I'm not a snail egg connoisseur, but my trochus breed like crazy. If they are cerith, not sure what the survival rate is, but i'm guessing you'll get a few at least, assuming nothing else eats them first...
Looks like cerith snail eggs to me. We have a bunch of cerith snails as part of our CUC and they lay eggs every few weeks that look exactly like that. I'm not sure how long they take to hatch but I have yet to notice any tiny snails in the tank so I'm assuming that something eats them when they hatch or eat the eggs when I'm not looking. Although I've never seen the fish pick at the eggs.