Benthic and fish aggregation inside an offshore wind farm: Which effects on the trophic web functioning?

Type Article
Date 2017-01
Language English
Author(s) Raoux Aurore1, 2, Tecchio Samuele1, Pezy Jean-Philippe2, Lassalle Geraldine3, Degraer Steven4, Wilhelmsson Dan5, Cachera Marie7, Ernande BrunoORCID6, Le Guen Camille1, Haraldsson Matilda1, Grangere Karine1, Le Loc'h FrancoisORCID7, Dauvin Jean-Claude2, Niquil Nathalie1
Affiliation(s) 1 : INormandie Univ UNICAEN, BOREA MNHN UPMC UCN CNRS IRD207 CS 14032, UMR 7208, F-14000 Caen, France.
2 : Normandie Univ UNICAEN, M2C UCN UR CNRS, UMR 6143, 24 Rue Tilleuls, F-14000 Caen, France.
3 : UR EABX Aquat Ecosyst & Global Changes, IRSTEA, 50 Ave Verdun, F-33612 Cestas, France.
4 : RBINS, Operat Directorate Nat Environm OD Nature, Marine Ecol & Management MARECO, Gulledelle 100, B-1200 Brussels, Belgium.
5 : Royal Swedish Acad Sci, Box 50005, SE-10405 Stockholm, Sweden.
6 : IFREMER, Lab Ressources Halieut, 150 Quai Gambetta,BP 699, F-62321 Boulogne, France.
7 : IUEM, LEMAR CNRS UBO IRDIfremer, Lab Sci Environnement Marin, UMR 6539, Technopole Brest Iroise,Rue Dumont Urville, F-29280 Plouzane, France.
Source Ecological Indicators (1470-160X) (Elsevier Science Bv), 2017-01 , Vol. 72 , P. 33-46
DOI 10.1016/j.ecolind.2016.07.037
WOS© Times Cited 16
Keyword(s) Marine renewable energies, Reef effect, Wind farm, Ecopath with Ecosim, Ecosystem-based approach
Abstract As part of the energy transition, the French government is planning the construction of three offshore wind farms in Normandy (Bay of Seine and eastern part of the English Channel, north-western France) in the next years. These offshore wind farms will be integrated into an ecosystem already facing multiple anthropogenic disturbances such as maritime transport, fisheries, oyster and mussel farming, and sediment dredging. Currently no integrated, ecosystem-based study on the effects of the construction and exploitation of offshore wind farms exists, where biological approaches generally focused on the conservation of some valuable species or groups of species. Complementary trophic web modelling tools were applied to the Bay of Seine ecosystem (to the 50 km2 area covered by the wind farm) to analyse the potential impacts of benthos and fish aggregation caused by the introduction of additional hard substrates from the piles and the turbine scour protections. An Ecopath ecosystem model composed of 37 compartments, from phytoplankton to seabirds, was built to describe the situation “before” the construction of the wind farm. Then, an Ecosim projection over 30 years was performed after increasing the biomass of targeted benthic and fish compartments. Ecological Network Analysis (ENA) indices were calculated for the two periods, “before” and “after”, to compare network functioning and the overall structural properties of the food web. Our main results showed (1) that the total ecosystem activity, the overall system omnivory (proportion of generalist feeders), and the recycling increased after the construction of the wind farm; (2) that higher trophic levels such as piscivorous fish species, marine mammals, and seabirds responded positively to the aggregation of biomass on piles and turbine scour protections; and (3) a change in keystone groups after the construction towards more structuring and dominant compartments. Nonetheless, these changes could be considered as limited impacts of the wind farm installation on this coastal trophic web structure and functioning.
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Raoux Aurore, Tecchio Samuele, Pezy Jean-Philippe, Lassalle Geraldine, Degraer Steven, Wilhelmsson Dan, Cachera Marie, Ernande Bruno, Le Guen Camille, Haraldsson Matilda, Grangere Karine, Le Loc'h Francois, Dauvin Jean-Claude, Niquil Nathalie (2017). Benthic and fish aggregation inside an offshore wind farm: Which effects on the trophic web functioning? Ecological Indicators, 72, 33-46. Publisher's official version : https://doi.org/10.1016/j.ecolind.2016.07.037 , Open Access version : https://archimer.ifremer.fr/doc/00347/45843/