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

Abstract

International audienceAs 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, northwestern 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 km 2 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 key-stone 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

Trophic flow structure of a neotropical estuary in northeastern Brazil and the comparison of ecosystem model indicators of estuaries

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Marine Renewable Energy in the Mediterranean Sea: Status and Perspectives

“…Similar surveys have been presented in [279] in order to quantify fishermen's perception in Ireland and the UK [280]. Other concerns regarding the impacts on fish behavior patterns and trophic web functioning have been described in [281,282], respectively. Despite the concerns discussed above, results reveal a generally positive attitude (70% of fishermen) towards the coexistence of fisheries and MRE projects.…”

A network meta‐analysis of threats to South American fish biodiversity

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“…Trait-based approaches from the individual to the ecosystem level could be a good starting point for solving open questions about biological invasions (Carvalho, 2018) and climate change (Strayer, 2012) in fresh waters and marine environments. Also, works evaluating food web interactions can be useful in predicting long-term tendencies in fisheries (Libralato & Agnetta, 2019) and climate change (Ainsworth et al, 2011;Villasante et al, 2016) and the short-term aspects of anthropogenic stressors on the environment (Ainsworth & Mumby, 2015;Raoux et al, 2017).…”