Relationships between river discharge and abundance of age 0 redhorses (Moxostoma spp.) in the Oconee River, Georgia, USA, with implications for robust redhorse

River Research and Applications
By: , and 

Links

Abstract

Robust redhorse (Moxostoma robustum) and notchlip redhorse (M. collapsum) are two species of redhorses that reside in the lower Oconee River, Georgia. Robust redhorse is listed as a state endangered species in Georgia and North Carolina, and attempts to investigate factors affecting its reproductive success have met with limited success. Therefore, catch of robust redhorse young were combined with catch of notchlip redhorse to increase sample size. These congeners with similar spawning repertoire were assumed to respond similarly to environmental conditions. River discharge during spawning and rearing seasons may affect abundance of both redhorses in the lower Oconee River. An information-theoretic approach was used to evaluate the relative support of models relating abundance of age 0 redhorses to monthly discharge statistics that represented magnitude, timing, duration, variability and frequency of river discharge events for April through June 1995–2006. The best-approximating model indicated a negative relationship between the abundance of redhorses and mean maximum river discharge and the number of high pulses during June as well as a positive relationship with intermediate duration of low flows during April–June. This model is 9.6 times more plausible than the next best-fitting model, which revealed a negative relationship between the abundance of redhorses and mean maximum river discharge during May and the number of high pulses during June as well as a positive relationship between abundance and intermediate duration of low flows during April–June. Management implications from the results indicate low-stable flows for at least a 2-week period during spawning and rearing may increase reproductive success of robust and notchlip redhorses.

Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Relationships between river discharge and abundance of age 0 redhorses (Moxostoma spp.) in the Oconee River, Georgia, USA, with implications for robust redhorse
Series title River Research and Applications
DOI 10.1002/rra.2566
Volume 29
Issue 6
Year Published 2013
Language English
Publisher John Wiley & Sons
Publisher location John Wiley & Sons
Contributing office(s) Coop Res Unit Atlanta
Description 9 p.
First page 734
Last page 742
Online Only (Y/N) N
Additional Online Files (Y/N) N