Juvenile growth and survival of heat-shocked triploid hybrid saugeyes, Stizostedion vitreum × S. canadense

Abstract

Triploid hybrid saugeyes may be a desirable stocking alternative because diploid saugeyes are fertile and can compromise the genetic integrity of parental stocks. Four groups of saugeye eggs were heat-shocked 5 min after fertilization for 15 min at 31°C, which resulted in an 86.7 ± 9.4% triploidy rate and 57.8 ± 24.3% survival to the eyed-stage. Heat shocked and control saugeyes were stocked in two ponds for 40 days at 395 000 ind.ha^-1. Mean length and weight of triploid and heat-shocked diploid saugeyes were greater (P < 0.01) than unshocked diploid saugeyes. Survival of heat-shocked saugeyes (22.4%) was lower than unshocked saugeyes (94.7%). Heat-shocked fish (n = 25 851) harvested from ponds were stocked for 153 days in O'Shaughnessy Reservoir, Ohio, USA. Triploids were 34 mm shorter and weighed 41 g less than heat-shocked diploids (P < 0.01). Mean length and weight of triploids were comparable with unshocked diploids elsewhere in Ohio.