The State Department of Agriculture has closed the entire Oregon coast to recreational mussel and clam harvesting because of the risk of toxins that cause paralytic shellfish poisoning. Agency spokesman Bruce Pokarney said Monday that most of the north and central coast had already been closed to mussel harvesting and the state has banned razor clam harvesting since midsummer for conservation reasons.

The conservation closure ends Oct. 1, but clamming will remain off-limits until toxin levels subside. The agency will test for toxins weekly, as tides permit. Shellfish contaminated with PSP toxins can cause minor to severe illness. Symptoms usually start with the tingling of the mouth and tongue. Severe poisoning can result in dizziness, numbness and paralysis.