The state of Washington routinely experiences seasonal restrictions on commercial and recreational shellfish harvest due to two toxic phytoplankton syndromes, Paralytic Shellfish Poisoning (PSP) and Amnesic Shellfish Poisoning (ASP), which is often referred to as Domoic Acid Poisoning (DAP). The biotoxin that causes PSP temporarily interferes with the transmission of nerve impulses in warm-blooded animals, causing symptoms in humans such as, numbness and tingling of the lips, tongue, face and extremities, difficulty talking, breathing, swallowing and muscle incoordinations. Symptoms develop quickly (within 1-2 hours of consumption) and can result in death. The species that causes PSP in Washington state marine waters is Alexandrium catenella. Alexandrium is usually present in small numbers; however, when environmental conditions are optimum, rapid reproduction occurs. Filter-feeding shellfish can accumulate the toxins to dangerous levels during these "blooms". Domoic acid poisoning is caused by eating fish, shellfish or crab containing the toxin. Symptoms include vomiting, nausea, diarrhea and abdominal cramps within 24 hours of digestion. In severe cases, neurological symptoms develop within 48 hours and include headache, dizziness, confusion, disorientation, loss of short-term memory, motor weakness, seizures, profuse respiratory secretions, cardiac arrhythmias, coma and possibly death. Domoic acid produced by marine diatoms of the genus Pseudo-nitzschia, was first detected on the Pacific coast in 1991 when several pelican and cormorant deaths were link to domoic acid in anchovies. The Washington State Department of Health routinely monitors for PSP and ASP in shellfish from areas throughout the state. Areas are closed for harvest of molluscan shellfish when PSP toxin levels are equal to or exceed 80 ug toxin/100 grams shellfish tissue. Molluscan shellfish areas are closed when domoic acid (DA) levels reach 15 ppm in a composite sample of six shellfish (this level was changed to 20 ppm in 2001), whereas Dungeness crab areas are closed when DA levels reach 30 ppm in three of six individual crab viscera.

The state of Washington routinely experiences seasonal restrictions on commercial and recreational shellfish harvest due to two toxic phytoplankton syndromes, Paralytic Shellfish Poisoning (PSP) and Amnesic Shellfish Poisoning (ASP), which is often referred to as Domoic Acid Poisoning (DAP). The biotoxin that causes PSP temporarily interferes with the transmission of nerve impulses in warm-blooded animals, causing symptoms in humans such as, numbness and tingling of the lips, tongue, face and extremities, difficulty talking, breathing, swallowing and muscle incoordinations. Symptoms develop quickly (within 1-2 hours of consumption) and can result in death. The species that causes PSP in Washington state marine waters is Alexandrium catenella. Alexandrium is usually present in small numbers; however, when environmental conditions are optimum, rapid reproduction occurs. Filter-feeding shellfish can accumulate the toxins to dangerous levels during these "blooms". Domoic acid poisoning is caused by eating fish, shellfish or crab containing the toxin. Symptoms include vomiting, nausea, diarrhea and abdominal cramps within 24 hours of digestion. In severe cases, neurological symptoms develop within 48 hours and include headache, dizziness, confusion, disorientation, loss of short-term memory, motor weakness, seizures, profuse respiratory secretions, cardiac arrhythmias, coma and possibly death. Domoic acid produced by marine diatoms of the genus Pseudo-nitzschia, was first detected on the Pacific coast in 1991 when several pelican and cormorant deaths were link to domoic acid in anchovies. Therefore, this dataset only contains PSP data for 1957-1988. The Washington State Department of Health routinely monitors for PSP and ASP in shellfish from areas throughout the state. Areas are closed for harvest of molluscan shellfish when PSP toxin levels are equal to or exceed 80 ug toxin/100 grams shellfish tissue. Molluscan shellfish areas are closed when domoic acid (DA) levels reach 15 ppm in a composite sample of six shellfish (this level was changed to 20 ppm in 2001), whereas Dungeness crab areas are closed when DA levels reach 30 ppm in three of six individual crab viscera.

The state of Washington routinely experiences seasonal restrictions on commercial and recreational shellfish harvest due to two toxic phytoplankton syndromes, Paralytic Shellfish Poisoning (PSP) and Amnesic Shellfish Poisoning (ASP), which is often referred to as Domoic Acid Poisoning (DAP). The biotoxin that causes PSP temporarily interferes with the transmission of nerve impulses in warm-blooded animals, causing symptoms in humans such as, numbness and tingling of the lips, tongue, face and extremities, difficulty talking, breathing, swallowing and muscle incoordinations. Symptoms develop quickly (within 1-2 hours of consumption) and can result in death. The species that causes PSP in Washington state marine waters is Alexandrium catenella. Alexandrium is usually present in small numbers; however, when environmental conditions are optimum, rapid reproduction occurs. Filter-feeding shellfish can accumulate the toxins to dangerous levels during these "blooms". Domoic acid poisoning is caused by eating fish, shellfish or crab containing the toxin. Symptoms include vomiting, nausea, diarrhea and abdominal cramps within 24 hours of digestion. In severe cases, neurological symptoms develop within 48 hours and include headache, dizziness, confusion, disorientation, loss of short-term memory, motor weakness, seizures, profuse respiratory secretions, cardiac arrhythmias, coma and possibly death. Domoic acid produced by marine diatoms of the genus Pseudo-nitzschia, was first detected on the Pacific coast in 1991 when several pelican and cormorant deaths were link to domoic acid in anchovies. The Washington State Department of Health routinely monitors for PSP and ASP in shellfish from areas throughout the state. Areas are closed for harvest of molluscan shellfish when PSP toxin levels are equal to or exceed 80 ug toxin/100 grams shellfish tissue. Molluscan shellfish areas are closed when domoic acid (DA) levels reach 15 ppm in a composite sample of six shellfish (this level was changed to 20 ppm in 2001), whereas Dungeness crab areas are closed when DA levels reach 30 ppm in three of six individual crab viscera.

Harmful algal bloom (HAB) events are becoming more common in Alaska as ocean temperatures rise due to climate change. These events carry the risk of producing dangerous levels of HAB-derived toxins in the marine environment, including paralytic shellfish toxins (PSTs). PSTs pose a serious threat to uppertrophic populations (e.g., marine mammals, sea birds, predator fish), where a likely mechanism of delivery is via consumption of forage fish that have themselves been exposed to PSTs. Recent statewide occurrences, such as seabird die-off and marine mammal stranding events, have raised concerns about this pathway, highlighting a need to better understand its mechanisms. The issue is a lack of data-driven information regarding PST exposure levels in forage fish due to field data being difficult to obtain. This project sought to facilitate new collaborative science that addressed this issue by becoming better positioned to pursue future funding opportunities (phase I). Our approach was to conduct 'proof of concept' activities for the husbandry of Alaska forage fish species while simultaneously engaging with end users. We used these inputs to inform a proposal that would secure funds for continuation of this effort as a multi-year research project (phase II). As the only National Estuarine Research Reserve (NERR) in Alaska, the Kachemak Bay NERR was able to act as a collaborative platform bringing necessary expertise within Alaska and nationally to the planning table, as well as engage with end users to ensure that research findings met user needs at various scales.

The methods saxiphilin radioreceptor assay, mammalian Na channel, the commercial cell culture MIST kit, mouse lethality bioassay and HPLC analysis were compared for measuring paralytic shellfish toxins. To compare 5 methods of measuring paralytic shellfish toxins. Proportions of individual paralytic shellfish toxins (STX, dcSTX, neoSTX, GTX1, GTX2, GTX3, GTX4, C1, C2, dcGTX2, dcGTX3) to total toxin content of the samples is given where discernable by HPLC analysis.

Using two unrelated STX-binding proteins (the rat brain Na channel and a saxiphilin from the xanthid crab Liomera tristis), this study experimentally validated the predicted combined effects of binary and ternary mixtures of paralytic shellfish toxins (PSTs). All toxin dilutions (tritiated saxitoxin ([3H]STX), STX dihydrochloride, neoSTX, dcSTX, and GTX5) were in 0.01 M acetic acid. The L. tristis saxiphilin assay was conducted in high protein binding 96 well filtration plates and the rat brain Na channel binding of [3H]STX was measured using a microtiter plate method.The model predicts the amount of inhibition by toxin mixtures in competitive binding assays from which an IC50 (concentration that inhibits radioligand bindingby 50%) can be calculated. IC50 values and their 95% confidence limits from experimental data were derived using the single site curve equation of Graphpad Prism (Ver 4.0, Graphpad Software, San Diego, CA), with fitting constrained to a slope of 1 and a baseline of 0. To understand how toxin mixtures may act at the Na channel receptor via which PSTs exert their neurotoxicity.To test if the presence of weaker toxins dilutes stronger toxins The strong dominance of a mixture by the most potent toxins has implications for measurement of toxic test samples and for standards that may contain low levels of highly potent bioactive impurities.

In this study, a microtitre plate binding assay using a saxiphilin isoform [3H]STX from the centipede Ethmostigmus rubripes, was challenged with differing conditions of salt concentration and identity, pH and the addition of non-toxic extracts of commercial shellfish.Elements present (Na, K, Mg, Ca, Zn, Ni, Mn, Cr, Sr, Mo, Al, V, Fe, Cu, Pb, Co) in the shellfish extracts (green lipped mussel, Perna canalicularis; Sydney rock oyster, Saccostrea glomerata; and pipis, Donax deltoides) were measured by inductively coupled plasma spectroscopy. The effects upon the assay by the four most common salts of these elements, NaCl, KCl, CaCl2 and MgCl2 were studied by varying their concentrations (0-800 mM).The effect of pH upon the assay was measured by replacing the assay buffer in standard conditions with a buffer mixture of Tris (20 mM) -Mes (10 mM) -acetic acid (10 mM), adjusted with tetramethylammonium hydroxide or HCl to indicated pH which ranged from 3.4 to 9.0. To investigate the microtitre plate saxiphilin assay's ability to deal with potential interfering compounds from shellfish extracts, and the effect of acidic pH necessary for toxin stability when extracting PSTs from shellfish.