Course:FNH200/Projects/2026/Shark Fin: An Endangered Food Under Scrutiny

1. Introduction

Figure 1. A shark’s dorsal fin, one of several types of fins targeted in the commercial shark fin trade.

Shark fin is a cartilaginous appendage of sharks, primarily used to make shark fin soup, a prized delicacy in Chinese cuisine. The history of eating shark fin dates back to the Song Dynasty more than a thousand years ago, when it symbolized wealth and prosperity. Although shark fin itself has almost no taste, it is valued for its distinctive texture. Chemically, shark fin is supported by an extracellular matrix composed of collagen, elastin, and proteoglycans, but its nutritional value is negligible compared to the broth used to cook it. High market demand has led to the wasteful practice of "finning," which involves cutting fins from live sharks and discarding them back into the sea. This has contributed to declining shark populations, with estimates suggesting up to 80 million sharks are killed annually. As a result, international regulatory bodies have increasingly listed shark species under CITES Appendix II to monitor and restrict trade, though enforcement remains challenging.

2. History & Cultural Background

Shark fin has been consumed as a luxury food in China for centuries. Historical research suggests it became popular during the Song dynasty (960 - 1279) and was later established as haute cuisine at imperial banquets during the (1368 - 1644) (Fabinyi, 2012). During the Ming and Qing periods, expanding trade networks increased access to preserved marine products. Because fresh seafood was difficult and expensive to transport, dried shark fin became a valuable commodity associated with status and culinary sophistication (LSE, 2025).

Shark fin soup became especially prominent in southern Chinese banquet traditions. It has commonly been served at weddings and formal banquets, where its high cost represents status and prosperity (Fabinyi, 2012; LSE, 2025). The fin contributes little flavour and is valued mainly for its fibrous texture, while most flavour comes from the broth and accompanying ingredients (LSE, 2025).

Historically, shark fin was mainly accessible to wealthy consumers. Economic growth and rising incomes during the 1980s and 1990s broadened access and expanded the shark-fin market (Fabinyi, 2012). This commercialization provides important context for current concerns about the safety, authenticity, and species composition of shark-fin products.

3. Ingredient & Chemical Composition

Figure 2. Dried shark fins after processing, which removes many physical characteristics used for visual species identification.

Despite its prestige, shark fin has little inherent nutritional or flavour value. Its structural strength comes from elastoidin, a fibrous protein related to but chemically distinct from mammalian collagen. Unlike true collagen, elastoidin does not dissolve into gelatin when boiled, allowing processed fins to retain their needle-like strands after hours of cooking (Chen & Chiou, 2013). Dried shark fin consists primarily of protein, with trace amounts of fat and carbohydrate and no significant source of omega-3 fatty acids. Because the fin itself is largely tasteless, its market value rests mainly on texture and status.

4. Food Safety & Health Risks (Mercury & BMAA)

4.1 Bioaccumulation in Shark Tissue

As long-lived apex predators, sharks accumulate environmental contaminants through biomagnification, where toxin concentrations increase up the food chain. Two contaminants of concern are mercury, primarily methylmercury, and β-N-methylamino-L-alanine (BMAA), a neurotoxin produced by cyanobacteria. A 2016 study of fin and muscle tissue from ten shark species across the Atlantic and Pacific detected both contaminants in every species sampled. Researchers noted that mercury and BMAA may act synergistically, meaning their combined neurotoxic effects could exceed those of either compound alone (Hammerschlag et al., 2016).

4.2 BMAA, Mercury, and Shark Cartilage Supplements

Exposure also extends to shark cartilage supplements marketed in traditional Chinese medicine for claimed health benefits. An analysis of sixteen commercial shark cartilage products found BMAA in fifteen, at concentrations from 86 to 265 micrograms per gram; mercury was also detected at lower concentrations (Mondo et al., 2014). BMAA exposure has been linked in scientific literature to neurodegenerative conditions such as Alzheimer's disease and amyotrophic lateral sclerosis (ALS), although a direct causal relationship in humans has not been established due to limited epidemiological data (Hammerschlag et al., 2016).

4.3 Comparison to Food Safety Guidelines

The U.S. Food and Drug Administration (FDA) sets an action level of 1 part per million (ppm) for mercury in fish intended for human consumption. Predatory species such as shark can exceed this threshold because of their position in the marine food chain. Consequently, the FDA and Environmental Protection Agency (EPA) advise pregnant women, nursing mothers, and young children to avoid shark. No equivalent guideline currently exists for BMAA, which remains less understood than mercury.

5. Food Fraud & DNA Authentication

The international trade in shark-derived food products is often opaque. Dried fins and processed meats move through complex global supply chains where species substitution, mislabelling, and trade in protected species can occur.

5.1 Vulnerability Drivers: Morphological Processing and Ambiguous Nomenclature

Shark products are vulnerable to fraud because processing removes external taxonomic traits. Decapitation, skinning, bleaching and boiling to isolate internal fin needles can make visual identification impossible (Marchetti et al., 2020). Permissive labelling also allows generic names such as flake or cação (Sharrad et al., 2023). Sharrad et al. (2023) found that 70% of sampled shark fillets failed to match standard trade designations or concealed threatened species.

5.2 Molecular Authentication Methodologies: Mitochondrial DNA Barcoding and Minibarcodes

DNA barcoding of the standardized 650 base pair mitochondrial cytochrome c oxidase subunit I (COI) gene can identify species (Marchetti et al., 2020). However, drying, bleaching and cooking degrade DNA into shorter fragments, causing standard primers to fail (Cardeñosa et al., 2017). Researchers therefore developed minibarcode assays targeting short diagnostic fragments within COI and NADH2 genes, allowing species identification from degraded fins, powders and cooked soups (Cardeñosa et al., 2017; Marchetti et al., 2020).

5.3 Conservation, Regulatory and Public Health Consequences

Mislabelling can allow illegal catches to bypass CITES Appendix II restrictions, enabling threatened hammerheads and silky sharks to enter markets undetected (Cardeñosa et al., 2017; Sharrad et al., 2023). Shark meat may also be substituted for valuable fish such as swordfish (Eppley & Coote, 2025). Because predatory sharks bioaccumulate methylmercury and BMAA, fraudulent sales can also increase consumer exposure to neurotoxic contaminants (Marchetti et al., 2020).

6. Conservation Status & Regulation

Extracting elasmobranchs for luxury culinary markets has caused severe marine defaunation. Addressing this crisis requires assessing population declines and closing regulatory loopholes.

6.1 Global Conservation Trajectories and Extinction Risk

Commercial fishing has caused major population declines. Pacoureau et al. (2021) reported a 71% decline in oceanic shark and ray abundance since 1970 alongside an eighteenfold increase in fishing pressure, leaving three quarters of pelagic species threatened with extinction. Dulvy et al. (2021) found that 37.5% of all chondrichthyans face extinction risk, with overfishing as the primary driver. Slow reproductive growth and low fecundity make recovery difficult under continued harvesting.

6.2 International Trade Governance and Regulatory Limitations

CITES Appendix II listings have prompted exporting nations to establish management frameworks and export quotas (Bond et al., 2025). However, Worm et al. (2024) found that global shark mortality increased from 76 to 80 million individuals annually between 2012 and 2019 despite anti-finning rules. Requirements for whole-carcass landings have also stimulated markets for shark meat, showing that trade regulations need to be supported by catch limits and landing-site monitoring (Bond et al., 2025; Worm et al., 2024).

7. Conclusion

The shark-fin issue connects marine conservation, food authentication and public safety. Market fraud can conceal the trade of endangered species while exposing consumers to bioaccumulated contaminants. Addressing population declines requires combining fisheries catch limits, DNA-based authentication and transparent labelling to improve consumer safety and protect marine ecosystems (Dulvy et al., 2021; Pacoureau et al., 2021).

8. Potential Exam Question

Question: Why is shark fin considered especially difficult to authenticate compared to most other traded seafood products?

a) Shark meat spoils faster than other fish

b) Fins are usually removed, dried, and sold under generic labels before species can be identified visually

c) Sharks have no distinguishing physical features between species

d) DNA testing does not work on cartilage-based tissue

Correct answer: (b)

Explanation: This question should be included on the final exam because it connects two ideas from the course: food fraud/authentication and conservation biology. Before researching this project, our team assumed mislabeling was mostly a matter of dishonest sellers; we were surprised to learn that the physical process of finning itself, which strips away the features needed for species identification, is what makes fraud so hard to detect and enforce against in the first place. Understanding this distinction is directly relevant to how food scientists use tools like DNA barcoding to solve real supply-chain problems, which is a core theme of FNH 200.