Fishing has caused dramatic declines in shark populations worldwide (Baum et al., 2003; Ward-Paige et al., 2012; Valdivia et al., 2017; Roff et al., 2018). As a result, one-third of shark species are threatened with extinction and designated as Critically Endangered, Endangered, or Vulnerable by the International Union for Conservation of Nature (IUCN) (Dulvy et al., 2021). Moreover, a recent study found that despite international efforts to conserve and protect sharks, global shark mortality from fishing is still rapidly increasing (Worm et al., 2024).

The shark fin and meat trade is a global market with the global trade for shark meat steadily expanding since the early 2000s (Dent and Clarke, 2015). Sharks are harvested for food (e.g., shark fin soup and meat) and other commercial products (e.g., squalene which is commonly used in moisturizing skincare products), and in many regions they are targeted specifically for their culturally and economically valuable fins (Clarke, 2004; Man et al., 2014). Although shark finning is generally considered the main threat to shark populations, the market for shark meat (from the bodies of sharks) has been increasing globally (Dent and Clarke, 2015) and has surpassed the fin market in terms of both volume and value (Niedermüller et al., 2021). The troubling growth in the global trade of shark meat is due to several factors, including growing consumer demand for seafood, the overfishing of other stocks, and perversely, regulations designed to reduce shark finning (Dent and Clarke, 2015; Niedermüller et al., 2021; Worm et al., 2024).

Most shark products, especially fins, are exported to countries in East and Southeast Asia such as China, Hong Kong, Taiwan, Singapore, Malaysia, and Vietnam (Vannuccini, 1999; Boon, 2017; Cardeñosa et al., 2020). In contrast, some of the world’s largest consumers of shark meat are in South America and Europe, particularly Italy, Brazil, Uruguay, and Spain (Dent and Clarke, 2015; Niedermüller et al., 2021). In these regions non-threatened shark species are often sold legally; however, the meat is typically labeled incorrectly (e.g., labeling a shortfin mako shark as a blacktip shark) or ambiguously as “shark” (Barbuto et al., 2010; Almerón-Souza et al., 2018; Pazartzi et al., 2019) ( Figure 1 ). Ambiguous labeling is common in the sale of a variety of seafood products, e.g., use of labels such “scallops” or “squid” without species-level identification. Cundy et al. (2023) found in Australia that ambiguously labeled seafood products had higher rates of mislabeling than products labeled to species. For example, samples labeled as “shark” or “flake” were often identified as chimaeras (Callorhinchus spp.) rather than a species of shark. Previous studies have found that shark meat is often mislabeled (Agyeman et al., 2021) or ambiguously labeled as “shark” regardless of species (Bornatowski et al., 2013; Pazartzi et al., 2019; Abdullah et al., 2020). Shark meat is also commonly sold under various ambiguous and colloquial terms that obscure its identity from consumers (Bornatowski et al., 2013). For example, in South Africa shark is sold as “ocean filets’’ or “skomoro”, in Brazil elasmobranchs (i.e., sharks, skates, and rays) are sold as “cação” (Bornatowski et al., 2013), in Australia shark is sold under the term “flake” (Braccini et al., 2020), and in the United Kingdom small sharks are commonly sold as “rock salmon”, “huss”, “rock eel”, and “rigg” (Hobbs et al., 2019). In the United States, the term “dogfish” (referring to sharks in the family Squalidae) is also commonly used, which may mislead consumers into believing they are purchasing a generic fish product rather than a species of shark.

The use of ambiguous, colloquial labeling has been shown to confuse consumers about what they are purchasing. For example, Bornatowski et al. (2015) interviewed customers at fish markets in Southern Brazil and found that 61% of respondents claimed that they ate cação but not shark. Similarly, López de la Lama et al. (2018) found that 77.5% of Peruvians that eat shark meat were unaware that they were consuming shark since it was commonly labeled with the colloquial term “tollo”. Hobbs et al. (2019) reported that shark (primarily spiny dogfish Squalus acanthias) is commonly sold in takeaway fish and chips meals across the United Kingdom. The study also found that the sale of shark is common in UK grocery stores and seafood markets including IUCN Critically Endangered scalloped hammerhead (Sphyrna lewini). Likewise, Munguia-Vega et al. (2022) found that in Mexico, scalloped hammerhead and several other IUCN Endangered and Vulnerable species were being sold generically as “cazon”, a term used in the Mexican seafood trade to mean any shark meat.

Generic umbrella terms also allow for species that are subject to international trade restrictions under the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) to enter the market undetected. Moreover, ambiguous labeling and mislabeling hinder efforts to monitor and manage species-specific population trends, undermining stock assessments, sustainable catch quotas, and international reporting obligations and potentially allowing declines in vulnerable species to go unnoticed.

Although shark products are widely traded in the global food system, substantial information gaps remain regarding their trade frequency, geographic extent, species identity, and numerous other aspects of the shark trade (Dent and Clarke, 2015; Van Houtan et al., 2020; Niedermüller et al., 2021). Limited information on the shark trade constrains our ability to quantitatively evaluate the implications of shark consumption for human health (e.g., exposure to heavy metals) and marine biodiversity conservation. Improved species-specific market labels and trade data are essential to more accurately evaluate these risks and inform policy decisions. Between 2010 and 2023, 17.1% of commercial seafood samples (i.e., bony fish and shellfish) analyzed in the United States were found to have unacceptable market names (Ahles et al., 2025). Despite the potential conservation and public health implications, only four studies have used molecular techniques (e.g., DNA barcoding) to quantify the accuracy of shark product labeling in the United States (Wallace et al., 2012; Cardeñosa, 2019; Hellberg et al., 2019; Eppley and Coote, 2025). DNA barcoding (i.e., used for species identification based on short, standardized DNA sequences) is an essential tool when investigating shark product mislabeling because in most cases when shark products are sold it is extremely difficult to visually identify the species because distinguishing morphological characteristics are removed.

The purpose of this study was to quantify the identity of “shark” meat sold in the United States. We purchased 30 samples from grocery stores and online jerky vendors. Using standard DNA barcoding techniques, we identified 29 of the 30 samples to the species level. We found that Critically Endangered sharks, including great hammerhead (Sphyrna mokarran) and scalloped hammerhead, are available in grocery stores. Moreover, of the 29 samples that were successfully identified to the species level, 93% were labeled ambiguously and one of the two products labeled at the species level was mislabeled.

Twenty nine of the 30 samples were successfully identified to the species level with at least one of the three genes. Twenty-seven were labeled ambiguously as “shark”: all 10 of the jerky samples and 17 of the 19 filets. One of the two samples labeled at the species level was mislabeled (i.e., sold as blacktip shark but was shortfin mako) and only one sample was correctly labeled, and it was a blacktip shark. Twenty nine of the 30 samples were identified as shark and came from 11 species, including three species listed by the IUCN as Critically Endangered: great hammerhead, scalloped hammerhead, and tope (Galeorhinus galeus) ( Figure 3 , Supplementary Table S1 ). The average price in USD of the fresh shark meat was $6.30/lb ± 2.88 ($13.86/kg ± 6.51) with prices ranging from $2.99/lb ($6.59/kg) to $11.99/lb ($26.41/kg). The average price of the shark jerky was $5.08/oz ± 0.99 ($207.37/kg ± 37.21).

Overall, we found a high level of ambiguous and incorrect shark product labeling and evidence of IUCN listed endangered species in the U.S. food supply. Thirty one percent of our samples were classified by the IUCN as Endangered or Critically Endangered species ( Figure 3 ). All nine of these samples were also either ambiguously or incorrectly labeled. Out of the 29 samples, only one was correctly labeled and it was from a blacktip shark. Although our sample size is relatively small (n = 29), we still detected multiple Critically Endangered and CITES Appendix II species being sold in U.S. markets. These results are concordant with those of similar studies that were conducted in the United States and Canada (Wallace et al., 2012; Hellberg et al., 2019). For example, all 35 shark products (i.e., jerky, shark fin soup, cartilage pills, and fresh or grilled fillets) collected from Orange and Los Angeles Counties, CA, USA and online by Hellberg et al. (2019) were labeled ambiguously.

Vague and inaccurate labeling can greatly impact the conservation of marine predators by concealing the sale of endangered species. Although consumers are indeed being sold “shark”, there are at least 536 species of sharks (Dulvy et al., 2021) ranging in size, diet, habitat, and conservation status. For example, scalloped hammerhead sharks are Critically Endangered with a population that continues to decline globally (Rigby et al., 2019). Several aspects of the life history of hammerhead sharks make them especially vulnerable to fishing (Gallagher et al., 2014). Despite their status, the scalloped hammerhead was identified as one of the species labeled ambiguously as “shark” in our study. Ensuring transparency and traceability is essential for maintaining legal and sustainable trade in sharks and for preventing the sale of protected species (Niedermüller et al., 2021). In the United States, the Food and Drug Administration (FDA) has issued a Seafood List specifying acceptable common names, market names, and scientific names required for commercial trade (The United States Food and Drug Administration, 2025). However, as of 2025, the acceptable market name for all listed shark species is “shark” (The United States Food and Drug Administration, 2025), diminishing the regulatory effectiveness of species-specific labeling. In contrast, the European Union has implemented a more comprehensive labeling requirement under Regulation (EU) 1379/2013 which mandates that seafood labels include the scientific name, method of harvest or production, catch area, country of origin, fishing gear used, and other relevant information (Council of the European Union & European Parliament, 2013). Sellers in the United States should be required to provide species-specific names, and when shark meat is not a food security necessity, consumers should avoid purchasing products that lack species-level labeling or traceable sourcing (Niedermüller et al., 2021).

Shark fins are a highly sought out product throughout Asia (Eriksson and Clarke, 2015) specifically for shark fin soup. The lower caudal fin of hammerheads (Sphyrna spp.) and the shortfin mako (Isurus oxyrinchus) are considered to have the best quality fin needles for consumption (Clarke et al., 2007), resulting in a high demand for these species. Cardeñosa et al. (2022) found that scalloped hammerhead was the third most common species sold in a Hong Kong fish market as fins. The shortfin mako was the sixth most common species (Cardeñosa et al., 2022). Additionally, Almerón-Souza et al. (2018) found scalloped hammerhead to be the most abundant species when testing shark meat sold in Brazil. These and other shark species threatened with extinction are present-to-common in the food supply in numerous countries around the world.

Eight of our 29 samples were labeled as “mako shark” (n = 7) or “shortfin mako” (n = 1). A higher demand for mako shark fins and meat could be why most mislabeled meat products were labeled as mako. Makos (i.e., Isurus oxyrinchus and Isurus paucus), threshers (i.e., Alopias spp.), larger hammerheads (i.e., Sphyrna lewini, Sphyrna mokarran, and Sphyrna zygaena), and all requiem sharks (e.g., Carcharhinus brevipinna, Negaprion brevirostris, Carcharhinus limbatus, and Rhizoprionodon terraenovae) are all classified under CITES Appendix II which require export permits due to their extreme vulnerability if trade is not strictly controlled. Fifty eight percent of our samples were listed under CITES Appendix II. Catch location was only available for four out of the 30 samples, three being labeled as “caught in the USA” and one labeled as “caught in Hawaii”. Due to this we were unable to determine if the shark meat had been locally sourced in the United States for most of the samples. All of the shark species that we identified are commonly caught in the United States and internationally (IUCN, 2022) which could create potential for CITES violations. Mislabeling is sometimes used to disguise CITES restricted or endangered species (e.g., Sphyrna lewini, Sphyrna mokarran, and Isurus oxyrinchus) being harvested for the fin trade since different species of shark meat can look identical when fileted or dried as jerky.

The Shark Conservation Act of 2010 (H.R. 81. Shark conservation act of 2010, Public Law 111-348., Pub. L. No. 111–348 (2010) requires that all sharks in the United States, with one exception (Mustelus canis), be brought to shore with their fins naturally attached. This law has forced fishermen to land the entire shark rather than only taking the fins and disposing the body at sea, thereby potentially increasing the amount of shark meat being sold as a byproduct. Shark meat is oftentimes considered to be “junk meat” due to its unpleasant smell and taste which is a result of high amounts of urea in the tissue (Suryaningsih et al., 2020). In Europe and North America, few countries restrict the sale of species categorized as Critically Endangered by the IUCN (Frank and Wilcove, 2019). The market cost for most of our samples was very low compared to the other species of fish, especially in grocery stores. For example, a scalloped hammerhead filet was only $4.99/lb ($10.99/kg) while red snapper (Lutjanus campechanus) can commonly be sold as much as $27/lb ($59.4/kg) (Spencer et al., 2020). Given the massive ecological cost of harvesting such an important, rare, and long-lived predator (e.g., scalloped hammerhead) it is remarkable how low their market price is.

Shark products can contain heavy metals including arsenic and mercury (Garcia Barcia et al., 2020) with the highest concentrations in muscle tissue (Tiktak et al., 2020). Consumption of these heavy metals can have negative effects on human health (Tiktak et al., 2020; Souza-Araujo et al., 2021). For example, García Barcia et al. (2022) found high levels of mercury in meat and fin products from large hammerhead species, Sphyrna mokarran, S. zygaena, and S. lewini, and advised consumers to avoid these species. They also recommended that “species specific advisories to be issued for meat and fin products from oceanic whitetip (Carcharhinus longimanus) and dusky smooth-hound sharks (Mustelus canis), which should be avoided by women of childbearing age again due to high mercury levels” (García Barcia et al., 2022). We were sold three of these five species (i.e., scalloped hammerhead, great hammerhead, and dusky smooth-hound) all of which were labeled generically as “shark”. Consumption of mercury can cause damage to the brain and central nervous system while arsenic can lead to skin, bladder, and lung cancer (Ratcliffe et al., 1996; Honda et al., 2006; Ravenscroft et al., 2011; Skalny et al., 2022). Consumption of these metals has been related to fetal cognitive development complications and infant death (Honda et al., 2006; Farzan et al., 2013; Tolins et al., 2014; Quansah et al., 2015). The ambiguous labeling of shark meat can be detrimental to human health. When consumers are purchasing ambiguously labeled or mislabeled shark meat, they have no way to know what species they are consuming and what the associated health risks might be.

Our sampling and inferences about shark steak mislabeling are biased towards North Carolina. However, the jerky samples were purchased from national vendors (all based in the United States) therefore the inferences made from those samples are representative of the geographic region. Due to our limited sample size, future work should include a larger, more geographically widespread sampling to better characterize the sale of shark products. The species composition of shark meat being sold in the United States and the rest of the world is still largely unknown. Increased monitoring and accurate, verified product labels for shark meat are necessary given the high proportion of species threatened with extinction found within our small sample size. Fields et al. (2020) recently used genetic stock identification to identify source populations of the scalloped hammerheads found in the Hong Kong fin trade. Genetic stock identification could also be used to decipher what specific populations or regions the shark meat is coming from (e.g., scalloped hammerheads from the Eastern Pacific). With a comprehensive genetic database of shark stocks in the United States, and for vulnerable populations, this method could provide a better understanding of whether these CITES listed species are being imported illegally and if these sharks are being fished from overexploited regions.