With the start of the razor clam fishery just a month away, the 2002-03 season was shaping up as one of the best ever in Washington state. Stock assessments conducted by the Washington Department of Fish and Wildlife (WDFW) and tribal biologists found an abundance of clams, while coastal tide charts revealed plenty of opportunities for digging. Just as important, test results from the Washington Department of Health (WDOH) indicated that marine toxin levels at all five state razor clam beaches were well within the range considered safe to human health.
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| Damien Mulinix, Chinook Observer |
| A clam digger chases down a razor clam during a beach opening. |
All this was welcome news to recreational diggers, coastal communities and area tribes, which have a substantial interest in razor clams. When the season is open, more than 30,000 clam diggers may descend on the Washington coast in a single weekend, filling beaches, restaurants and motels from Long Beach to Kalaloch. During nighttime openings in fall and winter, diggers' lanterns form twinkling constellations that stretch for miles along the shoreline.
For coastal communities, this influx of visitors generates more than $12 million per year in economic activity during winter and spring when business is otherwise slow. For coastal tribes, which are entitled by treaty to 50 percent of the shellfish harvest, razor clams play an important role in both commercial and subsistence fisheries. The Quinault Nation conducts a major commercial razor clam fishery on several northern beaches and a small non-tribal commercial fishery around the Willapa Spits supplies markets for fresh clams and crab bait.
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| Kevin Hong, The Daily World |
| Razor clam openings can draw as many as 30,000 diggers to coast beaches in a single day. |
But visions of a successful season began to fade in mid-September 2002 when - just three weeks before the first scheduled opening - WDFW shellfish managers received some troubling news: Water samples collected from coastal beaches under a new testing procedure revealed extremely high concentrations of microscopic algae, the diatom Pseudo-nitzschia.
Dan Ayres, lead WDFW coastal shellfish biologist, was concerned. Under conditions that are not fully understood, certain species of Pseudo-nitzschia can produce domoic acid, a marine toxin that can be harmful - and sometimes fatal - to humans, marine mammals and birds. Razor clams, which consume algae and concentrate domoic acid in their body tissue, can become a link in this toxic food chain. Although razor clams, themselves, are not affected by domoic acid, those clams imbued with the toxin can poison humans and other species who eat them.
"Those water samples definitely raised a red flag with the season opener just a couple weeks off," Ayres said. "A bloom of Pseudo-nitzschia isn't necessary a problem in itself, but it can turn into a big problem if it starts to produce domoic acid."
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| Click on map to enlarge. |
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Unfortunately, that is just what happened. Six days before the scheduled Oct. 5 season opener, a new round of tests revealed elevated levels of domoic acid in samples of clam meat taken at all five state razor clam beaches. Toxin levels at the three northern beaches - Copalis, Mocrocks and Kalaloch - already exceeded the state and federal "action level" of 20 parts per million (ppm), the point at which shellfish are considered unsafe for human consumption. At the other two beaches - Long Beach and Twin Harbors - toxin levels had risen from 3 ppm in the previous test to 16 ppm in a single week.
After discussions with WDOH and tribal shellfish managers, WDFW decided to postpone the razor clam season opening for the entire Washington coast. The Oregon Department of Fish and Wildlife, facing similar circumstances, suspended its razor clam fishery the same week.
"Given the rapid rise in clam toxicity, increasing algae counts and a strong recommendation by staff at the Washington Department of Health, postponing the fishery coast-wide appeared to be the only responsible course of action," Ayres said. "We knew people would be disappointed, but we decided it was better to be safe than sorry."
Domoic acid poisons another razor clam season
That decision proved fortuitous. By the end of October, domoic acid levels in clams tested at all five Washington razor clam beaches soared above 100 ppm, reaching 185 ppm at Copalis and Mocrocks. By that point, WDFW was sending sample clams WDOH for analysis on a weekly basis.
Ayres knew from experience it would likely be some time before coastal beaches could safely be opened for digging. Although toxin levels in the water column began to subside within a few weeks of the algae bloom, razor clams can retain the toxin in their body tissues for months. Twice before - in 1991 and again in 1998 - Washington's coastal beaches remained closed to razor clam digging throughout the season as test after test found that the clams contained toxin levels deemed unsafe for human consumption.
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| A WDFW scientific technician records information on clams taken in a test dig. |
As fall turned to winter, the 2002-03 season appeared to be following the same pattern. By the end of January, toxin levels in razor clams at all five Washington beaches remained well above the 20 ppm action level, ranging from a high of 103 ppm at Kalaloch to a low of 59 ppm at Twin Harbors. By February of 2003, the problem spread to crab in Willapa Bay. Testing conducted by WDOH found high levels of domoic acid in the viscera of Dungeness crab, which likely had been feeding on razor clams, prompting the first toxin-related closure of crab fishing in the bay since 1991.
Although the Willapa Bay crab fishery was cleared to reopen in April, toxin levels in coastal razor clams remained above the level considered safe for human consumption throughout the spring. Finally on May 30, with the annual spawning period for razor clams fast approaching, WDFW abandoned the 2002-03 razor clam season without authorizing a single dig.
For the third time since 1991, clam diggers had lost an entire season to the marine toxin produced by the Pseudo-nitzschia algae. The Quinault Nation's commercial razor clam fishery was idled and coastal communities lost millions of dollars in tourism business.
The good news was that no human illnesses or deaths were reported from domoic acid poisoning, despite months of potentially lethal toxicity levels in coastal razor clams. "Nobody likes to see the razor clam season closed down, but I think everyone agrees that human health has to be the first priority," said Frank Cox, biotoxin coordinator for WDOH. "There has never been a human fatality from domoic acid poisoning in Washington state, and we want to keep it that way."
Coastal states see growing marine toxin problem
The Pseudo-nitzschia diatom that derailed the 2002-03 razor clam season is one of thousands of species of microalgae that form the base of the ocean food chain. While only about 2 percent of these species produce toxic blooms, these single-celled plants present a significant health risk in virtually every coastal area of the United States and around the world.
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| Researchers rig a buoy with instruments to track algae blooms. |
Sometimes called "red tides," toxic algae blooms occur when environmental conditions spark a proliferation in cell growth, sometimes coloring the water with their pigment. The term is misleading, however, because toxic blooms actually come in a variety of colors - yellow, orange, brown, pink, red or translucent - and have little to do with the tides. Moreover, not all colorful algal blooms are toxic. Noctiluca, which produces brilliant red streaks the color of tomato soup, has no known ill effects on humans. For these reasons, scientists generally use the term "harmful algal blooms"(HABs) to describe blooms that are toxic to humans, fish and other animals.
According to the National Centers for Disease Control, an average of 30 cases of HAB-related poisoning are reported in the United States each year. Although most victims survive, three deaths and 183 illnesses have been attributed to HABs in the four Pacific coast states (primarily Alaska) since 1980. Nationwide, economic losses resulting from fishing closures and other efforts to protect public health exceed $50 million per year, according to Dr. Donald Anderson, a senior scientist at Woods Hole Oceanographic Institution in Massachusetts and a leading national expert in HABs.
Many scientists, including Anderson, believe the problem is getting worse. In March 2003, Anderson told a congressional subcommittee holding hearings on the issue that "virtually every coastal state is now threatened by harmful or toxic algal species, whereas 30 years ago, the problem was much more scattered and sporadic. The number of toxic blooms, the economic losses from them, the types of resources affected, and the number of toxins and toxic species have all increased dramatically in recent years."
Two marine toxins threaten human health in Washington
Domoic acid is one of two marine toxins that present the greatest threat to human health in Washington state. The other is paralytic shellfish poisoning (PSP), which affects more U.S. coastline than any other marine toxin associated with toxic blooms. A third type of alga called Heterosigma has caused significant losses of both wild and cultivated salmon in Washington state and British Columbia, but does not appear to affect human health.
Frank Cox, the WDOH biotoxin coordinator, recalls the case of a man who nearly died of PSP in 2000 after eating mussels harvested from a closed beach on Carr Inlet in southern Puget Sound. "He was totally paralyzed by the time he was admitted to the intensive care unit and would have suffocated without a mechanical respirator," Cox said. "But once he got rid of the toxin, he was just fine. It was like it never happened."
That is not always the case with domoic acid poisoning, which can cause permanent brain damage, resulting in severe, short-term memory loss. For that reason, the condition - also known as "amnesic shellfish poisoning" (ASP) - has sometimes been misdiagnosed as Alzheimer's disease. "If ASP doesn't kill a person outright, it can cause severe short-term memory loss," Cox said. "Many victims wind up in nursing homes. There's a well-known case of a physics professor who could still teach, but totally lost his ability to remember simple things like where he parked his car."
While ASP and PSP attack the body in different ways, the two toxins are similar in a number of ways:
- ASP and PSP are both usually contracted by eating toxic shellfish.
- Both toxins can be fatal if consumed in sufficient quantities.
- Cooking or freezing contaminated shellfish does not remove the toxins.
- There is no known antidote for either type of poisoning, although immediate medical attention can sometimes prevent loss of life.
Domoic Acid Poisoning
(Amnesic Shellfish Poisoning)
Associated Algae: Pseudo-nitzschia
Likely sources: Razor clams and Dungeness crab
Symptoms: Vomiting, nausea, diarrhea and abdominal cramps within 24 hours of ingestion. In more 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.
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Domoic acid was first identified as a shellfish toxin in 1987, when three people died and more than 100 others became ill after eating toxic mussels on Prince Edward Island in eastern Canada. Some who survived require lifelong nursing care. Although there was evidence of the toxin in North American waters before that time, the outbreak in eastern Canada brought the first public awareness of the problem.
Domoic acid was first detected on the West Coast in 1991, when dozens of brown pelicans and cormorants were found dead or suffering unusual neurological symptoms in Monterey Bay, California. By October of that year, toxin levels were soaring from northern California to the north coast of Washington state, prompting coastwide shellfish closures. Although no one died from the 1991 outbreak, 25 people in Washington became ill during the first recorded incidence of domoic acid poisoning on the West Coast. Economic losses associated with Washington fisheries alone were estimated at $7.6 million.
Shorter episodes of elevated toxin levels in Washington waters followed in 1993 and 1994, before the next major coast-wide outbreak in 1998. As in 1991, the first sign of trouble appeared on the central California coast, where sea lions were observed hauling themselves out of the water, wandering onto roads and highways and displaying other signs of disorientation. By June of 1998, more than 50 California sea lions from San Luis Obispo to Santa Cruz died after eating anchovies and sardines containing high levels of domoic acid.
By July of that year, elevated levels of domoic acid were detected in razor clams in Washington and Oregon. After the 1991 experience, WDFW had established a monitoring program in conjunction with WDOH that provided clear evidence of rising toxin levels. As in 1991, toxin levels in 1998 remained elevated for months, resulting in the last season-long closure before 2002.
Paralytic Shellfish Poisoning
(PSP)
Associated Algae: Alexandrium dinoflaellates
Likely sources: Clams, mussels, oysters, geoduck and scallops, as well as moon snails and other gastropods. Crab guts, but not crab meat, have also been found to contain unsafe levels of PSP.
Symptoms: The lips and tongue may begin to tingle within minutes. This may progress to the fingers and toes, followed by loss of control of arms and legs and difficulty in breathing. If enough toxin is ingested, muscles of the chest and abdomen can become paralyzed. Death can result in as little as two hours, as muscles used for breathing become paralyzed.
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Unlike domoic acid, which was first recognized as a public health hazard in North America less than 20 years ago, PSP has a long history in the Pacific Northwest. The earliest documented case occurred in 1793, when five members of British explorer George Vancouver's crew became ill - one fatally - after eating toxic mussels from the central British Columbia coast. Native peoples were undoubtedly aware of the danger long before then, and outbreaks of the toxin have become increasingly common since then in Washington state and many other parts of the world.
In 1942, two children and an adult died after eating PSP-laden mussels and butter clams taken from the Strait of Juan de Fuca, prompting WDOH and WDFW to impose seasonal closures on shellfish harvesting in the Strait for the next 50 years. Since then, WDOH has systematically expanded its testing program, routinely announcing beach closures whenever toxin levels exceed health standards established by the U.S. Food and Drug Administration (USFDA).
"First we monitored the Strait of Juan de Fuca and the coast, then it was the San Juan Islands and the Bellingham area," said Cox, who has worked as the WDOH marine biotoxin coordinator since 1978. "Now we monitor pretty much the whole state. PSP first became a problem in northern Puget Sound in 1978 and it has continued to spread south since then."
Although no human fatalities have been reported from PSP in Washington state since 1942, people still get sick every few years - usually after eating toxic shellfish collected from closed beaches, Cox said.
"We do everything we can to make people aware of the hazards," Cox said. "But some people get a false sense of security when they eat shellfish from a closed beach and nothing happens. Then they get a hold of some toxic clams and they're in real trouble."
From monitoring to long-range forecasting
Monitoring procedures for marine toxins in state waters have come a long way since 1991, when state agencies scrambled to arrange tests for domoic acid upon hearing of the initial outbreak in California. Using carefully prescribed protocols, WDOH now tests more than 1,100 shellfish samples for domoic acid and another 3,500 samples for PSP each year. Results of those tests, once a two-week wait, are now available within 48 hours. Biotoxin warnings are routinely posted in several languages at state beaches, released to the news media and carried on WDOH's website (http://www.WDOH.wa.gov/).
"We're no longer in crisis mode," said Cox, who played a leading role developing the statewide testing program. "On the other hand, shellfish tissue analysis is a reactive program. It only tells us what's already here - not what's ahead."
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| Rapid Test Kits like these can provide an immediate indication of toxin levels. |
Dan Ayres, the WDFW coastal shellfish manager most directly responsible for planning razor clam openings, is keenly aware of that distinction. Thanks to a new monitoring program that quantifies Pseudo-nitzschia blooms near ocean beaches, Ayres effectively got two weeks' advanced warning of the domoic acid outbreak that shut down the 2002-03 razor clam season. But, as he told a congressional subcommittee in March of 2003, two months would have been better.
"If, as a fishery manager, I had two months' notice of a pending problem, it might be possible to adjust season openings to take advantage of at least some harvest opportunities before the toxin is ingested by the shellfish and the fisheries must close," Ayres told the House Subcommittee on Environment, Technology and Standards during hearings on HABs nationwide. "These harvest opportunities would lessen the blow to the various stakeholders who depend on these fisheries."
ORHAB Partners
- Washington Department of Fish and Wildlife
- Washington Department of Health
- Washington Department of Ecology
- University of Washington
- Northwest Fisheries Science Center
- National Centers for Coastal Ocean Science
- Olympic Coast National Marine Sanctuary
- Pacific Shellfish Institute
- Makah Tribe
- Quinault Indian Nation
- Battelle Marine Sciences Laboratory
- Saigene Corporation
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Ayres is not alone in his desire to find ways to forecast toxic outbreaks before they occur. In 1999, concerned about the increasing frequency of domoic acid events on the coast, representatives from several state and federal agencies, coastal tribes, academic organizations and marine-related businesses joined forces to form the Olympic Region Harmful Algal Bloom (ORHAB) partnership. Members of the group, who meet regularly to coordinate their activities, share primary goals:
- To understand the environmental conditions that initiate and maintain blooms of harmful species.
- To develop a sampling program and models for the prediction and mitigation of HABs.
- To develop, test and implement new technologies for monitoring marine toxins.
In 2000, ORHAB qualified for a five-year grant from the Centers for Coastal Ocean Science at the National Oceanic and Atmospheric Administration (NOAA), which has supported such activities as training field staff in testing procedures, using satellite imagery to track Pseudo-nitzschia blooms and developing a model to predict future blooms. The federal grant program, known as MERHAB (Monitoring and Event Response for Harmful Algal Blooms), also allowed ORHAB to launch the water-testing program that gave state fisheries managers their first indication of the domoic acid outbreak in 2002.
"The MERHAB grant supported our efforts to take coastal monitoring to the next level," said Dr. Vera Trainer, program manager of the NOAA Northwest Fisheries Science Center (NWFSC) and lead investigator for the ORHAB group. "It also helped bring all the ORHAB partners together around common goals."
Although the MERHAB grant runs out in June of 2005, the Washington State Legislature approved a $3 surcharge on shellfish licenses in 2003 to support the WDFW water-testing program and WDOH biotoxin programs in future years. In addition, ORHAB partners and other scientists across the United States recently received an $8.7 million federal grant to conduct study what researchers believe may be the primary source of domoic acid on the Washington coast.
Searching for answers
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| NOAA Coastwatch |
| The blue swirl at the top of this satellite photo marks the Juan de Fuca eddy. |
Off the Strait of Juan de Fuca, where tidal action draws water from Puget Sound into the Pacific Ocean, a giant eddy forms each spring, spinning counterclockwise in 30-mile-wide gyre. Clearly visible in satellite photos, the Juan de Fuca eddy is an area of persistent upwelling, churning up nutrients that make it highly productive for a wide variety of marine life. It is also a "hotspot" for domoic acid and the Pseudo-nitzschia blooms that produce it, as marine scientists found during research cruises with the Olympic Coast National Marine Sanctuary (OCNMS) in 1997 and 1998.
"The evidence points to the eddy as a `bioreactor' for toxic blooms during certain times of the year," said Trainer, one of the scientists who conducted research on the toxin aboard those cruises. Moreover, on-board measurements taken by Trainer and her colleagues, coupled with beach samples, indicate that domoic acid generated in the eddy drifts southward, then moves toward shore during the first major storm in fall.
"The transport of domoic acid from the eddy to the coast is supported by our measurements of toxin in seawater on the beaches after fall storms," she said. "Unfortunately, it also appears to coincide with the traditional start of the recreational razor clam season. We don't know why domoic acid is a problem some years and not others, but we want to find out."
That is just one of many questions Trainer and fellow scientists at the NWFSC and the University of Washington School of Oceanography hope to answer during the course of a five-year study funded through the federal Ecology and Oceanography of Harmful Algal Blooms program at NOAA. Together with UW oceanography professor Barbara Hickey, Trainer will lead six three-week research cruises to study the physiology, toxicology, ecology and oceanography of Pseudo-nitzschia and its relationship with the Juan de Fuca eddy. Using measuring instruments attached to fixed and "drifter" buoys, the scientists will attempt to determine what makes the eddy so hospitable for toxic algae, what causes the production and release of domoic acid and how that acid is transported from the eddy to shellfish beds.
"This kind of basic research is critical if we ever want to get a handle on the growing problem of domoic acid and other marine toxins in this state," Trainer said. "Our goal is to be able to predict these blooms much like the weather service can predict a hurricane. That way, resource managers and others can take action days or even weeks before the toxins show up in shellfish."
That would suit Dan Ayres, the WDFW coastal shellfish manager, just fine.
"This job has changed a lot since the first domoic acid outbreak in 1991," Ayres said in September 2003 after approving the first razor-clam dig in more than a year. "The focus used to be on the long-term health of the clams and the best way to meet public expectations for digging opportunities. Now, with domoic acid levels skyrocketing every few years, things can change practically overnight. I suspect we'll have to deal with domoic acid for the foreseeable future, but it would sure be great to have some advanced notice of the next outbreak."
Related
Links:
Olympic Region Harmful Algal Blooms
http://www.nwfsc.noaa.gov/orhab/
Washington Department of Fish and Wildlife
http://wdfw.wa.gov/fish/shelfish/razorclm/domacid.htm
Washington Department of Health
http://www.doh.wa.gov/ehp/sf/default.htm
NOAA Northwest Fisheries Science Center
http://www.nwfsc.noaa.gov/research/divisions/ec/hpep.cfm
National Centers for Coastal Ocean Science
http://coastalscience.noaa.gov/
