In July 2025, unusual mortalities of marine mammals and seabirds in and around Kachemak Bay, Alaska coincided with high bloom levels of the potentially harmful phytoplankton Pseudo-nitzschia. This event prompted tribal, state, and federal agencies to investigate the cause and assess potential human health risks. After ruling out avian influenza, the group is investigating whether the harmful algal bloom (HAB) produced toxins that contributed to these wildlife mortalities.
Blooms of Pseudo-nitzschia can produce the neurotoxin domoic acid (DA), which can accumulate in small fish and shellfish. Marine mammals and seabirds that feed on DA contaminated prey can suffer from severe illness or death. In humans, DA can cause amnesic shellfish poisoning.
The NCCOS supported event response is led by the Alaska HAB Network in partnership with the Alaska Department of Environmental Conservation, Alaska Veterinary Pathology Services, Chugach Regional Resources Commission, Kachemak Bay National Estuarine Research Reserve, Seldovia Village Tribe, the U.S. Fish & Wildlife Service’s Alaska Maritime National Wildlife Refuge, the U.S. Geological Survey’s Alaska Science Center, and NOAA’s Wildlife Algal-toxin Research and Response Network for the U.S. West Coast. Support from NCCOS and its scientists will facilitate the collection of additional samples for HAB toxin testing to assess and determine if HABs contributed to these wildlife mortalities and to better inform the public, subsistence harvesters, aquaculture farmers, and human health professionals of HAB risks in the region.
The NCCOS HAB Event Response Program is a national program that provides immediate support to help state, tribal, and local officials manage events and advance the understanding of HABs as they occur. For more information about the NCCOS HAB Event Response Program, contact nccos.hab.event.response@noaa.gov.
NOAA is authorized to respond to harmful algal bloom events by the Harmful Algal Bloom and Hypoxia Research and Control Act (33 U.S.C. §§ 4001 et seq.).
Please use the following hotlines if you notice anything unusual in Alaska:
Human health concerns – If you are experiencing symptoms of shellfish poisoning call 911 or your local health care provider immediately. Alaska healthcare providers who suspect or diagnose a disease that represents a public health emergency should immediately call 1-907-269-8000 during business hours or 1-800-478-0084 after hours.
Birds – For your safety, do not handle any sick birds or birds that are found dead. If you observe dead seabirds or encounter a sick or dead wild bird and the cause is not immediately apparent please call the U.S. Fish & Wildlife Service’s Alaska Sick or Dead Bird Hotline at (866)-527-3358.
Marine Mammals – For injured/stranded whales, seals, sea lions, porpoises, and dolphins call the NOAA Fisheries Alaska Statewide 24-Hour Stranding Hotline at (877) 925-7773.
Partner Links:
- Alaska Department of Environmental Conservation (ADEC)
- Alaska Harmful Algal Bloom (AHAB) Network, Alaska Ocean Observing System (AOOS)
- Alaska Maritime National Wildlife Refuge, U.S. Fish & Wildlife Service (USFWS)
- Alaska Science Center, U.S. Geological Survey (USGS)
- Alaska Veterinary Pathology Services
- Chugach Regional Resources Commission (CRRC)
- Kachemak Bay National Estuarine Research Reserve (KBNERR)
- Seldovia Village Tribe (SVT)
- Wildlife Algal-toxin Research and Response Network for the U.S. West Coast (WARRN-West), NOAA
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