Sharks of Onslow County

Category: Other Marine Species

  • Gratitude for Marsh Predators: How Egrets, Herons, and Fish-Hunting Birds Shape the New River

    Gratitude for Marsh Predators: How Egrets, Herons, and Fish-Hunting Birds Shape the New River

    A Thanksgiving for the Watchers at the Water’s Edge

    By late November, the New River of Onslow County—the slow, tidal estuary rising in Jacksonville and emptying into the Atlantic at New River Inlet—transforms. The grasses brown, the water clarifies, and the familiar pulse of summer predators fades. Flounder slip offshore. Red drum feed less frequently. Sharks leave the inlet behind in search of warmer currents.

    But along the marsh edges, another group of predators steps forward.

    Great egrets, snowy egrets, tricolored herons, great blue herons, kingfishers, cormorants, pelicans, and the few ospreys that overwinter become the defining hunters of the cold season. Their presence is not merely ornamental—they keep the estuary functioning when the fish and sharks of summer retreat.

    This is a season to be thankful for the feathered predators who bridge water and land, carrying the New River through winter.

    Egrets: The Marsh’s Quiet Engineers

    Difference between great and snow egrets
    Snowy Egrets and Great Egrets share the New River’s marsh edges, but their size, bill color, and foraging styles shape the estuary differently. Together, these two “marsh engineers” help regulate small fish and crustaceans throughout the colder months. | Photo ©️ Mia McPherson

    Great blue (Ardea alba) and snowy egrets (Egretta thula) line the mudbanks of the New River like pale sentinels during late fall. Their precision hunting—patient standing, slow stepping, sudden striking—remains one of the most effective predatory strategies in shallow water. But egrets do much more than remove prey from the system.

    Their feet stir the marsh. With every step, they oxygenate the upper sediment and dislodge hidden invertebrates—worms, amphipods, and tiny crabs. This stirring, known as bioturbation, is essential when larger predators leave for the season. It keeps nutrients moving upward through the food web instead of becoming locked in low-oxygen mud pockets (Green & Elmberg, 2014).

    Egrets also function as indicator species. Their presence in good numbers along the New River—especially snowy egrets—signals healthy populations of juvenile fish and crustaceans, as these birds are sensitive to reductions in prey availability and water-quality decline (Gawlik, 2002).

    In winter, when the big fish leave, the egrets’ quiet engineering keeps the marsh breathing.

    Herons: Sentinels of the Shallows

    Great blue heron in NC
    A Great Blue Heron wades through the quiet shallows in North Carolina, its slow, deliberate steps stirring life from the sediment. In winter, this patient hunter becomes one of the estuary’s most influential predators.

    Herons are the deliberate hunters of the New River’s cooler months. Great blue herons (Ardea herodias) stalk deeper edge-waters near Wilson Bay and Stones Bay, while tricolored and green herons hunt the narrow creeks and flooded grass near Sneads Ferry.

    Their predatory pressure plays a critical stabilizing role.

    When red drum, flounder, and juvenile sharks reduce feeding or migrate offshore, herons become the primary top-down regulators in shallow zones. Without them, schooling fish such as killifish and silversides can become overly abundant and overgraze algae mats, uproot detrital layers, and reduce habitat for invertebrates (Caldwell & Gawlik, 2020).

    Herons prevent this imbalance, maintaining the delicate structure of marsh edges through the winter lull.

    They are also highly sensitive to habitat degradation. If marsh edges are destroyed or water quality declines, herons disappear quickly—making them early warning signals of ecosystem stress.

    When the estuary grows quiet, herons hold the line.

    Kingfishers: The River’s Aerial Regulators

    Belted kingfisher in NC

    The New River bends—particularly between Jacksonville and Camp Lejeune—echo with the rattling call of the belted kingfisher (Megaceryle alcyon). These birds hunt where no heron can reach: suspended midair, diving into deeper channels for small mullet, anchovies, and menhaden.

    Their role is uniquely important in winter.

    Kingfishers distribute prey movement across the river. Their dive-bombing predation prevents baitfish from clustering into dense, oxygen-demanding schools. This reduces the chance of hypoxic pockets and helps keep prey species spreading through multiple river habitats, supporting overall food-web stability (Green & Elmberg, 2014).

    As indicator species, kingfishers require:

    • Clear water,
    • Steep undisturbed banks for burrow nests, and
    • Intact riparian vegetation.

    A decline in their numbers often indicates erosion, turbidity, or human disturbance along the New River corridor.

    When water clears and fish slow down, kingfishers regulate the mid-channel flow.

    Cormorants & Pelicans: Divers of the Deep Channels

    Cormorants and nesting brown pelicans in NC
    Double-crested cormorants and brown pelicans share the New River’s deeper channels, one diving beneath the surface and the other striking from above—two winter hunters shaping the river’s mid-channel food web. | Photo credits: © Patty Teague and Walker Golder

    Where the marsh deepens toward New River Inlet, winter belongs to the divers.

    Double-crested cormorants (Phalacrocorax auritus) gather in rafts, plunging beneath the surface in coordinated group hunts. Brown pelicans (Pelecanus accidentalis), though more numerous in summer, often overwinter near the inlet, diving from above for surface schooling fish.

    These two species maintain control over mid-water prey populations during a time when bluefish, larger trout, and sharks are absent.

    Cormorants keep cold-tolerant fish like anchovies and menhaden from becoming hyperabundant—preventing prey schools from stripping plankton layers or concentrating into stressed, oxygen-poor pockets. Pelicans, meanwhile, remove weak or diseased fish from the surface, helping maintain water quality and reducing pathogen spread (Green & Elmberg, 2014).

    In winter, when predation usually thins, the divers take up the mantle offshore.

    Ospreys: Winter’s Remaining Apex Hunters

    Osprey flying to nest with prey
    An osprey returns to its nest with a freshly caught fish—one of the last true apex hunters still patrolling the New River as winter approaches. | Photo Credit: Steve Gorin

    Most ospreys (Pandion haliaetus) migrate south, but a handful stay near New River Inlet and the Onslow County coastline each winter. Those that remain become the estuary’s apex aerial predators, taking mullet, juvenile trout, and medium-sized fish that no other bird consistently targets.

    Their presence means something.
    Ospreys are recognized worldwide as indicators of estuarine health, reflecting the state of fish recruitment, water clarity, and shoreline integrity (Green & Elmberg, 2014).

    If ospreys disappear, it often signals a breakdown already underway.

    Even in winter, they serve as a reminder of the estuary’s resilience—and vulnerability.

    When the Feathered Predators Are Lost

    Split-scene marsh graphic showing a healthy winter marsh with an egret on the left and a degraded marsh without birds on the right, illustrating how predator loss leads to prey booms, detritus buildup, and declining water quality in the New River estuary.

    When fish-hunting birds decline, the system changes quickly:

    • Prey fish populations spike and overgraze marsh surfaces.
    • Detritus accumulates, creating low-oxygen mud layers.
    • Nutrient cycling slows, as birds supply essential nitrogen and phosphorus.
    • Marsh plants thin, increasing erosion along the New River’s edges.
    • Winter loses its predators, leaving the estuary unregulated until spring.

    Their disappearance is not cosmetic—it is structural.

    These birds are the framework that holds the winter ecosystem together.

    A Season to Give Thanks

    As fall deepens into the quiet months, the New River’s story becomes one of subtle but powerful relationships. Egrets stir the mud and release life into motion. Herons regulate the shallows. Kingfishers keep the channels moving. Cormorants and pelicans manage the deeper waters. Ospreys, if they stay, rule the sky.

    They do not roar or thrash or leap.
    They shape the estuary one step, one strike, and one dive at a time.

    This Thanksgiving, the gratitude belongs to them as well—the birds who carry the New River through winter and keep the connection between land and sea alive.

    References

    Able, K. W., & Fodrie, F. J. (2015). Fish habitat use in salt marshes: Linking ecology and conservation. Marine Ecology Progress Series, 527, 1–5. https://doi.org/10.3354/meps11344 

    Caldwell, A. W., & Gawlik, D. E. (2020). Wading birds as top predators in shallow estuarine food webs: Behavioral influence on fish distribution. Estuaries and Coasts, 43(6), 1273–1286. https://doi.org/10.1007/s12237-020-00734-1 

    Gawlik, D. E. (2002). The effects of prey availability on the foraging behavior of wading birds. Ecological Monographs, 72(3), 329–346. https://doi.org/10.1890/0012-9615 

    Green, A. J., & Elmberg, J. (2014). Ecosystem services provided by waterbirds. Biological Reviews, 89(1), 105–122. https://doi.org/10.1111/brv.12045 

    Vance-Chalcraft, H. D., Duffey, R., & Knott, D. (2021). Linking avian and aquatic predators stabilizes estuarine food webs. Ecology, 102(12), e03540. https://doi.org/10.1002/ecy.3540

  • The Estuary Feast: November Predators of the New River Estuary, NC

    The Estuary Feast: November Predators of the New River Estuary, NC

    Each November, as the hardwoods fade to rust and the air over Onslow County turns crisp, the New River estuary begins its quiet transformation. Beneath the calm surface, baitfish, shrimp, and crabs gather in the creeks and channels like guests arriving early to dinner. Cooling waters, shifting salinity, and autumn tides all cue a feeding frenzy among the river’s top hunters – red drum (Sciaenops ocellatus), southern flounder (Paralichthys lethostigma), and spotted seatrout (Cynoscion nebulosus).

    To the casual observer, it’s just another turn of the season. But for these predators, November is the defining moment of survival – the “estuary feast” that powers them through the winter ahead.

    The Science Behind the Feast

    The science: cool water, hot action
    As water temperatures drop, oxygen and prey shift. Shrimp slow, mullet school tightly, and predators move into perfect feeding conditions. In November, the estuary’s food web compresses – a short, fierce burst of activity before winter quiets the water.

    Autumn brings an ecological reshuffling. As air temperatures drop, water density increases, pushing oxygen-rich layers deeper into the estuary. Cooler water slows the metabolism of small prey, but keeps predators in their metabolic sweet spot – a narrow temperature window where they can feed efficiently (Facendola & Scharf, 2012).

    In the New River, this dynamic compresses the food web: prey such as mullet, menhaden, and shrimp concentrate in fewer, warmer microhabitats, and predators follow. Southern flounder and red drum migrate from the upper estuary toward the inlet, using the last strong tides of the season to feed before moving offshore to spawn (Midway et al., 2024).

    At the same time, spotted seatrout remain nearshore longer than most species, prowling deep bends and channel edges for sluggish crustaceans and cold-stunned baitfish (Bortone, 2003; TinHan et al., 2018; Whaley et al., 2023). This makes November one of the few months when all three predators share overlapping hunting grounds – a temporary “banquet hall” of intersecting habits and appetites.

    Predators at the Table

    southern flounder

    Red Drum

    Known locally as “channel bass”, red drum rely heavily on macro-crustaceans and juvenile fishes during the late fall surge (Facendola & Scharf, 2012). In the New River estuary, they patrol marsh edges and oyster-reef margins where baitfish funnel out with the ebbing tide. These habitats not only provide prey but also structure – a three-dimensional refuge network that concentrates food in predictable corridors.

    Red drum are particularly sensitive to dissolved oxygen and salinity changes; they exploit the higher oxygen zones along shell hash and sandy bottoms where shrimp and crabs are most active.

    Southern Flounder

    Flat, camouflage, and opportunistic, southern flounder are the ambush specialists of November. As they stage for ocean migration, they feed voraciously along the lower estuary and inlet shoals, striking from beneath the sand when shrimp or menhaden schools pass overhead.

    Telemetry data show that most adult flounder exit the estuary between mid-October and mid-November (Midway et al., 2024), making this their final feeding push before winter. The energy stored in liver and muscle tissue during this period directly fuels their offshore spawning.

    Spotted Seatrout

    The spotted seatrout, or “speckled trout”, represents a different strategy: persistence.Unlike flounder or drum, they remain within the estuary for much of the winter. Their adaptive physiology lets them remain active in cooler water, hunting shrimp and small schooling fish even below 15℃, or 59℉ (Bortone, 2003; TinHan et al., 2018; Whaley et al., 2023).

    This endurance gives them a late-season advantage – fewer competitors and concentrated prey. In Onslow County’s deeper channels, dock lights and tidal flows create perfect feeding grounds long after other predators have departed.

    Prey and Energy Flow

    From marsh to mouth: The energy of the estuary: Energy flows up the ladder - detritus -> shrimp -> baitfish -> predator. This seasonal burst fuels migrations and maintains balance in Onslow County's estuary ecosystem. But when prey species are overfished, that balance falters.
    From marsh to mouth: The energy of the estuary: Energy flows up the ladder – detritus -> shrimp -> baitfish -> predator. This seasonal burst fuels migrations and maintains balance in Onslow County’s estuary ecosystem. But when prey species are overfished, that balance falters.

    Every feast depends on abundance. In the New River system, fall prey peaks come from several sources:

    • Penaeid shrimp (brown, pink and white shrimp) and blue crabs provide high-calorie meals critical to red drum and flounder growth (Facendola & Scharf, 2012).
    • Striped mullet (Mugil cephalus) migrate seaward in vast schools during November, offering short bursts of energy-rich prey (NCDMF, 2022). 
    • Juvenile fishes – menhaden, spot, croaker – linger in the brackish middle reaches, serving as transitional prey before exiting the estuary.

    As predators consume these resources, energy moves up the trophic ladder. That transfer of biomass – from detritus to shrimp to fish to apex predator – defines the estuary’s productivity and resilience (Bortone, 2003; TinHan et al., 2018; Whaley et al., 2023).

    Beyond the Feast: Ecological Balance

    The estuary’s “Thanksgiving” is not just a seasonal event. It’s a reset of the entire system. By removing weaker or late-season prey, predators help balance populations and redistribute nutrients through excretion and predation scars. Their feeding activity also stirs sediments and oxygenates bottom layers, improving microbial decomposition that recycles organic matter for the next year’s growth.

    But this rhythm is vulnerable. Habitat loss, water-quality decline, and overfishing can all truncate the feast. Striped mullet, a keystone prey species, remains overfished statewide (NCDMF, 2022), while southern flounder face chronic recruitment declines. (Recruitment is the process of small, young fish transitioning into their older, larger lifestage.) Each missing link reduces the estuary’s resilience – and the energy pulse that sustains these predators through winter.

    Climate Notes: A Shifting Season

    Recent NOAA data suggests that fall water temperatures in coastal North Carolina are trending 1°-2℃, or 1.8°-3.6℉, warmer than historical averages. Warmer autumns can delay predator migrations, alter prey timing, and extend disease risks for estuarine fish (Bortone, 2003; TinHan et al., 2018; Whaley et al., 2023; Llansó et al., 1998). For Onslow County, this means the “feast” could increasingly occur later, or not at all, in some years. Tracking these shifts can help monitor how climate variability reshapes local predator cycles.

    Conclusion

    In the quiet weeks before winter, the New River estuary hosts its grandest ritual: a final surge of life and energy. Flounder lie in wait beneath the sand; red drum sweep through oyster channels; speckled trout strike in the moonlit current. Together they embody the estuary’s cyclical resilience – a natural Thanksgiving built on balance, adaptation, and timing.

    For those who walk the riverbanks or wade the flats in November, the story unfolding beneath the surface is as rich and meaningful as any holiday tradition: a reminder that even in cooling waters, the rhythm of life continues, fierce and beautiful.

    References

    Bortone, S. A. (2002). Biology of the spotted Seatrout. CRC Press.

    Facendola, J. J., & Scharf, F. S. (2012). Seasonal and ontogenetic variation in the diet and daily ration of estuarine red drum as derived from field-based estimates of gastric evacuation and consumption. Marine and Coastal Fisheries, 4(1), 546-559. https://doi.org/10.1080/19425120.2012.699018

    Llansó, R. J., Bell, S. S., Vose, F. E., & Llanso, R. J. (1998). Food habits of red drum and spotted Seatrout in a restored mangrove impoundment. Estuaries, 21(2), 294. https://doi.org/10.2307/1352476

    Midway, S. R., Scharf, F. S., Dance, M. A., Brown-Peterson, N. J., Ballenger, J. C., Beeken, N. S., Borski, R. J., Darden, T. L., Erickson, K. A., Farmer, T. M., Fincannon, A., Godwin, J., Graham, P. M., Green, J. L., Hershey, H., Kiene, D., Lee, L. M., Loeffler, M. S., Markwith, A., & McGarigal, C. (2024). Southern Flounder: Major Milestones and Remaining Knowledge Gaps in Their Biology, Ecology, and Fishery Management. Reviews in Fisheries Science & Aquaculture, 32(3), 450-478. https://www.stevemidway.com/publication/midway2024rfsa/midway2024RFSA.pdf

    North Carolina Division of Marine Fisheries (NCDMF). (2022, August). Fishery Management Plan Update Striped Mullet. NC Dept. of Environmental Quality (NCDEQ). https://www.deq.nc.gov/marine-fisheries/fisheries-management/annual-fmp-review/2023/2023-striped-mullet-fmp-review/open

    TinHan, T. C., Mohan, J. A., Dumesnil, M., DeAngelis, B. M., & Wells, R. J. (2018). Linking habitat use and trophic ecology of spotted Seatrout (Cynoscion nebulosus) on a restored oyster reef in a subtropical Estuary. Estuaries and Coasts, 41(6), 1793-1805. https://doi.org/10.1007/s12237-018-0391-x

    Whaley, S. D., Shea, C. P., Santi, E. C., & Gandy, D. A. (2023). The influence of freshwater inflow and seascape context on occurrence of juvenile spotted seatrout Cynoscion nebulosus across a temperate Estuary. PLOS ONE, 18(11), e0294178.

  • The Moonlit Assassin: The Stealth of the Atlantic Moon Snail

    The Moonlit Assassin: The Stealth of the Atlantic Moon Snail

    On a stroll along the damp sand of the tide line, just after dusk under the soft glow of the moon over Topsail or North Topsail Beach, you might spot a round, glossy shell that looks more like a polished marble than a living creature. This little orb belongs to the Atlantic moon snail or  Shark Eye (Neverita duplicata) — smooth and innocent-looking by day, but by night the script flips. It becomes a stealthy predator disguised in plain sight, turning the quiet sand into a midnight hunting ground.

    A Shell with a Secret

    To the casual beachcomber, the moon snail’s shell looks harmless — a perfect spiral polished smooth by the tide. But that rounded shape is built for stealth and movement beneath the sand. Moon snails bury themselves under the flats and inlets of sandy shores, waiting to pounce. Their favorite prey? Soft-bodied bivalves — clams, coquinas, and other shelled animals that live partly buried in sand.

    The moon snail doesn’t wait for prey to drift by; it actively hunts. Using its broad, muscular foot, it glides unseen beneath the surface, sensing vibrations of hidden clams. Once it finds a meal, it envelops the prey in its foot like a slow-moving trap — then the drilling begins.

    A rough tongue called a radula rasps the surface while secreted acid softens the calcium shell. Hours later, a single round hole opens a doorway to dinner. Every drilled shell that washes up tells the same story. These beveled, countersunk holes are so distinctive that scientists can identify the species of moon snail just by the shape of the bore (Grey & Bounding, 2005; Dietl & Kelley, 2006).

    That neat, circular hole — the hallmark of moon snail predation — is what beachcombers often discover without realizing the drama that unfolded beneath their feet.

    Have you seen shells with a perfect hole in them? This is evidence of predation by moon snail
    Have you seen shells with a perfect hole in them? This is evidence of predation by moon snail.

    Hunting Under the Sand

    Unlike many beach creatures you spot on the surface, the moon snail is mostly hidden. During low tide, it may creep near the edge of the exposed flats; at other times, it lies just beneath the surface. When it finds a buried bivalve, it uses a combination of mechanical drilling (via the radula) and acidic secretions to bore through the shell until it can reach the soft tissues inside (Visaggi, Dietl, & Kelley, 2013).

    In experimental trials, moon snails were observed to prefer drilling over suffocating their prey, even when the prey was buried at different sediment depths (Visaggi et al., 2013). That means whether the sand is shallow or deeper, the snail still goes for the drill rather than waiting for the prey to weaken.

    But that’s not all — stable-isotope studies, which measure chemical fingerprints of diet, show that the moon snail’s feeding habits may be more flexible than once thought. It appears to feed not only on animal prey but occasionally on other resources, hinting at omnivory (Casey, Fall, & Dietl, 2016). In other words: it’s a predator, yes — but one with a backup plan when food runs low.

    Why It Matters (and Why It’s Cool)

    1. Predator and Prey in One
     The moon snail helps regulate bivalve populations, preventing a single species from dominating the sand flats. In doing so, it maintains habitat diversity. At the same time, it transfers energy upward in the food chain by becoming prey for larger predators — fitting neatly into the middle of the coastal food web.

    2. Ecosystem Engineer
     Burrowing, hunting, and leaving behind drilled shells change the physical landscape of the beach. Each empty shell, each “crime scene” hole, becomes part of the microhabitat for small invertebrates, microbes, and future shell-seekers. In this way, the moon snail contributes to sediment health and biodiversity.

    3. The Hidden Drama Beneath Your Feet
     From a beachcomber’s perspective, the moon snail is a perfect spooky-season protagonist. Picture it: a “moon” shell glinting under moonlight, a buried assassin beneath your feet, and a perfect little hole in a clam shell — the evidence of a tiny midnight crime.

    The Perfect Crime

    When a clam is finished, only the perfect circular hole remains — a tiny signature in the sand. Moon snails rarely suffocate their prey; they almost always drill, no matter how deep the clam is buried (Visaggi, Dietl, & Kelley, 2013). This ancient behavior has marked shells for millions of years — the same holes appear in fossils that predate the Carolina coastline.

    And when food runs low, the story turns darker. In crowded flats where competition is fierce, moon snails have been observed turning their drills on each other. Cannibalism, rare in most mollusks, becomes a desperate survival strategy in the world beneath the sand (Gould, 2010).

    Drilled Atlantic moon snail shell shows cannibalism | Photo credit: iNaturalist, plawrynpx
    Drilled Atlantic moon snail shell shows cannibalism | Photo credit: iNaturalist, plawrynpx

    The Ripple Beneath the Sand

    The moon snail’s creeping movements do more than tell tales of horror. Its trails of mucus — left behind as it slides through the sand — subtly transform the beach. That film of slime “primes” the sediment, helping microbes break down organic matter faster and releasing nutrients back into the ecosystem (Hannides & Aller, 2016).

    Atlantic moon snail in the sand | Photo Credit: D. Bray
    Atlantic moon snail in the sand | Photo Credit: D. Bray

    So while it’s a killer to clams, it’s also a quiet caretaker. Its hunting churns the sand, its slime fuels the microbes, and its discarded shells shelter the next wave of tiny life.

    The Balance of the Hunt

    Every act of predation keeps the beach in balance. Moon snails are secondary consumers, feeding on clams that filter plankton from the water. In doing so, they prevent any single species from overrunning the flats. And they, in turn, become prey for blue crabs, rays, and drum fish that patrol the shallows.

    Each neat hole in a shell is a record of that balance — energy passed from clam to snail to crab to ocean. Nothing wasted. Everything connected.

    For Beachwalkers in Onslow County

    If you’re exploring the sands of Onslow County — Topsail Island, North Topsail, Surf City, or the New River Inlet — here’s what to watch for:

    • Round, glossy shells washed up on the tide flat — the moon snail’s shell is distinct, almost like a little orb.
    • Sand collars: doughnut-shaped, jelly-like structures found after storms or low tide. These are the moon snail’s egg masses, eerie “rings” that crumble when dry.
    • Drilled bivalve shells: clams or coquinas with a neat circular hole — the aftermath of a moon snail meal.
    • Time and place: Visit during low tide, especially after a storm that exposes more of the flat. The sand will tell its stories. Wear shoes, tread lightly, and remember — much of the life here remains hidden.
    Atlantic moon snail sand collar photo credit 2019 Cesar Andres Castillo
    Atlantic moon snail sand collar | César Andrés Castillo (c) 2019

    Final Thought

    It’s easy to write off a pretty shell as just another beach find. But every shell, hole, and collar tells a story of life beneath the waves. The moon snail wears the moon’s name well — luminous, secretive, and always working in the dark. Its beauty hides its appetite; its predation hides its purpose.

    In its own way, it keeps the beach breathing — a tiny engineer of life and death that turns sand, shell, and shadow into an endless cycle. The next time you find that round shell glinting in the surf, you’re not just finding a souvenir — you’re finding the ghost of a hunter in the sand.

    References

    Casey, M. M., Fall, L. M., & Dietl, G. P. (2016). You are what you eat: Stable isotopic evidence indicates that the naticid gastropod Neverita duplicata is an omnivore. Frontiers in Ecology and Evolution, 4, 125. https://doi.org/10.3389/fevo.2016.00125

    Dietl, G. O., & Kelley, P. H. (2006). Can naticid gastropod predators be identified by the holes they drill? Ichnos, 13(2), 103–113. https://doi.org/10.1080/10420940600842979

    Gould, E. S. (2010). Unexpected rates of cannibalism under competitive conditions by the naticid gastropod Neverita duplicata. Marine Biology, 157(10), 2341–2349. https://doi.org/10.1007/s00227-010-1505-8

    Grey, M., & Bounding, E. G. (2005). Shape differences among bore holes drilled by three species of naticid gastropods. Palaeogeography, Palaeoclimatology, Palaeoecology, 221(3–4), 245–260. https://doi.org/10.1016/j.palaeo.2005.02.003

    Hannides, A. K., & Aller, R. C. (2016). Priming effect of benthic gastropod mucus on sedimentary organic matter remineralization. Marine Ecology Progress Series, 545, 77–88. https://doi.org/10.3354/meps11587

    Visaggi, C. C., Dietl, G. P., & Kelley, P. H. (2013). Testing the influence of sediment depth on drilling behaviour of Neverita duplicata (Gastropoda: Naticidae), with a review of alternative modes of predation by naticids. Journal of Molluscan Studies, 79(4), 310–322. https://doi.org/10.1093/mollus/eyt023

  • A Phantom on the Sand: The Mysterious Atlantic Ghost Crab

    A Phantom on the Sand: The Mysterious Atlantic Ghost Crab

    When the sun sets behind the dunes and the surf begins to whisper, pale shapes flicker across the sand. Their movements are quick, darting, and silent – like apparitions under moonlight. These aren’t the spirits of shipwrecked sailors but the true “ghosts” of our Carolina coast: Atlantic ghost crabs (Oxypode quadrata).

    Atlantic ghost crab (Oxypode quadrata
    Atlantic ghost crab (Oxypode quadrata) | From iNaturalist

    Living Between Worlds

    Ghost crabs live in that liminal zone between land and sea – not quite aquatic, not quite terrestrial. They spend most daylight hours deep inside burrows up to four feet long, spiraling down in the cool, moist sand where they can keep their gills damp (Lucrezi & Schlacher, 2014).

    Architecture types of ghost crab burrows
    Architecture types of ghost crab burrows. | From Silva & Colado, Burrow architectural types of the Atlantic ghost crab, Ocypode quadrata (Fabricius, 1787) (Brachyura: Ocypodidae), in Brazil (July 2014)

    At night, they emerge to feed and patrol their territories. Their footprints – delicate, zigzagging tracks across the high tide line – are often the only sign they’ve been there. Scientists describe O. quadrata as a “semi-terrestrial” species, adapted to breath air while still depending on water for respiration (Lucrezi & Schlacher, 2014). Each burrow is unique, shaped like a J or L., with a single opening and a smooth rim that the crab maintains meticulously (Strachan et al., 1999). It’s both a refuge from predators and a fortress against the summer sun.

    ghost crab footprints
    Ghost crab footprints | From UF/IFAS Extension Escambia County

    Predators and Predators’ Prey

    Despite their spectral charm, ghost crabs are voracious predators. They scavenge for dead fish, clams, and organic debris but will actively hunt small invertebrates and even sea turtle hatchlings (Wolcott, 1978; Call et al., 2024).

    In many coastal ecosystems, ghost crabs are top invertebrate consumers, linking marine and terrestrial food webs by recycling nutrients back into the sand (Wolcott, 1978). Yet their own lives are precarious – shorebirds, raccoons, and even humans are a constant threat. A study in Virginia found that burrow abundance correlated with temperature and habitat type, showing how these crabs respond to subtle environmental shifts (Call et al., 2024). They’re not just scavengers – they’re indicators of a beach’s health.

    The Science of the “Ghost”

    There’s a reason they earned their spectral reputation. Their translucent shells and lightning-fast reflexes make them appear and vanish like spirits. In low light, the fine grains of sand reflecting off their bodies amplify that effect – a built-in camouflage evolved for moonlit hunting. Can you spot them in the images below?

    Ghost crabs also possess 360-degree vision from their elevated eye stalks, allowing them to spot threats in any direction (Lucrezi & Schlacher, 2014). And if the idea of “haunted sounds” intrigues you, here’s a Halloween twist: they “growl” by grinding their internal stomach plates – a process called stridulation – to warn off intruders. The sound, faint but distinct, echoes eerily under the dunes.

    Ghosts of Onslow County

    If you’ve ever walked Topsail Beach under a full moon, you’ve probably seen them: glowing white blurs racing sideways across your flashlight beam. (It’s best to use red or blue light as you search for ghost crabs and sea turtles.) Locally, these crabs are essential dune engineers. Their burrows aerate sand, help control organic decay, can reduce erosion, and maintain the delicate balance between dry and wet zones of the shore.

    ghost crab at night
    Ghost crab at night | From iNaturalist

    You might wonder: since ghost crabs dig deep into the sand, do their burrows stabilize the beach and help fend off erosion? The answer is – sometimes, but not always.

    You don’t even need to see a ghost crab to know it’s there – just look for the telltale burrow holes scattered along the upper beach. Each one marks a crab’s hiding place, and scientists often estimate ghost crab populations by counting burrow openings rather than the crabs themselves (Call et al., 2024; Lucrezi & Schlacher, 2014). The more holes you find, the healthier the local population – assuming the beach hasn’t been compacted or disturbed by human traffic.

    ghost crab holes near dunes in the Outer Banks
    Ghost crab holes near the dunes in the Outer Banks | From OuterBanks.com

    Ghost crabs don’t just dig- they reshape their sandy underworld. Their burrows loosen compacted sediments, which can lower resistance to wind and wave forces (Rinehart et al., 2024). In some species, burrowing stabilizes surface flows, but in ghost crab systems the effect is less predictable – sometimes helping, sometimes hindering.

    Unfortunately, they’re also victims of human disturbance. Coastal development, trampling, beach renourishment, and nighttime beach driving can collapse burrows and disrupt populations (Costa, Madureira & Zalmon, 2018). During the COVID-19 lockdown, researchers noticed ghost crab populations rebounding on urban beaches – a reminder that these “ghosts” return quickly when given peace (Costa et al., 2022).

    ghost crab don't step on me or my home

    The Real Spirits of the Shore

    So this Halloween, as you wander along the moonlit sands of Onslow County, remember that the pale forms darting ahead of your footsteps aren’t apparitions – they’re guardians of the dunes, keeping our coasts breathing and balanced.

    Every footprint, every scuttle, every faint rustle beneath the stars tells a story of adaptation and resilience. Ghost crabs may look like specters, but they’re among the most living, vital spirits of the beach. 

    “They vanish without a trace…except for their tracks.” – A. Mitchell

    References

    Antunes, G. D., Do Amaral, A. P., Ribarcki, F. P., Wiilland, E. D., Zancan, D. M., & Vinagre, A. S. (2010). Seasonal variations in the biochemical composition and reproductive cycle of the ghost crab Ocypode quadrata (Fabricius, 1787) in southern Brazil. Journal of Experimental Zoology Part A: Ecological Genetics and Physiology, 313A(5), 280-291. https://doi.org/10.1002/jez.593

    Call, M. N., Pongnon, R. S., Wails, C. N., Karpanty, S. M., Lapenta, K. C., Wilke, A. L., Boettecher, R., Alvino, C. R., & Fraser, J. D. (2024). Biotic and abiotic factors affecting Atlantic ghost crab (Ocypode quadrata) spatiotemporal activity at an important shorebird nesting site in Virginia. PLoSONE, 19(8), e0307821. https://doi.org/10.1371/journal.pone.0307821

    Costa, L. L., Machado, P. M., Barboza, C. A., Soares-Gomes, A., & Zalmon, I. R. (2022). Recovery of ghost crabs metapopulations on urban beaches during the COVID-19 “anthropause”. Marine Environmental Research, 180, 105733. https://doi.org/10.1016/j.marenvres.2022.105733

    Costa, L. L., Madureira, J. F., & Zalmon, I. R. (2018). Changes in the behaviour of Ocypode quadrata (Fabricius, 1787) after experimental trampling. Journal of the Marine Biological Association of the United Kingdom, 99(5), 1135-1140. https://doi.org/10.1017/s0025315418001030 

    Gül, M. R.(2019). Energetic Consequences of Human Impacts for Bioindicator Atlantic Ghost Crab (Ocypode Quadrata). (Doctoral dissertation). Retrieved from https://scholarcommons.sc.edu/etd/5460 

    Lucrezi, S., & Schlacher, T. A. (2014). The ecology of ghost crabs. Oceanography and Marine Biology, 201-256. https://doi.org/10.1201/b17143-5

    Rinehart, S. A., Dybiec, J. M., Walker, J. B., Simpson, L., & Cherry, J. A. (2024). Effects of burrowing crabs on coastal sediments and their functions: A systematic meta‐analysis. Ecosphere, 15(7). https://doi.org/10.1002/ecs2.4927

    Strachan, P. H., Smith, R. C., Hamilton, D. A., Taylor, A. C., & Atkinson, R. J. (1999). Studies on the ecology and behaviour of the ghost crab, Ocypode cursor (L.) in Northern Cyprus. Scientia Marina, 63(1), 51-60. https://doi.org/10.3989/scimar.1999.63n151

    Wolcott, T. G. (1978). Ecological role of ghost crabs, Ocypode quadrata (Fabricius) on an ocean beach: Scavengers or predators? Journal of Experimental Marine Biology and Ecology, 31(1), 67-82. https://doi.org/10.1016/0022-0981(78)90137-5

  • More than Armor: How Shark Skin Shapes Survival

    More than Armor: How Shark Skin Shapes Survival

    Have you ever wondered why, if you touch a shark from head to fin, it feels smooth—but from fin to head, it’s skin is rough like sandpaper? Sharks and rays (elasmobranchs) share a common “armor” made of tooth-like dermal denticles (shark skin) embedded over a collagen-rich dermis. This design grants abrasion resistance, drag reduction, and strong defenses against biofouling. And they heal fast!

    But denticle shape, size, density, and even skin thickness differ by species, sex, body region, and life stage. Around Onslow County, that means an Atlantic sharpnose shark doesn’t “feel” or function exactly like a spiny dogfish. A blacktip’s leading-edge denticles aren’t the same as those along its flank, and a cownose ray’s smoother disc tells a completely different hydrodynamic story than nearby requiem sharks.

    This diversity in structure and function is not just fascinating—it’s functional biology in action, shaping how local species move, heal, and interact with the waters along Onslow County.

    What all elasmobranch skin has in common

    Dermal denticles (placoid scales)

    Great white shark denticles
    Great white shark denticles | © Trevor Sewell/Electron Microscope Unit, University of Cape Town

    Sharks and rays share an external armor of dermal denticles—tiny tooth-like structures that reduce drag, resist abrasion, and deter fouling (Domel et al., 2018; Feld et al., 2019). These micro-ridges even inspire engineered materials designed to minimize friction and bacterial attachment (Arisoy et al., 2018; Sakamoto et al., 2014).

    A collagen-rich dermis

    Dogfish dermis
    Dogfish Dermis | From Shark dissection, Mayfield Schools, n. d. https://www.mayfieldschools.org/Downloads/sharkdissection%20%281%29.pdf

    Beneath those denticles lies a collagen-dense dermis that anchors and supports them, distributing stress and contributing to flexibility and toughness (Hagood et al., 2023, 2025). 

    Rapid wound healing

    Examples of wounds found on great white sharks
    Examples of wounds found on great white sharks | From A classification system for wounds and scars observed on white sharks (Carcharodon carcharias), Anderson et al., 2025.

    Many sharks heal rapidly—re-epithelializing within days and closing large injuries in weeks to months (Womersley et al., 2021).

    Where shark skin differs: species, sex, body region & ontogeny

    Shark skin of an Atlantic spiny dogfish
    Shark skin of an Atlantic spiny dogfish | From Dermal denticles of three slowly swimming shark species: Microscopy and flow visualization, Feld et al., 2019.

    Species differences.
    Denticle shape, ridge count, and spacing vary by ecology. Pelagic species emphasize hydrodynamics, while benthic species prioritize abrasion resistance (Feld et al., 2019).

    Body-region mosaics.
    Different zones of the same shark serve unique functions: snouts may have smooth, tile-like denticles; trunk and fin edges feature ridged, flow-controlling types (Gabler-Smith et al., 2021).

    Sexual dimorphism and mechanical variation.
    Hagood et al. (2023) found that male and female sharks differ in denticle structure and stiffness—traits likely linked to mating behavior and mechanical stress.

    Ontogenetic and ecomorphological changes.
    As sharks grow, skin stiffness and collagen fiber orientation evolve, tuning hydrodynamic and mechanical performance (Hagood et al., 2025).

    Sharks vs. rays (and skates): same toolkit, different emphasis

    Fossil dermal denticle of a ray found in North Carolina | From Ray Dermal Denticle (post by user “Al Dente”, May 31, 2011, https://www.thefossilforum.com/topic/21344-ray-dermal-denticle/

    Rays and skates share the elasmobranch blueprint but apply it differently. Cownose rays (Rhinoptera bonasus) maintain smooth discs for gliding over sand, concentrating tougher denticles along midlines or tails. Stingrays, meanwhile, modify certain denticles into venomous spines—an adaptation to benthic life (Smith & Merriner, 1987).

    Mucus: the invisible modifier

    Fischer, Lauder, and Wainwright (2025) discovered that mucus secretion selectively coats certain body regions, altering roughness, ridge exposure, and tactile function. This flexible coating regulates drag, microbial colonization, and frictional properties. Combined with collagen variation (Hagood et al., 2023, 2025), it reveals shark skin as a living, adaptive surface rather than static armor.

    Mucus being collected from blacktip reef sharks | By Mauvis Gore

    Local lens: Onslow County species & mucus implications

    • Atlantic sharpnose shark (Rhizoprionodon terraenovae) — Mucus along fin and tail tips fine-tunes hydrodynamics (Fischer et al., 2025).
    • Blacktip shark (Carcharhinus limbatus) — Fin-tip mucus reduces flow separation during rapid bursts (Domel et al., 2018; Fischer et al., 2025).
    • Spiny dogfish (Squalus acanthias) — Abrasion-resistant denticles limit fouling; mucus films aid transitions (Feld et al., 2019; Pogoreutz et al., 2019).
    • Bonnethead (Sphyrna tiburo) — Mucus along cephalofoil edges smooths high-shear zones (Fischer et al., 2025; Doane et al., 2020).
    • Cownose ray (Rhinoptera bonasus) — Disc-margin mucus reduces friction and microbial buildup (Smith & Merriner, 1987; Pogoreutz et al., 2019).

    Microflow around denticles: visualizing eddies and recirculation

    Feld et al. (2019) used microscopy and micro-Particle Image Velocimetry to reveal recirculation bubbles and coherent vortices downstream of denticle ridges. Even at low speeds, these micro-eddies enhance self-cleaning and reduce fouling by increasing localized shear stress. In Onslow County’s spiny dogfish and other bottom dwellers, such micro-flow effects likely complement mucus modulation (Fischer et al., 2025) and the micro-whirlpools described by Choi (2012), confirming that shark skin actively interacts with flow.

    Microstructure and biomimetic insights

    Gabler-Smith et al. (2022) compared natural shark denticle surfaces to engineered riblet models and found that synthetic designs fail to capture the fine ridge geometry and spacing that real denticles use to control turbulent flow. These ridges, grooves, and curvature features are essential for maintaining boundary layer stability and minimizing drag.

    Flow control and denticle bristling in the shortfin mako shark (Isurus oxyrinchus). The outward flare of dermal denticles reduces drag by preventing flow separation and wake turbulence. |
    From “The speedy secret of shark skin,” by A. W. Lang, 2020, Physics Today, 73(4), 62–63. (2020).

    Building on that foundation, Lang (2020) demonstrated that shortfin mako sharks (Isurus oxyrinchus) take this mechanical sophistication a step further. Their denticles can actively bristle—flexing outward up to 50° in milliseconds when the local flow begins to reverse. This rapid, passive response delays flow separation, reduces pressure drag, and smooths turbulent eddies. In essence, mako skin behaves like a living flow-control surface that adjusts dynamically to hydrodynamic forces.

    Lang’s work underscores that the mako’s speed and efficiency derive not only from its streamlined body but also from this microstructural flexibility. When viewed alongside the mini-whirlpool mechanisms observed by Choi (2012) and the mucus-texture modulation reported by Fischer et al. (2025), it becomes clear that shark skin represents a hierarchy of adaptive flow solutions—ranging from microscopic bristling denticles to chemical and structural tuning at the surface.

    For Onslow County species such as blacktip and spinner sharks, similar flow-adaptive strategies likely exist at smaller scales: flexible denticle alignment, mucus film adjustment, or localized stiffening along the fin and tail margins. Together, these traits demonstrate how elasmobranch skin functions as both armor and engine, a natural template for future biomimetic technologies in marine and aerospace design.

    Mini whirlpools and flexible flow control

    According to LiveScience, flexible shark skin samples generate tiny whirlpools that enhance propulsion when the surface bends dynamically (Choi, 2012). These results, together with mucus smoothing and collagen adaptability, show that shark skin functions as an active flow-control system—part armor, part hydrodynamic engine (Fischer et al., 2025; Hagood et al., 2023, 2025).

    Interfacing skin, gills, and chemical exposure

    Fish gills actively metabolize dissolved substances. Similarly, shark mucus and microbiome layers may act as chemical filters, reducing exposure to pollutants in Onslow County’s estuarine waters (Wood & Giacomin, 2016).

    Conservation and historical context: denticles as time capsules

    Scanning electron micrograph of fossil dermal denticles illustration functional morphotypes and ridge spacing | From Dillon, O’Dea & Norris, 2017, Fig. 2.

    Beyond living sharks, dermal denticles persist long after death, providing a fossil record of shark diversity. Researchers have extracted and identified denticles from reef sediments to reconstruct past shark communities—essentially using these microscopic scales as ecological fingerprints through time (Dillon, 2015). Applying similar sediment-based studies to the Onslow County coast could help reveal how local shark assemblages have changed, offering a baseline for modern conservation and recovery efforts.

    Functional synergy in Onslow County sharks

    FunctionBiological BasisExample in Onslow County Species
    Drag reduction & flow controlDenticle ridges, mucus overlays, and flexible flow (Domel et al., 2018; Fischer et al., 2025; Choi, 2012)Blacktip & sharpnose sharks
    Mechanical resilienceCollagen and denticle variation (Hagood et al., 2023, 2025)Juvenile vs. adult bonnetheads
    Microbiome stabilityDenticle–mucus regulation (Doane et al., 2020; Pogoreutz et al., 2019)Coastal species
    Chemical protectionSkin–mucus detox filtering (Feeding through your gills…, 2016)Estuarine sharks & rays
    Self-cleaning microflowRecirculating eddies near denticles (Feld et al., 2019)Atlantic spiny dogfish
    Paleo-conservation insightFossilized denticle records (Dillon, 2015)Coastal sediment archives
    Healing & maintenanceRapid re-epithelialization (Womersley et al., 2021)Atlantic spiny dogfish & cownose rays

    References

    Anderson, S. D., Kanive, P. E., Chapple, T. K., Andrzejaczek, S., Block, B. A., & Jorgensen, S. J. (2025). A classification system for wounds and scars observed on white sharks (Carcharodon carcharias). Frontiers in Marine Science, 12, Article 1520348. https://doi.org/10.3389/fmars.2025.1520348

    Arisoy, F. D., Gurkan, U. A., Yagci, B. B., Calamak, S., Dokmeci, M. R., & Demirci, U. (2018). Bioinspired photocatalytic shark-skin surfaces with antibacterial properties. Scientific Reports, 8, 16363. https://doi.org/10.1038/s41598-018-34334-1 

    Choi, C. Q. (2012, February 21). Sharks’ scales create tiny whirlpools for speedy swimming. LiveScience. https://www.livescience.com/18385-shark-skin-mini-whirlpools.html

    Dillon, E. (2015, October 9). Shark skin sleuthing. Save Our Seas Foundation. https://saveourseas.com/update/shark-skin–sleuthing/

    Dillon, E. M., O’Dea, A., & Norris, R. D. (2017). Dermal denticles as a tool to reconstruct shark communities. Marine Ecology Progress Series, 566, 117–134. https://doi.org/10.3354/meps12018

    Doane, M. P., Haggerty, J. M., Kacev, D., Papudeshi, B., & Dinsdale, E. A. (2020). The skin microbiome of elasmobranchs follows phylosymbiosis, but in teleost fishes, the microbiomes converge. Microbiome, 8(1), 123. https://doi.org/10.1186/s40168-020-00840-x 

    Domel, A. G., Weaver, J. C., Haj-Hossein, I., Wang, Z., Bertoldi, K., Lauder, G. V., & Vaziri, A. (2018). Shark skin-inspired designs that improve aerodynamic performance. Journal of the Royal Society Interface, 15(140), 20170828. https://doi.org/10.1098/rsif.2017.0828 

    Wood, C., Giacomin, M. (2016) Feeding through your gills and turning a toxicant into a solution. Journal of Experimental Biology, 219(20), 3218–3228. https://doi.org/10.1242/jeb.145625 

    Feld, K., Kolborg, A. N., Nyborg, C. M., Salewski, M., Steffensen, J. F., & Berg-Sørensen, K. (2019). Dermal denticles of three slowly swimming shark species: Microscopy and flow visualization. Biomimetics, 4(2), 38. https://doi.org/10.3390/biomimetics4020038 

    Fischer, M. J., Lauder, G. V., & Wainwright, D. K. (2025). Slippery and smooth shark skin: How mucus transforms surface texture. Journal of Morphology, 286(4), e70046. https://doi.org/10.1002/jmor.70046 

    Gabler-Smith, M. K., Lauder, G. V., et al. (2022). Ridges and riblets: Shark skin surfaces versus biomimetic models. Frontiers in Marine Science, 9, 975062. https://doi.org/10.3389/fmars.2022.975062 

    Gabler-Smith, M. K., Staab, K. L., & Motta, P. J. (2021). Dermal denticle diversity in sharks: Novel patterns on the interbranchial skin. Biology Letters, 17(12), 20210349. https://doi.org/10.1098/rsbl.2021.0349 

    Hagood, M. E., Motta, P. J., Staab, K. L., & Porter, M. E. (2023). Relationships in shark skin: Mechanical and morphological correlates of dermal denticles. Integrative and Comparative Biology, 63(6), 1154–1166. https://doi.org/10.1093/icb/icad085 

    Hagood, M. E., Wainwright, D. K., Motta, P. J., & Vaziri, A. (2025). Ecomorphology and ontogeny modulate the mechanical properties of shark skin. Journal of Experimental Zoology Part B: Molecular and Developmental Evolution. Advance online publication. https://doi.org/10.1016/j.jcz.2025.xxxxxx 

    Lang, A. W. (2020, April). The speedy secret of shark skin. Physics Today, 73(4), 62–63. https://digital.physicstoday.org/physicstoday/april_2020/MobilePagedArticle.action?articleId=1575067

    Pogoreutz, C., Yakob, L., Zhang, Y., Al-Saoudi, N. H., Olsson, A., El-Sherbiny, M., … Hajdu, E. (2019). Similar bacterial communities on healthy and injured shark skin samples suggest absence of severe bacterial infections. Animal Microbiome, 1, 11. https://doi.org/10.1186/s42523-019-0011-5 

    Sakamoto, A., Oikawa, K., & Yamaguchi, M. (2014). Antibacterial effects of protruding and recessed shark-skin micropatterned surfaces. Biofouling, 30(5), 593–602. https://doi.org/10.1080/08927014.2014.930720 

    Smith, J. W., & Merriner, J. V. (1987). Age and growth, movements and distribution of the cownose ray (Rhinoptera bonasus) in the western North Atlantic Ocean. Environmental Biology of Fishes, 20, 233–242. https://doi.org/10.1007/BF00004913 

    Womersley, F., Rohner, C. A., Gibbons, M. J., Richardson, A. J., & Jaine, F. R. A. (2021). Wound-healing capabilities of whale sharks (Rhincodon typus). Conservation Physiology, 9(1), coaa137. https://doi.org/10.1093/conphys/coaa137

  • Flat-Finned Neighbors: Rays and Skates Along Topsail & New River

    Flat-Finned Neighbors: Rays and Skates Along Topsail & New River

    If you love watching for fins in Onslow County, remember: not every fin belongs to a shark. Sharks, rays, skates, and sawfishes are all elasmobranchs—cartilaginous fishes with skeletons of flexible cartilage instead of bone. Along our beaches and in the New River estuary, you’ll most often meet rays and skates, the sharks’ closest cousins. Below are the species you’re most likely to spot, when they show up, what they eat, who eats them, their environmental preferences, and their conservation status.

    Quick ID: Ray vs. Skate

    • Rays generally have a whip-like tail; many (not all) have a venomous spine.
    • Skates lack a stinging spine and often have small dorsal fins near the tail tip.
    • Both glide over sand flats, sounds, and estuary mouths where they vacuum up clams, crabs, and small fishes.
    skates and ray anatomical differences
    Credit: Florida Museum

    Atlantic Stingray (Hypanus sabinus) — Our year-round neighbor in the estuary

    Small, spade-shaped, and sand-colored, the Atlantic stingray frequents shallow, warm, and often brackish waters, including the lower New River and surf zones off Topsail. It’s one of the most euryhaline elasmobranchs (tolerant of a wide salinity range), which is why folks see them from tidal creeks to nearshore surf (Johnson & Snelson, 1996).

    When to look: Late spring through fall in very shallow water on warm days (watch for “flying” jumps as they evade predators or parasites).

    Give them space: Shuffle your feet in the shallows to avoid accidental tail-spine contact.

    Diet (Prey): Worms, amphipods, small crustaceans, and mollusks, dug up from the sandy bottom.
    Predators: Large sharks (bull, hammerhead), some large fish (groupers, snappers), and wading birds preying on juveniles.

    Conservation status:

    • IUCN: Least Concern.
    • U.S. Status: Not protected under ESA or CITES; not managed in fisheries.
      Note: Stable populations, though freshwater groups sometimes show reproductive decline tied to water quality.
    hypanus sabinus

    Cownose Ray (Rhinoptera bonasus) — The bronze “wings” of summer

    Bronze-backed and wing-tipped, cownose rays cruise past Topsail in late spring and summer, sometimes in tight schools. Large multi-year telemetry studies show cownose rays migrate seasonally along the Atlantic coast, using mid-Atlantic estuaries for pupping and mating, then overwintering off central Florida (Ogburn et al., 2018).

    Local note: Schools moving along Onslow County beaches are most common mid- to late summer, especially on calm, clear mornings.

    Diet (Prey): Hard-shelled bivalves (clams, oysters, scallops) and crabs, crushed with strong dental plates.
    Predators: Large sharks such as sandbar, bull, and tiger sharks.

    Conservation status:

    • IUCN: Vulnerable.
    • U.S. Status: Not federally protected; some states (e.g., Maryland) have moratoria on killing contests.

    Note: At risk due to low reproductive rates, heavy schooling, and targeted culling in parts of its range.

    Rhinoptera bonasus

    Butterfly Ray (Genus Gymnura) — Rare, paper-thin glider

    Two butterfly rays—smooth butterfly ray and spiny butterfly ray—occur only sporadically here, near the northern edge of their ranges. Long-term sampling in Onslow Bay recorded both species mostly April–November, usually as young individuals (Schwartz, 2011).

    Where to look: Quiet sandy flats adjacent to inlets during warm months—rare sightings, treat them as a bonus.

    Diet (Prey): Small benthic fishes, shrimp, and crabs.
    Predators: Large sharks, particularly sandbar and hammerhead.

    Conservation status:

    • IUCN: Endangered (spiny butterfly ray).
    • U.S. Status: Not listed under ESA or CITES.

    Note: Populations declining globally; extremely rare in NC, where records are incidental.

    Gymnura species

    Clearnose Skate (Raja eglanteria) — The subtle, spotted skate

    Clearnose skates favor our nearshore sandy bottom habitats and show up all year, with peak catches outside the hottest months. In a recent year-round analysis of the North Carolina nearshore elasmobranch community, clearnose skates were among the most abundant species and were often juveniles, highlighting how our inner shelf provides important habitat (Roskar et al., 2024).

    Local tip: Anglers bottom-fishing near the bar or just off the beach encounter skates more often in the cooler seasons.

    Diet (Prey): Worms, amphipods, squid, and small fishes suctioned from the sand.
    Predators: Large sharks (sandbar, sand tiger, smooth dogfish) and occasionally other large rays or skates.

    Conservation status:

    • IUCN: Least Concern.
    • U.S. Status: Not protected individually, but included in the Northeast Skate Complex Fishery Management Plan, from Maine to Cape Hatteras, NC.

    Note: Common, often caught as bycatch; no special protections beyond fishery quotas.

    Raja eglanteria

    Mermaid’s Purses & Season Guide

    Elasmobranch egg cases—often called “mermaid’s purses”—sometimes wash up on our beaches in Onslow County. They are protective capsules laid by skates (relatives of sharks and rays). Each capsule once held a developing embryo. If you find one, it will most likely be an egg casing of a clearnose skate.

    Rays and stingrays (Atlantic stingray, cownose ray, butterfly rays) give birth to live pups—so their egg cases will never be found.
    Skates (like clearnose skate) are oviparous and the main source of egg cases on our shores.

    Clearnose skate egg casing or mermaid's purse

    Seasonal Timing in Onslow County

    SpeciesEgg Case SeasonWhat to Expect on Beaches
    Clearnose SkateSpring–Summer (Apr–Jul)Freshly laid egg cases in spring; more likely to wash ashore in late spring/early summer.
    Little Skate (rare in Onslow)Spring (Apr–May) & Fall (Oct–Dec)Occasionally reported; smaller cases than clearnose.
    Atlantic Stingray, Cownose Ray, Butterfly RaysNoneLive-bearers (no egg cases).

    Environmental Preferences: Temperature & Salinity

    The presence of rays and skates in Onslow County shifts with water temperature and salinity. These factors determine when species move inshore, offshore, or migrate seasonally.

    SpeciesTemperature PreferenceSalinity ToleranceSeasonal Pattern in Onslow Co.
    Atlantic Stingray15–30 °C (59–86 °F); prefers warm shallowsFreshwater → marine (highly euryhaline)Common spring–fall in estuary & surf
    Cownose Ray20–30 °C (68–86 °F)Marine & brackish; avoids freshwaterPeaks summer (Jun–Sep) in schools
    Butterfly Rays20–30 °C (68–86 °F)Marine & estuarineRare, Apr–Nov in warm surf/inlets
    Clearnose Skate10–25 °C (50–77 °F); cooler monthsMostly marine; avoids low salinityMost common fall–spring nearshore
    Smalltooth Sawfish>20 °C (68 °F); cold-sensitiveMarine & brackish estuariesHistorically summer visitor; now extirpated locally

    A seasonal cast: What rotates through Onslow waters and when?

    Multiple studies show our coast hosts a seasonally shifting elasmobranch assemblage—from warm-season rays nearshore to cool-season species on the inner shelf—driven largely by temperature. While many surveys historically emphasized sharks, batoids (rays & skates) make up a large fraction of biomass on our continental shelf, and Onslow’s inner shelf and estuary mouths act as corridors and nurseries through the year (Roskar et al., 2024).

    What about sawfish?

    Smalltooth sawfish (Pristis pectinata)—a ray with a chainsaw-like rostrum—is the most likely sawfish historically near NC, with a U.S. range that once extended to North Carolina. Today, it’s critically endangered and largely restricted to Florida, with only rare Northern reports (Brame et al., 2019).

    Diet (Prey): Small schooling fishes (mullets, herrings) and crustaceans, stunned or stirred up with its saw-like snout.
    Predators: Juveniles preyed on by large sharks; adults have few natural predators.If you ever encounter one, do not handle—it is federally protected.

    Pristis pectinata

    Conservation & Ecology Summary Table

    SpeciesIUCN StatusU.S. StatusPrey (Diet)Predators
    Atlantic Stingray (H. sabinus)Least ConcernNot protectedWorms, crustaceans, mollusksSharks, large fish, birds (juveniles)
    Cownose Ray (R. bonasus)VulnerableNot federally listedClams, oysters, scallops, crabsSharks (bull, tiger, sandbar)
    Clearnose Skate (R. eglanteria)Least ConcernManaged in Northeast Skate FMPWorms, amphipods, squid, small fishSharks, rays, humans (bycatch)
    Spiny Butterfly Ray (G. altavela)EndangeredNo U.S. federal listingSmall fish, shrimp, crabsSharks
    Smalltooth Sawfish (P. pectinata)Critically EndangeredESA Endangered; CITES Appendix ISmall fishes, crustaceansSharks (juveniles); few as adults

    How our community can help

    • Observe & report: Photograph rays, skates, or egg cases (from a safe distance) and note date, location, water conditions.
    • Respect nursery areas: Summer shallows often host juveniles; avoid disturbing resting rays.
    • Support clean water projects: Healthy estuary bottoms = healthy benthic prey = healthier ray & skate populations.

    References

    Brame, A. B., Wiley, T., Carlson, J., Fordham, S., Musick, J., & Grubbs, R. D. (2019). Biology, ecology, and status of the smalltooth sawfish Pristis pectinata in the USA. Endangered Species Research, 39, 9–23. https://doi.org/10.3354/esr00947

    Johnson, M. R., & Snelson, F. F., Jr. (1996). Reproductive life history of the Atlantic stingray, Dasyatis sabina (Pisces, Dasyatidae), in the freshwater St. Johns River, Florida. Bulletin of Marine Science, 59(1), 74–88.

    Ogburn, M. B., Bangley, C. W., Aguilar, R., Fisher, R. A., Curran, M. C., Webb, S. F., & Hines, A. H. (2018). Migratory connectivity and philopatry of cownose rays Rhinoptera bonasus along the Atlantic coast, USA. Marine Ecology Progress Series, 602, 197–211. https://doi.org/10.3354/meps12686

    Roskar, G., Morley, J. W., & Buckel, J. A. (2024). Seasonality and relative abundance within an elasmobranch assemblage near a major biogeographic divide. PLOS ONE, 19(6), e0300697. https://doi.org/10.1371/journal.pone.0300697

    Schwartz, F. J. (2011). Butterfly rays (Gymnuridae) of North Carolina. Journal of the North Carolina Academy of Science, 127(4), 275–284.

    Sulikowski, J. A., Williams, L. J., Kneebone, J., & Tsang, P. C. W. (2022). Rangewide population structure of the clearnose skate Raja eglanteria. Transactions of the American Fisheries Society, 151(2), 143–155. https://doi.org/10.1002/tafs.10351

    NOAA Fisheries. (n.d.). Smalltooth Sawfish (Pristis pectinata). Retrieved 2025, from https://www.fisheries.noaa.gov/species/smalltooth-sawfish