Hakai Magazine

Cover image courtesy of St. Martin’s Press. Background photo by Norbert Wu/Minden Pictures/Corbis

Book Review: Sex in the Sea

A PG-rated peek at the sex lives of sea creatures.

Authored by

by Brittany Shoot

Article body copy

Maybe you’ve heard a version of this story or one like it. In 2001, fishermen near the island of Little Cayman noticed thousands of Nassau groupers—a spawning aggregation of about 7,000 fish, to be precise—swarming a particular reef every full Moon. The nets went down. The grouper stock took a nosedive. In the years that followed, even as the groupers were fished to precipitously low levels, they kept coming back to that same spot for their full Moon orgies. Today, the Nassau grouper population is slowly bouncing back, but the bony fish is still listed as a species of concern by the US National Marine Fisheries Service.

In her debut book, Sex in the Sea: Our Intimate Connection with Sex-Changing Fish, Romantic Lobsters, Kinky Squid, and Other Salty Erotica of the Deep, Marah J. Hardt explores a range of similar cases linked by one common theme: getting it on.

Every section of the book is a riveting crash course in undersea sex, often with lurid, if not outright odd introductions to the activities of some species, such as sharks capable of virgin birth and sea worms that self-inseminate by stabbing themselves in the head. With plenty of amusing synonyms and humorous euphemisms, Hardt describes the often elaborate ways in which sea creatures reproduce, how humans impact marine mating, and the far-reaching effects of fish sex on issues such as local shoreline stability and global food security.

Hardt, a coral reef ecologist by training, also notes how humans are one of the most effective contraceptives when it comes to supporting sea creature sex. In the 1990s, sea snail populations plummeted worldwide when female snails absorbed endocrine-disrupting chemicals in polluted waters and started growing penises that blocked oviducts and caused fatal reproductive failure. If that sounds extreme, well, it is. This type of chain reaction is increasingly common, deadly, and costly.

But as Hardt optimistically explains, it’s not too late to turn the tide of crashing libidos, cresting desires, or nets cast too wide. By better understanding the sex lives of sea creatures, humans can propose and support better policies to protect our underwater friends from overfishing and other disruptions.

Sex in the Sea: Our Intimate Connection with Sex-Changing Fish, Romantic Lobsters, Kinky Squid, and Other Salty Erotica of the Deep By Marah J. Hardt
232 pp. St. Martin’s Press