This makes me picture a mermaid culture that developed the idea of underwater animal husbandry in order to maintain a steady supply of fish for their dinner tables.
Sharks were gradually domesticated in this society as a result of them hanging around the merpeople when they were culling their fish stocks.
Now shark teeth are the strongest currency and status symbol of mermaid society. Keeping your pet sharks healthy is as important as keeping yourself healthy, so mermaid culture unravels when the sharks mysteriously begin disappearing. Where did they go? Will the shark shepherds be able to track them down before it’s too late?
Someone hurry up and write this book. I can’t wait to see how it ends!