Jennie@ifish
12-08-2001, 05:28 AM
Some important information about Oregon Clams...
Jennie,
There has been some confusion and questions regarding why Oregon was not open while Washington was for Razor clam harvesting. Now that Oregon is open it is a mute point, but I think it is important that the public understands why the beaches get closed and why they aren't always open at the same time.
Eventhough Oregon's clatsop beaches are geographically only a few miles from the Longbeach Penninsula in Washington, they are nearly worlds apart geologically. Specifically, the Columbia River is a huge environmental barrier and it keeps things separate very well, including biological toxins such as domoic acid and Paralytic shellfish poisoning.
Domoic Acid, also known as Amnesic Shellfish Poisoning ( ASP), occurs in shellfish as well as other marine animals. It is caused by a plankton called a diatom. This is not a new toxin, just a new problem. Only by accident was the toxin picked up in another toxin test, though domoic acid has been a problem on the east coast for some time prior to Oregons first detection.
When there becomes a plankton "bloom", or what some refer to as a red tide (though it will be other colors), there can be a very high abundance of the plankton that can cause domoic acid. Razor clams as well as many other shellfish, are filter feeders that filter out plankton from the water column. When a Razor clam ingests the diatom that causes domoic acid, the acid is stored in the muscle and fatty tissues of the clam. In time, the clam will naturally depurate (flush out) the toxin from its body. Domoic acid is not harmful to clams or other cold blooded creatures, it can and does have effects on warm blooded animals.
In humans the symptoms from eating clams or other shellfish that have concentrations of domoic acid usually occur from 1-5 hours from the time of ingestion, though there have been cases where it took 24 hours after ingestion. Symptoms for mild cases include, vomiting, diarrhea, nausea and headaches. Moderate cases include confusion, disorientation and more extremes of the mild symptoms. Heavy or extreme cases include memory loss, seizures, coma and worst case scenario death. People react differently to the toxin based on individual sensitivity to the toxin, individuals health, and the amount of toxin ingested. Most people who have been poisoned by domoic acid in low doses probably passed it off as the flu or food poisoning since the symptoms are comparable. In low concentrations, it begins to concentrate first in the neck, gills and gastrointestinal tract. Always clean or remove those areas from the clam.
Domoic acid as well as PSP (paralytic shellfish poisoning) cannot be destroyed or cooked out of the clam. It cannot be artificially purged out of the clam by putting them in tap water, cornmeal water, baking soda baths, or any other solution.
If you have any further questions please feel free to contact me.
Sincerely,
Matt Hunter
-------------------------------------------------------
Matthew Hunter
Oregon Department Fish and Wildlife
Marine Resources Program
North Coast Shellfish Biologist
2001 Marine Drive, Room 120
Astoria, Or 97103
(503)325-2462 ext. 116
(503)325-8227 FAX
email: matthew.v.hunter@state.or.us
Jennie,
There has been some confusion and questions regarding why Oregon was not open while Washington was for Razor clam harvesting. Now that Oregon is open it is a mute point, but I think it is important that the public understands why the beaches get closed and why they aren't always open at the same time.
Eventhough Oregon's clatsop beaches are geographically only a few miles from the Longbeach Penninsula in Washington, they are nearly worlds apart geologically. Specifically, the Columbia River is a huge environmental barrier and it keeps things separate very well, including biological toxins such as domoic acid and Paralytic shellfish poisoning.
Domoic Acid, also known as Amnesic Shellfish Poisoning ( ASP), occurs in shellfish as well as other marine animals. It is caused by a plankton called a diatom. This is not a new toxin, just a new problem. Only by accident was the toxin picked up in another toxin test, though domoic acid has been a problem on the east coast for some time prior to Oregons first detection.
When there becomes a plankton "bloom", or what some refer to as a red tide (though it will be other colors), there can be a very high abundance of the plankton that can cause domoic acid. Razor clams as well as many other shellfish, are filter feeders that filter out plankton from the water column. When a Razor clam ingests the diatom that causes domoic acid, the acid is stored in the muscle and fatty tissues of the clam. In time, the clam will naturally depurate (flush out) the toxin from its body. Domoic acid is not harmful to clams or other cold blooded creatures, it can and does have effects on warm blooded animals.
In humans the symptoms from eating clams or other shellfish that have concentrations of domoic acid usually occur from 1-5 hours from the time of ingestion, though there have been cases where it took 24 hours after ingestion. Symptoms for mild cases include, vomiting, diarrhea, nausea and headaches. Moderate cases include confusion, disorientation and more extremes of the mild symptoms. Heavy or extreme cases include memory loss, seizures, coma and worst case scenario death. People react differently to the toxin based on individual sensitivity to the toxin, individuals health, and the amount of toxin ingested. Most people who have been poisoned by domoic acid in low doses probably passed it off as the flu or food poisoning since the symptoms are comparable. In low concentrations, it begins to concentrate first in the neck, gills and gastrointestinal tract. Always clean or remove those areas from the clam.
Domoic acid as well as PSP (paralytic shellfish poisoning) cannot be destroyed or cooked out of the clam. It cannot be artificially purged out of the clam by putting them in tap water, cornmeal water, baking soda baths, or any other solution.
If you have any further questions please feel free to contact me.
Sincerely,
Matt Hunter
-------------------------------------------------------
Matthew Hunter
Oregon Department Fish and Wildlife
Marine Resources Program
North Coast Shellfish Biologist
2001 Marine Drive, Room 120
Astoria, Or 97103
(503)325-2462 ext. 116
(503)325-8227 FAX
email: matthew.v.hunter@state.or.us