Here in Southeast Alaska clams can have high Paralytic Shellfish Poisoning at all times of the years. Dungeness Crabs, and snails that drill into clams can also be inedible. Alexandrium SP. is our primary culprit of the deadly saxitoxins. Research has shown the algae that cause the "red tide" here in Southeat Alaska are not the dangerous ones. You can never tell unless a test is done whither the clam you just dug is hot or not. We have had mussels measured at 20,000 micrograms per 100 grams of tissue. 80 mg/100gms is the accepted level. Geoduck research has shown hot and cool clams right next to each other. Some species tend to hold the toxins longer than others. Scott. -----Original Message----- From: Conchologists of America List Sent: Friday, May 22, 1998 10:28 AM To: ScottW; [log in to unmask] Subject: More on Sargasso Sea -Reply There is no direct connection between sargassum drifts and red tide. About the only thing the two phenomena have in common is that they both involve algae. Sargassum is a macroscopic (visible to the unaided eye) brown alga, or "seaweed". The organisms responsible for red tide are microscopic, s ingle-celled algae, most often of the genus Gymnodinium, though other related genera are sometimes involved. The individual organisms measure less t han 0.04 mm, and are normally present in sea water in small numbers, doing no harm. But occasionally, for reasons not fully understood, they multipl y rapidly, to the point where thousands of them may be present per milliliter of sea water. Since the organisms themselves contain a reddish pigment , the water, when so many organisms are present, actually looks red. This is what is called a "red tide". In addition to the red pigment, these org anisms contain a small amount of a protein that is violently toxic to humans. Bivalve mollusks, because of the way they feed (filtering particulate matter from the water), concentrate this toxin in their tissues, and become dangerously (sometimes lethally) poisonous to anyone who eats them. The harvesting of bivalves is prohibited during a red tide, and for a period thereafter, which of course is detrimental to the shellfish industry. Fortu nately, red tides are usually quite localized. When people hear that *shellfish* are dangerous to eat, they stop buying not just bivalves, but also snails, squid, lobster, crabs, shrimp, and even ordinary fish, though these are actually safe to eat; so these industries suffer as well. Paul Monfils