A new study finds that the illegal trade of fins from four threatened shark species persisted in the Hong Kong market from 2015 to 2021. The analysis uncovers a substantial discrepancy between international records of fin exports and reality, with implications for fisheries regulation and management. In 2013, five overexploited shark species were listed on Appendix II of the Convention on International Trade of Endangered Species (CITES): The scalloped hammerhead (Sphyrna lewini), smooth hammerhead (S. zygaena), great hammerhead (S. mokarran), oceanic whitetip (Carcharhinus longimanus), and porbeagle (Lamna nasus). Since then, unreported and uncertified exports of fins from the species have been illegal. Building upon their 2024 Science Advances study, which characterized the illegal trade of small-sized shark species’ fins in Hong Kong (see below), Diego Cardeñosa and colleagues have now examined the evolution of illegal fin trade for these five threatened species in the Hong Kong fin market over nearly a decade. First, they analyzed fin trimmings gathered from 2014 to 2021 and determined that fins from four of the five species – excepting the porbeagle shark – were notably common in the sample set. They scaled this ratio using a statistical model and determined these illegal fins remained ubiquitous in the market from 2015 to 2021. Their findings were at odds with trade records maintained by CITES, indicating rampant illegal trade activity. Next, Cardeñosa et al. estimated how many nations that do not report their species exports were likely contributing fins from the threatened species. They used “DNA zip-coding” to track the four traded species to their originating regions, including those near non-reporting nations. The authors argue it is highly unlikely that large exporters with global industrial fleets known to catch these species are not exporting their fins, citing China, Spain, and Taiwan as examples. They recommend stronger port state measures, implementation of species-level custom codes, and market surveillance through genetic monitoring to provide external support to CITES.

For reporters following research on the shark fin trade, a 2024 Science Advances study, coauthored by many of the same authors of the current study, reported that almost 75% of small-sized shark fins and fin trimmings come from smaller species traded in Hong Kong markets: https://www.science.org/doi/10.1126/sciadv.adq6214

An adult great white shark has just one predator: the orca. Until recently, orcas have only been observed regularly preying on these sharks in South Africa, where they usually prefer to hunt larger adults, which provide more food once caught. But now scientists have observed a specialist shark-hunting pod in the Gulf of California repeatedly targeting juvenile white sharks, flipping them upside-down and taking out their energy-rich livers to share with the pod. They could be taking advantage of a local shark nursery to hunt younger, less experienced individuals which are easier to catch and subdue.