Nina Prasil-Delaval1, 2, David Mouillot3, Eric Feunteun1, Gaëlle Legras2, Amandine Avouac3, Laure Velez3, Quentin Ternon1, Anthony Maire4, Valentin Danet2, Pierre Thiriet2
1BOREA (MNHN, CNRS, IRDSUUCN, UA), France - 2PatriNat (OFB, MNHN, CNRS, IRD), France - 3MARBEC (IRD, Ifremer, Université de Montpellier, CNRS), France - 4EDF R&D, France
Coastal reef fish assemblages have been studied for decades because of their important role in providing multiple key contributions to nature and people worldwide. These contributions are primarily driven by diverse fish traits, yet the environmental and anthropogenic drivers that shape the functional structure of reef fish assemblages at different scales are still poorly known. Furthermore, knowledge on reef fish ecology is heterogenous at the European scale especially in the Northeast Atlantic Ocean, while the Mediterranean Sea has been rather well studied to this day.
To address this issue, an important fieldwork effort was deployed for the past years to sample reef fish assemblages along the French Atlantic coast, using several sampling methods. We focus here on the use of Underwater Visual Census (UVC) and metabarcoding of environmental DNA to study reef fish assemblages off the Atlantic coast of France. By analyzing data collected with these two methods, we bring new knowledge regarding French Atlantic reef fish assemblages and the spatial distribution of the species that compose these assemblages and determine their functional structure. We also showcase the complementarity of these two methods to characterize reef fish assemblages in this data deficient region. Their combination allows the assessment of different metrics characterizing the functional structure of reef fish assemblages. The spatial patterns of these metrics will be explained by a set of environmental and anthropogenic factors.
In this communication, we will present the preliminary results of our study, that confirm our working hypotheses regarding the complementarity of both methods, as eDNA brings new insights in species distribution at the biogeographical level, while UVC provides quantitative metrics that improves comprehension of the vertical structure of reef fish assemblages, depending on depth and habitat structure, highlighting habitat preferences of reef fish species at finer scales.
Biography
As a PhD student, Nina Prasil—Delaval focuses her research on temperate reef fish assemblages in the North-East Atlantic Ocean and the Mediterranean Sea. She aims to contribute to the methodological development of their observation and monitoring in these two marine regions through the development of a long-term monitoring strategy, based on the combination of 3 complementary methods (UVC, BRUV and eDNA metabarcoding) and the development of bioindicators.