Effect of a Simulated Cold-Front on Hatching Success of Yellow Perch Eggs

Gradually warming water temperature during yellow perch (Perca flavescens) egg and larval stages has been associated with stronger year classes, whereas an abrupt drop in temperature associated with a cold-front during this period can result in weaker or missing year classes, presumably because of egg or larvae mortality. We subjected yellow perch eggs to sudden declines in temperature and then monitored hatching success of those eggs relative to eggs held at a constant temperature. An experiment in 2007 decreased water temperature by 6°C in 24 h; however, no significant difference in mean hatching success was observed between treatment (48%, SE=5.8) and control tanks (55%, SE=6.0). Another experiment in 2008 decreased water temperature by 8°C in 45 min. Again no significant difference in hatching success was observed between treatment (37%, SE=5.6) and control tanks (38%, SE=5.0). Abrupt temperature drops did not reduce hatching success of yellow perch in laboratory experiments and thus do not appear to be a mechanism affecting perch recruitment at the egg stage tested in our two trials.