Once limited to the U.S. south Atlantic and the Gulf of Mexico, Alexandrium monilatum has extended its range to the lower Chesapeake Bay, where it affects commercial fisheries and shellfisheries. The dynamics of toxins produced by this harmful alga remain poorly understood. We are characterizing the impacts of A. monilatum and its toxins on fish and shellfish, and the association between bloom dynamics and toxicity as related to the accumulation and transfer of toxin through food webs.

Why We Care
The recent intensification and expansion of A. monilatum blooms in the Chesapeake Bay region is cause for concern due to its potential ecological and economic impacts. With the shellfish aquaculture industry rapidly expanding and now worth over $48 million to Virginia alone, it is critical that we understand the risk posed to the health of oyster stocks, as well as blue crabs and striped bass.

Project scientists are assessing the impacts of A. monilatum and its toxins on multiple trophic levels, including the effects on aquaculture stocks. Our studies will benefit policy makers, shellfish growers, hatchery managers and restoration strategists by providing information that will allow them to develop plans to mitigate the impacts of A. monilatum blooms.

What We Are Doing
The team is using dose response bioassays on sheepshead minnows and field assays on juvenile oysters to determine the impacts of A. monilatum and the toxin goniodomin A (GDA) on shellfish and finfish. The researchers are also developing methods to quantify toxin in the water, and in oyster, crab, and vertebrate tissues.

The scientists will couple these toxin measurements with molecular and microscopic methods to follow transport of A. monilatum and toxin through animal tissues, providing insight into mechanisms of toxicity and metabolism of toxin, as well as elucidating pathways of trophic transfer. The team plans to hold two workshops to communicate results to end-users, including regional regulators, aquaculture industry members, NGOs and citizen groups involved in oyster restoration activities, and other scientists involved in harmful algal bloom research in the Chesapeake Bay region.

Dr. Kimberly Reece of the Virginia Institute of Marine Science (VIMS) at the College of William and Mary leads this project, along with her VIMS colleagues Juliette Smith, Wolfgang Vogelbein, Ryan Carnegie, William Reay, and Hamish Small. The project is funded through the NCCOS Ecology and Oceanography of Harmful Algal Bloom (ECOHAB) Program.