Environmental DNA (eDNA) offers a way to characterise marine biodiversity and assist fisheries management at unprecedented scales and accuracy, and with barely no damaging impacts on marine life or habitats. This theme session represents a milestone in DNA-enhanced fisheries science, by focusing on the range of eDNA applications that have direct relevance to our understanding of the dynamics of exploited stocks and the broader processes that underpin sustainability of marine resources. The session will showcase the recent progress made through the integration of eDNA methods with concepts and challenges pertaining to fisheries sciences.
Session format
The conveners will set the scene and introduce the session, including a summary of the strands explored by the contributors to this session.
The rest of the session will be an open discussion based on the “SWOT" approach to understanding and shaping the future synergies between eDNA and fishery sciences. The aim is to evaluate the intrinsic/internal Strengths (S) and Weaknesses (W) of eDNA science in this context, as well as investigate the external Opportunities (O) and Threats (T) associated with the broader world of fisheries science and practice. We will use a live “dynamic whiteboard" to identify concepts and actions that fit with the S. W. O. T. framework and hopefully reach a coherent vision to guide future efforts in this burgeoning field.
Background
Increasingly nimble and affordable DNA sequencing technologies have underpinned the recent explosion of a novel, simple and elegant approach to assess ocean biodiversity, based on the retrieval and screening of the DNA invariably present in the water column. This DNA is released by organisms through various processes (shedding, excretion of fluids, spawning) and is referred to as 'environmental DNA' (eDNA). While caveats and limitations may punctuate the development of this burgeoning field, its many advantages, in terms of power, accuracy and transferability, are undeniable. Furthermore, eDNA analysis offers a way to study marine biodiversity with minimal impacts on organisms and habitats. Environmental DNA has indeed been shown to detect a greater spectrum of taxonomical diversity per unit effort than traditional visual and capture-based methods. It has also proven highly effective at: tracking rare, elusive and invasive species; characterizing spatial and temporal patterns across different scales and habitats; capturing functional diversity features and prey-predator associations; and it even appears suitable to infer relative abundances. Consequently, eDNA methods have elicited a level of enthusiasm and intake among ecologists and environmental biologists that is unparalleled in the history of genetics and molecular biology.
Fisheries science is one key arena where eDNA analysis has entered the frame, with several authors suggesting that DNA-based approaches can have beneficial impacts on fisheries management. In particular, eDNA methods can integrate scientific surveys to expand our knowledge on data poor stocks, provide greater resolution of spawning grounds and timing than capture methods, and potentially contribute to stock delineation. Furthermore, fishing vessels are being increasingly touted as wide-ranging sentinels that can bolster marine biodiversity monitoring through data collection, which could include eDNA sampling. Nevertheless, there is still considerable confusion as to what eDNA can/cannot do in the context of fisheries, and what avenues are most likely to lead to effective and robust applications.
