Tag: NC coastal sharks

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 | *© 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 | 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 | 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

Function	Biological Basis	Example in Onslow County Species
Drag reduction & flow control	Denticle ridges, mucus overlays, and flexible flow (Domel et al., 2018; Fischer et al., 2025; Choi, 2012)	Blacktip & sharpnose sharks
Mechanical resilience	Collagen and denticle variation (Hagood et al., 2023, 2025)	Juvenile vs. adult bonnetheads
Microbiome stability	Denticle–mucus regulation (Doane et al., 2020; Pogoreutz et al., 2019)	Coastal species
Chemical protection	Skin–mucus detox filtering (Feeding through your gills…, 2016)	Estuarine sharks & rays
Self-cleaning microflow	Recirculating eddies near denticles (Feld et al., 2019)	Atlantic spiny dogfish
Paleo-conservation insight	Fossilized denticle records (Dillon, 2015)	Coastal sediment archives
Healing & maintenance	Rapid 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

October 6, 2025

Serrated or Smooth? How to Tell What Sharks Eat by its Design in Onslow County, NC

Shark teeth aren’t just pointy souvenirs—they’re precision tools evolved over millions of years to match each shark’s preferred prey. In Onslow County, North Carolina, our coastal waters are home to a variety of shark species, each with teeth designed for specific feeding strategies and a story to tell. By looking closely at tooth shape, size, and serration, you can often identify which shark it came from and what it was built to eat.

Anatomy (Morphology) of a Shark Tooth & the Hidden Threat of Ocean Acidification

Each shark tooth is made up of several specialized parts:

Crown: The visible portion, covered by hard enameloid.
Apex: The pointed tip for puncturing or slicing.
Cutting edges & serrations: Sharp features for gripping and sawing through prey.
Crown-root boundary: Transition area between crown and root.
Root: Anchors the tooth in the jaw, often showing a nutritive groove and basal margins.

Traditionally, these structures have been celebrated as one of nature’s most effective feeding tools (Whitenack & Motta, 2010). However, new studies show they are increasingly vulnerable to environmental change.

Recent experiments simulating rising pH from increasing CO₂ emissions or ocean acidification— has revealed that it directly corrodes shark teeth. In laboratory tests, blacktip reef shark (Carcharhinus melanopterus) teeth placed in simulated future ocean conditions (pH 7.3) showed severe corrosion after just eight weeks. Damage included cracks, holes, loss of serrations, and weakened crowns (Baum et al., 2025). Media reports confirmed that acidified conditions caused up to 50% more deterioration compared to present-day seawater (Carrington, 2025; Sample, 2025).

Although sharks can continually replace their teeth, researchers warn that weaker, more brittle teeth increase energetic costs for replacement and may lower hunting efficiency (Baum et al., 2025). Even apex predators may face feeding challenges if climate-driven acidification continues to progress.

Shark Tooth Acidification — Changes in shark teeth from acidification | Baum et al.,2025

Tooth Shapes and What They Mean

1. Triangular & Serrated – Meat Slicers

Example species: Bull shark, sandbar shark, great hammerhead
Purpose: Wide, flat, saw-like surfaces slice chunks from fish, sea turtles, and marine mammals.
Evidence: Goodman et al. (2022) showed that bull shark teeth change shape as they grow, sharpening slicing ability in adulthood.

2. Needle-Like – Fish Grabbers

Example species: Blacktip shark, spinner shark, sand tiger shark
Purpose: Narrow, pointed teeth pierce slippery baitfish.
Evidence: Dynamic testing by Corn et al. (2016) confirmed needle-like teeth are ideal for gripping fast prey.

3. Flat & Molar-Like – Shell Crushers

Example species: Bonnethead (rear teeth), ray-eating sharks
Purpose: Flat, rounded surfaces crush crabs and clams.
Evidence: Paleobiology reviews show repeated evolution of molar-like teeth in benthic-feeding sharks (Höltke, 2024).

4. Combination Dentition – Versatile Feeders

Example species: Tiger shark
Purpose: Distinctively serrated and curved teeth capable of slicing through shell, bone, and skin.
Evidence: Structural mechanics research highlights tiger shark teeth as one of the most versatile cutting designs (Whitenack & Motta, 2010).

shark teeth identification by feeding type

Matching Tooth to Shark in Onslow County

Tooth Type	Likely Shark Species	Prey Preference
Broad, serrated triangle	Bull shark, sandbar shark	Fish, turtles, rays
Slender, pointed	Blacktip, spinner	Baitfish
Flat, rounded	Bonnethead (rear teeth)	Crustaceans, mollusks
Notched, curved	Tiger shark	Variety – fish, shellfish, carrion

Onslow Bay is also famous for fossil shark teeth, including Otodus megalodon and Otodus chubutensis. Many fossil teeth recovered offshore show borings from invertebrates, evidence of how these giant teeth became part of seafloor lag deposits (Maisch et al., 2019).

Why Tooth Shape Matters for Identification

Tooth form reflects diet: needle-like teeth for baitfish, serrated triangles for larger prey, and molariform crushers for shelled invertebrates. This functional diversity is critical to shark ecology, and new threats like acidification highlight how even small changes to tooth integrity could alter feeding success (Baum et al., 2025; Corn et al., 2016).

Watch: Shark Tooth Anatomy 101

This video will walk you through shark anatomy, crown vs. root, serrations, and how tooth shape maps to diet. You can apply those cues to common Onslow County species.

Direct link: Watch on YouTube: https://www.youtube.com/watch?v=TV6g8BMiImM

Freshly Shed vs. Fossil Shark Teeth

Not every tooth you find along the shore tells the same story. Some were shed by a living shark just days or weeks ago, while others are relics from ancient seas.

Freshly shed shark teeth are typically light-colored—white, ivory, or pale gray—and sharp-edged. They feel lightweight because they haven’t undergone mineralization. These often wash ashore in inlets and estuaries where sharks actively feed.
Fossil shark teeth, in contrast, are much heavier and darker. Over time, sediments bury the tooth. Water carrying dissolved minerals like iron, manganese, and phosphorus percolates in, gradually replacing the tooth’s organic materials through permineralization. These minerals imbue the tooth with color—commonly deep hues like black, brown, or blue—reflecting the surrounding geology rather than the tooth’s age or species (FossilGuy.com, n.d.; Maisch et al., 2019).

Why Fossil Shark Teeth Vary in Color

Though the sediment’s mineral content is a major driver, color patterns can get complex:

Enamel vs. root: The enamel and root differ chemically, so each may take up minerals differently—sometimes resulting in bi-colored teeth (FossilGuy.com, n.d.).
Mineral source matters: A black or dark-colored tooth might indicate fossilization in phosphate-rich sediments, whereas iron-rich layers can yield reddish or orange tones (FossilGuy.com, n.d.).
Post-fossilization changes: Groundwater exposure or burrowing organisms can leach or deposit minerals unevenly, leading to partial bleaching, streaks, speckles, or even multicolored patterns (FossilGuy.com, n.d.).

fossil shark teeth are colored by sediment type

Fossil Teeth of Onslow County

On the beaches of Topsail, Emerald Isle, and Bear Island (Hammocks Beach State Park), collectors may find fossilized teeth spanning extinct and modern lineages:

Otodus megalodon – Massive triangular teeth (3–5 inches) from the giant prehistoric predator.
Otodus chubutensis – Similar but slightly more curved than megalodon teeth.
Carcharhinid teeth – Smaller triangular fossils from relatives of today’s bull, sandbar, and blacktip sharks.
Occasional hammerhead and tiger shark fossils, generally identifiable by their distinctive shapes.

Onslow Bay’s Miocene–Pliocene sedimentary deposits make it a rich source of permineralized shark teeth—and the colors seen reflect the local sediment chemistry (e.g., phosphate vs. iron-rich layers) rather than the teeth’s exact age (FossilGuy.com, n.d.; Maisch et al., 2019). Many fossil hunters prize these finds not only for their form and rarity but also for the geological story encapsulated in their hues.

Fossil shark teeth species in Onslow County NC

Can You Spot the Shark Teeth?

Shark teeth can be found along the beach and come in all sizes and colors. Some are so tiny that they can only be seen by close examination of the sand or even under the microscope!

Final Thought

Every shark tooth found in Onslow County tells a story—of predator and prey, adaptation, and even global climate change. By learning how form meets function, we not only identify species but also glimpse the pressures shaping their survival today.

References

Baum, M., Haussecker, T., Walenciak, O., Köhler, S., Bridges, C. R., & Fraune, S. (2025). Simulated ocean acidification affects shark tooth morphology. Frontiers in Marine Science, 12, 1597592. https://doi.org/10.3389/fmars.2025.1597592

Carrington, D. (2025, August 27). Toothless sharks? Ocean acidification could erode predator’s vital weapon, study finds. The Guardian. https://www.theguardian.com/environment/2025/aug/27/ocean-acidification-erodes-sharks-teeth-affecting-feeding

Corn, K. A., Farina, S. C., Brash, J., Summers, A. P., & Kolmann, M. A. (2016). Modeling tooth–prey interactions in sharks: The importance of dynamic testing. Royal Society Open Science, 3(5), 160141. https://doi.org/10.1098/rsos.160141

FossilGuy.com. (n.d.). Why are fossil shark teeth different colors? An explanation of why fossils are different colors. Retrieved September 1, 2025, from https://www.fossilguy.com/topics/shark-teeth-colors/index.htm

Goodman, K., Goldbogen, J. A., & Bizzarro, J. J. (2022). Ontogenetic changes in the tooth morphology of bull sharks (Carcharhinus leucas). Journal of Fish Biology, 101(6), 1396–1408. https://doi.org/10.1111/jfb.15181

Höltke, O. (2024). A review of the paleobiology of some Neogene sharks. Diversity, 16(3), 147. https://doi.org/10.3390/d16030147

Maisch, H. M. IV, Becker, M. A., & Chamberlain, J. A. Jr. (2019). Macroborings in Otodus megalodon and Otodus chubutensis shark teeth from the submerged shelf of Onslow Bay, North Carolina, USA. Ichnos, 26(4), 377–388. https://doi.org/10.1080/10420940.2019.1693755

Sample, I. (2025, August 27). How ocean acidification is taking the bite out of sharks’ teeth. The Times. https://www.thetimes.co.uk/article/ocean-acidification-corrodes-shark-teeth-fk985lnw7

Whitenack, L. B., & Motta, P. J. (2010). Performance of shark teeth during puncture and draw: Implications for the mechanics of cutting. Journal of Morphology, 271(3), 469–479. https://doi.org/10.1002/jmor.10809

September 17, 2025

Think You Know Your Sharks? The 3 Most Misidentified
Many sharks have similar appearances in body shape and colorations, especially when viewed from above. Juvenile sharks can be difficult to identify because their markings and proportions are not developed to fully resemble adults. The ability to obtain clear, prolonged views of sharks underwater can be difficult due to shark movement and water clarity. Not all people that encounter sharks have the specialized knowledge required for accurate identification.

But which sharks are often misidentified in North Carolina, and why? It’s often like a game of “can you spot the differences?” when trying to identify similar species. Let’s review the top 3 misidentified sharks in NC.

? Who are the Top 3 Misidentified Shark

1. Sandbar shark (Carcharhinus plumbeus) vs dusky shark (Carcharhinus obscurus)

Why They Are Confused

Both sharks can grow to large sizes with a bulky appearance with overlapping habitats. Both have a brown to bronze upper body that fades into a white belly. They look similar because they are members of the same shark genus, Carcharhinus or Requiem sharks, that share some of the same qualities such as, slender to stout bodies, their first dorsal fin is larger than their second dorsal fin, have a long upper tail lobe, and single-cusped blade-shaped teeth.

Key Differences
- Sandbar shark: Large, tall dorsal fin with its leading edge located ahead of its pectoral fins
- Dusky shark: Slightly less bulky than the sandbar shark with a shorter dorsal fin that originates behind its narrower pectoral fins, and a snout length that is equal to or shorter than its mouth width making it appear more pointy. Side note: dusky sharks prefer cooler water temperatures, between 66 and 82 degrees fahrenheit, so they may not be seen frequently in warm summer waters.
Upper image, dusky shark; Lower image, sandbar shark. Photo Credit: Zogaris & Maddalena, 2014

Dusky shark vs Sandbar Shark. Photo Credit: UNF Institute for Environmental Research and Education, 2018

2. Blacktip shark (Carcharhinus limbatus) vs spinner shark (Carcharhinus brevipinna)

Why They Are Confused

Both sharks leap from the water and spin during feeding. They look similar because they are members of the same shark genus, Carcharhinus or Requiem sharks, that share some of the same qualities such as, slender to stout bodies, their first dorsal fin is larger than their second dorsal fin, have a long upper tail lobe, and single-cusped blade-shaped teeth.

Key Differences
- Spinner shark: More slender, all fins (except the anal fin) are often black-tipped, spins more during breaching
- Blacktip shark: Heavier body than the spinner shark, only dorsal and pectoral fins have black tips, and the anal fin has a white tip.
Blacktip shark vs spinner shark. Photo Credit: International Game Fish Association, 2020

Photo Credit: Florida Sportsman

3. Atlantic sharpnose shark (Rhizoprionodon terraenovae) vs juvenile blacktip shark (Carcharhinus limbatus)

Why They Are Confused

The juvenile blacktip shark has not fully developed into its final adult stage, so it lacks markings and definition that can distinguish it better from Atlantic sharpnose shark. The blacktip, in its adult stage, can reach up to 6 feet, while the Atlantic sharpnose shark only reaches a maximum length of 3.5 that makes it a similar size to a juvenile blacktip shark. Both forage in shallower waters and share the same habitat.

Key Differences
- Juvenile blacktip sharks: Have black tips on their fins, and a white tipped anal fin. Gray to gray-brown coloration with a white underside.Wedge-shaped line or Z-shaped line along its sides.
- Atlantic sharpnose sharks: Have white spots along its side, second dorsal fin, blacktipped, originating over or behind its anal fin. This will be the only black tipped fin on this species.
Juvenile blacktip shark. Photo Credit: Galapagos Science Center, 2025

Juvenile blacktip shark. Photo Credit: Wilder_Boone, iNaturalist, 2025

Adult Atlantic sharpnose shark. Photo Credit: Joshua_Rains, iNaturalist, 2025

Safety Note: Are They Dangerous?

Most sharks seen nearshore in Onslow County are not aggressive toward humans and play a crucial role in ocean health. Most sightings are brief and harmless. That said, avoid swimming near fishing piers or schools of baitfish, especially at dawn or dusk, and between fishers casting from the shore.

Why It Matters

Correct species identification helps:
- Local fishermen adhere to fishing regulations
- Researchers track species populations
- Beachgoers feel informed and safe
- Conservationists protect nurseries and feeding grounds
Want to Help?

Have you seen a shark? I am looking for information on locations of juvenile sharks. You can report sightings or photos to support my independent research by posting on my social media channels or email. Please follow our Instagram and Facebook pages to stay informed, ask questions, or post your pictures!
August 5, 2025
Sharks of Onslow County: A Closer Look Beneath the Surface
_{Atlantic blacktip sharks, NOAA Fisheries}

North Carolina’s coastline is more than just a scenic destination — it’s a living, shifting ecosystem where over 70 species of sharks either pass through or call home. Here in Onslow County, we sit at the edge of a thriving marine highway where sharks play vital roles in the health and balance of the ocean. This blog is your guide to understanding them — through science, seasonal insight, and observation.

Who’s Behind This Blog?

I’m an independent marine scientist based in Onslow County, North Carolina. My research focuses on marine predators, particularly sharks, and their presence in our coastal waters. I started this blog to share what I learn with the local community — from migration patterns to myth-busting to how sharks help keep our ocean healthy.

Sharks in Our Local Waters

Many are surprised to learn that North Carolina’s coastal waters support such a wide variety of sharks. Some species are seasonal visitors, others are year-round residents. Here’s a quick snapshot of some that appear regularly in the Onslow County area:
- Blacktip & spinner sharks – both known for their acrobatic, spinning leaps from the water
- Sandbar sharks – large, powerful, and often found near sandbars and inlets
- Bonnethead sharks – smaller relatives of hammerheads with distinctive shovel-shaped heads
- Atlantic sharpnose sharks – small, sleek, and common in summer
- Tiger, bull & great white sharks – less common nearshore but known to pass through our deeper waters
Each season brings changes — both in the number of sharks and the species we see. That’s part of what makes the local waters so dynamic.

Why They Come and Go

Shark activity near Onslow County shifts throughout the year depending on:
- Water temperature – Move with the seasons to avoid colder waters in the winter
- Prey availability – Sharks follow fish, rays, and crustaceans that can trigger migrations
- Mating and pupping – Some species use NC’s estuaries and shallow coastlines as nursery grounds
Most sharks migrate along the Gulf Stream current and smaller coastal currents and eddies, passing through North Carolina during their journeys between cooler and warmer waters.

Sharks and People: What’s True and What’s Hype?

You’ve probably seen viral headlines about shark sightings or encounters — but here’s the truth:
- Shark encounters in NC are extremely rare — you’re far more likely to be injured by beach gear than a shark.
- Sharks are not targeting humans. Most incidents happen when sharks mistake a person for prey in murky water.
- Healthy shark populations = healthy oceans. Sharks keep fish populations in balance, helping reefs and seagrasses thrive.
The more we learn about sharks, the less fear they inspire — and the more respect they earn.

What You Can Expect from This Blog

Each week or two, I’ll share:
- Local shark updates
- Myth-busting posts
- Seasonal migration guides
- Photos, sightings, and stories from the NC coast
- Educational resources for students and families
- Ways to get involved in citizen science or local shark conservation
This blog is for curious minds, beach lovers, teachers, parents, and anyone who’s ever wondered:
“What’s swimming just offshore?”

Let’s Stay Connected
- Follow me on Facebook and Instagram for real-time updates and shark facts.
- Got questions or sightings to share? Send them my way — I may feature them in a future post.
Thanks for reading, and welcome to your new window into the wild, fascinating world just beneath the surface.
? ? – Angelique Mitchell
July 17, 2025

Tag: NC coastal sharks

More than Armor: How Shark Skin Shapes Survival

What all elasmobranch skin has in common

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

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

Mucus: the invisible modifier

Local lens: Onslow County species & mucus implications

Microflow around denticles: visualizing eddies and recirculation

Microstructure and biomimetic insights

Mini whirlpools and flexible flow control

Interfacing skin, gills, and chemical exposure

Conservation and historical context: denticles as time capsules

Functional synergy in Onslow County sharks

References

Serrated or Smooth? How to Tell What Sharks Eat by its Design in Onslow County, NC

Anatomy (Morphology) of a Shark Tooth & the Hidden Threat of Ocean Acidification

Tooth Shapes and What They Mean

1. Triangular & Serrated – Meat Slicers

2. Needle-Like – Fish Grabbers

3. Flat & Molar-Like – Shell Crushers

4. Combination Dentition – Versatile Feeders

Matching Tooth to Shark in Onslow County

Why Tooth Shape Matters for Identification

Watch: Shark Tooth Anatomy 101

Freshly Shed vs. Fossil Shark Teeth

Why Fossil Shark Teeth Vary in Color

Fossil Teeth of Onslow County

Can You Spot the Shark Teeth?

Final Thought

References

Think You Know Your Sharks? The 3 Most Misidentified

? Who are the Top 3 Misidentified Shark

1. Sandbar shark (Carcharhinus plumbeus) vs dusky shark (Carcharhinus obscurus)

Why They Are Confused

Key Differences

2. Blacktip shark (Carcharhinus limbatus) vs spinner shark (Carcharhinus brevipinna)

Why They Are Confused

Key Differences

3. Atlantic sharpnose shark (Rhizoprionodon terraenovae) vs juvenile blacktip shark (Carcharhinus limbatus)

Why They Are Confused

Key Differences

Safety Note: Are They Dangerous?

Why It Matters

Want to Help?

Sharks of Onslow County: A Closer Look Beneath the Surface

Who’s Behind This Blog?

Sharks in Our Local Waters

Why They Come and Go

Sharks and People: What’s True and What’s Hype?

What You Can Expect from This Blog

Let’s Stay Connected