Paralytic shellfish toxins and seabirds: evaluating sublethal effects, behavioral responses, and ecological implications of saxitoxin ingestion by common murres (Uria aalge)

Details

• Journal Title:
  Harmful Algae
• NOAA Program & Office:
  NOS (National Ocean Service) ; NCCOS (National Centers for Coastal Ocean Science) ; Sea Grant
• Sea Grant Program:
  AKU (Alaska Sea Grant)
• Description:
  Paralytic shellfish toxins (PSTs), including saxitoxin (STX) and its congeners, are neurotoxins that can be produced during harmful algal blooms and cause illness or death in humans, fish, seabirds, and marine mammals. Since 2014, multiple large-scale seabird mortality events have occurred in Alaska waters, with STXs detected in some carcasses. To investigate the sublethal behavioral and ecological effects of STX on seabirds, we conducted captive dosing trials with common murres (Uria aalge). We gavaged purified STX (dehydrated STX dihydrocholoride, STX-diHCl) or an Alexandrium catenella culture extract into murres, monitored behavioral responses and recovery times, and assessed tissue concentrations in individuals that died or were euthanized. Using a modified up-and-down dose-finding scheme, we estimated a median effective dose (ED50) of 89 µg STX-equivalents (eq) kg-1 for STX-diHCl and 366 µg STX-eq kg-1 for the A. catenella extract based on ecologically relevant behavior. Differences between the ED50 estimates could reflect uncertainties in toxin equivalency factors for PST congeners, which are based on studies using purified toxins in mice and may vary across taxa or toxin matrices. Post-dosing concentrations of STX varied by tissue type across individuals, with quantifiable levels ranging from 3 to 379 µg STX-eq 100g-1. Evidence of biotransformation of STX in A. catenella extract-dosed birds was observed. We also measured the chronic effects of dosing with sublethal levels of STX-diHCl over seven-days, which resulted in lower fish intake among treatment birds compared to controls (-187 g day-1). This investigation improves our understanding of the ecological effects of PSTs on seabird health.
• Keywords:
  Algal Bloom Common Murre Paralytic Shellfish Poisoning Saxitoxin Algal Bloom Common Murre Paralytic Shellfish Poisoning Effective Dose Harmful Algal Bloom Paralytic Shellfish Toxin
• Source:
  Harmful Algae 148 (2025) 102919
• DOI:
  https://doi.org/10.1016/j.hal.2025.102919
• Format:
  PDF
• Document Type:
  Journal Article
• Funding:
  Grant no. NA20NOS4780195
• License:
  https://creativecommons.org/licenses/by/4.0/
• Rights Information:
  CC BY
• Compliance:
  Submitted
• Main Document Checksum:
  urn:sha-512:53320aba772d30ad82c439627a700167a6fab68d4408113e57d00d02f36cceefd28956871f76f58e51b3e4231226d5718df7a13808053c618c2ca4923984dd00
• Download URL:
  https://repository.library.noaa.gov/view/noaa/74088/noaa_74088_DS1.pdf
• File Type:
  [PDF - 1.32 MB ]