TY - JOUR
T1 - Larval fish sensitivity to a simulated cold-water pulse varies between species and age
AU - Raymond, Scott
AU - Ryall, Jordi
AU - Koehn, John
AU - Fanson, Ben
AU - Hill, Sarah
AU - Stoessel, Daniel
AU - Tonkin, Zeb
AU - Sharley, Joanne
AU - Todd, Charles
AU - Campbell, Ashlen
AU - Lyon, Jarod
AU - Turner, Mark
AU - Ingram, Brett
PY - 2022/7
Y1 - 2022/7
N2 - The release of cold-water from hypolimnetic zones of impoundments sharply reduces downstream riverine water temperature. This cold-water pollution (CWP) can extend for hundreds of kilometres, severely challenging the physiological ability of aquatic fauna, particularly ectotherms such as fish, to maintain essential processes such as metabolism, development and growth and survival. The impact of CWP on native fish, especially early life stages, is poorly known. We investigated the effect of a 24-hour exposure to a range of environmentally-related water temperatures (8, 10, 12, 14, 16, 18 and 20°C) on three age-classes (<24-hour-old, 7-day and 14-day-old larvae) of two Australian native fish species: Murray cod (Maccullochella peelii) and Macquarie perch (Macquaria australasica). Overall, larvae of M. peelii were more sensitive to lower water temperatures and hence CWP than M. australasica, indicated by higher rates of equilibrium loss. Larvae of M. peelii were most sensitive to exposure at seven days old whereas M. australasica larvae were most sensitive at <24-h-old. Using our results, we modelled pre- and post-impoundment temperature scenarios and estimated the downstream CWP footprint for both species in an Australian river reach. Larvae of M. peelii were predicted to be absent from the first 26 km of river downstream of the impoundment compared with no impact on the distribution of M. australasica. Managing riverine water temperature below impoundments is fundamental to promoting positive outcomes for endemic fish on not only a local, but global basis. This study emphasises the differential impact of CWP among the critical early life stages and fish species and highlights the urgent need to better manage hypolimnetic water releases to improve downstream river ecosystems.
AB - The release of cold-water from hypolimnetic zones of impoundments sharply reduces downstream riverine water temperature. This cold-water pollution (CWP) can extend for hundreds of kilometres, severely challenging the physiological ability of aquatic fauna, particularly ectotherms such as fish, to maintain essential processes such as metabolism, development and growth and survival. The impact of CWP on native fish, especially early life stages, is poorly known. We investigated the effect of a 24-hour exposure to a range of environmentally-related water temperatures (8, 10, 12, 14, 16, 18 and 20°C) on three age-classes (<24-hour-old, 7-day and 14-day-old larvae) of two Australian native fish species: Murray cod (Maccullochella peelii) and Macquarie perch (Macquaria australasica). Overall, larvae of M. peelii were more sensitive to lower water temperatures and hence CWP than M. australasica, indicated by higher rates of equilibrium loss. Larvae of M. peelii were most sensitive to exposure at seven days old whereas M. australasica larvae were most sensitive at <24-h-old. Using our results, we modelled pre- and post-impoundment temperature scenarios and estimated the downstream CWP footprint for both species in an Australian river reach. Larvae of M. peelii were predicted to be absent from the first 26 km of river downstream of the impoundment compared with no impact on the distribution of M. australasica. Managing riverine water temperature below impoundments is fundamental to promoting positive outcomes for endemic fish on not only a local, but global basis. This study emphasises the differential impact of CWP among the critical early life stages and fish species and highlights the urgent need to better manage hypolimnetic water releases to improve downstream river ecosystems.
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U2 - 10.4081/jlimnol.2022.2056
DO - 10.4081/jlimnol.2022.2056
M3 - Comment/debate
AN - SCOPUS:85134610793
SN - 1129-5767
VL - 81
JO - Journal of Limnology
JF - Journal of Limnology
IS - 1
M1 - 2056
ER -