Where Have All the Seashells Gone?

If you've noticed seashell depletion on the beaches you visit, just know that it's not just a matter of light-fingered vacationers. Organized poaching has become a serious global concern. Vincent Nijman is an anthropology professor at Oxford Brookes University in the U.K. In a 2015 study he co-authored, Nijman documented the illegal trade of Indonesia's protected shells.

The Indonesian government keeps a list of mollusks that are illegal to trade or collect within the republic's jurisdiction. Chambered nautiluses, Triton's trumpets and some giant clams are among the creatures ostensibly protected by law there.

Yet poaching is rampant. Nijman's paper tells of 20 illegal shipments that were intercepted by the Indonesian authorities between 2008 and 2013. Put together, these busts yielded more than 42,000 shells — valued at $700,000 — of protected species.

"It is very important to note that we are not talking about individual tourists collecting a couple of shells on the beach, putting them in their suitcase and bringing them home," Nijman says in an email. "We are talking about [a] large-scale, commercial trade where the shells are collected ... by active fishing (scuba diving, cages, etc.) and where entire sections of the ocean floor are emptied."

He stresses that poachers like to grab occupied shells and then destroy the mollusks within them. "When alive, the shell is in pristine condition," he says. This means it will fetch a higher price because shells "that are washed up on the beach are often damaged."

Mollusks aren't the only animals who've been hurt by the reckless overhunting of seashells. When snails, nautiluses and other sea animals die of natural causes, other creatures like to move into their former shell homes. "The most obvious examples are hermit crabs, which use empty shells as protective armor," says Michal Kowalewski, an ecologist at the University of Florida whom we spoke to via email. "There are in fact many marine habitats where it is hard to find an empty shell ... [because] hermit crabs inhabit almost all of them." Indeed, it appears that shell availability is an "important limiting factor" for the vagabond crustaceans.

And housing is just one service that unused shells offer. "There are many other organisms that bore into shells for shelter or to mine them for calcium carbonate," Kowalewski adds. "Boring sponges are a good example." Certain other animals prefer to latch themselves onto the outsides surfaces, turning them into sturdy anchors. "[A] whole variety of organisms utilize shells that way, including mollusks, arthropods (barnacles), bryozoans, foraminifera, annelid worms and many others." Even birds have a use for shells: Vasa parrots will ingest ground-up seashells as a mineral supplement.

Llarga Beach is a pretty little slice of the Iberian Peninsula. Located in Salou, Spain, it's a hot vacation destination that's enjoyed increasing popularity. Wanting to know more about how this rise in human activity was affecting the ecosystem, Kowalewski rolled up his sleeves and hit the scene. From July 1978, through July 1981, he and his colleagues put together monthly catalogs of all the seashell material they could find on Llarga Beach. Kowalewski returned decades later for a new round of surveys beginning in 2008 and ending in 2010.

His discoveries were not encouraging. Tourism data revealed an almost threefold increase in visitation between 1980 and 2010. During that same period, the number of seashells on Llarga Beach fell by more than 60 percent. Coincidence? Probably not.

Other beachside communities should be worried about the same kind of decline in seashells — and not just for environmental reasons. Shells tend to break up into particles that are bigger than typical sand grains. That helps beaches fight erosion. Seashell fragments, as Kowalewski puts it, "can form pavements that may make it harder" for winds, waves and water currents to move shoreline sediment around. If we remove too many seashells, it'll become harder for our beaches to resist the forces of erosion.

"To belabor the obvious," Kowalewski says, "shoreline erosion may have substantial consequences for us because coasts are heavily populated and [it] can affect buildings and other infrastructure."

So what's the solution? "In many countries there are excellent laws in place to prevent overharvesting," Nijman notes. "Companies and individuals ... should follow the existing regulations and the authorities should enforce [them]." He adds that prosecutors and judges must take large-scale poaching operations more seriously. "It is an economic crime and should be handled as such."

Meanwhile, it might behoove the rest of us to take more pictures and fewer keepsakes from the beaches we all love.