NETFISH (FR)

Mon, 27 Oct 2025 00:00:00 +0000

In nature, animals never live in isolation: they interact with each other and with their environment. These interactions, sometimes direct (such as predation or competition), create cascading effects that influence the entire community. The ability of multiple species to coexist is therefore essential to maintaining the richness and stability of ecosystems. By studying how species use space, time, or resources, the concepts of ecological niche and niche partitioning have helped explain their capacity to live together and form a balanced ecosystem. That said, in the event of external disturbances, this balance could be disrupted at different biological levels, raising concerns for the conservation and management of ecosystems.

Due to its morphology, functioning, and status as a biodiversity hotspot concentrated primarily along the coastline, the Mediterranean appears particularly vulnerable to anthropogenic and environmental pressures. Studying the impact of such pressures on Mediterranean rocky reef ecosystems known for the key habitat functions they provide remains crucial. The results could provide marine park managers with valuable insights to address emerging challenges including marine heatwaves or the intensification of anthropogenic activities producing noise pollution.

Between June and August 2025 in the Anse de Sainte Catherine (southern France), twenty hydrophones intended for high-resolution telemetry were deployed in an area with heavy touristic activity during the summer period. 93 fish were tagged across 11 different species with an average size of 12 cm (min. 8.5 cm): Chromis chromis, Coris julis, Symphodus tinca, Spondyliosoma cantharus, Parablennius gattorugine, Symphodus ocellatus, Symphodus rostratus, Gobius cruentatus, Scorpaena notata, Scorpaena porcus, Muraena helena, Serranus cabrilla and Serranus scriba.

Objectives
The NETFISH project aims to understand how metacommunities in a rocky reef are structured by intra- and interspecific processes, across three objectives:

Understanding intraspecific behavioural interactions in two rocky reef species. Here, we will shed light on the spatial use, activity rhythms, and social organisation of two rocky reef fish populations: the damselfish Chromis chromis and the rainbow wrasse Coris julis.
Understanding interspecific behavioural interactions within our monitored community. This component will question how different species coexist and interact. By examining the spatial use and activity rhythms of each species, as well as the social organisation of the community, we will explore spatio-temporal niche partitioning.
Characterising the impact of external disturbances (noise pollution, marine heatwaves) on the community at the study site, drawing on a range of behavioural proxies (e.g. swimming speed, mobility, depth, and habitats used). The analysis will also address the intra and interspecific levels of resilience and adaptive capacity of the monitored fish community.

Project Partners

PhD student, Anaïs Laurioux, University of Montpellier, UMR MARBEC (France)
Dr. Johann Mourier, University of Montpellier, UMR MARBEC (France)
Dr. Jérome Bourjea, IFREMER, UMR MARBEC (France)
Dr. Frédéric Bertucci, IRD, UMR MARBEC (France)
Dr. Marc Besson, University of Sorbonne, (France)
Marine park of the Gulf of Lion (France)

Funding

Intra- and interspecific processes | 3D Fish Telemetry

NETFISH (FR)