Molecular Identification of Shark Meat Traded as Cação in Southwestern State of São Paulo, Brazil

Abstract

The meat of sharks and rays is commonly traded in Brazil under the generic name of cação. This compromises the monitoring of which species are being traded. In the present study, molecular marker techniques were applied to the species-level identification of elasmobranch meat traded in the southwest of the State of São Paulo. A total of 15 meats purchased in 2019 were partially sequenced (up to 655 base pairs) for the mitochondrial cytochrome c oxidase subunit I (COI) gene. Of these meats, 14 were from Blue Shark, Prionace glauca, and one from Shortfin Mako Shark, Isurus oxyrinchus. Only two (13,3%) out of the 15 cação meat were species identified on its product label – the other meat was only labeled as cação. Both shark meat that had the scientific name stated on the package label correctly corresponded to the species identification obtained through DNA sequencing. It is suggested that similar studies be conducted in other non-coastal regions of the country to further understanding of the cação trade in locations where elasmobranch consumption is not habitual. The present study was the first to detect the Shortfin Mako Shark sold as cação in Brazil.Keywords: DNA Barcoding, elasmobranch, molecular marker, conservation

Endangered shark species traded as “cação” in São Paulo during the COVID-19 lockdown: DNA-barcoding a snapshot of products

“…It is possible that a reduction in monitoring and enforcement during the COVID-19 lockdown might also have increased the trade of endangered shark species, potentially explaining the sale of threatened and prohibited species identified here. However, comparison to the results of Merten Cruz et al [23] and Queiroz et al [36] gathered before the lockdown did not show a significant difference in the species traded.…”

“…Blue shark was by far the most prevalent species identified in products (80%) included in this study. Other Brazilian studies have also identified P. glauca as the most commonly sold species, accounting for between 24% [12] and 93% [36] of products. The result is consistent with the fact that blue shark represents 49-90% of the total pelagic sharks captured by commercial longline fisheries [9,38], making this species the most common and widely traded shark in Brazil and internationally [24,39].…”

“…To explore the impact of COVID-19 lockdown on patterns of species commercialisation, a comparison was made between this study and two DNA barcode investigations conducted pre-pandemic [23,36]. No significant difference between the species traded pre-pandemic and during lockdown was demonstrated.…”

“…Conversely, longfin mako sharks are only sporadically recorded as caught by Brazilian longline fisheries and are frequently grouped with I. oxyrinchus and other shark species in fisheries monitoring data [48]. Mako sharks have rarely been identified in previous barcode investigations of shark products in Brazil [23,25,36]. These results suggest that mako sharks may be a more significant component of Brazilian shark meat trade than previously thought, including in the region of São Paulo.…”

“…To explore the impact of COVID-19 lockdown on patterns of shark product commercialisation, a comparison was made between the data gathered here and two recent prepandemic DNA barcoding studies investigating the trade of shark species in Brazil. This includes the work of Merten Cruz et al [23] who collected 55 shark samples along the Brazilian coastline in 2017, including 17 sourced in São Paulo State and Queiroz et al [36] who collected 15 products from within São Paulo State in 2019. These represent the closest investigations in terms of geographic and temporal scope (that were conducted before lockdown), for comparison to this study.…”