eDNA Techniques Reveal the Impact of Invasive Species on Endangered Fish Along the Mediterranean Coast of Spain (by Tessa Lynn Nester)

By Tessa Lynn Nester, PhD Candidate at Museo Nacional de Ciencias Naturales (CSIC) in Madrid, Spain and 2023 eDNA Collaborative Microgrant recipient

Hi! My name is Tessa and I’m a second-year PhD student, working on my doctoral thesis at the National Museum of Natural Sciences in Madrid, Spain. My current research focuses on the use of eDNA for detecting endangered and invasive fish species along the Mediterranean Coast of the Iberian Peninsula, with a particular focus on the Endangered Spanish toothcarp (Aphanius iberus) and the invasive Eastern mosquitofish (Gambusia holbrooki). We believe that the presence of the invasive mosquitofish has played a major role in the decline of Spanish toothcarp populations. For this reason, I am also conducting a diet study using eDNA metabarcoding to determine whether this negative impact is due to predation or to a competition for resources. 

 Water collection for eDNA sampling and metabarcoding in Valencia, Spain

So far, our results have revealed that predation may be likely, and that the invasive mosquitofish has expanded its range at an alarming rate. But we have many more samples to collect and analyze before we can come to any conclusions!

For this reason, I was delighted to receive a microgrant by The eDNA Collaborative this past June so that I can take a course on the latest and most relevant bioinformatic tools in conservation genetics. I’m looking forward to improving my skills in bioinformatics and applying this knowledge to my research.