The North Beach razor clam fishery was shut down Thursday afternoon (June 16) after dangerously high levels of the PSP toxin were found in samples.Sandra Davies, a resource management biologist at Fisheries and Oceans in Prince Rupert, said the levels in the North Beach sample were above the safe limit but not as extreme as those found recently in Alaskan shellfish. PSP, or paralytic shellfish poisoning, has sent at least a dozen people to hospital in southeastern Alaska in the past month.Fisheries and Oceans has closed all commercial and recreational razor clam fishing on the north coast of Graham Island. Cockle harvesting is also closed.Ms Davies said crabs are not affected by PSP, only bivalve shellfish. The toxin does not harm the shellfish but concentrates in their bodies as they consume algae. Humans who eat contaminated shellfish can have a range of symptoms, from tingling in the tongue and lips, to tingling and numbness extending to the arms and legs, and nausea. In extreme cases, breathing can be affected. Cooking or freezing contaminated shellfish does not destroy the toxin.The geoduck fishery, taking place this year around Prince Rupert, was closed down a few weeks ago due to PSP, Ms Davies said.A PSP closure, also known as a "red tide", is not unusual at this time of year, Ms Davies said. The levels usually go down within a few weeks.With the exception of North Beach, most of Haida Gwaii is under a blanket closure for shellfish harvesting because there is no testing, Ms Davies said. The only other place open for shellfish on Haida Gwaii is Kagan Bay, where there is a shellfish farm and samples are tested regularly. So far, Kagan Bay samples are fine, Ms Davies said.Fisheries and Oceans was posting signs at North Beach to let people know about the closure, Ms Davies said. As well, Haida Fisheries sent a news bulletin door to door in the Massett area as soon as the closure was announced.