Mermaid

Martha is a character in.

Biography
Martha is a mermaid who inhabits Martha's Bay, the body of water on Koholint Island that is named after her. Schule Donavitch made a statue of her called "The Mourning Mermaid," which is placed near Martha's Bay, although it is not complete. She asks Link to retrieve her lost necklace that was taken away by the waves. When Link returns her the necklace, she rewards him with one of her scales. Link can place the scale on The Mourning Mermaid statue to reveal a hidden passage where he finds the Magnifying Lens.

Trivia
In the Japanese, French, and German versions of the game, Link instead had to find her lost bikini top. This was most likely deemed too racy and was changed in the American version.