How many Secret Seashells are there?
Honestly — I don’t know. Secret Seashells are deposited in a number of ways; some are on the map, some are dropped by destructibles, and yet more are created on demand by quests. There is thus no convenient way to count them, and I never kept a tally when I put them all in. I just threw them down where they felt right. I think there are about 23. But don’t quote me on that. There are many more than enough in the map to activate the secret.