Are these eggs?

I have posted an image of what look like bumpy slugs in alt.
binaries.pictures.garden whit the subject "what are these??"
These growths appeared a week or so after adding an Apple snail to the pond.
I don't know if theres any corrilation or anything to worry about.
If they are Apple snails, I will need lots more plants and and more algae
for them.
Even with feeding my one snail romain lettuce, he or she has eated ALL my
plants.