Anweiler et al.: Effects of temperature and hypoxia on the metabolic performance of Morone saxatilis 
339 
2010 
2011 
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1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5 6.0 6.5 7.0 7.5 8.0 8.5 9.0 9.5 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5 6.0 6.5 7.0 7.5 8.0 8.5 9.0 9.5 
DO level (mg/L) 
Figure 1 
Relationships of temperatures to dissolved oxygen (DO) levels recorded at 2 sites in the Ashley River in South Carolina 
during the summers (June-August) of 2010-2015. Observations were recorded in 15-min intervals by using 2 YSI 
6600EDS V2-2 multiparameter water-quality monitoring devices (or sondes; YSI Inc., Yellow Springs, OH). Sondes 
were deployed in the Ashley River at river kilometer (rkm) 21 and rkm 39, measured from the river’s confluence 
with Charleston Harbor. Gray dots indicate values recorded at the site at rkm 21, a location that represents a 
marsh-dominated estuarine habitat. Black dots indicate values recorded at the site at rkm 39, which is a transition 
zone between estuarine emergent wetland and palustrine forested wetlands. For comparison, asterisks indicate 
temperatures and DO concentrations used in treatments in this study. 
the basis of how natural resource managers monitor sys¬ 
tems and estimate fish survival in systems. 
Changes in AMS of juveniles due to temperature and 
DO level were measured to understand how these condi¬ 
tions might affect the survival of stocked fish during 
their first summer in the Ashley River. Because AMS, 
when expressed as a function of temperature, typically 
takes the approximate form of a bell-shaped curve that 
aligns with organismal performance (Neill and Bryan, 
1991; Portner and Farrell, 2008; Portner, 2010), we pre¬ 
dicted that 1) SMR would increase with increasing tem¬ 
perature; 2) MMR, AMS, and exhaustion time would be 
greatest at 25°C and would be lower at 20°C and 32°C, 
consistent with the recorded temperature preference for 
juveniles (Coutant and Carrol, 1980; Coutant et al., 
1984); and 3) MMR, AMS, and exhaustion time would 
decrease with decreasing DO concentration. Hypotheses 
2 and 3 are consistent with observations that striped 
bass avoid DO levels less than 3.0 mg/L and prefer 
temperatures less than 30°C (Zale et al., 1990; Bjorgo 
et al., 2000; Schaffler et al., 2002). 
Materials and methods 
Experimental animals and acclimation conditions 
Experiments were conducted at the Marine Resources 
Research Institute (MRRI), South Carolina Department 
of Natural Resources (SCDNR), in Charleston, South 
Carolina. Striped bass larvae (2013 year class) were pro¬ 
duced from wild-caught adults from the Santee Cooper 
reservoirs. Larvae were grown to small juveniles in fertil¬ 
ized, brackish ponds (salinity: ~7) at the SCDNR Waddell 
Mariculture Center and transported to the MRRI, located 
in Charleston Harbor. Fish were initially held indoors 
in circular 1600-L fiberglass tanks in order to accli¬ 
mate them to feeding routines until they were 1 year old. 
