Harmful algal blooms of Dinophysis have recently emerged as a human health threat in the U.S., resulting in closures of shellfish harvesting to prevent Diarrhetic Shellfish Poisoning. We are working to identify the drivers (stimuli) of Dinophysis success in four regions with important shellfisheries (Texas, Washington, New York, and Virginia), and to create a baseline for a regional early warning system and understanding how future climate/nutrient scenarios will influence blooms.

Why We Care
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. Recently, harmful algal blooms caused by Dinophysis spp. have emerged as a human health threat in the U.S.

Since first noticed on the Texas coast in 2008, monitoring programs have detected D. ovum in six of the last eight years in Texas, resulting in closures of shellfish harvesting to prevent DSP. Since 2011, regulators have enforced closures annually at multiple sites throughout Puget Sound, Washington, due to DSP from D. acuminata and D. fortii. Toxin levels in shellfish exceeding FDA regulatory limits have been reported in New York, Maine, and Massachusetts due to blooms of D. cf. acuminata, and blooms of D. norvegica have occurred in the Gulf of Maine. Chesapeake Bay and the larger Delmarva Peninsula region (Delaware, Maryland, and Virginia) harbor toxin-producing species of Dinophysis. This region, however, provides contrast as a relatively new area of concern, with evidence of an approaching tipping point.

Given the rapid increase in frequency of Dinophysis blooms on nearly every U.S. coast, with clear regional variability in timing and species, it is essential to identify the drivers (stimuli) of Dinophysis success in coastal ecosystems using a coordinated, nationwide effort.

What We Are Doing
We are working to identify and quantify factors controlling Dinophysis blooms and DSP across the U.S. as a means of developing optimized regional early warning systems and management plans.

The project team hypothesizes that a combination of temperature, stratification, prey, and nutrient input combine to determine the success of Dinophysis in U.S. coastal ecosystems. The team’s carefully coordinated and collaborative study will include high-resolution phytoplankton time series, field collections, and multi-factorial laboratory experiments using isolates of Dinophysis species from important shellfish harvesting sites in the U.S. (e.g., Gulf of Mexico, Puget Sound, Long Island Sound, and Chesapeake Bay). This cross-regional comparative study will identify not only potential drivers, but create a baseline for understanding how future climate and eutrophication scenarios will influence intensity, frequency, and toxicity of blooms.

The main outcome of this project is the implementation of optimized DSP early warning systems as a critical first step toward ensuring public safety while also minimizing negative economic impacts on local communities. The project team will also identify the environmental regulators of DSP toxin production and Dinophysis species success, providing the context with which to better understand, predict, and detect potential threats now and under future climate and nutrient management scenarios.

Dr. Juliette Smith of the Virginia Institute of Marine Science (VIMS) at the College of William and Mary leads this project. Co-leads are Lisa Campbell (Texas A&M University), Christopher Gobler and Theresa Hattenrath-Lehmann (Stony Brook University), Vera Trainer (NOAA Northwest Fisheries Science Center), and Jonathan Deeds (U.S. Food and Drug Administration). The project is funded through the NCCOS Ecology and Oceanography of Harmful Algal Bloom (ECOHAB) Program.