Ah okay, I don't believe that shells can be transferred since they're a very limited currency, though that's something to ask the staff about. Good luck anyways ^^
As of currently, the only way to earn seashells is when you first join the forum and you're automatically given 10. But after those are gone, that's it.
I've also heard that if you're a 2-year member and have more than 20 posts, you get seashells for that too, but that may have just been a one-time thing for older members since the seashell feature is relatively new.