As the boat headed back to shore, the mermaid now inhabiting John's body considered things. She was in a human body but she decieded a man's body would simply not suffice. While the experiance would certainly be different, she wanted a body that was beautiful. This average male body wasn't good enough. On the other hand, this airheaded girl - who she had figured out was named Jena - had a better body than anyone else on the boat. The mermaid made her choice.
As everyone began to disembark from the boat, the mermaid used the bodyswap ring to put her mermaid consciousness into Jenna's body and Jenna's consciousness into John's body.