Sponges have been identified as natural samplers of environmental DNA (eDNA) due to their filter feeding behaviour. This natural sampler DNA (nsDNA) has been obtained from opportunistic sponge samples previously collected for other purposes, and in controlled laboratory conditions to understand how nsDNA compares to aquatic eDNA methods. Yet there have still been few attempts to practically assess the effectiveness of sponges for monitoring coastal biodiversity. Here we compare traditional underwater visual census (UVC) surveys, aquatic eDNA, and sponge nsDNA to monitor diurnal fish assemblages in a marine protected area (Dafni Beach, Zakynthos, Greece) and an area of significance to tourism and culture (Korakonissi, Zakynthos, Greece). Differences in fish assemblages were apparent across the three methods. Invasive species could be detected across the three methods but only the common and very established <em>Siganus</em> spp were recorded by UVC. We found that some sponge species were less effective as natural samplers, but the ubiquitous and accessible nature of these organisms make them powerful and cost-effective solutions for monitoring MPAs, especially where the labour and taxonomic expertise required by UVC and field expertise required by eDNA are not easily available.

Primary Presenter: Erika Neave, Liverpool John Moores University (e.f.neave@ljmu.ac.uk)

Authors:

Erika Neave, Liverpool John Moores University  (e.f.neave@ljmu.ac.uk)

Peter Shum, Liverpool John Moores University  (p.shum@ljmu.ac.uk)

Charalampos Dimitriadis, National Marine Park of Zakynthos  (xdimitriadis@marine.aegean.gr)

Ana Riesgo, Museo Nacional de Ciencias Naturales de Madrid  (anariesgogil@gmail.com)

Stefano Mariani, Liverpool John Moores University  (s.mariani@ljmu.ac.uk)