Govind Tekale
A groundbreaking study has linked a powerful neurotoxin from harmful algal blooms to the deaths of northern fur seals in the Bering Sea near Alaska. According to the research published in Marine Mammal Science journal, scientists identified that saxitoxin produced by the microscopic algae Alexandrium catenella caused these marine mammal fatalities. The investigation began after a member of the Aleut Community discovered deceased fur seals and numerous fish washed up on St. Paul Island’s shore in August 2024.
Members of the tribal environmental team preserved six of the seal bodies for expert veterinary examination.
“As the Arctic Ocean ecosystem gets warmer, harmful algal blooms are becoming more frequent, getting stronger, and spreading further,” said Dr. Kathi Lefebvre, a research biologist at NOAA’s Northwest Fisheries Science Center who led the study.
Harmful algal blooms occur when naturally-occurring microscopic algae multiply rapidly in marine waters. These tiny organisms produce potent neurotoxins that can be deadly to marine life and humans. The toxins enter the food web when small marine animals eat the toxic algae. The poison then moves up the food chain as larger animals eat the smaller contaminated ones.
The scientific investigation yielded strong evidence pointing to saxitoxin in the food chain as the primary cause of death for the fur seals. Lab analysis found significant amounts of this toxin in various marine life including fish, clams, worms, and detected it in the seals’ urine. Scientists on research vessels sampling nearby waters identified Alexandrium catenella, the microscopic organism responsible for producing this dangerous toxin.
For the Unangax̂ people of St. Paul Island, these findings have serious implications.
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“St. Paul is experiencing a rapidly transforming marine ecosystem with significant impacts on our community,” said Dr. Lauren Divine, Director of the Ecosystem Conservation Office for the Aleut Community of St. Paul Island. “The culture, economy, health, and food security of our people are closely tied to ocean health, and northern fur seals are vital to Unangax̂ cultural identity and wellbeing.”
The research represents a collaborative effort between Tribal scientists, government agencies, and academic institutions. Their work has strengthened our understanding of how climate change affects marine ecosystems and provides valuable data for monitoring and managing harmful algal blooms.
While saxitoxin can cause paralytic shellfish poisoning in humans who eat contaminated seafood, researchers note that the current situation doesn’t pose an immediate human health risk. However, the increasing frequency of these toxic blooms in warming Arctic waters remains a growing concern for marine wildlife and coastal communities that depend on healthy ocean ecosystems.
This study offers critical insight into an emerging threat facing northern fur seals and the broader marine environment as Arctic waters continue to warm at unprecedented rates.
