Fifteen years of extensive and inadvertent elasmobranch trade in Brazil detected by DNA tools

Abstract

The trade of elasmobranchs (sharks and rays) in Brazil raises significant concerns due to the country's rich endemic biodiversity. The present study explores the use of DNA-based tools to monitor the Brazilian elasmobranch trade, focusing on their role in identifying processed products and supporting conservation efforts. A systematic search of literature was carried out and included 35 peer-reviewed articles published between 2008 and 2023. We observed a shift in research focus since 2015 from the development of DNA-based tools to direct trade application. Molecular identification challenges, including costly sequencing and limited resources in national databases, were identified along with proposed solutions, such as protocol optimization and exploration of cost-effective alternatives. Biases in trade analysis papers, particularly a lack of research in the Northeast region of Brazil, as well as issues with sample sizes were evident. Species identified using DNA-based tools included the critically endangered Scalloped Hammerhead Shark (Sphyrna lewini), appearing in 46% of the evaluated papers, followed by the Blue Shark (Prionace glauca), and several others threatened species, including the critically endangered endemic Brazilian Guitarfish (Pseudobatos horkelii) and the recently categorized vulnerable Sharpnose Shark (Rhizoprionodon porosus). Other species were reassessed, including previously non-threatened species that are now at risk, emphasizing the need for conservation measures. Our findings highlight the importance of continuing genetic monitoring of shark and ray trade in Brazil, calling for conservation efforts and law enforcement to protect elasmobranch populations, and recommending strategies for accurate species identification, expanded research, and effective management.

Mitochondrial genome structure and composition in 70 fishes: a key resource for fisheries management in the South Atlantic

“…The study and resource building for DD and NT species should be a conservation priority, since the DD status may represent an already threatened species without human knowledge, whilst NT represents species that are close to endangered categories. It has been shown that shark and ray species that were previously classified as DD and NT have now become threatened [58]. Another conservation gap that many Latin American fisheries resources face is the lack of assessment of species conservation status.…”