Vaginal Fantasy Book Club discussion

I didn't see a thread dedicated to this, forgive me if there is one already.

I figured we should have a place where we can write what we do remember about books that we've read and can't for the life of us remember the title to, because there's a good chance someone here will remember.

To start us off, there are two books that I need help identifying.

1) An anthology of short stories which were YA and on the cover was an embossed white unicorn. If I recall correctly, it was an anthology of unicorn-related or featuring tales. The one story I remember reading was of two girls, and one or both were ill. At some point in the story, one of them likens narwhals as the unicorns of the sea (or something to that effect), and possibly mentions something about the spires of coral castles under the sea. Then one (the one doing all the telling of the elaborate underwater castles and whatnot), walks into the sea one day and never comes out. Some people assume she committed suicide, but her friend hopes/wonders if her friend was a mermaid and returned to the underwater castle.

2) There was a teenage girl living on an island in a tropical region. I believe she was alone there, but I could be wrong. At some point she hunts king crabs or some sort of giant fantastical crabs. It may or may not have been fantasy, but it was definitely YA. That's all I can remember of this second one, sadly.

Could the second be Island of the Blue Dolphins? Karana gets left behind when her people leave and she survives on her own for 12 years or so.

Wow, that was fast! Yes, I do believe you are right with the Island of the Blue Dolphins.

Immortal Unicorn maybe?

I should have done this sooner! Immortal Unicorn is the one. I can tell just by looking at the cover. Thanks!