Dr. Rob Dillon, Coordinator

Thursday, June 14, 2007

More Snake River Gastropods Studied for Delisting

To the FWGNA group:

Last Wednesday the Snake River Office of the US Fish and Wildlife Service announced new comprehensive status reviews for two federally listed freshwater gastropods, the threatened hydrobiid Taylorconcha serpenticola and the endangered Valvata utahensis. Press releases are available as PDF downloads below.

These actions were prompted by petitions to delist the snails from the Idaho Governors Office of Species Conservation, Idaho Power Company, and several state irrigation districts. The petitioners argue that both snail populations are much larger and more broadly distributed than previously believed, that they are not threatened by existing dam and diversion projects, and that the danger of future environmental degradation in the Snake River has been reduced.

The situation is quite reminiscent of Pyrgulopsis idahoensis, which underwent a comprehensive status review in 2005 and was ultimately recommended for delisting by the FWS last fall. That decision was based largely on new genetic and morphological data suggesting that P. idahoensis is not endemic to the Snake River, but rather conspecific with several other nominal Pyrgulopsis species found elsewhere in the Pacific northwest. See my posts of April '05, December '05, and October '06 to jog your memory.

The most recent status reviews have not been precipitated by new genetic data, nor are the petitioners challenging the present range limitations of T. serpenticola and V. utahensis to the Snake River. Rather, they focus on recent reports by Richards et al. (2006) and Hinson (2006) suggesting that Snake River populations of Taylorconcha and Valvata are simply not as rare or as endangered as previously believed.

I have been unable to learn much about the Richards and Hinson reports, or indeed even obtain their full citations. In any case, workers with additional data or other information bearing on the conservation status of T. serpenticola and V. utahensis are encouraged to contact the FWS before the public comment period ends on September 7, 2007.

And even if you've never laid eyes on the Snake River or any element of its controversial gastropod fauna, you may find last Wednesday's FWS press releases to be interesting reads. Both include the complete articles from the Federal Register, feature surprising amounts of biological information, and offer dim windows into the forbidding world of public policy.

We'll keep in touch,

Press Releases:

Utah Valvata Snail to Undergo Comprehensive Status Review [PDF]
Service to Take Further Look at Delisting Bliss Rapids Snail [PDF]