2017-03-02 / Front Page

Shellfish harvesting closed due to algae

Contamination forced the closure of shellfish harvesting yesterday in areas of Rhode Island Sound, lower Narragansett Bay and the Sakonnet River.

The ban will remain in effect while the R.I. Health Department conducts further water tests.

According to state environment officials, the ban was issued because of a harmful algae bloom caused by phytoplankton. Carnivorous snails, such as whelk and moon snails, still can be farmed, officials said.

Impacted areas include water south of the Jamestown and Newport bridges. Also closed is the mouth of the Sakonnet River, as well as the area south of Point Judith stretching east to Gooseberry Neck.

The closure stems from shellfish samples collected Sunday and Monday from five lower bay locations off Jamestown, Newport and Little Compton. The samples were tested for domoic acid and four locations had acidic levels ranging from 14 parts per million to 32 ppm. The U.S. Food and Drug Administration requires mandatory closures at 20 ppm.

Domoic acid is a bio-toxin caused by the phytoplankton Pseudo-nitzschia spp, an algae that causes a neurological disorder known as amnesic shellfish poisoning.

The illness damages brain neurons by causing an influx of calcium. Symptoms that appear in the first 24 hours after ingesting the affected shellfish include vomiting, nausea, diarrhea and cramps. In more severe cases, it can take up to three days to develop additional symptoms, such as headaches, dizziness, disorientation, blurred vision, short-term memory loss, seizures and an irregular heart beat. In rare cases, amnesic shellfish poisoning has led to comas and death.

A similar bloom led to a shellfishing ban last fall in Narragansett Bay. For updates on closure areas, the state has a 24-hour hotline at 222-2900.

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