DNA analysis of traded shark fins and mobulid gill plates reveals a high proportion of species of conservation concern

Abstract

Continuously increasing demand for plant and animal products causes unsustainable depletion of biological resources. It is estimated that one-quarter of sharks and rays are threatened worldwide and although the global fin trade is widely recognized as a major driver, demand for meat, liver oil, and gill plates also represents a significant threat. This study used DNA barcoding and 16 S rRNA sequencing as a method to identify shark and ray species from dried fins and gill plates, obtained in Canada, China, and Sri Lanka. 129 fins and gill plates were analysed and searches on BOLD produced matches to 20 species of sharks and five species of rays or – in two cases – to a species pair. Twelve of the species found are listed or have been approved for listing in 2017 in the appendices of the Convention on International Trade in Endangered Species of Fauna and Flora (CITES), including the whale shark (Rhincodon typus), which was surprisingly found among both shark fin and gill plate samples. More than half of identified species fall under the IUCN Red List categories ‘Endangered’ and ‘Vulnerable’, raising further concerns about the impacts of this trade on the sustainability of these low productivity species.

DNA analysis of a large collection of shark fins from a US retail shop: species composition, global extent of trade and conservation - a Technical Report from the Monterey Bay Aquarium

“…Our data bolster several recent retail market surveys that have also concluded that the shark fin market is highly diverse and highly endangered (Cardeñosa et al, 2018; Feitosa et al, 2018; Fields et al, 2018; Steinke et al, 2017). Steinke et al (2017) found 20 species in 72 shark samples from Vancouver, Canada. Fields et al (2018) found 59 species and 17 higher taxonomic groups when they monitored 3,952 samples from Hong Kong retail shops from 2014-2015.…”

“…Extensive capture of ocean-going sharks in long-line and net fisheries has led to the global collapse of many shark species (Baum et al, 2003; Nicholas K. Dulvy et al, 2008). However, the extent of the shark fin trade suggests that many other species are being similarly affected (Fields et al, 2018; Steinke et al, 2017). Recent assessments furthermore indicate some coastal shark populations have declined nearly 90% in the last 50 years (Martin et al, 2016).…”

“…Feitosa et al (2018) surveyed several retail fish markets in northern Brazil from 2014-2016, and from government inspections obtained in 2007, identifying 17 mostly regional and coastally-distributed species from 427 fins. In other cases, reliance on relatively small data sets [ n =72 in (Steinke et al, 2017)] may not show the complete spectrum of commercial species. Another issue is that short DNA sequences can sometimes fail to differentiate closely related species.…”

Use of mucus as a non‐invasive sampling method for DNA barcoding of stingrays and skates (batoid elasmobranchs)

“…Although batoids are not usually targeted commercially, incidental catches by artisanal and industrial fisheries worldwide are common and have contributed to the overexploitation of several species (Molina & Cooke, 2012). Additionally, some large stingrays (order Myliobatiformes), and guitarfishes and sawfishes (order Rhinopristiformes), are highly endangered due to the high commercial value obtained through the international (and mostly illegal) market for fins and gill plates (Couturier et al, 2011;Steinke et al, 2017).…”

Shark Finning and the Molecular Identification of Shark Species: Review and Perspectives

“…Methods such as protein electrophoresis [41,[44][45][46], restriction length polymorphisms (RFLPs) [39,42], PCR methods [40,[47][48][49][50][51][52][53], species identification using insertion-deletion regions (indels) [54], and the nucleotide sequencing approaches mainly focused on mitochondrial genes and commonly using the DNA barcoding methodology, such as presented by several studies [55][56][57][58][59][60][61][62][63][64][65][66][67][68][69][70]. Pank et al…”