Abstract

Overview

High-voltage direct current (HVDC) subsea cables, essential for power transport between various locations including offshore facilities, generate magnetic fields. These fields may pose risks to marine life, particularly to demersal fishes like Atlantic haddock whose larvae rely on Earth's natural magnetic fields for orientation during dispersal.

Findings

• A study was conducted on 92 haddock larvae, exposing them to magnetic fields within the 50 to 150 µT range, simulating the conditions near a subsea cable.
• The testing revealed that there was no significant change in spatial distribution within the groups under study.
• A detailed observation showed a reduction in median swimming speed by 60% and a decrease in acceleration by 38% in nonexploratory larvae, underlining a potential behavioral alteration due to exposure to the magnetic fields.
• Exploratory larvae showed no significant change in swimming behavior, suggesting varying susceptibilities among larvae based on their inherent behavioral traits.

Conclusion

The research supports the conclusion that while HVDC cable-generated magnetic fields do not universally affect all haddock larvae, they have a pronounced adverse effect on those categorized as nonexploratory. This could potentially lead to broader ecological impacts on the haddock population in natural marine environments.