Electromagnetic fields from submarine power cables: A 35 Year synthesis of effects on aquatic biota

Abstract

Submarine power cables (SPCs) associated with offshore renewable energy developments emit electromagnetic fields (EMFs) that can influence aquatic biota. Although research on this topic has increased, a comprehensive, systematic synthesis of observed effects across taxa and life stages, and biological contexts has been lacking. Following PRISMA 2020 guidelines (PROSPERO ID: 1138188), we systematically reviewed peer-reviewed and grey literature published between 1990 and 2024. Of 1637 records screened, 67 eligible field and laboratory studies were included. Significant behavioural and physiological responses to EMF exposure were reported in 66% of studies, with early life stages (embryos, larvae, juveniles) and magnetosensitive taxa, particularly fishes and crustaceans being most frequently affected. Effects occurred even at environmentally relevant intensities (<250 μT). Laboratory experiments more frequently detected effects than field studies, which were generally fewer, shorter in duration, and methodologically heterogeneous. Sensitivity heatmaps identified developmental stages and freshwater species as particularly sensitive, with notable taxonomic disparities. EMFs from SPCs can elicit ecologically relevant responses in aquatic biota, particularly during sensitive developmental windows and in magnetically responsive taxa. Emerging evidence further indicates that sex specific responses represent an important and previously under recognised dimension of EMF sensitivity. However, major uncertainties persist regarding chronic, population and ecosystem level impacts. Future research should prioritise standardisation of exposure characterisation and reporting, routine inclusion of sex and life stage as biological variables and coordinated laboratory to field validation. Integrating EMF considerations into marine spatial planning, environmental regulation, and biodiversity conservation frameworks will be essential to support proportionate ecological risk assessment and management of offshore renewable energy infrastructure.

AI evidence extraction

Main findings

This systematic review included 67 eligible field and laboratory studies on EMFs from submarine power cables. Significant behavioural and physiological responses were reported in 66% of studies, with early life stages and magnetosensitive taxa, particularly fishes and crustaceans, most frequently affected; effects were reported even at environmentally relevant intensities below 250 μT. Laboratory studies detected effects more often than field studies, while major uncertainties remained regarding chronic, population-level, and ecosystem-level impacts.

Outcomes measured

• Behavioural responses
• Physiological responses
• Sensitivity by life stage
• Taxonomic sensitivity
• Sex-specific responses
• Chronic, population-level, and ecosystem-level impacts (uncertain)

Limitations

• Field studies were fewer than laboratory studies
• Field studies were generally shorter in duration
• Methodological heterogeneity across studies
• Major uncertainties remain regarding chronic impacts
• Major uncertainties remain regarding population-level impacts
• Major uncertainties remain regarding ecosystem-level impacts
• Need for standardisation of exposure characterisation and reporting
• Need for laboratory-to-field validation

Suggested hubs

• policy (0.58)
  The abstract discusses marine spatial planning, environmental regulation, biodiversity conservation, and ecological risk assessment related to submarine cable EMFs.

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    "study_type": "systematic_review",
    "exposure": {
        "band": null,
        "source": "submarine power cables",
        "frequency_mhz": null,
        "sar_wkg": null,
        "duration": "1990 to 2024 literature reviewed; included field and laboratory studies"
    },
    "population": "Aquatic biota, including fishes, crustaceans, freshwater species, and early life stages (embryos, larvae, juveniles)",
    "sample_size": 67,
    "outcomes": [
        "Behavioural responses",
        "Physiological responses",
        "Sensitivity by life stage",
        "Taxonomic sensitivity",
        "Sex-specific responses",
        "Chronic, population-level, and ecosystem-level impacts (uncertain)"
    ],
    "main_findings": "This systematic review included 67 eligible field and laboratory studies on EMFs from submarine power cables. Significant behavioural and physiological responses were reported in 66% of studies, with early life stages and magnetosensitive taxa, particularly fishes and crustaceans, most frequently affected; effects were reported even at environmentally relevant intensities below 250 μT. Laboratory studies detected effects more often than field studies, while major uncertainties remained regarding chronic, population-level, and ecosystem-level impacts.",
    "effect_direction": "harm",
    "limitations": [
        "Field studies were fewer than laboratory studies",
        "Field studies were generally shorter in duration",
        "Methodological heterogeneity across studies",
        "Major uncertainties remain regarding chronic impacts",
        "Major uncertainties remain regarding population-level impacts",
        "Major uncertainties remain regarding ecosystem-level impacts",
        "Need for standardisation of exposure characterisation and reporting",
        "Need for laboratory-to-field validation"
    ],
    "evidence_strength": "moderate",
    "confidence": 0.9499999999999999555910790149937383830547332763671875,
    "peer_reviewed_likely": "yes",
    "keywords": [
        "submarine power cables",
        "electromagnetic fields",
        "aquatic biota",
        "offshore renewable energy",
        "fish",
        "crustaceans",
        "early life stages",
        "magnetosensitive taxa",
        "systematic review",
        "marine spatial planning"
    ],
    "suggested_hubs": [
        {
            "slug": "policy",
            "weight": 0.57999999999999996003197111349436454474925994873046875,
            "reason": "The abstract discusses marine spatial planning, environmental regulation, biodiversity conservation, and ecological risk assessment related to submarine cable EMFs."
        }
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}

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