RELATIONSHIPS BETWEEN RIVER DISCHARGE AND ABUNDANCE OF AGE 0 REDHORSES (MOXOSTOMA SPP.) IN THE OCONEE RIVER, GEORGIA, USA, WITH IMPLICATIONS FOR ROBUST REDHORSE

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. Copyright © 2012 John Wiley & Sons, Ltd.

State-space models to describe survival of an endemic species in the Little Tennessee River basin

“…Little is known about what factors influence adult Sicklefin Redhorse survival. However, other large bodied catastomids, Robust Redhorse and Notchlip Redhorse (Moxostoma collapsum), have been extensively studied and other life history metrics (e.g., age-0 survival) are related to discharge (Peterson et al, 2013). For example, Robust Redhorse and Notchlip Redhorse age-0 survival has been linked to river discharge (Peterson et al, 2013).…”

“…However, other large bodied catastomids, Robust Redhorse and Notchlip Redhorse (Moxostoma collapsum), have been extensively studied and other life history metrics (e.g., age-0 survival) are related to discharge (Peterson et al, 2013). For example, Robust Redhorse and Notchlip Redhorse age-0 survival has been linked to river discharge (Peterson et al, 2013). It was found that mean maximum discharge during April and June was negatively related to age-0 abundance and intermediate duration of low flows was positively related to age-0 abundance.…”

“…The omission of discharge in the survival model used here does not imply Sicklefin Redhorse populations are not affected by stream flow. Discharge was not included in this study because only age-0 survival in other catastomids have been linked to discharge (Peterson et al, 2013) and this study only estimated survival of adult fish. Interestingly, the three years of low survival of adult Sicklefin Redhorse in the Little Tennessee River coincided with the three lowest discharge years in the time series.…”

The influence of thermal cues on the reproductive phenology ofSilverShiner,Notropis photogenis

“…(Cooke & Bunt, 1999;Reid, 2006). In contrast, the earlier establishment of natural low, stable flows characteristic of the summer hydrograph may accelerate the initiation and cessation of spawning and lead to increased reproductive success (Cull Peterson et al, 2013). Silver Shiner is a drift-feeding fish, actively capitalizing on both aquatic and terrestrial prey in the surface drift (Burbank et al, in press).…”

Relationship between environmental variables and egg abundance of the four major Chinese carps, downstream of the Three Gorges Reservoir

“…Previous studies have shown the abundance of some fish species in the early life stage implied quantifiable relationships with hydrological or thermal variations (Peterson, Jennings, & Peterson, 2013; Li et al, 2013; Rolls et al, 2013; Wang et al, 2014b), and that can serve as precise tool for monitoring the effects of anthropogenic flow regulation (Humphries & Lake, 2000; Tan et al, 2010; Xu et al, 2015). By monitoring fish resources of early life stages response to regulated flow condition, critical management requirements regarding ecological flows in regulated rivers might be identified (Gilligan & Schiller, 2003; King et al, 2010; Rolls et al, 2013).…”