Survival and hatching success of stonefly eggs (Paragnetina media) following ingestion by three stream fishes

The effects of predation by three stream fishes (emerald shiner, creek chub , and mottled sculpin) on the survival and hatching success of eggs of the northern stonefly, Paragnetina media (Walker), were investigated with feedi ng and incubation experiments. Stonefly eggs displayed a 75% survival rate through the digestive system, but no statistically significant difference ( p > 0.05) was observed in the recovery of intact eggs from the three fishes . Approximately 73% of the eggs that passed through the emerald shiners and mottled sculpins hatched within 60 days. Significantly fewer eggs (p = 0.0 02, 63%) hatched following passage through the creek chubs. Previous studie s have shown that stonefly eggs can survive periods of freezing, desiccatio n, and harsh physical conditions. The present study shows that stonefly egg s can also survive passage through the digestive system of predatory stream fishes and this may represent a previously uninvestigated mechanism for lo calized dispersal.