Short term temperature fluctuations affect embryonic and larval development of yellow perch (Perca flavescens)

Abstract

Early life stages of fishes are critical stages due to their importance in enhancing recruitment. Given the high mortality through the embryonic and larval stages, managers have started investigating factors that impact these stages. Environmental factors, such as water temperature, have been found to play a larger role in early life survival. Climate change predications will be more apparent in northern temperate systems like the Great Lakes. Yellow perch Perca flavescens are an important sport fish in the region whose populations have been declining since the 1980s. Yellow perch recruitment is highly erratic due to the species dependence on spring water temperatures. With warming waters occurring earlier in the seasons, it is unsure how wild yellow perch will adapt. The objective of this study was to determine how variations in temperature regimes during the egg incubation period would impact embryonic and larval development in yellow perch. Four different temperature treatments were used in this study: steady temperature at 16°C, a gradient starting at 12°C increasing by 1-2°C every 3-4 days, a heat shock on day six of 20°C for 16 hours to mimic a heat wave event, and finally, a cold shock on day six of 10°C temperatures for 16 hours to mimic a cold snap event. The results of this study confirm that water temperatures severely impact embryonic development and incubation periods of yellow perch, having a significant impact on the percent of failed larvae at the end of the incubation period (P= 0.0005), with the cold shock affecting the lowest percent of failed larvae (0.8%) while the steady treatment had the highest percent (22.9%). Temperature treatment did have a significant impact on the time it took for larvae to successfully hatch out (P<0.001), but no significant effect on observed mortality and estimated mortality (P= 0.96), percent of surviving larvae (P=0.35), or average growth rate of larvae (P=0.16).This study reveals that yellow perch are better adapted to withstand acute cold shifts in water temperature than acute warming events. Climate change could potentially hinder an already struggling Lake Michigan yellow perch population.

Developing a Biomarker to Cold Shock in the Yellow Perch, Perca flavescens

“…However, they did find a change with net confinement stress at one-week post-hatch depicting, the HPI axis begins to be prevalent at this life stage (Jentoft et al, 2002). Another study that introduced cold shock on yellow perch embryos, found it to account for less mortality that the steady temperature treatment (Sepulveda Villet, 2021). Another notable study conducted on yellow perch in response to handling and salinity stress found that handling at 20°C might result in lesser activation of the stress response, whereas plasma cortisol was elevated in the 14°C and 26°C treatments with handling stress; In the normal condition, 14°C had the least amount of plasma cortisol.…”