Current Status of Bull Trout Abundance, Connectivity, and Habitat Conditions in the Walla Walla Basin. 2007 Update

摘要

This update is intended to provide preliminary results from work conducted during 2007 regarding migratory bull trout life history, abundance, distribution, and habitat conditions in the Walla Walla Basin, and to provide insight into the effect of physical and hydrologic conditions on bull trout biology and connectivity between local populations and core areas. There were 128 migratory bull trout redds identified during 2007 redd surveys conducted in the South Fork Walla Walla River (SFWW) index area. This was similar to the 126 redds identified during 2006 index area surveys, but relatively low when compared to the time series of index area redd counts from 1994-2007. USGS-USU identified a decreasing trend in abundance for the migratory portion of the population in their 2006 annual report.