Female Crabs Are More Sensitive to Environmentally Relevant Electromagnetic Fields from Submarine Power Cables
Abstract
Overview
The expansion of offshore wind and marine renewable energy devices (MREDs) has led to an increase in anthropogenic electromagnetic fields (EMFs) from submarine power cables (SPCs). These EMFs, generated by SPCs, can exceed 2,700 μT—substantially higher than the natural geomagnetic field—and may directly impact the behavior of benthic animals, such as crabs.
Findings
- Recent research explored EMF sensitivity in juvenile shore crabs (Carcinus maenas), focusing on sex-specific behavioral responses.
- In controlled trials using a Helmholtz coil system, 120 crabs (with a 1:1 sex ratio) were exposed to EMFs of 500, 1000, and 3,200 μT for ten minutes.
- Female crabs consistently demonstrated a strong attraction to EMF-exposed zones, spending up to 131% more time in these areas and significantly less time in low-field zones.
- Females also influenced group movement patterns, while males showed no consistent spatial preference or heightened activity, even at the highest EMF exposure.
Conclusion
Sex-specific sensitivity to SPC-generated EMFs could disrupt crucial female-driven behaviors like seasonal migrations and larval release in shore crabs. This increased attraction might cause disorientation, aggregation, or migration delays, potentially impacting sex ratios and larval export. The research provides the first direct evidence of sex-based EMF responses in crustaceans and underscores the need to consider sex as a vital variable in ecological risk assessments related to offshore energy infrastructure.
⚠️ EMF exposure represents a significant environmental variable with direct links to behavioral and ecological disruption in benthic marine species, warranting careful monitoring and risk assessment.