Can marine conservation really benefit from environmental DNA?

The analysis of trace DNA retrieved from seawater has recently come to the fore as a potentially game-changing tool for marine biodiversity assessment and monitoring. Superficially, the idea of recording species presence (and... [ view full abstract ]

The analysis of trace DNA retrieved from seawater has recently come to the fore as a potentially game-changing tool for marine biodiversity assessment and monitoring. Superficially, the idea of recording species presence (and relative abundance) from vast stretches of the marine environment, based on the retrieval of tiny molecules isolated from generally small volumes of water can induce scepticism. Yet, several studies are now showing that this is a real possibility, with environmental DNA (eDNA) typically showing a significantly greater detection-per-effort ratios than traditional capture-based methods. Nevertheless, what remains unclear is whether, and to what extent, eDNA screening can be of use in marine conservation management.

Here, we present empirical data from several coastal marine habitats around Britain, demonstrating fish eDNA detection performance between two and four times greater than established netting techniques. We also caution against issues related to sequence databases, sampling methods and data interpretation, which currently hinder the applicability of eDNA for marine conservation, and discuss existing mitigation strategies and prospective targets that will transform eDNA science into an effectively applied conservation tool.