Model predicts algal toxin levels in shellfish due to warmer ocean waters

Hazardous levels of domoic acid, a natural toxin that accumulates in shellfish, have been linked to warmer ocean conditions in waters off Oregon and Washington for the first time by a National Oceanic and Atmospheric Association (NOAA)-supported research team, led by Oregon State University scientists. The results are published in the Proceedings of the National Academy of Sciences.

Domoic acid, produced by certain types of marine algae, can accumulate in shellfish, fish, and other marine animals. Consuming enough of the toxin can be harmful or even fatal. Public health agencies and seafood managers closely monitor toxin levels and impose harvest closures where necessary to ensure that seafood remains safe to eat. NOAA is supporting research and new tools to help seafood industry managers stay ahead of harmful algae events that are increasing in frequency, intensity, and scope.

“We describe a completely new method to understanding and predicting toxic outbreaks on a large scale, linking domoic acid concentrations in shellfish to ocean conditions caused by warm water phases of natural climate event cycles like Pacific Decadal Oscillation (PDO) and El Nino,” said Morgaine McKibben from Oregon State University, the lead author of the study.

Using extensive time series of biological, chemical, and physical data, this study creates a climate-based risk analysis model that predicts where and when domoic acid in shellfish will likely exceed regulatory thresholds. The researchers will make this model freely available to support fisheries management decisions in Oregon, Washington, and California.

“Commercial and recreational shellfish fisheries along the West Coast are a multi-million-dollar industry,” said Marc Suddleson, NOAA harmful algal bloom program manager. “Improving our ability to accurately predict algal toxin levels in shellfish supports timely and targeted fishery closures or openings, essential to avoiding economic disruption and safeguarding public health.”

In 2015, domoic acid-related closures led to a decline in value of nearly $100 million for the West Coast Dungeness crab fishery, according to the Fisheries of the U.S. Report 2015.

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