![]() Recent advances in molecular technologies, in particular the emergence of high-throughput sequencing (HTS), are rapidly changing the way biomonitoring programmes are undertaken 13. However, the identification of cryptic or small juvenile life stages in situ or within complex samples remains challenging 11, 12. ![]() Morpho-taxonomy is particularly well suited for conspicuous organisms, such as macrofauna or macroalgae that can be readily identified. Current marine surveillance programmes largely rely on traditional morphological identification of NIS during visual surveys by divers and from biological samples collected by a variety of methods, including grabs, benthic sleds, trawls, and passive sampling devices such as settlement plates 8, 9, 10. Artificial substrata such as wharf piles and pontoons, which might be less attractive for native taxa, provide opportunistic NIS with vacant niches where they can settle and establish thriving populations 6, 7.Įarly detection of NIS is a critical factor to inform timely implementation of measures and allow the greatest chance of successful management 1. The ports and marinas where these vessels berth often act as hubs for the spread of NIS 5, 6. One of the major vectors responsible for the transfer of marine NIS is global shipping via ballast water 3 and hull fouling 4. Combining morpho-taxonomy and molecular analysis methods will likely enhance the detection of NIS from complex biofouling.īiological invasions of non-indigenous species (NIS) can cause severe economic and environmental impact contributing to biodiversity loss 1, 2. The data highlight several on-going challenges, including: differential marker resolution, primer biases, incomplete sequence reference databases, and variations in bioinformatic pipelines. Morpho-taxonomy detected an additional 14% of all identified NIS comprising mainly of bryozoan taxa. Metabarcoding detected the largest proportion of those NIS: 77% via 18S rRNA/PR2 and NCBI and 35% via COI/BOLD and NCBI. Using all methods, 48 potential NIS were identified. There were higher assignment rates to NCBI reference sequences, but poorer taxonomic identification. Highest resolution of metazoan taxa was identified using 18S rRNA assigned to PR2. In this study, the ability of morpho-taxonomy and metabarcoding (18S rRNA and COI) using three reference databases (PR2, BOLD and NCBI) to characterize biodiversity and detect non-indigenous species (NIS) in biofouling was compared on 60 passive samplers deployed over summer and winter in a New Zealand marina. Molecular tools, such as metabarcoding, may improve their detection. ![]() Cryptic organisms or those in early life stages can be difficult to distinguish by conventional morphological taxonomy. Marine infrastructure can favor the spread of non-indigenous marine biofouling species by providing a suitable habitat for them to proliferate. ![]()
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