Conclusion and perspectives
This study demonstrated that the dietary DNA metabarcoding of freshwater
scavenger shrimps offers a comprehensive and reliable snapshot of fish
assemblages in neotropical rivers. As the cost and speed of molecular
analyses continue to decrease, the relative ease of sampling and
processing makes this method particularly suitable for carrying out
rapid biodiversity assessments. Crustacean-derived dDNA likely provides
fine-scale, recent insights, making it a valuable tool for detecting the
localized ecosystem impacts of anthropogenic disturbances, such as
overfishing, gold mining, deforestation, or dam construction, on fish
communities along river networks. However, this should be seen as a
complement to traditional WFD approaches, as it does not provide data on
fish abundance, biomass or condition, which remain essential for
effective management. Additionally, the method’s ability to detect small
and elusive species could make it particularly useful for early
detection of invasive species or for monitoring rare native species that
are difficult to capture using conventional methods.