By Alex Scott
If you are lucky enough to have found an abalone shell on the beach, it’s probably one of your most treasured beach finds. The shell’s inner layer, called nacre or mother of pearl, reveals a rainbow of iridescent colors that has been coveted and collected by humans for centuries. Various civilizations have used these shells for decorative purposes, including jewelry, architecture, weapons, mosaics, musical instruments, and even eating utensils. But these treasures are so much more than their shiny interiors, to both scientists and beachcombers.
Red abalone, or Haliotis rufescens, is one of seven species of abalone commonly found off the west coast of North America, from the shorelines of Canada all the way down to the warm Baja waters. Abalone are hardy animals, making their homes on the coastlines of almost every continent (except near the poles) and feeding on algae and kelp in the tidal and intertidal regions of the ocean. These gastropods are related to snails, with both sharing a twisted shell, and limpets, which also have a strong, muscular “foot” that keeps them attached to the rocks. Like salmon and flamingos, abalone change color depending on what color algae they eat, sometimes unintentionally creating a beautiful striped pattern on their shells.
Emily Pierce has been interested in mollusks since she kept snails as pets during her childhood, which earned her the nickname “Snail Girl.” Now she pursues that interest professionally at the invertebrate zoology and molecular biology lab at Moss Landing Marine Laboratories, on California’s Central Coast, with support from the Monterey Abalone Company and her graduate school program. Although her advisor initially wanted Emily study crabs, Emily says she fought to study abalone instead because of her lifelong interest in mollusks. The classification of abalone is an immense and ongoing project, and marine biologists like Emily Pierce are working out when the abalone originally evolved and to which species it is most related.
Left to right: Emily at work in her lab. Juvenile red abalone. Teaching the next generation of abalone lovers in Moss Landing, California.
Emily’s research into abalone focuses on environmental DNA, or eDNA, for population size research so researchers can understand how best to protect these amazing creatures. As Emily puts it, “Because it takes so long for abalone to reach maturity, these animals are in danger of being over-harvested and harmed by disease and climate change, so we really need to know where they are. It is expensive and time consuming to send divers out to scour areas for abalone, so hopefully one day we can go out, take a liter of seawater, and figure out what is below with more accuracy!” She has about 200 abalone (which she calls her “babies”) in an aquarium, whose eDNA she uses to compare
to the eDNA retrieved from the ocean.
Abalone are more quick and agile than one might expect of a snail-like creature; when they sense algae nearby they can “run” towards the food, and when Emily flips them over to get a DNA sample from their large foot, she has to move quickly or else the abalone will flip itself right back over in an instant.
Red abalone, like many members of the haliotid family, are considered a delicacy by humans and various marine animals such as crabs, lobsters, octopuses, and starfish, but have become scarcer due to over-harvesting. An abalone’s lifespan is about 40 years, and it takes a few years for them to mature and reproduce, so harvesting them from the ocean before they can spawn can prove deleterious to overall population sizes. In the United States, consumers can currently only eat red abalone raised in abalone farms until the wild abalone numbers increase. When harvested in the wild, regulations typically require that the abalone be seven inches long, which is usually after they are six to twelve years old.
Left to right: Abalone shell pieces drilled for jewelry by Ann Jamogchian @mendo.gems. Abalone and kelp jewelry by Jessica Anderson @lowtidelanding. Abalone keys on the saxophone of Anthony Paolini. Abalone and sea glass necklace by Aileen Cabral @artofseaglass.
Abalone shells have been used by humans for more than 100,000 years, from ancient African and Chinese cultures to various Native American tribes, all of whom not only ate abalone but also used their shells for jewelry and as a form of currency. To this day, the iridescent nacre shell of the abalone has remained a prize to humans all over the world. Abalone shells are still used today in jewelry as well as other accessories like furniture, buttons, and musical instruments. Their pearls are also highly valued for their distinctive swirling colors.
But the most profitable part of the abalone has always been its meat. Throughout modern history, abalone meat was a delicacy, eaten only on special occasions. It wasn’t until the early 1900s, as the shellfish became more and more sought after, that laws were passed in the United States to limit the amount of abalone fishing, which had already decreased the population significantly. Commercial farming of abalone that began in Japan and China in the 1950s, and was taken up worldwide, also helped to curb the fishing of wild abalone, and is now the main source of abalone meat for most of the world.
In Northern California, recreational abalone hunting is currently closed until at least 2021, as the population of red abalone is currently in rapid decline. “The loss of the abalone population is attributed to many factors,” says Mendocino artist Ann Jamgochian. “Human-related factors include poaching and over harvesting due to the increased popularity of the sport. Environmental factors kicked in about five years ago, when an unusual disease killed millions of sea stars, which eat sea urchins. Without their key predator in place, the sea urchin population exploded. As the urchin population increased, the kelp forests on which both abalone and sea urchins depend has been literally stripped clean along California’s northern coastline. As a result of starvation, large numbers of abalone have died, and those still alive have stopped growing and reproducing due to the environmental stress.”
Hopefully, the Endangered Species Act and organizations like the National Oceanic and Atmospheric Administration are helping scientists like Emily Pierce study abalone and make sure humans can continue to enjoy this beautiful animal for generations to come. Emily adds, “The best way to help abalone populations thrive is by not disturbing any abalone you may come across while tidepooling, supporting local abalone farms, and spreading awareness about the need to protect abalone!”
Emily Pierce can be found on her website, emilythemarinebiologist.wordpress.com, on Instagram @emilythemarinebiologist, and on her podcast, called Nudibrains.