David Baptiste, a fisherman on the Caribbean island of Black Conch, meets a mermaid named Aycayia, who was drawn to David's boat by his singing. When Aycayia is caught by two American fishermen, David rescues her and takes her back to his house, where she starts to transform back into a woman. As Aycayia readjusts to life on land, she and David fall in love.
The Mermaid of Black Conch contains examples of:
- 20 Minutes into the Past: Published in 2020, but set mostly in 1976. David's journal entries date to 2015 and 2016.
- Alliterative Family: Arcadia has two brothers named Archie and August.
- Bathtub Mermaid: After David rescues Aycayia, he keeps her in a tub, which he fills with water and a box of salt. She stays there for about ten days, until her legs start to separate.
- Beautiful Singing Voice: Aycayia's name translates to Sweet Voice, and it's one of the reasons the other women in her village were jealous of her. In the present day, David and Arcadia both think she lives up to her name. Arcadia compares her voice to honey.
- Bound and Gagged: After the fishermen haul Aycayia aboard, they gag her and tie her hands.
- Childhood Friend Romance: Arcadia Rain and her former lover, Life, became best friends when she was eight and he was nine. When Arcadia was eleven, she was sent to boarding school in a convent in Barbados, but she always planned to elope with Life. Unfortunately, Arcadia is one of the few white people on Black Conch, lives on land that was once worked by slaves, and after her parents die, she inherits most of the town of St. Constance. It wasn't as much of a problem when she and Life were children, but as an adult Life never fully trusted her or felt like they could be equals.
- Disappeared Dad: Life wanted to have a career in the world outside Black Conch. When he found out Arcadia was pregnant, he realised he'd be tied to the island forever. Just as importantly, he would always be subordinate to Arcadia. He left by ferry during the night, leaving Arcadia to raise Reggie by herself. Until he comes back and sneaks into her house late at night. Arcadia almost shoots him before she recognises him.
- Fish out of Temporal Water: Aycayia knows that ships are larger and faster than they used to be, but she's ignorant of everything that's happened on land in the last thousand years and is bewildered by things like modern technology and the need to wear clothes.
- Forced Transformation: Aycayia used to be a Taíno woman living in a village in Cuba, but the other women became jealous of her beauty and had her exiled. Even after that, the men kept going to watch her dance, so the women prayed to the Goddess Jagua to banish her to the sea. Jagua turned Aycayia into a mermaid and also turned Guanayoa, a woman who had been previously exiled for being old, into a sea turtle. Then she summoned a hurricane to blow both of them far away from Cuba.
- Handshake Refusal: Hank Clayson, one of the fishermen who caught Aycayia, flags down Arcadia's jeep and extends his hand, but she ignores it and shouts, "What de ass been going on here?"
- Heal It with Booze: After David takes Aycayia to his house, he pours rum on the wound from the gaff hook.
- Homeschooled Kids: Arcadia's ten-year-old son Reggie is deaf. There are no schools for the deaf on Black Conch, so she hired an American tutor to teach the two of them ASL so she could homeschool him. Reggie is mostly happy but very isolated. He considers Aycayia to be his First Friend.
- How Dad Met Mom: Reggie likes to be told the story of how his parents became friends. Life cut off one of Arcadia's pigtails in school. When Arcadia got home, her mother cut off the other pigtail to make it even. She's worn her hair short ever since.
- Interrupted Suicide: When Aycayia starts to transform back into a mermaid, she decides to commit suicide by hanging herself with a vine. David finds her and cuts her down. When Aycayia wakes up, she asks David to let her die. He doesn't, but he wonders if he made the right decision by saving her.
- Kick the Dog: When Hank's father Thomas goes to Arcadia Rain's house to report the mermaid's "theft", Reggie's two dogs run to greet him. He kicks one of them.
- Love at First Sight: David is enchanted by Aycayia from the moment she first rises from the waves to listen to him sing.
- Mermaid Problem: Invoked. The fact that Aycayia can't have sex is very much part of her curse.
- No Periods, Period: Averted, Aycayia getting her period is a sign that she's fully turned back into a human.
- Nostalgic Narrator: Part of the book consists of David's journal entries from the 2010s.
- Older Than They Look: Aycayia looks no older than twenty, but she's at least a thousand years old.
- Rain of Something Unusual: Reggie and Aycayia are caught in a rainstorm when thousands of live fish start falling from the sky. Aycayia hears women laughing and realises that the curse has followed her onto Black Conch. After a few minutes the rain stops, leaving Arcadia's lawn covered in fish. Later, as Hurricane Rosamund is beginning, the same laughter is heard, and sea creatures of all kinds start falling from the sky. The islanders think the storm is just picking up fish from the ocean, but Aycayia knows it's a message from Jagua.
- Reading Lips: Reggie reads lips in Black Conch English and reads books in Standard English.
- So Beautiful, It's a Curse: Aycayia's beauty and singing voice drew the attention of men, whose wives became jealous and prayed to Jagua to exile her to the sea.
- Switching P.O.V.: The book switches between an omniscient narrator, David's journal entries, and Aycayia's narration in free verse.
- Unwilling Suspension: The fishermen bring Aycayia to the jetty and hang her up by the tail next to the big game fish. She hangs there all evening while drunken passersby ogle her and sometimes sexually assault her. After it gets dark, David cuts her down and takes her away.
