DNA barcoding reveals the diversity of sharks in Guyana coastal markets

Abstract

A fundamental challenge for both sustainable fisheries and biodiversity protection in the Neotropics is the accurate determination of species identity. The biodiversity of the coastal sharks of Guyana is poorly understood, but these species are subject to both artisanal fishing as well as harvesting by industrialized offshore fleets. To determine what species of sharks are frequently caught and consumed along the coastline of Guyana, we used DNA barcoding to identify market specimens. We sequenced the mitochondrial co1 gene for 132 samples collected from six markets, and compared our sequences to those available in the Barcode of Life Database (BOLD) and GenBank. Nearly 30% of the total sample diversity was represented by two species of Hammerhead Sharks (Sphyrna mokarran and S. lewini), both listed as Endangered by the International Union for Conservation of Nature (IUCN). Other significant portions of the samples included Sharpnose Sharks (23% -Rhizoprionodon spp.), considered Vulnerable in Brazilian waters due to unregulated gillnet fisheries, and the Smalltail Shark (17% -Carcharhinus porosus). We found that barcoding provides efficient and accurate identification of market specimens in Guyana, making this study the first in over thirty years to address Guyana's coastal shark biodiversity.Keywords: BOLD, Carcharhinidae, Elasmobranch, Guianas, Sphyrnidae.Um desafio fundamental para a pesca sustentável e a proteção da biodiversidade nos neotrópicos é a identificação precisa das espécies. A biodiversidade dos tubarões costeiros da Guiana é pouco compreendida, porém essas espécies estão sujeitas tanto à pesca artesanal quanto à pesca industrializada não costeira. Para determinar quais espécies de tubarões são frequentemente capturadas e consumidas ao longo do litoral da Guiana, utilizamos DNA barcoding para identificar espécimes comumente encontrados e adquiridos em mercados. Nós sequenciamos o gene mitocondrial coI para 132 espécimes adquiridos de seis mercados e comparamos estas sequências com as disponíveis no Barcode of Life Database (BOLD) e GenBank. Quase 30% da diversidade total amostrada foi constituída por duas espécies de tubarões martelo (Sphyrna mokarran e S. lewini), ambas listadas como espécies ameaçadas pela UICN. Outras porções significativas da amostragem incluem Cações-Frango (23% -Rhizoprionodon spp.), considerados vulneráveis em águas brasileiras, devido a pesca de arrasto não regulamentada, e o Cação-azeiteiro (17% -Carcharhinus porosus). Descobrimos que o barcoding é uma forma identificação eficiente e precisa para espécimes de mercado na Guiana, tornando este estudo o pioneiro na documentação da biodiversidade dos tubarões costeiros da Guiana.

DNA-based identification reveals illegal trade of threatened shark species in a global elasmobranch conservation hotspot

“…However, the presence of so many species at risk of extinction in one of the most important fishing zones and elasmobranch conservation hotspots is a major concern both for conservation and the long-term sustainability of local fisheries. In Guyana’s coast, the western part of the elasmobranch conservation hotspot where BNC is classified 18 , thirteen shark species were identified using COI 36 , of which nine (~70%) are listed as either threatened, vulnerable or near threatened by IUCN. Only four species are not shared ( Isogomphodon oxyrhynchus , Mustelus canis , M .…”

Elasmobranch species in the artisanal fishery of Sucre State, Venezuela

“…In a different study carried out off Cubagua, also located in the northeastern region, Cordovés et al (2010) found that the most frequently captured ray species were H. guttatus (48.9%), Myliobatis freminvillei (18.0%), and H. americanus (15.7%). However, further to the east, between Trinidad and Tobago and Guyana, the most important species in commercial landings were R. lalandii and C. porosus (Shing 2006, Kolmann et al 2017. Altogether, these results show that sharks belonging to the genus Mustelus and rays belonging to the genus Hypanus are important elasmobranch groups in the northeastern region of Venezuela.…”

“…(18.0%) y H. americanus (15.7%). Por otra parte, más hacia la zona oriental, entre Trinidad y Tobago, y Guyana, las especies más importantes en las capturas comerciales fueron R. lalandii y C. porosus (Shing 2006, Kolmann et al 2017. Estos resultados, en su conjunto, muestran que los tiburones del género Mustelus y las rayas del género Hypanus constituyen grupos de elasmobranquios importantes en la región nororiental de Venezuela.…”

Does legislation affect elasmobranch conservation and research in Brazil? A case study from Paraná State

“…Although, there is a new, quick and cheaper version being used named ''Multiplex real-time PCR'' (<4 hours and $0.94 USD per sample), being capable to detect nine of the twelve sharks listed under CITES in a single reaction (Cardeñosa et al 2018), but still depends on a good workstation in field to support all the equipment's and a source of electricity to cover all these elements, prerequisites scarcely found in field of most regions of Brazil. Still, not all species are barcoded and available for comparison (Kolmann et al 2017). Some even cheaper alternatives are available such as the software's created to allow an accurate identification through the use of fins photos (e.g., iSharkFin).…”