Discovering Coquina Clams at Cocoa Beach

After 25 years of visiting Cocoa Beach, a discovery of coquina clams transformed my appreciation for the ecosystem, revealing its beauty, complexity, and intrinsic connections to life.

A Familiar Shore, Newly Seen

For nearly two and a half decades, I’ve strolled the sands of Cocoa Beach—since my first visit in March 2001—comforted by the rhythmic Atlantic waves and the familiar stretch of shoreline. I thought I knew this beach intimately; from the way the sunrise paints the water orange to the feel of wet sand under my feet. Yet it wasn’t until a clear morning in February 2025 that I recognized one of its tiniest treasures: the coquina clam. In the past, I might have walked past countless little shells and the tiny siphons and feet in the sand without a second glance. Now, with newfound awareness, I realize an entire world had been bustling at my toes all along.

February 2025: Discovering the Coquina Clams

Early one February morning, as the high tide receded, I noticed something magical happening at the water’s edge. Tiny coquina clams—each no larger than a fingernail—were emerging from the sand only to swiftly burrow down again between each wave.​

These living coquina clams were found in the receeding high tide on a February 2025 morning on Cocoa Beach, Brevard County, Florida

Their small wedge-shaped shells, in colors of pastel pinks, purples, yellows, and whites, peeked out for a moment and then vanished, synchronized with the pulse of the ocean. It was as if the beach itself had come alive with confetti-like jewels, re-positioning themselves with every ebb and flow. I stood entranced, wondering how I’d missed this subtle dance for so many years. That morning marked the beginning of my quest to learn about these little clams that had been hiding in plain sight.

Life Beneath the Sand

Once my eyes were opened, I began observing and researching the coquina clams’ hidden world. I learned that each delicate clam is a filter feeder, siphoning in microscopic phytoplankton, algae, and organic particles from the surf. This constant filtering not only feeds the clam but also helps clean and clarify the coastal waters by removing excess nutrients. Coquinas live a fast-paced, transient life by necessity: they typically survive 1–2 years in the wild and can endure a mere few days without the ocean’s moving water.​

No wonder they race to burrow when the waves recede—staying submerged is a matter of life and death, as they rely on the surf for both food and oxygen. In their brief lifespan, they continually ride the tides, migrate in swarms up and down the beach, and rebury themselves between each wave to avoid being swept away.

I found it astonishing that such small creatures possess the agility and tenacity to “surf” the waves and dig themselves back into wet sand within seconds, a graceful routine I had unknowingly witnessed that February morning.

Beyond their daily habits, coquina clams also undergo a remarkable life cycle beneath the sand. They spawn in the warmer months, releasing gametes into the water for external fertilization. The resulting larvae drift as plankton for a time before settling into the sand and metamorphosing into tiny clams. With no parental care to guide them these young coquinas must immediately fend for themselves in the surf zone. Perhaps it’s this independent, perilous beginning that drives them to cluster in large colonies—while they aren’t social in a communicative sense, hundreds of coquinas often live side by side in favorable spots, turning patches of wet sand into vibrant mosaics of color and life​.

Walking the beach now, I recognize these patches: slightly raised, pebbly areas that, when a wave washes over, suddenly bristle with tiny siphons and feet as the clams feed and reposition. It’s humbling to realize that under each footstep, an entire hidden ecosystem of coquinas might be thriving.

Shells on the Shore: Beauty and Predation

With my new awareness, even the empty shells strewn along the high tide line told a story. I began to collect some of the colorful coquina shells scattered on the sand, marveling at their variety—no two looked exactly alike. Some were solid orange or yellow, others striped with purple and white, each as delicate as a butterfly wing. Many of these shells were intact, evidence of clams that had lived out their short lives or perhaps fallen prey to gentle endings. Others, however, bore mysterious perfectly round holes on their surfaces. At first glance, I thought a tiny drill had punched through them, and in a way, I was right. Those small holes are the signature of predatory snails that haunt the sands: creatures like moon snails (also known as shark’s-eye snails) and whelks that prey on coquinas by literally boring into their shells. These sand-dwelling snails wrap themselves around a clam and use a tongue-like organ called a radula—akin to a miniature saw—to drill a neat hole through the coquina’s shell, aided by acidic secretions to soften the calcium carbonate. Once the hole is complete, the snail devours the clam from within, leaving behind an empty, perforated shell as a grim calling card of the food chain in action.

Seeing those tiny “murder holes,” as beachcombers jokingly call them, on coquina shells transformed my perspective on the shell collections I had casually admired for years. Each shell in my hand represented a life that had been an integral part of the beach ecosystem. Some had been snatched by shorebirds or fish the instant they were exposed by the retreating tide, becoming breakfast for a sanderling or a pompano. Others, as the holes revealed, had been victims of an even stealthier predator under the sand. It struck me that every fragment and hollowed shell on the beach is evidence of a relationship—predator and prey, life and death intertwined on the shore. Instead of seeing a random assortment of pretty shells, I now saw a record of the beach’s vibrant food web written in calcium carbonate. The realization filled me with both wonder and respect: this sunny tourist beach holds quiet tales of survival as dramatic as any wilderness, if one knows where to look.

The Coquina’s Ecological Role

As I dug deeper (both into the sand and the literature), I discovered that coquina clams are far more than a footnote in the beach ecosystem—they are a keystone of coastal ecology. By filtering plankton and detritus from the surf, countless coquinas collectively act as tiny water purifiers, helping maintain water quality along the shore. Their presence in large numbers indicates a beach’s health; in fact, abundant coquina populations signal that the beach environment is robust and unspoiled. A stretch of sand teeming with coquina clams suggests natural, shifting sands and minimal human interference, as these clams thrive best where coastal processes remain undisturbed. In this way, coquinas are like a barometer for the shoreline: if I continue to find them at Cocoa Beach, it means the beach is still alive and supporting complex life.

Coquina clams also form a critical link in the food chain. Numerous shorebirds rely on them as a food source—those flocks of little sandpipers and plovers skittering at the water’s edge have, all along, been feasting on coquinas right under my nose. Fish that patrol the surf, like the Florida pompano and various kinds of drum (whiting), gulp them up as the waves churn the sand​.

These coquina clam shells were found February 2025 on Cocoa Beach, Brevard County, Florida

Even ghost crabs and other scavengers benefit, feeding on clams that wash ashore. And of course, the predatory snails under the sand have a specialized taste for them. It’s a reminder that even a creature only an inch long can be a cornerstone of an entire food web, sustaining animals up the chain from mollusks to birds to fish. Standing on the beach now, I often pause and watch the frenetic chase of the shorebirds in the surf, aware that without the coquina clams beneath the foam, that familiar coastal ballet could cease to exist.

Humanity and the Coquina: Intertwined Histories

It’s not only animals that have interacted with coquina clams—we humans have a longstanding relationship with them as well. Historically, Floridians made use of coquinas as a food source. Local folklore and old recipes describe coquina broth and chowder, a delicate soup made by briefly boiling these tiny clams to extract their flavor.​

Because each clam is so small, you’d need hundreds to make a pot of soup, so it’s not a common dish today except perhaps as a novelty. Still, the idea that the sands I walk on could literally be cooked into a chowder is a charming and earthy connection between food and place. Early indigenous peoples and European settlers alike would have recognized coquinas as an edible bounty in times when every bit of protein counted.

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Humans have also found value in the shells of coquinas beyond admiring their beauty. Over time, vast deposits of coquina shells on ancient beaches hardened into a soft limestone rock called coquina stone (the term “coquina” itself comes from the Spanish for “shellfish” or “cockle,” reflecting its composition)​.

In a fascinating twist of fate, this sedimentary rock—essentially millions of fused clam shells—became a building material. Here in Florida, coquina stone was quarried and used to construct some of our oldest structures. The historic fortifications in St. Augustine, like Fort Matanzas and Castillo de San Marcos, were built from coquina stone, their walls made resilient by a matrix of coquina clam shells​.

I find it poetic that the same little clams I only just learned to appreciate have literally been the building blocks of human shelters that have stood for centuries. Even today, crushed coquina shells are used in landscaping and as decorative ground cover—perhaps you’ve seen driveways or garden paths that gleam with fragments of pink and purple shells.​

Our lives overlap with the coquina in subtle ways: from the architecture of coastal Florida to the aesthetics of our beach towns.

Modern conservationists note another connection: by protecting natural beach dynamics, we also protect coquina populations, which in turn supports the whole ecosystem. This means being mindful about coastal development, beach renourishment projects, and even how many shells tourists collect. I’ve become more aware that picking up a few pretty coquina shells as souvenirs is fine, but we must leave plenty behind for the beach to recycle and for other creatures to use. For example shorebirds glean minerals from them. The humble coquina clam has given me a new appreciation for how intimately tied human activity is to the smallest inhabitants of the shore.

Reflections: Wonder in the Little Things

My journeys to Cocoa Beach were enhanced: what began as a casual observation in 2025 has blossomed into a profound shift in the way I experience the beach. I feel as if I’ve been given new eyes—now I notice the glint of tiny shells in the sand and know there’s life (or a story of life) attached to each one. The joy of discovery I felt upon noticing the coquina clams has reignited a childlike curiosity in me. It’s astounding that after decades of visits, there was still a secret to uncover on those familiar shores. This realization makes me wonder: What else have I been missing? It’s a reminder that nature has layers upon layers of wonder, even in places we think we know intimately. Sometimes it just takes a shift in perspective, a bit of knowledge, or a quiet moment of attention to peel back the veil.

In reflecting on the coquina clams of Cocoa Beach, I’ve learned not only about a specific species and its role in the world, but also about myself and the value of lifelong learning. These clams, in their smallness and ubiquity, taught me to slow down and appreciate the intricate tapestry of life at my feet. Now, each time I visit the beach, I smile seeing the waves bring in that rush of foam and sand, knowing a hidden troupe of coquinas is hard at work filtering water, dodging predators, and holding up the very balance of the shore. I often kneel down now, running my fingers gently through the wet sand to feel them retreat, and I silently thank them — for cleaning the water, for feeding the birds and fish, for building historic forts (unbeknownst to themselves), and for showing me that wonder can be found in the smallest of places. Cocoa Beach, through the lens of the coquina clam, feels like a brand new world I’ve been lucky enough to discover, even after all these years​

I look forward to other hidden marvels awaiting discovery on my next visit.

References


Abbott, R. T. (1974). American Seashells: The Marine Mollusca of the Atlantic and Pacific Coasts of North America. Van Nostrand Reinhold Company.

Andrews, J. (1994). Shells and Shores of Texas. University of Texas Press.

Brusca, R. C., & Brusca, G. J. (2003). Invertebrates (2nd ed.). Sinauer Associates.

Denny, M., & Gaines, S. (2000). Encyclopedia of Tidepools and Rocky Shores. University of California Press.

Futch, C. R., & Burger, J. (1976). The ecology of coquina clams (Donax variabilis) in the southeastern United States. Marine Biology Journal, 34(2), 157-168.

Leal, J. H. (2002). Seashells of Southern Florida: Living Marine Mollusks of the Florida Keys and Adjacent Regions. Smithsonian Institution Press.

Mikkelsen, P. M., & Bieler, R. (2008). Seashells of Southern Florida: Marine Bivalves, The Bivalvia. Princeton University Press.

Morton, B. (1988). Particulate Matter Processing in Bivalves: An Overview. Journal of Marine Ecology, 19(3), 103-123.

Ruppert, E. E., Fox, R. S., & Barnes, R. D. (2004). Invertebrate Zoology: A Functional Evolutionary Approach (7th ed.). Cengage Learning.

Stanley, S. M. (1970). Relation of shell form to life habits of the Bivalvia. Geological Society of America Memoir, 125, 1-296.

Voss, G. L. (1980). Seashells of the Gulf and Atlantic Coasts. Houghton Mifflin Harcourt.

Wells, H. W., & Gray, I. E. (1960). Habitat selection and the distribution of the coquina clam (Donax variabilis). Ecological Monographs, 30(1), 55-77.

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Cocoa Beach’s Unique Nine-Armed Sea Star Encounter

In Cocoa Beach, I encountered a Nine-armed Sea Star, which I returned to the ocean, reflecting on its ecological role and the wonders of marine life.

Walking along the shoreline of Cocoa Beach in the early morning light, I encountered a remarkable sight—a Nine-armed Sea Star (Luidia senegalensis) sprawled on the damp sand. Its long, slender arms stretched outward in a perfect starburst pattern, each limb tapering to a fine point. The sandy beige coloration of its body blended with the surrounding beach, accentuated by a darker stripe running down the center of each arm. Scattered around it were small shells and fragments, remnants of the ocean’s ebb and flow, testifying to the high tide that had deposited this fascinating creature ashore.

The scientific name Luidia senegalensis provides insight into the taxonomy and classification of this intriguing sea star. The genus Luidia is named after the 18th-century Portuguese naturalist Francisco Luid, who contributed significantly to marine biology. The species name senegalensis refers to its first recorded discovery along the coast of Senegal in West Africa. As a member of the phylum Echinodermata and the class Asteroidea, the Nine-armed Sea Star shares lineage with other starfish, sea urchins, and sand dollars, distinguished by their radial symmetry and water vascular system used for movement and feeding.

As I paused to observe it more closely, I marveled at the intricate details of its structure. Unlike the more familiar five-armed sea stars, this specimen had nine arms radiating from a small central disc. The surface of its body appeared smooth, with tiny tube feet lining the underside of each arm—a biological marvel designed for locomotion and feeding.

This starfish washed up on high tide. I seemed alive so I returned it to the surf during ebb tide, hoping the ebb current would return it to deeper water.

The Nine-armed Sea Star, common along Florida’s coastline, is a voracious predator within the benthic ecosystem. It primarily preys on bivalves such as clams and mussels, using a fascinating feeding strategy. Unlike most predators that rely on speed and strength, this sea star employs patience and ingenuity. It wraps its flexible arms around a bivalve, exerting a slow and steady force to pry the shell open. Once a small gap is achieved, the sea star everts its stomach through its mouth and into the prey’s shell, secreting digestive enzymes that liquefy the soft tissues within. This external digestion allows the sea star to consume its prey without the need for teeth or jaws—a perfect example of nature’s ingenuity.

Despite its delicate appearance, the Nine-armed Sea Star plays a crucial role in the marine ecosystem. By preying on bivalves, it helps regulate their populations, preventing overgrazing of seagrass beds and maintaining a balanced food web. Additionally, it serves as a food source for larger marine predators, such as fish and sea turtles. Its presence signifies a healthy intertidal environment, where nutrient cycles and predator-prey relationships are in dynamic equilibrium.

As I considered the sea star’s role in the ecosystem, I wondered about its journey to this point. These creatures undergo a fascinating life cycle, starting as tiny, free-swimming larvae that drift with ocean currents. Over time, they undergo metamorphosis, settling onto the seabed and gradually developing into their iconic star shape. The resilience and adaptability of these creatures are truly astounding, capable of regenerating lost arms and thriving in diverse habitats.

Realizing that this sea star likely found itself stranded by the receding high tide, I felt a sense of responsibility to help it return to its natural environment. Picking it up gently, I carried it toward the water’s edge, where the ebb tide was beginning to pull the sea back into its vast domain. With a final look at its striking form, I placed it carefully into the shallow waves, hoping that the ebb current would carry it back to the sandy seabed where it belonged.

As the waves lapped around my feet, I imagined the sea star resuming its journey, gliding along the ocean floor in search of its next meal. The interconnectedness of all marine life became evident in that moment—each creature playing its part in an intricate and delicate dance of survival.

Walking back along the shoreline, I reflected on the experience. My fleeting encounter with the Nine-armed Sea Star was a reminder of the wonders hidden beneath the ocean’s surface and our role in preserving them. Every tide brings new discoveries, and every ebb offers a second chance—for the sea star, and perhaps for us as well.

Cocoa Beach, with its gentle waves and abundant life, had once again provided an unforgettable encounter with nature. The starfish, now safely returned to the ocean, would continue its unseen work beneath the waves, a quiet but essential denizen of the underwater world.

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A Serendipitous Meeting: The Hermit Crab and the Moon Snail

Washed up together on a sunlit shore, a hermit crab and a Moon Snail tell an extraordinary tale of survival and resilience in the vast ocean. Discover how these unlikely companions reveal the intricate dance of life beneath the waves and the profound connections that bind marine ecosystems. Dive into their captivating story and uncover the secrets of their intertwined destinies.

The high tide left behind a myriad of treasures scattered along the shore. Among the shells and seaweed, two unlikely companions lay side by side—a Moon Snail and a hermit crab. This serendipitous meeting speaks volumes about the intricate dance of life in the ocean’s depths.

Life Beneath the Waves

Hermit crabs are fascinating creatures, exhibiting behaviors and adaptations that ensure their survival in the ever-changing marine environment. These crabs are not born with shells. Instead, they scavenge for empty shells discarded by snails, meticulously choosing the perfect fit. The shells provide essential protection against predators and environmental hazards.

In their early life stages, hermit crabs undergo a series of molts, shedding their exoskeletons to grow. Each molt presents a critical opportunity to upgrade their shell, moving to a larger one as they increase in size. This constant need for new housing drives a competitive dynamic among hermit crabs, with individuals often engaging in “shell exchanges” where one crab may forcibly evict another from its shell.

The Hermit and the Moon Snail

The Moon Snail, known scientifically as Neverita duplicata, is a predatory mollusk famous for its distinctive, moon-shaped shell. These snails are both feared and admired in the marine community for their voracious appetite and remarkable hunting tactics. They drill into the shells of their prey, typically other mollusks, using a specialized appendage called a radula, combined with acidic secretions to bore through the hard exterior. Click me for another post with more information about the Moon Snail.

The juxtaposition of the Moon Snail and the hermit crab washed up together is a tableau that invites deeper contemplation. How did these two distinct beings come to share the same stretch of sand?

A Dance of Survival

It’s likely that the hermit crab, in its search for a suitable home, found itself in the proximity of the Moon Snail. The Moon Snail, a relentless hunter, could have been following its own trail of prey when the tide caught them both off guard. The ocean’s currents, indifferent to their individual struggles, deposited them together on the beach, a fleeting moment of stillness in their otherwise tumultuous lives.

This meeting is a stark reminder of the interconnectedness of marine life. The hermit crab relies on the discarded shells of snails for survival, while the Moon Snail’s role as a predator keeps the balance in check, ensuring that no single species dominates the ecosystem.

Reflections on Resilience

The image of the hermit crab within its borrowed shell speaks to the resilience and adaptability inherent in nature. These crabs are perpetual nomads, continually seeking, adapting, and thriving in environments that can be both generous and harsh. Their survival hinges on their ability to repurpose and reuse, a lesson in resourcefulness that resonates beyond the tidepools.

The Moon Snail, with its powerful drilling capabilities, exemplifies the raw force of nature. Its presence is a reminder of the predatory relationships that underpin marine ecosystems, driving evolution and diversity through a relentless cycle of life and death.

The Final Tide

As we ponder the scene before us, it’s worth considering the broader implications of these two creatures’ lives. The ocean, vast and unfathomable, is a realm where survival is an art form, honed by millennia of adaptation. The hermit crab and the Moon Snail, though vastly different in form and function, share a common thread—their existence is a testament to the delicate balance of nature.

The hermit crab’s journey, from shell to shell, mirrors our own quests for security and stability. The Moon Snail’s predatory prowess underscores the inevitable challenges we face. Together, they remind us that life, in all its forms, is a continuous interplay of seeking and surviving, of finding and losing, of moments of stillness and sudden change.

In the end, the hermit crab and the Moon Snail, brought together by the whims of the tide, offer a glimpse into the profound and often unseen connections that weave the tapestry of life beneath the waves. Their story is a poignant reflection on resilience, adaptability, and the ever-present dance of survival that defines the natural world.

A top view of the shell occupied by a Hermit Crab found on Cocoa Beach, Brevard County, Florida. The Space Coast.

An Uncertain Identification

The identification of our hermit crab companion is made challenging by the absence of one of its claws, a vital characteristic for precise classification. This missing claw hints at the hardships faced by hermit crabs in their dynamic and sometimes perilous environments. Whether lost in a struggle with a predator or another hermit crab, this detail serves as a reminder of the tenacity and resilience required for survival in the marine world. While the exact species remains a mystery, the broader story of the hermit crab’s life and survival remains clear and compelling.

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