Abstract
BackgroundPoorly regulated international trade in ornamental fishes poses risks to both biodiversity and economic activity via invasive alien species and exotic pathogens. Border security officials need robust tools to confirm identifications, often requiring hard-to-obtain taxonomic literature and expertise. DNA barcoding offers a potentially attractive tool for quarantine inspection, but has yet to be scrutinised for aquarium fishes. Here, we present a barcoding approach for ornamental cyprinid fishes by: (1) expanding current barcode reference libraries; (2) assessing barcode congruence with morphological identifications under numerous scenarios (e.g. inclusion of GenBank data, presence of singleton species, choice of analytical method); and (3) providing supplementary information to identify difficult species.Methodology/Principal FindingsWe sampled 172 ornamental cyprinid fish species from the international trade, and provide data for 91 species currently unrepresented in reference libraries (GenBank/Bold). DNA barcodes were found to be highly congruent with our morphological assignments, achieving success rates of 90–99%, depending on the method used (neighbour-joining monophyly, bootstrap, nearest neighbour, GMYC, percent threshold). Inclusion of data from GenBank (additional 157 spp.) resulted in a more comprehensive library, but at a cost to success rate due to the increased number of singleton species. In addition to DNA barcodes, our study also provides supporting data in the form of specimen images, morphological characters, taxonomic bibliography, preserved vouchers, and nuclear rhodopsin sequences. Using this nuclear rhodopsin data we also uncovered evidence of interspecific hybridisation, and highlighted unrecognised diversity within popular aquarium species, including the endangered Indian barb Puntius denisonii.Conclusions/SignificanceWe demonstrate that DNA barcoding provides a highly effective biosecurity tool for rapidly identifying ornamental fishes. In cases where DNA barcodes are unable to offer an identification, we improve on previous studies by consolidating supplementary information from multiple data sources, and empower biosecurity agencies to confidently identify high-risk fishes in the aquarium trade.
Highlights
Globalisation in the form of international trade breaches biogeographical as well as administrative boundaries, enabling organisms to colonise regions beyond their contemporaneous natural ranges [1]
Conclusions/Significance: We demonstrate that DNA barcoding provides a highly effective biosecurity tool for rapidly identifying ornamental fishes
A total of 678 cyprinid fish specimens were collected during the study, and these were identified to 172 species in 45 genera using morphological characters
Summary
Globalisation in the form of international trade breaches biogeographical as well as administrative boundaries, enabling organisms to colonise regions beyond their contemporaneous natural ranges [1]. Biosecurity challenges exist in effectively monitoring and managing the complex pathways involved [1,7,8], with a key issue for risk assessment being the identification of traded biological materials to species [9,10,11] Effective cataloguing of both potential propagules (all traded species) and known invasive alien species, can inform risk analyses and facilitate pre- or post-border control measures (i.e., import restrictions and quarantine). In circumstances where species cannot be diagnosed by morphology and/or only certain life history stages can be identified, standardised molecular protocols for species identification are important for biosecurity [9,10,11] These techniques still require further testing and reference libraries need to be expanded to encompass more species. We present a barcoding approach for ornamental cyprinid fishes by: (1) expanding current barcode reference libraries; (2) assessing barcode congruence with morphological identifications under numerous scenarios (e.g. inclusion of GenBank data, presence of singleton species, choice of analytical method); and (3) providing supplementary information to identify difficult species
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
