Population Status and Trends of Colorado Pikeminnow of the Upper Colorado River, 1991-2005. Final Report

摘要

Mark-recapture studies from 1991 through 2005 were used to assess population trends of Colorado pikeminnow Ptychocheilus lucius in the upper Colorado River. Three multi-year data collection efforts were made: 1991-1994, 1998-2000, and 2003-2005. Primary objectives included capturing and marking Colorado pikeminnow equal to or greater than 250 mm long from throughout the study area, developing estimates of population abundance and survival rate and assessing trends in recruitment. Although results of the first two study periods have been provided in previous reports, data from these earlier efforts were reanalyzed using new techniques. Here, a synthesis is provided of the updated information from the earlier studies and the results from the most recent study period.