Low Genetic Diversity and Complex Population Structure in Black Piranha ( Serrasalmus rhombeus ), a Key Amazonian Predator

A groundbreaking study reveals the black piranha (Serrasalmus rhombeus), a keystone predator in the Amazon basin, exhibits alarmingly low genetic diversity and signs of inbreeding across half of its surveyed sites within the Central Amazon Conservation Complex. Despite its ecological significance, this species lacks conservation attention, with no regulatory framework or strategies currently in place. Researchers analyzed 248 samples from 14 tributaries using Genotyping-by-Sequencing, uncovering complex population structures influenced more by historical events than contemporary factors. Surprisingly, the study also identified higher dispersal capacity and potential cryptic species, highlighting the need for urgent conservation action to protect this vital Amazonian predator.

Thomas, A., Sylvain, F.-É., Normandeau, E., Leroux, N., Holland, A., Val, A. L., & Derome, N. (2025). Low Genetic Diversity and Complex Population Structure in Black Piranha ( Serrasalmus rhombeus ), a Key Amazonian Predator. Ecology and Evolution, 15(2). Portico. https://doi.org/10.1002/ece3.70824