Lethal Thermal Maxima for Age‐0 Pallid and Shovelnose Sturgeon: Implications for Shallow Water Habitat Restoration

Abstract

We evaluated temperature tolerance in age-0 pallid and shovelnose sturgeon (Scaphirhynchus albus and Scaphirhynchus platorynchus), two species that occur sympatrically in the Missouri and Mississippi Rivers. Fish (0.04-18 g) were acclimated to water temperatures of 13, 18 or 24°C to quantify temperatures associated with lethal thermal maxima (LTM). The results show that no difference in thermal tolerance existed between the two sturgeon species, but that LTM was significantly related to body mass and acclimation temperature. Multiple linear regression analysis was used to estimate LTM, and outputs from the model were compared with water temperatures measured in the shallow water habitat (SWH) of the Missouri River. Observed SWH temperatures were not found to yield LTM conditions. The model developed here is to serve as a general guideline in the development of future SWH.

Influence of a dynamic rearing environment on development of metabolic phenotypes in age-0 Lake Sturgeon, Acipenser fulvescens

“…At 55 dph and 271 dph, CTmax was assessed to the nearest 0.01°C for individuals as described previously by Deslauriers et al . (2016) with slight modifications.…”

Status of knowledge of the Shovelnose Sturgeon (Scaphirhynchus platorynchus,Rafinesque, 1820)

“…While most SVS, when gradually acclimated to temperatures ranging from 26 to 30°C, were able to survive for an extended period (Kappenman et al., ), temperatures 26°C and greater can act as an environmental stressor leading to reduced growth rate and increased mortality (Kappenman et al., ; Phelps et al., ; Hupfeld et al., ). In controlled experiments with shorter acclimation periods, the lethal thermal maxima and point of loss of equilibrium of SVS were determined to range from ~30 to 35°C (Hupfeld et al., ; Deslauriers et al., ). Young of the year SVS thermal tolerance increased with greater body mass and acclimation temperature (Deslauriers et al., ).…”

“…In controlled experiments with shorter acclimation periods, the lethal thermal maxima and point of loss of equilibrium of SVS were determined to range from ~30 to 35°C (Hupfeld et al., ; Deslauriers et al., ). Young of the year SVS thermal tolerance increased with greater body mass and acclimation temperature (Deslauriers et al., ). While upper thermal tolerances of SVS are similar to sympatric PS (Deslauriers et al., ), there appears to be differences in preference for thermal niches between SVS and PS (see Blevins, ; Meyer et al., ).…”

“…Young of the year SVS thermal tolerance increased with greater body mass and acclimation temperature (Deslauriers et al., ). While upper thermal tolerances of SVS are similar to sympatric PS (Deslauriers et al., ), there appears to be differences in preference for thermal niches between SVS and PS (see Blevins, ; Meyer et al., ).…”

“…While water temperature rarely exceeds 30°C in most of the range, thermal threats that exceed tolerances have been identified (high summer river temperatures, loss of riparian habitat, power plant thermal effluent, etc. ), and climate change concerns raised (Hupfeld et al., ; Deslauriers et al., ). We speculate that climate warming may cause the range of SVS to contract northward as southern regions become too warm for growth.…”