Mangroves are equally – some would argue even more – important than coral reefs when it comes to the services we receive from them, yet they are afforded much less protection in comparison. Increasing the knowledge on the extent to which reef organisms use mangroves will add to the pressure to protect them. My PhD will use the power of environmental (e)DNA to study the connectivity between mangroves and their adjacent coral reef habitats, by examining and analysing the genetic contents of water samples collected in Opwall’s marine site in Tela, Honduras. A single litre of seawater can contain genetic material from hundreds of different species from bacteria to megafauna. In aquatic environments, eDNA is most often intracellular, contained within shed skin cells, faeces or mucus, and research has shown it degrades beyond detection within a maximum of two weeks. This makes eDNA a very powerful tool for characterising communities, as it gives a reliable snapshot of life present in an environment, without the need to physically observe the animals. By collecting samples at least twice a year we hope to uncover any seasonal patterns of habitation. Although I will be focusing mainly on fish species, I will use techniques aimed at detection of a variety of taxa to get a more comprehensive picture of the overall biodiversity in both systems – and if/how they overlap.