Award: ICER-1415195

Blooms of harmful marine algae result in significant environmental and human health impacts that affect nearly all coastal environments throughout the US and worldwide. In Alaska, the most severe and persistent harmful algal bloom (HAB) problem causes shellfish toxicity known as Paralytic Shellfish Poisoning (PSP). Toxins that cause PSP are produced by marine algae called Alexandrium which form resting cysts that overwinter on the seafloor. When Alexandrium blooms, filter feeding shellfish accumulate these toxins to concentrations that are unsafe for human consumption and in extreme cases may lead to paralysis and death. The research supported by this award utilized ecological and social science approaches to identify the locations and environmental conditions that support these toxic Alexandrium bloom events in the Juneau/Icy Strait region of northern Southeast Alaska and assess how coastal communities understand, respond to and may reduce vulnerability to PSP. The results of our ecological studies identified the source locations, supporting environmental conditions and timing of toxic Alexandrium bloom events in northern Southeast Alaska. This project produced the first Alexandrium cyst distribution map for a region historically impacted by PSP. Knowing distributions of this dormant life stage is critical to understanding the initiation sites of toxic blooms. The cyst distribution map is a product that allows researchers, resource managers and harvesters to better understand spatial patterns of these toxic algae and locate potentially high-risk harvest areas. From paired environmental and phytoplankton monitoring, we identified temperature, river discharge and local weather to be key factors that regulate Alexandrium bloom development and persistence in Southeast Alaska. We determined that monitoring air and water temperature, along with local weather (precipitation and wind) could be used to predict toxic Alexandrium bloom events within days while river discharge may be used to project the magnitude and/or duration of the bloom. Implementing a hindcasting approach allowed us to identify a seasonal window of Alexandrium "bloom opportunity" from May through September with environmental conditions being consistently favorable to bloom development in May and June. Long-term monitoring of the environmental factors identified through this research can be used to enhance early warning capacity of toxic bloom events that cause shellfish toxicity in northern Southeast Alaska. Local and traditional knowledge acquired from shellfish harvesters, through interviews and surveys, allowed us to document shellfish harvest activities in the study region as well as understand perceptions about shellfish safety and PSP. We learned that harvesting shellfish in Southeast Alaska is deeply culturally important, a "way of life". Harvested shellfish are shared with family and within the community. We found a clear demographic distinction in harvest activities and perceptions and understanding of PSP. Active shellfish harvesters are predominately male, and although aware of the risk of PSP, continue to consume shellfish from Southeast Alaska beaches, whereas non-active shellfish harvesters express a higher degree of uncertainty about consuming recreational or subsistence shellfish. Shellfish harvesters from rural communities, primarily Alaska Natives, reported having lesser understanding of the causes of PSP compared to respondents living in more urban areas. Our research indicates that harvesters in rural communities of Southeast Alaska may be at highest risk of PSP. We also confirmed that traditional knowledge may serve to reduce the risk of encountering toxic shellfish by teaching seasonal avoidance harvest practices but only if harvesters are better informed about how various shellfish species accumulate and expel paralytic shellfish toxins. Our research concludes that targeted education and outreach to identified high risk shellfish harvest communities that integrated both traditional and western (i.e., scientific) knowledge would be an effective approach to reducing vulnerability to PSP in Southeast Alaska. The findings of this research have been widely shared with communities of interest in Alaska through targeted community presentations, one-page research summaries, environmental workshops, academic and agency meetings, scientific conferences and peer-review publication. Most notably, the outcomes of this project continue to be communicated with Alaska Natives and other stakeholder groups through on-going partnerships with the Southeast Alaska Tribal Toxins (SEATT) and the Alaska Harmful Algal Bloom (AHAB) networks. Last Modified: 02/27/2020 Submitted by: Elizabeth D Tobin