Sharks in hot soup: DNA barcoding of shark species traded in Singapore

Liu, Celine J.N.; Neo, Shu Hui; Rengifo, Nathalia M.; French, Ian; Chiang, S.L; Ooi, Mathias; Soon, Nathaniel; Yeo, Jing Ying; Bungum, Haaken Zhong; Ota, Kurumi; Koul, Arina A.; Poh, Yan Hong; Wainwright, Benjamin J.

doi:10.1016/j.fishres.2021.105994

Cited by 22 publications

(16 citation statements)

References 12 publications

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“…Our samples constitute a more diverse collection of nine species of shark, possibly indicating that the pet food industry in the United States and Asia is supported by different supply chains. Like Cardeñosa (2019), we found the blue shark, Prionace glauca, in our samples, and other barcoding work performed in Southeast Asia has shown a high occurrence of the blue shark in the fin trade (Wainwright et al, 2018;Liu et al, 2021). Despite being one of the most frequently traded species in Hong Kong (Fields et al, 2018(Fields et al, , 2020, the blue shark is not listed under CITES Appendices I or II and is only listed as near threatened on the IUCN red list.…”

Section: Discussionsupporting

confidence: 46%

“…Blue sharks do appear to be a victim of increasing fishing effort and are widely identified in the fin trade throughout Southeast Asia, and scientific evidence already suggests that blue shark fishing should be regulated (Simpfendorfer and Dulvy, 2017). This apparent high fishing pressure may warrant a greater degree of protection and justify listing blue sharks on the IUCN Red List and inclusion on the CITES Appendix II (Liu et al, 2021). The second most encountered shark in our pet food was the silky shark (C. falciformis).…”

Section: Discussionmentioning

confidence: 98%

“…To circumvent these challenges, a number of minibarcoding techniques have been developed which use only a small fragment (100-200 bp) of the original gene (Hajibabaei et al, 2006;Meusnier et al, 2008;Shokralla et al, 2015), and a shark-specific mini-barcode has been developed to allow DNA amplification from challenging or degraded samples (Cardeñosa et al, 2017). These shorter fragments can be used to successfully make shark species' identifications in highly processed products and samples, such as dried fins, shark liver oil, and environmental DNA (eDNA; Wainwright et al, 2018;Ip et al, 2021;Liu et al, 2021).…”

Section: Introductionmentioning

confidence: 99%

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DNA Barcoding Identifies Endangered Sharks in Pet Food Sold in Singapore

French

Wainwright

2022

Front. Mar. Sci.

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Shark populations have declined by more than 70% over the past 50 years. These declines have largely been attributed to increases in fishing efforts. Despite increased public awareness surrounding the conservation of sharks, three-quarters of all oceanic shark species are currently considered at risk of extinction. Here, we use DNA barcoding to identify shark DNA found in pet food purchased within Singapore. We identified a number of sharks that have some degree of control over their trade exerted under the auspices of the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES), or through their classification as threatened by the International Union for Conservation of Nature (IUCN). The most commonly identified shark was the blue shark, Prionace glauca, a species that is not listed in CITES or classified as threatened by the IUCN, but one which scientific evidence suggests is overexploited and should have its catch regulated. The second most commonly encountered species was the CITES Appendix II listed silky shark, Carcharhinus falciformis. None of the products specifically listed shark as an ingredient, listing only generic terms, such as “ocean fish,” “white fish,” and “white bait.” The vague terminology used to describe pet food ingredients, and in some cases, the mislabeling of contents, prevents consumers – in this case, pet owners – from making informed and environmentally conscious decisions; consequently, pet owners and animal lovers may unwittingly be contributing to the overfishing of endangered sharks.

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Section: Discussionsupporting

confidence: 46%

Section: Discussionmentioning

confidence: 98%

Section: Introductionmentioning

confidence: 99%

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DNA Barcoding Identifies Endangered Sharks in Pet Food Sold in Singapore

French

Wainwright

2022

Front. Mar. Sci.

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“…This list includes species not necessarily threatened with extinction, but in which trade must be controlled in order to avoid utilization incompatible with their survival (CITES, 1994). Unfortunately, work from around the globe regularly shows that fins from CITES-listed sharks are traded within, and throughout many countries [ 7 , 9 , 10 ]. This trade is made possible and is extremely difficult to prevent because once a fin is removed from a carcass and processed for sale, the majority of the diagnostic features that can be used in visual identification are lost, then becoming nearly impossible to identify the species of shark to which a fin belonged without molecular methods [ 9 , 11 , 12 ].…”

Section: Introductionmentioning

confidence: 99%

What Is in Your Shark Fin Soup? Probably an Endangered Shark Species and a Bit of Mercury

Choy¹,

Wainwright

2022

Animals

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Shark fin soup, consumed by Asian communities throughout the world, is one of the principal drivers of the demand of shark fins. This near USD 1 billion global industry has contributed to a shark population declines of up to 70%. In an effort to arrest these declines, the trade in several species of sharks is regulated under the auspices of the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES). Despite this legal framework, the dried fins of trade-regulated sharks are frequently sold in markets and consumed in shark fin soup. Shark fins found in soups break down into a fibrous mass of ceratotrichia, meaning that identifying the species of sharks in the soup becomes impossible by visual methods. In this paper, we use DNA barcoding to identify the species of sharks found in bowls of shark fin soup collected in Singapore. The most common species identified in our samples was the blue shark (Prionace glauca), a species listed as Near Threatened on the International Union for Conservation of Nature (IUCN) Red List with a decreasing population, on which scientific data suggests catch limits should be imposed. We identified four other shark species that are listed on CITES Appendix II, and in total ten species that are assessed as Critically Endangered, Endangered or Vulnerable under the IUCN Red List of Threatened Species. Globally, the blue shark has been shown to contain levels of mercury that frequently exceed safe dose limits. Given the prevalence of this species in the examined soups and the global nature of the fin trade, it is extremely likely that consumers of shark fin soup will be exposed to unsafe levels of this neurotoxin.

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“…DNA can be obtained from a tiny piece of tissue and it is more resistant to degradation and food processing. Therefore, DNA-based authentication is being widely employed to identify species in seafood [15,21,[23][24][25][26][27][28][29][30].…”

Section: Introductionmentioning

confidence: 99%

Product Authentication Using Two Mitochondrial Markers Reveals Inconsistent Labeling and Substitution of Canned Tuna Products in the Taiwanese Market

Chang

Kao

Huang

2021

Foods

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Fish of the tribe Thunnini represent a significant proportion of the stock caught by the fishing industry, with many of these fishes being collectively called tuna. However, only certain species can be used legally as an ingredient in canned tuna products, depending on regional food regulations. In Taiwan, only Thunnus species or Katsuwonus pelamis can be used as canned tuna. Here, we authenticated 90 canned tuna products, including 25 cat food samples, by sequencing two mitochondrial regions, 16S rRNA (16S) and the control region (CR). BLAST analysis revealed that Sarda orientalis, Euthynnus affinis, Auxis rochei, and Auxis thazard are all used as substitutes for legitimate tuna products. We found that 63.33% of investigated samples are true canned tuna, i.e., contain Thunnus species or skipjack tuna. We advocate that the Taiwanese government publishes an official standardized list of fishes, especially so that scientific, Chinese and vernacular names can be assigned unambiguously based on a “one species-one name policy”, thereby clarifying which species can be used in seafood products such as tuna. Furthermore, we feel that the large-scale and long-term monitoring of canned tuna products is warranted to fully assess the extent of tuna product adulteration in Taiwan.

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Sharks in hot soup: DNA barcoding of shark species traded in Singapore

Cited by 22 publications

References 12 publications

DNA Barcoding Identifies Endangered Sharks in Pet Food Sold in Singapore

DNA Barcoding Identifies Endangered Sharks in Pet Food Sold in Singapore

What Is in Your Shark Fin Soup? Probably an Endangered Shark Species and a Bit of Mercury

Product Authentication Using Two Mitochondrial Markers Reveals Inconsistent Labeling and Substitution of Canned Tuna Products in the Taiwanese Market

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