Midwest Region Conserving the nature of America

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Species of Concern

Decision on the Status Recommendation for the Indiana Crayfish


The U.S. Fish and Wildlife Service’s Bloomington, Indiana, Ecological Services Field Office has reviewed the relevant published and unpublished data for the Indiana crayfish and has prepared a status assessment report for the species. Based on that review the Bloomington Field Office has recommended that the Indiana crayfish (Orconectes indianensis) not be elevated to the status of a Candidate Species, but that it remain as a regional "Species of Concern." The endangered species program staff in the Service’s Region 3 Office support that recommendation. Therefore, Region 3 has determined that the Indiana crayfish will not be elevated to the status of a Candidate Species at this time. The species will be retained as a "species of concern" and Region 3 will remain the lead region for ongoing review of its status.


"Species of concern" is an informal term that refers to those species which Region 3 believes might be in need of concentrated conservation actions. Such conservation actions vary depending on the health of the populations and types and degree of threats. At one extreme, there may only need to be periodic monitoring of populations and threats to the species and its habitat. At the other extreme, a species eventually may require listing as a Federal threatened or endangered species and become the subject of a Federal recovery program. Species of concern receive no legal protection under the Endangered Species Act as a result of this informal designation, and the use of the term does not necessarily mean that the species will eventually be proposed for listing as a threatened or endangered species. As funding and staffing levels permit, Region 3 evaluates Species of Concern to determine the extent of their conservation needs and to determine whether additional legal protection should be sought for them.


The Field Office status recommendation indicates that the species’ historical distribution was limited to the southern portions of Illinois and Indiana. (An early inclusion of Kentucky in the species’ range is not supported by other researchers.) However, there were no systematic surveys carried out in Indiana prior to 1993. The current Indiana population appears to be nearly as widespread as it was historically, ranging across portions of eight counties. The extent of Indiana crayfish distribution in the State makes it highly unlikely that the species could be extirpated by a single catastrophic event. The current proximity of the populations to each other likely would allow recolonization if a population was extirpated. However, the core of the Indiana distribution – the Patoka River watershed – suffers from significant degradation resulting from coal mining, stream channelization, and poor water quality, and Indiana crayfish numbers have decreased within the Patoka drainage.


It is believed that an historical range contraction occurred in Illinois sometime between comprehensive crayfish surveys conducted in the early 1900's and the 1970's. However, since that time there is no evidence of a further range reduction. Similar to the situation in Indiana, the Illinois mainstay of the crayfish – the Saline River system – is degraded, and the North and Middle forks of the Saline River no longer support Indiana crayfish. Threats to water quality and the crayfish in the two states include pollution from coal mining and oil extraction, siltation, and stream channelization and clearing.


While there is insufficient evidence to show that these ongoing threats are causing an ongoing population decline, the threats are sufficiently serious to cause Region 3 to retain the species as a "Species of Concern."


The Service recommends that the following management activities be carried out to improve the status of the Indiana crayfish:

1) Due to the apparent reduction in historical range in Illinois and the habitat degradation in the core of the Indiana range, the species should be closely watched. A more comprehensive monitoring protocol should be developed and implemented to document changes in the species’ population and distribution and threats to it and to its habitat. This protocol should include the sampling methodology used by Page in 1985 and 1994 to ensure comparable data; however, sampling intensity should be increased.


2) Identify and reduce specific threats to the water quality of the streams which are still inhabited by the Indiana crayfish. Conservation agreements with private landowners should be developed throughout the watersheds occupied by the species.


Questions concerning this species should be directed to the Service’s Bloomington, Indiana, Ecological Services Field Office which has the lead responsibility for data collection and analysis for this species. Questions about the process of listing a species as threatened or endangered should be directed to the Regional Listing Coordinator at 612-725-3536 extension 241.


September 25, 1997


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