ECOHAB19: Multidisciplinary approach to a cross-regional problem: Dinophysis and DSP toxicity.
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Introduction to the Problem: Species of Dinophysis, known to produce toxins that cause diarrhetic shellfish poisoning (DSP), have threatened the safety of shellfish consumers in Asia and Europe for decades. Only in the last decade has DSP become a human health threat in the US. Since first detected on the coast of Texas in 2008, D. ovum has been detected in six of the last eight years and has resulted in the closures of shellfish harvesting to prevent DSP. Since 2011, closures due to DSP from D. acuminata and D. fortii have also been enforced annually at multiple sites throughout Puget Sound, WA, and toxin levels in shellfish exceeding FDA regulatory limits have been reported in New York and Massachusetts due to D. cf. acuminata. Most recently Maine has undergone closures as a result of D. norvegica (ME) and the unknown toxicity of novel toxin dihydro-dinophysistoxin-1 (dihydro-DTX1). Chesapeake Bay and the larger DELMARVA region (Delaware, Maryland, and Virginia) harbor toxin-producing species of Dinophysis. The region, however, provides contrast as a relatively new area of concern, with evidence of an approaching tipping point.
Rationale: DSP has emerged as a significant and expanding seafood safety threat in coastal regions across the country and observations of intensifying blooms in TX, WA, NY, and New England may signal further expansion into new regions. Despite this immediate threat to human and ecosystem health, little is known of the environmental and biological drivers of Dinophysis growth and toxin production in the US, species or subpopulation (strain) variation, and the relative toxicity of the novel dihydro-DTX1. Objectives: 1) Develop a nationwide network of IFCBs that is optimized for monitoring and providing early warning of Dinophysis spp. blooms; 2) Investigate environmental and biological drivers of Dinophysis spp. blooms and toxicity in situ within and across regions; 3) Quantify rates of growth and toxin production of Dinophysis spp. to a range of environmental and biological factors using controlled laboratory experiments; 4) Develop informative markers for species identification and investigate physiological responses among Dinophysis spp. to environmental and biological factors; 5) Determine the toxicity of dihydro-DTX1; and 6) Evaluate the potential for climate change to expand the threat of DSP in the US; and 7) Partner with State, Tribal, and industry groups to address management needs, disseminate results, and aid regional management programs. Outputs & Outcomes: This project is expected to improve shellfish management plans and
response to Dinophysis spp, blooms. The integration of new and enhanced IFCB-based early warning systems into HAB monitoring programs will inform management decisions regarding resource allocation and shellfish bed closures/re-openings in Gulf of Mexico, Chesapeake Bay, Long Island Sound, Puget Sound, Gulf of Maine and Nauset Marsh Estuary. Resource managers will also gain a better understanding of the physiological responses, vertical distribution, seasonality and average concentrations of DSP toxins in Dinophysis spp. and their biological and environmental controls. Incorporation of a TEF (toxicity equivalency factor) and modified DSP quantification method for dihydro-DTX1 into management will result in more surgical closures, especially in the Gulf of Maine, and potentially in the Puget Sound and DELMARVA regions
where D. norvegica is present but not currently dominant.