Abstracts Acre-Chafin
Abstracts Acre-Chafin Last Edited 6/5/2017 0252 ASIH STOYE ECOLOGY & ETHOLOGY IV, Friday 14 July 2017 Matthew Acre1, Timothy Grabowksi2, Dakus Geeslin3, Allison Pease1, Nate Smith3 1Texas Tech University, Lubbock, TX, USA, 2Hawaii Cooperative Fishery Research Unit, Hilo, HI, USA, 3Texas Parks and Wildlife, Austin, TX, USA Movements and Demography of Cycleptus elongatus in the lower Colorado River, TX Alteration of flow regime, e.g., timing, duration, flashiness, and magnitude of discharge, has serious implications to fluvial specialists inhabiting large rivers that have evolved flow-dependent life histories. Blue Sucker Cycleptus elongatus, is one such species that is considered vulnerable throughout its range due to its habitat requirements and life- history traits. However, the relationships between stream discharge and habitat use and recruitment in C. elongatus have not been thoroughly examined, particularly in southern portions of its range. The primary objectives of this research were to assess effects of varied streamflow levels, regulated by water releases from upstream reservoirs, on C. elongatus movement, habitat use, and recruitment in the lower Colorado River downstream of Austin, Texas. Radio and acoustic telemetry was used to characterize movement in response to river discharge changes. Results suggest large-scale movements are related to season and flow regime prior to a relocation event. Furthermore, home range and minimum displacement are correlated with riffle density. Additionally, fin-ray sections (n = 105) taken from specimens during mark-recapture efforts were used to estimate age and associate relative year-class strength with historical flow regimes. Preliminary results suggest the population in the lower Colorado River has had limited recruitment, and stronger cohorts appear to be associated with years with higher discharge.
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