Semper fidelis? Site fidelity and population turnover in suckers of the Southwest using PIT telemetry

Authors: Michael Booth, Alex S. Flecker, Nelson G. Jr. Hairston

Year: 2012 (xliv)

Abstract

Movement of organisms within stream ecosystems is an important mechanism controlling an array of processes, including population dynamics, resource distribution, and the spatiotemporal effects of engineering taxa. Recent analyses suggest that movement has two components: displacement (large scale movement) and turnover (short distances) of individuals. Turnover of individuals is rarely considered in movement studies, but it can be important because it determines population structure and baseline population size for a particular habitat. We used stationary antennas and PIT (passive integrated transponders) tags to monitor individual habitat use and turnover of Sonora suckers (Catostomus insignis) and desert suckers (Catostomus clarki) within a 150-250m reach during 2009 and 2010. While a large number of tagged fish used our stationary antenna reach, only a limited subset of these fishes were consistently present. The population size of our focal reach was variable, ranging from 12 to >45 individuals. Turnover rates were variable from day to day, ranging from 0 to >65%. The few individuals that were consistently present in the focal reach still made extended (one or more days) departures from their home pools. However, some individuals displayed substantial fidelity to a particular habitat despite forays elsewhere, returning to the focal reach for the duration of the study.