February 26, 2024

The secrets of the shark fin trade in Singapore

On the vibrant streets of Southeast Asia’s culinary landscape, amid the bustling fish markets where the smell of exotic delicacies fills the air, an undercover investigation into the world of the shark fin trade here has revealed shocking revelations.

Shark fins have long been prized as a delicacy and are woven into the cultural fabric of festive celebrations and health promotions in many Asian regions, such as Singapore. It is a sovereign city-state and island state in Southeast Asia, on the southern tip of the Malay Peninsula, just north of the equator. Singapore plays a crucial role in the complex network of the shark fin trade. Here, the fins are often exported in dried form and marketed with general terms such as ‘shark fin’ or ‘dried seafood’, rather than specifying the species of origin. This lack of specificity in labeling creates challenges in enforcing and monitoring trade as it can be ambiguous or deliberately vague. And that’s a huge problem, since two-thirds of the sharks involved in the global fin trade are endangered or come from declining populations. Despite growing awareness of the need for shark conservation, consumption of shark fin products remains rampant in Asia, contributing to a staggering $1 billion industry. Sharks’ slow growth, late sexual maturity, and low reproductive output make them particularly vulnerable to overfishing, disrupting entire marine ecosystems and causing trophic cascades.

Led by scientist Kai-Lin Selena Shen from YALE-NUS College, an international team collected 505 shark fin samples from 25 different local seafood and traditional Chinese medicine shops in Singapore. “Each species has a unique DNA sequence. Using this sequence, we then compare it to known species IDs and the associated DNA sequence – these are available in public databases such as BOLD or GenBank,” says co-author Benjamin John Wainwright. Using advanced DNA barcoding techniques, what they discovered was both astonishing and alarming: a whopping 27 different shark species, three of which are classified by the International Union for Conservation of Nature as critically endangered, four as endangered and ten as vulnerable. The top five most common species in this study was the dairy shark (Rhizoprionodon acutus; the most common), the silky shark (Carcharhinus falciformis), school shark (Galeorhinus galeus), scalloped hammerhead shark (Sphyrna lewini) and the smooth hammerhead (Sphyrna zygaena).

Do consumers know they are buying animals on the brink of extinction? It’s hard to know. But the scientists aren’t that surprised: “Unfortunately, this is not particularly surprising and is a pattern seen around the world.”

“The entire seafood supply chain is rife with opportunities for mislabeling and product substitution – more responsibility within global supply chains would help, but much of this fishing takes place far out at sea, or in provinces where resources are limited, so it is very easy to mislabel and any rules/regulations can easily be broken,” Wainwright explains. As a signatory of CITES, Singapore is required to prevent and control trade in regulated species across its borders. However, this task is challenging. Once a shark’s fin is removed and processed, it becomes nearly impossible to identify the species through visual methods alone. This is the core problem: fins are imported under general terms such as ‘dried seafood’, without specifying the species. Customs officials would have to visually inspect each fin and may have to resort to genetic techniques for identification, which is time-consuming and may not always be feasible. “How can you create policies and regulations to protect sharks if you have no idea about the species involved in the trade? In one box/bag/shipment you can have hundreds of species of sharks sourced from markets all over the world. It is a very big challenge to ensure that products are labeled correctly.”

This lack of accurate labeling not only hinders control efforts, but also poses a serious risk to consumers, potentially exposing them to unsafe levels of toxic metals. Sharks accumulate toxins at different rates, with pelagic species expected to have elevated mercury levels. The indiscriminate consumption of shark fins poses health risks to consumers, with reports of toxic metal concentrations above established safe limits. “Work we published last year shows significant differences in toxic metal concentrations between species and whether or not that species occurs in pelagic or coastal environments. Given this, accurate labeling and better supply chain accountability could help prevent the sale of species known to contain toxic metals above safe human consumption limits, Wainright says.

As traditional methods of species identification prove inadequate, DNA barcoding is emerging as a beacon of hope: “We hope to leverage advances in DNA sequencing technology and the ability to determine where a shark fin came from comes/was captured. Very similar techniques will be used in this work. to those used in human ancestry testing (e.g. 23andME, ancestry.com),” Wainright concludes. “We are working locally with other shark researchers in Singapore/Southeast Asia and have ongoing/upcoming projects that will investigate toxic metal concentrations in shark meat from sharks caught in the region. The shark meat trade is now even bigger than the fin trade, so understanding this trade is becoming increasingly important. We will also provide this trade with a DNA barcode to see which species are involved.”

As science advances, so do the prospects for change. With improved sequencing technologies and improved regulatory frameworks, the journey towards sustainable shark conservation is gaining momentum. By providing consumers with knowledge about the origins of species, governments can pave the way for informed choices, safeguarding both marine biodiversity and public health. The fate of sharks hangs in the balance, and only through informed choices, robust regulations and international cooperation can we hope to preserve the oceans’ top predators for generations to come.

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