychobranchus fasciolaris was likely not the dominant species collected but could be used due to its thick shell.

Threats [top]

Major Threat(s): Zebra Mussels (Dreissena polymorpha) have nearly destroyed native freshwater mussel communities in the Great Lakes. Approximately 60% of sites where the Kidneyshell was found historically are now infested with Zebra Mussels. Populations in the Grand and Thames rivers were likely extirpated due to the combined effects of sewage pollution and agricultural impacts. The two remaining populations in Canada, are threatened by factors related to intensive agriculture, especially heavy loadings of silt and nutrients. Muskrats (Ondatra zibethicus) are also a potential limiting factor, since the Kidneyshell is one of the mussel species on which they prey (COSEWIC 2003).

IUCN Threats assessment performed for COSEWIC 2013. Appendix I.

Elsewhere the threats include pollution, habitat management (dredging channels disturbing mussels on riverbed) and impoundment.

Conservation Actions [top]

Conservation Actions: Ptychobranchus fasciolaris is Federally Endangered in Canada and is currently listed as endangered in Ontario, Illinois and Mississippi and special concern in Alabama and Indiana, and is therefore afforded some protection in these states. The Kidneyshell is not currently listed or proposed for listing under the U.S. Endangered Species Act.

Citation: Bogan, A.E. & Woolnough, D. 2017. Ptychobranchus fasciolaris. The IUCN Red List of Threatened Species 2017: e.T18824A62905619. . Downloaded on 18 June 2018.
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