Emerging from the murk: threats, challenges and opportunities for the global swim bladder trade

Mitcheson, Yvonne Sadovy de; To, A; Wong, Nga Wing; Kwan, Hiu Yin; Bud, Wing Sum

doi:10.1007/s11160-019-09585-9

Cited by 49 publications

(46 citation statements)

References 47 publications

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“…3 and Additional le 1). According to previous studies, maws from Boesemania microlepis commonly have a spider body shape [10]. However, in contrast to S2, which matched Boesemania microlepis, S1 and S3 matched Bahaba taipingensis (Chinese bahaba) with a low percent similarity (95%).…”

Section: Discussionmentioning

confidence: 91%

“…However, sh maws from croakers are replaced by maws from other sh species intentionally or unintentionally because of the lack of effective methods for species identi cation and classi cation. This has caused confusion in the sh maw market [10,14]. In the present study, various kinds of sh maw samples with different trade names, prices, morphotypes and sources were collected, and species identi cation was successfully performed using mtDNA 16S rRNA nucleotide sequences.…”

Section: Discussionmentioning

confidence: 99%

“…In the present study, sample S41 had a darker colour than the other samples (see Additional le 1), and a musty odour was noted, which indicated that the failure of ampli cation of S41 may have been due to unsuitable long-term storage. In most cases, larger and thicker sh maws are preferred by consumers [10,26]. Therefore, some traders heat and melt small sh maws.…”

Section: Discussionmentioning

confidence: 99%

“…Family Sciaenidae (croakers) is a major taxon available in the medical sh maw market since most of the sh from family Acipenseridae are endangered and rarely observed. However, sh maws from non-croaker species such as eel, perch, cat sh and carp are also sold on the market to meet the increasing demand [10].…”

Section: Introductionmentioning

confidence: 99%

“…In most cases, not only the sh species but also the market name and price of sh maws is determined by traders based on ambiguous morphological characteristics. Identi cation depends on a trader's individual experience because there is no systematic approach with which to distinguish sh maws based on their morphological features [10]. In addition, for the purpose of long-term preservation, fresh swim bladders are placed in the sun and gradually turned to dry when making sh maws.…”

Section: Introductionmentioning

confidence: 99%

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Molecular Identification of Commercial Fish Maws using mtDNA 16S rRNA Nucleotide Sequences

Zhang¹,

Deng²,

Li³

et al. 2020

Preprint

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Background: Fish maws (dried swim bladders of fish) have long been used as a medicinal material and valuable tonic food which are very popular in Southeast Asia. It is difficult to identify the original species of fish maws sold on the market due to a lack of taxonomic characteristics. The present study aims to investigate the origin of commercial fish maws using DNA sequencing based on a partial sequence of the mtDNA 16S rRNA gene.Methods: Mitochondrial genomic DNA was extracted from a total of 44 individual fish maw samples collected from different markets by a QIAamp® DNA Mini Kit. The fragments of the 16S rRNA gene were amplified by PCR and bidirectionally sequenced using an ABI 3730 genetic analyser. Sequence assembly was performed with DNASTAR SeqMan software, and the resulting sequence was compared with reference sequences in GenBank using BLAST. Interspecific divergence and intraspecific variation were calculated by the Kimura 2-parameter model. Sample sequences were clustered in MEGA 6 using a neighbour-joining tree.Results: Forty-two of 44 fish maw samples were sequenced successfully. Fourteen taxa matched known fish species in the DNA sequence database, and 10 of them were supported by high homogeneity (99-100%). According to the results, 88% of the total samples belonged to family Sciaenidae. The clustering and genetic distance results, including in-group divergence and out-group divergence, indicated conﬁdence in species identiﬁcations. Moreover, there was no strict correspondence between the commercial names provided by traders and the origin of the fish maws. This study also found a probable correlation between the molecular characteristics and morphological features of fish maws from croakers and non-croakers.Conclusion: In this study, DNA sequencing based on mtDNA 16S rRNA was carried out successfully to identify the origin of ~95% of the samples. This result indicated that 16S rRNA is a suitable barcode for identifying fish maws. The identification results allowed us to learn more about the fish species available in the fish maw market in Guangdong-Hongkong-Macao Great Bay. In addition, the association between trade category and species found in this study provides both consumers and merchants with an important reference for identifying the origin of fish maws.

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Section: Discussionmentioning

confidence: 91%

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Molecular Identification of Commercial Fish Maws using mtDNA 16S rRNA Nucleotide Sequences

Zhang¹,

Deng²,

Li³

et al. 2020

Preprint

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Conservation of Estuarine Fishes

Cowley¹,

Tweedley²,

Whitfield³

2022

Fish and Fisheries in Estuaries

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Is the demand for fish swim bladders driving the extinction of globally endangered marine wildlife?

Smith,

Mansur,

Shamsuddoha

et al. 2023

Aquatic Conservation

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International trade in croaker swim bladders or maws and incidental catches in fisheries targeting croakers for their maws pose a global problem that needs addressing to protect target croakers and globally threatened small cetaceans, sharks, rays and marine turtles. The lesson of the likely imminent extinction of the vaquita porpoise (Phocoena sinus) in the Gulf of California, Mexico, owing to entanglement in gillnets targeting the totoaba croaker for its maw, is that the underlying threats to marine species must be addressed well before precipitous declines make their extinction inevitable. Opportunistic interviews with fishers and fish traders in Bangladesh indicate that the increasing demand for fish maws, selling for as much as 5,000 USD per kg, may be intensifying small‐scale coastal fisheries and bycatches of globally threatened marine wildlife, especially due to the potential for a windfall profit. In 137 croaker catches made in gillnets, sharks were bycaught in 22%, marine turtles in 8% and rays in 3% of catches. Of particular concern were six bycatches of 125 Critically Endangered scalloped hammerhead sharks (Sphyrna lewini), 11 bycatches of 20 Vulnerable (VU) olive ridley turtles (Lepidochelys olivacea) and two bycatches of 13 VU longtail butterfly rays (Gymnura poecilura). A recent IUCN Motion for ‘Controlling and monitoring trade in croaker swim bladders to protect target croakers and reduce incidental catches of threatened marine megafauna’ recommends conducting an analysis on the impacts of the demand for and trade in fish maws on croaker species and threatened marine megafauna, regulating trade in fish maws through national laws and developing a potential proposal to list croaker species in the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES). To prevent species extinctions, additional measures focusing on fishery management will be needed.

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Emerging from the murk: threats, challenges and opportunities for the global swim bladder trade

Cited by 49 publications

References 47 publications

Molecular Identification of Commercial Fish Maws using mtDNA 16S rRNA Nucleotide Sequences

Molecular Identification of Commercial Fish Maws using mtDNA 16S rRNA Nucleotide Sequences

Conservation of Estuarine Fishes

Is the demand for fish swim bladders driving the extinction of globally endangered marine wildlife?

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