Conservationists have concerns about fish health when man-made structures are introduced into marine ecosystems.
Norway’s Hywind Tampen is the largest floating wind farm in the world, and researchers wanted to monitor its impacts on saithe, tusk, and ling fish populations.
Specimens were collected from around the platforms and reference waters further away, and data about diet and condition were gathered.
Although there was little difference in the ling diet between the sites, those near the turbines showed lower body condition.
How field sampling is carried out around floating offshore wind infrastructure
Researchers looking for understanding about how floating wind platforms, anchors, and tethers affect ocean wildlife carried out field sampling at Hywind Tampen in the Norwegian North Sea.
The facility is miles offshore. The turbines are mounted on massive floating concrete spar foundations.
These are anchored to the ocean floor by heavy steel cables, and together, the infrastructure introduces artificial surfaces across the entire water column.
A total of 179 fish were collected. These were pelagic saithe (Pollachius virens), benthic tusk (Brosme brosme), and demersal ling (Molva molva). The fish were picked up directly around the turbine array and from wind farm-free reference sites miles away from the energy facility’s footprint.
Biologists logged each fish’s body length and weight and applied Fulton’s condition factor, which is an index used to measure stored body energy reserves.
While stomach samples were gathered during the study, they were largely empty and provided insufficient data for visual prey identification. Instead, researchers assessed potential diet and habitat shifts by analyzing carbon, nitrogen, and sulfur stable isotopes in ling muscle and liver tissues.
This allowed comparisons to be made between the baselines in the open ocean and wind energy zones.
Fish diets are consistent from the turbine arrays to the control locations
The analyses of the stomach contents and tissue showed that the diets of the turbine fish and control specimens were consistent.
Across all three species, their primary prey remained the same regardless of their distance away from the wind farm.
Saithe are fast swimmers that hunt pelagic crustaceans and small schooling fish in the upper water column. Benthic tusk and demersal ling like to feed closer to the seafloor, picking off bottom-dwelling invertebrates, crabs, and small groundfish.
These habits remained unchanged.
Submerged turbine bases are known to function as artificial reefs. They attract biofouling organisms and small prey, and eventually, larger species move in.
However, Hywind Tampen did not cause any major shifts in predators’ feeding choices, according to the Norwegian Institute for Water Research.
These data show that floating wind arrays do not fundamentally alter established feeding habits for wide-ranging fish populations in the North Sea, leaving overall prey consumption unchanged despite new submerged infrastructure.
Physiological mechanics behind ling body condition and management trade-offs
Despite eating similar prey, ling caught directly near Hywind Tampen turbines had significantly lower body condition scores than control fish.
Researchers observed lower condition factors and lower liver nitrogen-isotope values in ling at the Hywind Tampen offshore wind farm. It is a pattern that may indicate trade-offs between shelter access and diet provision.
Unlike open-water saithe, ling are bottom-dwelling predators that settle around hard underwater structures like anchor pads and mooring lines. Navigating turbulent water flows created by submerged cables requires constant swimming adjustments, which burns extra energy daily.
Stress affects metabolic rates
Low-frequency sound emissions and vibrations from spinning turbines can also raise chronic stress, elevating baseline metabolic rates.
When combined with competition for shelter among fish crowding around anchor sites, ling burn energy reserves faster than they restock them through feeding.
These findings reveal that floating wind developments create uneven physical trade-offs across different marine species. While mobile pelagic fish adapt easily, substrate-attached species face real bioenergetic strain.
As offshore wind projects expand globally, environmental planners must account for species-specific habitat needs during site reviews.
The full study can be found here: Andrews AJ and Brooks S (2026) Stable isotope insights into artificial reef effects of floating offshore energy structures in Norwegian North Sea codfishes. Front. Mar. Sci. 13:1743207. doi: 10.3389/fmars.2026.1743207
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