How would the proposed Humboldt offshore wind project affect fish and invertebrates?

Quillback rockfish (Sebastes maliger). Source: CDFW (6)

The main concerns (1) regarding impacts to fish and invertebrates are related to electromagnetic fields (EMFs) (2) and impacts (3) to the upwelling system. Some species of fish have been found to use magnetic fields during migration, while some species have been observed to have changed swimming speeds in their larvae due to EMFs (13). This study (14) as well as this study (21) noted no distinctive movement changes or effects on activity in crustaceans in high EMF zones and habitats. In regard to upwelling, “current evidence (15) suggests that turbine induced wind wake effects on upwelling are likely minimal” however, other effects from offshore wind infrastructure like localized turbulence may affect habitat and foraging conditions for fish.

There are also potential benefits to fish from offshore wind farms. On the East Coast, offshore wind turbine platforms are acting as artificial reefs (4) that enhance fish habitat. Some researchers have also theorized that, by reducing fishing, offshore wind farms can also benefit fish species in ways similar to a marine protected area (5). In other words, "within the boundaries of offshore wind farms, changes in certain practices/activities could lead to a reserve effect during the operational phase. Combined with the introduction of new structures in the marine environment (foundations, floaters, cable protection systems, etc.), this reserve effect could be amplified by the reef effect, these two effects being intrinsically linked" (8). While turbine platforms and cables can provide artificial reef habitat, the cables and other infrastructure may potentially facilitate the spread of invasive, non-native species (15). A publication from COME3T (9) concluded that there is a low risk of offshore wind farms facilitating the introduction and spread of non-native species through transportation and construction, and recommended ways to mitigate the risk through these channels by limiting the amount of time offshore wind components are stored in ports.​

Salmon are local and significant species identified as a high priority for monitoring by the California Marine Sanctuary Foundation in the California Offshore Wind Environment Monitoring Framework (15). There is concern that offshore wind infrastructure may alter their migration patterns or magnetic cues used for navigation. In a study (20) done in the San Francisco estuary, Chinook Salmon successfully migrated despite the presence of underwater cables and possible EMF distortion. Another study (19) noticed slight delays and small deviations in salmon migration routes in the presence of powered cables. Existing anthropogenic factors have already affected salmon’s habitat and migration, reducing their adaptive capability, and making them more vulnerable to potential impacts from offshore wind.

In October 2023, a bill passed establishing California Offshore Wind Energy Fisheries Working Group which consists of representatives from various relevant government agencies, tribes, fishing and wind energy committees, and other stakeholders. The bill focuses on developing a statewide strategy to mitigate impacts (12) to fishing and fisheries from offshore wind energy projects. Mitigation measures prioritize fishery productivity, viability, and long-term resilience. 

In Humboldt Bay and along the Humboldt Coast, infrastructure and port development is expected to alter physical and ecological conditions, possibly changing habitat and foraging conditions for fish (15). Maintenance such as dredging and cable maintenance may cause seafloor disturbances. Humboldt Bay is already annually dredged to maintain navigable channels (17) and historically, effects of dredging in the bay have been noted as temporary and minimal (18). Coastal construction can increase turbidity which may degrade kelp forests and other vegetation that native, coastal fish rely on for habitat and foraging (15).

Further Reading

This bulletin (10) from COME3T explains more about potential impacts off offshore wind farms to coastal fish and their essential habitats. COME3T also published potential impacts on commercial fisheries species (8). The California Ocean Science Trust released this factsheet (7) about potential impacts to fish due to floating offshore wind in California. The California Marine Sanctuary Foundation published these guidelines (15) for foundational and species specific monitoring recommendations.

References

1. Vanderhein, I. (2022, December 1). North Coast Fisherman Fear for the Future of Commercial Fisheries as Offshore Wind Efforts Advance. Lost Coast Outpost. https://lostcoastoutpost.com/2022/dec/1/offshore-wind/ 

2. U.S. Bureau of Ocean Energy Management. (2023, December). Electromagnetic Fields (EMFs) from Offshore Wind Facilities. www.boem.gov/sites/default/files/documents/renewable-energy/state-activities/BOEM-Electromagnetic-Fields-Offshore-Wind-Facilities_1.pdf 

3. Raghukumar, K., Nelson, T., Chang, G., et al. (2024, February 27). A Numerical Modeling Framework to Evaluate Effects of Offshore Wind Farms on California’s Coastal Upwelling Ecosystem. California Energy Commission. www.energy.ca.gov/publications/2024/numerical-modeling-framework-evaluate-effects-offshore-wind-farms-californias 

4. The Nature Conservancy. (2024, June 4). Turbine Reefs: Designing Offshore Wind Power to Improve Habitat for Marine Life. www.nature.org/en-us/what-we-do/our-priorities/protect-water-and-land/land-and-water-stories/wind-turbines-restoring-habitat/ 

5. Ashley, M.C., Mangi, S.C., and Rodwell, L.D. (2014, March). The potential of offshore windfarms to act as marine protected areas – A systematic review of current evidence. Marine Policy, 45: 301-309. www.sciencedirect.com/science/article/abs/pii/S0308597X13001991

6. NOAA Fisheries. (2023, December 14). Overfished Declaration for Quillback Rockfish off California Likely to Limit Fishing. www.fisheries.noaa.gov/feature-story/overfished-declaration-quillback-rockfish-california-likely-limit-fishing

7. California Ocean Science Trust. (2024, July). Impacts to Fish and Seafloor Habitats. www.oceansciencetrust.org/wp-content/uploads/2024/07/OST-Science-Factsheet-5-Fish-Final.pdf

8. France Energies Marines. (2022, March). The reef effect induced by wind farms and their grid connection. Tethys. https://tethys.pnnl.gov/sites/default/files/publications/COME3T-bulletin-3-effet-recif-EN-BD.pdf

9. France Energies Marines. (2019, December). Does the colonisation of offshore renewable energy farms facilitate the introduction and spread of non-indigenous species? Tethys. https://tethys.pnnl.gov/sites/default/files/publications/COME3T-bulletin2-non-indigenous-species.pdf

10. France Energies Marines. (2024, March). What are the potential effects of offshore wind farms on coastal fish and their essential habitats? Tethys. https://tethys.pnnl.gov/sites/default/files/publications/FEM-COME3T-Bulletin-10_English.pdf

11. Wiley. (2024, November 26). Limited Evidence Base for Determining Impacts (Or Not) of Offshore Wind Energy Developments on Commercial Fisheries Species. https://tethys.pnnl.gov/sites/default/files/publications/Gill_et_al_2024.pdf 

12. Bill text: Ca SB286 | 2023-2024 | regular session | chaptered | Legiscan. (2023, October 10). https://legiscan.com/CA/text/SB286/id/2844359 

13. Floating Offshore Wind Dynamic Cable EMF Environmental Review | Tethys. (n.d.). Retrieved May 26, 2026, from https://tethys.pnnl.gov/publications/floating-offshore-wind-dynamic-cable-emf-environmental-review?utm_source=Tethys&utm_campaign=ade4993ba2-Tethys+Blast+19+December+2025_COPY_01&utm_medium=email&utm_term=0_-8ebb5ebe17-523855749

14. Cote et. al. (2026). The Effects of Electrified Submarine Cables on Movements of Two Commercially Important Crustacean Species. https://www.sciencedirect.com/science/article/pii/S0025326X2600874X?via%3Dihub

15. California Marine Sanctuary Foundation (2026). California Offshore Wind Environmental Monitoring Framework. https://opc.ca.gov/wp-content/uploads/2026/08/CA-Offshore-Wind-Env-Monitoring-Framework-508.pdf

16. Environmental Protection Agency. (2026). Effects of Ocean and Coastal Acidification on Marine Life.

    https://www.epa.gov/ocean-acidification/effects-ocean-and-coastal-acidification-marine-life

17. Humboldt Bay Harbor, Recreation, and Conservation District. (2024). Dredging. https://humboldtbay.org/dredging

18. US Army Corps of Engineers (2012). Five‐Year Programmatic Environmental Assessment and Analysis, Humboldt Harbor and Bay Operations and Maintenance Dredging. https://humboldtbay.org/sites/humboldtbay.org/files/documents/Humboldt%20OM%20EA_FY2012-FY2016_09_JAN_2012.pdf

19. Wyman et. al. (2018). Behavioral responses by migrating juvenile salmonids to a subsea high-voltage DC power cable. https://link.springer.com/article/10.1007/s00227-018-3385-0

20. Klimley et. al. (2017). Chinook salmon and green sturgeon migrate through San Francisco Estuary despite large distortions in the local magnetic field produced by bridges. https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0169031

21. Love et. al. (2017). Assessing potential impacts of energized submarine power cables on crab harvests. https://www.sciencedirect.com/science/article/abs/pii/S0278434317301759