Stability of the relationships among demersal fish assemblages and environmental-trawling drivers at large spatio-temporal scales in the northern Mediterranean Sea
Bastien Mérigot, Jean-Claude Gaertner, Anik Brind’Amour, Pierluigi Carbonara, Antonio Esteban, Cristina Garcia-Ruiz, Michele Gristina, Taha Imzilen, Angélique Jadaud, Aleksandar Joksimovic, Stefanos Kavadas, Jerina Kolitari, Irida Maina, Porzia Maiorano, Chiara Manfredi, Reno Micallef, Panagiota Peristeraki, Giulio Relini, Mario Sbrana, Maria Teresa Spedicato, Ioannis Thasitis, Stefania Vittori, Nedo Vrgoc

Supplementary material

Trawling pressure and environmental changes may affect the composition of fish assemblages. Our knowledge on large spatio-temporal patterns of demersal fish composition remains incomplete for the Mediterranean Sea. We investigated (1) the spatio-temporal stability of demersal assemblages, (2) the relationships between these assemblages and potential structuring factors (trawling pressure and environmental conditions) in order to assess the dynamic of the assemblage structure at the scale of the northern Mediterranean Sea. We analysed a dataset of 18062 hauls from 10 to 800 m depth performed annually during the last two decades across 17 Geographical Sub-Areas (GSAs) (MEDITS program). A multi-table analysis (STATICO-CoA) evidenced a strong inter-GSAs stability in the organization of assemblages, with specificities for some GSAs. The most stable structuring factors were linked to combined gradients of chlorophyll a, phytoplancton carbon biomass and temperature, inversely correlated with depth, salinity and nutrient gradients (axis 1 of the STATICO-CoA compromise, 93.74% of the total variability). A common pattern linking the distribution of species to these environmental gradients was evidenced for most of the 17 GSAs. Estimate of trawling pressure showed a minor role in the organization of the assemblages for the spatial scale and years investigated (axis 2, 4.67%).

Keywords: species composition; stability; demersal assemblages; environment; fishing pressure; large scale; co-inertia analysis; STATICO-CoA
Contents of this volume Sci. Mar. 83S1 : 153-163 Back PDF
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