Species composition of the largest shark fin retail-market in mainland China

Abstract

Species-specific monitoring through large shark fin market surveys has been a valuable data source to estimate global catches and international shark fin trade dynamics. Hong Kong and Guangzhou, mainland China, are the largest shark fin markets and consumption centers in the world. We used molecular identification protocols on randomly collected processed fin trimmings (n = 2000) and non-parametric species estimators to investigate the species composition of the Guangzhou retail market and compare the species diversity between the Guangzhou and Hong Kong shark fin retail markets. Species diversity was similar between both trade hubs with a small subset of species dominating the composition. The blue shark ( Prionace glauca ) was the most common species overall followed by the CITES-listed silky shark ( Carcharhinus falciformis ), scalloped hammerhead shark ( Sphyrna lewini ), smooth hammerhead shark ( S. zygaena ) and shortfin mako shark ( Isurus oxyrinchus ). Our results support previous indications of high connectivity between the shark fin markets of Hong Kong and mainland China and suggest that systematic studies of other fin trade hubs within Mainland China and stronger law-enforcement protocols and capacity building are needed.

Indo‐Pacific origins of silky shark fins in major shark fin markets highlights supply chains and management bodies key for conservation

“…However, all fins (e.g., dried, frozen) undergo some level of processing and trimming so it is unlikely that a random sample of fin trimmings would not detect at least some Atlantic silky sharks if they were present in these two markets. Additionally, endemic Atlantic shark species and populations have previously been detected in these markets through these, and similar, sampling efforts, arguing against this potential source of bias (Cardeñosa, Fields, Babcock et al, 2018;Cardeñosa, Fields, Babcock, Shea et al, 2020;Cardeñosa, Shea, Zhang et al, 2019;Fields et al, 2018;Fields et al, 2020). While our sampling in Hong Kong and Guangzhou was robust, there is a possibility that Atlantic silky shark fins from some parts of the basin are in the international trade but have supply chain end-points in other cities in China, or in other nations such as Singapore, Taiwan, Japan or Thailand.…”

“…The shark fin retail market of Guangzhou, China, comprises a large fourstory mall with mixed wholesale and retail shops with serial numbers, where shark fins and other highly priced traditional Chinese medicine products are sold. Every 2-3 months, from June 2015 to August 2017, 10 vendors were randomly selected from the complete shop list for each sampling event (Cardeñosa, Fields, Babcock, Shea et al, 2020). Two bags of processed shark fin trimmings were purchased from each randomly selected shop, yielding a total of 20 bags of trimmings per sampling.…”

“…Understanding the species composition of wildlife trade hubs can help identify the species most in need of conservation interventions; tracing the population-of-origin of these species then helps to identify the key management jurisdictions that can operationalize these interventions (Cardeñosa, Fields, Babcock et al, 2018;Chapman, Pinhal, & Shivji, 2010;Fields et al, 2018;Fields et al, 2020). While many genetic studies in Asian shark fin markets and South American and European shark meat consumption centers have elucidated priority species for conservation (Bunholi et al, 2018;Cardeñosa, Fields, Babcock et al, 2018;Cardeñosa, Fields, Babcock, Shea et al, 2020;Clarke, Magnussen, Abercrombie, McAllister, & Shivji, 2006;Fields et al, 2018;Hobbs, Potts, Walsh, Usher, & Griffiths, 2019), there has been far less application of genetic tracing of products in these hubs to source population-of-origin Chapman et al, 2010;Fields et al, 2020). Nonetheless, sharks frequently exhibit genetic population structure from the local to the ocean basin scale, which should enable product tracing of this kind assuming that a robust baseline of genetic diversity is mapped across the species distribution (Chapman, Feldheim, Papastamatiou, & Hueter, 2015).…”

“…A high proportion of pelagic sharks are overexploited due to high overlap with fishing fleets targeting tuna and the demand for their fins in Asia incentivizing retention of these ostensibly "by-catch" species (Cardeñosa, Fields, Babcock et al, 2018;Cardeñosa, Fields, Babcock, Shea et al, 2020;Clarke et al, 2006;Clarke, Harley, Hoyle, & Rice, 2012;Dulvy et al, 2008;Fields et al, 2018;Queiroz et al, 2019). Pelagic shark management is primarily under the purview of Regional Fisheries Management Organizations (RFMOs) that set regulations for migratory species fished by multiple nations at the ocean basin scale…”

Isotopic Tracers Suggest Limited Trans-Oceanic Movements and Regional Residency in North Pacific Blue Sharks (Prionace glauca)

“…Blue shark populations have declined broadly, with high longline bycatch and mortality rates due to extensive overlap with commercial fisheries across much of their global range (Queiroz et al, 2016(Queiroz et al, , 2019. This is true for the North Atlantic (50-79% decline over 30 years; ICCAT, 2015) and Mediterranean (96.5-99.8% decline since the early 19th century; Ferretti et al, 2008) populations as a result of both targeted fisheries (i.e., for fins, meat, squalene) and bycatch (Clarke et al, 2006a,b;Cardeñosa et al, 2020), though the North Pacific population has recently been assessed as not overfished (ISC, 2017). While studies have challenged model-based inferences of shark population declines (Burgess et al, 2005), blue sharks are the major bycatch species in high-seas fisheries regionally (McKinnell and Seki, 1998;Francis et al, 2001) and perhaps globally (Clarke et al, 2006b;Campana et al, 2009).…”