Tropic of the Sea by Satoshi Kon.
Title: Tropic of the Sea.
Author: Satoshi Kon.
Genre: Fiction, manga, teen, fantasy.
Country: Japan.
Language: Japanese.
Publication Date: 1990 (published in translation in 2011).
Summary: Yosuke's family has a strange tradition - once every sixty years they receive an egg from a mermaid. When the egg matures his family dutifully returns it to the sea, where the whole process is then repeated. In exchange for this favor, the mer-people bless his coastal town with bountiful catches of fish and calm seas. But as a commercial development encroach on the sleepy seaside village and Yosuke's father is lured away from tradition towards modern property, and turns the egg into a tourist trap, what will happen to the promise their family made to the mermaids generations ago?
My rating: 7/10.