Warming seas heighten shellfish poisoning risk in Alaska
Climate change is expanding the reach of harmful algal blooms that cause paralytic shellfish poisoning in Alaska, threatening a growing shellfish farming industry. Oyster farmer Meta Mesdag faced nearly 10 weeks of closures in 2023 due to toxin detection, and businesses must test weekly during the season. Indigenous scientists with SEATOR are monitoring beaches and issuing public alerts to prevent illness.
The toxin behind these closures comes from Alexandrium catenella, a microscopic phytoplankton that multiplies rapidly under favorable conditions and contaminates filter-feeding shellfish. Alaska's state health department recorded 132 paralytic shellfish poisoning cases and five deaths between 1993 and 2021, though historical accounts note a 1799 incident at Poison Cove where roughly 100 people died after consuming toxic mussels.
SEATOR, a consortium of Indigenous scientists from Tlingit & Haida Tribes and other regional groups, monitors beaches and issues public alerts. Their work reflects a long cultural relationship with shellfish harvesting, balanced against an ancient, known risk that warming waters may now be intensifying across new areas of Alaska's coastline.
This story could affect both commercial shellfish farmers and subsistence harvesters across Alaska, as warming waters may expand toxic bloom zones into previously safe areas. Small businesses like Salty Lady face economic strain from extended closures, while Indigenous communities relying on traditional beach foods may lose a dependable protein source. Public health systems could see increased testing demands, though monitoring networks like SEATOR may help mitigate illness risks.