Introduction
When WWF Peru approached us to help survey six aquatic species including Amazon manatees, pink river dolphins and migratory catfish along the Marañon river in the Northern Peruvian Amazon as part of their Healthy Rivers programme, we knew that our aquatic eDNA service would prove an invaluable resource. Traditional methods would have meant conducting separate surveys for each species, but with eDNA they could all be surveyed together, along with the rest of the vertebrate fauna – saving money and time. Just three trips later, we delivered a comprehensive set of data to WWF covering a vast array of aquatic and non- aquatic species, including 375 fish, 155 mammals and 65 birds.
With NatureMetrics’ innovative aquatic eDNA service, we were able to fully achieve our goal of determining the spatial distributions of six culturally and commercially important aquatic species along the Marañon river, and we exceeded our goal by also detecting hundreds of additional vertebrate species, which we can now start to take into account in designing a sensitive index of basin health.
Without eDNA and NatureMetrics, we would have been restricted to visual surveys for river dolphins alone, itself requiring more field time than the eDNA survey. We would have been limited to opportunistic interviews for the other five target species, which are less reliable, auditable, and systematic. The hundreds of other species detections would not have been possible at all.
The mammals we found included 100 nonaquatic species:
Over half the species detected were fish – which is what we would expect as fish shed lots of DNA and the Amazon has the highest diversity of freshwater fish in the world.