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Magnetic fields produced by subsea high-voltage direct current cables reduce swimming activity of haddock larvae

2022 · Mixed · Moderate evidence

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MixedModerate evidencePaper 608

In a raceway tank simulating larvae drifting past a subsea HVDC-cable-like magnetic field (50–150 µT), exposure did not affect larvae spatial distribution. Among nonexploratory larvae (78%), magnetic-field exposure reduced median swimming speed by 60% and med…

Study snapshot

Publicationmanual · 2022
Study typeanimal
Reported directionMixed
Evidence ratingModerate

Abstract

Magnetic fields produced by subsea high-voltage direct current cables reduce swimming activity of haddock larvae Cresci A, Durif CMF, Larsen T, Bjelland R, Skiftesvik AB, Browman HI. Magnetic fields produced by subsea high- voltage direct current cables reduce swimming activity of haddock larvae (Melanogrammus aeglefinus). PNAS Nexus. 2022 Aug 27;1(4):pgac175. doi: 10.1093/pnasnexus/pgac175. Abstract High-voltage direct current (HVDC) subsea cables are used to transport power between locations and from/to nearshore and offshore facilities. HVDC cables produce magnetic fields (B-fields) that could impact marine fish. Atlantic haddock (Melanogrammus aeglefinus) is a demersal fish that is at risk of exposure to anthropogenic B- fields. Their larvae drift over the continental shelf, and use the Earth's magnetic field for orientation during dispersal. Therefore, anthropogenic magnetic fields from HVDC cables could alter their behavior. We tested the behavior of 92 haddock larvae using a setup designed to simulate the scenario of larvae drifting past a B-field in the intensity range of that produced by a DC subsea cable. We exposed the larvae to a B-field intensity ranging from 50 to 150 µT in a raceway tank. Exposure to the B-field did not affect the spatial distribution of haddock larvae in the raceway. Larvae were categorized by differences in their exploratory behavior in the raceway. The majority (78%) of larvae were nonexploratory, and exposure to the artificial B-field reduced their median swimming speed by 60% and decreased their median acceleration by 38%. There was no effect on swimming of the smaller proportion (22%) of exploratory larvae. These observations support the conclusion that the swimming performance of nonexploratory haddock larvae would be reduced following exposure to B-field from HVDC cables. The selective impact on nonexploratory individuals, and the lack of impact on exploratory individuals, could have population-scale implications for haddock in the wild. Open access paper: ncbi.nlm.nih.gov

Machine Enhanced Logic

AI evidence extraction

Structured fields below were generated from the paper’s abstract and metadata to make the evidence easier to inspect. Automated extraction may be incomplete or incorrect; verify important details against the original paper.

Study typeanimal
Effect directionmixed
PopulationAtlantic haddock (Melanogrammus aeglefinus) larvae
Sample size92
ExposureELF
Evidence strengthModerateConfidence: 78% · Peer reviewed: yes

Main findings

In a raceway tank simulating larvae drifting past a subsea HVDC-cable-like magnetic field (50–150 µT), exposure did not affect larvae spatial distribution. Among nonexploratory larvae (78%), magnetic-field exposure reduced median swimming speed by 60% and median acceleration by 38%, while no swimming effect was observed in exploratory larvae (22%).

Outcomes measured

  • Swimming speed
  • Acceleration
  • Spatial distribution in raceway
  • Exploratory behavior category (exploratory vs nonexploratory)

Limitations

  • Exposure duration not stated in abstract
  • Laboratory simulation in a raceway tank may not represent complex field conditions
  • Effects differed by behavioral subgroup (exploratory vs nonexploratory), limiting generalization to all larvae
View raw extracted JSON
{
  "study_type": "animal",
  "exposure": {
    "band": "ELF",
    "source": "subsea high-voltage direct current (HVDC) cable (simulated magnetic field)",
    "frequency_mhz": null,
    "sar_wkg": null,
    "duration": null
  },
  "population": "Atlantic haddock (Melanogrammus aeglefinus) larvae",
  "sample_size": 92,
  "outcomes": [
    "Swimming speed",
    "Acceleration",
    "Spatial distribution in raceway",
    "Exploratory behavior category (exploratory vs nonexploratory)"
  ],
  "main_findings": "In a raceway tank simulating larvae drifting past a subsea HVDC-cable-like magnetic field (50–150 µT), exposure did not affect larvae spatial distribution. Among nonexploratory larvae (78%), magnetic-field exposure reduced median swimming speed by 60% and median acceleration by 38%, while no swimming effect was observed in exploratory larvae (22%).",
  "effect_direction": "mixed",
  "limitations": [
    "Exposure duration not stated in abstract",
    "Laboratory simulation in a raceway tank may not represent complex field conditions",
    "Effects differed by behavioral subgroup (exploratory vs nonexploratory), limiting generalization to all larvae"
  ],
  "evidence_strength": "moderate",
  "confidence": 0.78,
  "peer_reviewed_likely": "yes",
  "keywords": [
    "HVDC",
    "subsea cable",
    "magnetic field",
    "B-field",
    "ELF",
    "marine fish",
    "haddock larvae",
    "behavior",
    "swimming speed",
    "acceleration",
    "orientation"
  ],
  "suggested_hubs": [
    {
      "slug": "occupational-exposure",
      "weight": 0.1,
      "reason": "Study concerns anthropogenic magnetic fields from power transmission infrastructure, though in a marine/animal context rather than human occupational exposure."
    }
  ]
}
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AI-extracted fields are generated from the abstract and metadata and may be incomplete or incorrect. This material is for informational purposes and is not medical advice.

Identifiers and source

DOI: 10.1093/pnasnexus/pgac175
PubMed: Not supplied

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