For general information, Yellow perch at hatching (yolk stage) are 5.5-7mm long and full fin development is at 8.5mm. Walleye fry at hatching begin feeding at 8.5-9mm long and after 21days are around 30-31.5 mm long which is 3.6 times longer than YP fry with full fin development (8.5mm). Walleye fry after 20-25 days should be able to consume newly hatched YP fry. If one could hold the YP eggs at a low temperature to slow hatching time and allow WE fry more time to grow at 1-1.5mm/day, the WE late larvae could more easily eat newly hatched YP. The study of low temperatures on the hatching success of YP eggs by Dr. Willis et al and reported in Pond Boss magazine (Mar-April 2010) that cold temperatures did not significantly reduce the YP egg hatch and fry survival.
YP eggs were gathered from lake water at 54F and the temperature was dropped in two tests; one at 11F to 43F and the other test dropped 14F to 37F for two days. Neither test showed a significant loss of hatching success compared to the control eggs at 54F. They then tested the temperature drop on the newly hatched YP by dropping the temperature by 6F and 13F from a starting temperature of 51F. No effect was noted for survival of the YP fry both control and test fry showed 91% survival.
Last edited by Bill Cody; 11/23/20 04:15 PM.
