Offshore wind turbines create all-you-can-eat havens where some fish can double in size

Certain species of fish can be up to two times bigger when living in protected offshore wind farm zones, a new study has found. 

Not only do the rough surfaces of turbine monopiles and submarine cables provide new habitats for sponges, corals, anemones and other sessile organisms, but that extra food source allows other creatures to thrive as well. 

“These benthic-dominated [ocean flora and fauna that live close to the seabed] ecosystems are critical for nutrient cycling, diversifying food webs and even storing carbon,” said Murdoch University emeritus professor Neil Loneragan, a coauthor on the paper in Global Ecology and Conservation.

“The results from the paper are very encouraging – they show wind turbines create a different localised marine environment with many positive attributes.”

The paper, by researchers from Murdoch and Dalian Ocean universities, compared data from the Zhuanghe offshore wind farm in China’s northern Yellow Sea with a control area without turbines around 6km east across 2023 and 2024.

It was built between 2019 and 2021 and is the largest offshore wind project in northeast China, with an installed capacity of 1.35  gigawatts (GW).

They fed Ecopath with Ecosim software models with biological and environmental survey data collected from the Zhuanghe wind farm and a nearby control area without any offshore wind activity.

What they found were more groups and more complexity in the oceanic food chain, especially for macroinvertebrates and fish, as seabed creatures had new surfaces to colonise, from footings to the gravel around monopile bases to other subseas infrastructure to colonise. 

The relative total impact of each functional group for (A) Zhuanghe OWF and (B) the control area in the northern Yellow Sea estimated by Ecopath software. Circle size shows the percentage relative biomass of each group.

Fat greenling fish were estimated to be twice as big in the offshore wind zone as out of it; the Korean rockfish was more than three times bigger, as is the predatory Asian rapa whelk. 

“Sessile organisms, such as the blue mussel Mytilus edulis and other suspension-feeding invertebrates colonized the monopiles in the OWF, constituted over 50 per cent of the total biomass,” the paper says.

“Most fish functional groups exhibited significantly greater biomass in the OWF area, particularly demersal [seabed-living] species, which is consistent with the findings from other studies and their suggestion that OWFs act as “fish aggregation devices”.

“For instance, our model showed that benthic fish biomass nearly doubled in the OWF area compared to the control area.”

And while the paper notes the risks created by exploration and construction, including habitat destruction and disturbances to birds, marine mammals and fish, it also notes that disrupting the seabed can stir up nutrients which adds to the food available. 

“Therefore, zooplanktivorous fish are more frequently observed within the OWF area, which likely contributes to the increased biomass of larger benthic and pelagic predators,” the paper says. 

“This increase could be linked to fishery restrictions in the OWF area, as relevant regulations often designate it as a no-take zone, thereby enabling it to function as a marine protected area that offers refuge to commercially targeted species.”

Overall, even though the researchers began collecting data just two years after the wind farm was finished, they still found signs that ocean life in the area is more stable, diverse and had more “functional integrity” than the control area nearby without turbines. 

If you would like to join more than 28,000 others and get the latest clean energy news delivered straight to your inbox, for free, please click here to subscribe to our free daily newsletter.