Often used for traditional medicinal purposes, as well as in Asian cuisine (such as the controversial shark fin soup), demand for shark fins and the gills of rays has demonstrated a steady growth since the 1980s. However, new research from the University of Guelph, Ontario, suggests that illegal and unreported catches far surpass the amount caught legally, making regulation and quota enforcement extremely difficult. Their estimates, using data from commercial trade, reveal the real statistics for shark catches worldwide are between 26 to 73 million sharks per year, three to four times greater than the figures provided by legal fisheries.
Using genetic materials and cutting-edge DNA barcoding technology, the researchers were able to assess dried fish from 129 market samples. Of those tested, 25 different species of shark and rays were identified, almost half of which are illegal to trade under the Convention on International Trade in Endangered Species of Wild Fauna and Flora agreement. In total, 80 per cent of traded species were classified as either ‘endangered’, ‘vulnerable’ or ‘near threatened’ on the IUCN’s Red List of Threatened Species.
One of the most surprising findings was the presence of ‘vulnerable’ whale shark gills in among the mobulid ray trade. ‘What is unclear is if this means that whale shark gills are also marketed for medicinal purposes,’ says Professor Mahmood Shivji, Director of the Guy Harvey Research Institute, Nova Southeastern University, Florida, and co-author of the research, ‘or if this finding is just a case of surreptitious substitution in the gill markets.’
The researchers behind the study are encouraging enforcement agencies to adopt this new DNA analysis technology in order to be able to better identify illegally imported dried and processed species.
This was published in the October 2017 edition of Geographical magazine.