DOMOIC ACID, DOLPHINS, SEA LIONS - USA: (CALIFORNIA)
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Date: Fri 19 Aug 2011
Source: Ventura County Star [edited]
<http://www.vcstar.com/news/2011/aug/19/dead-dolphins-sea-lions-found-on-oxnard-beach/>
Dead dolphins, sea lions found on Oxnard beach; natural neurotoxin blamed
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[A couple] were walking on the Oxnard Beach Thursday evening [18 Aug 2011] north of Fifth Street when they came across a grisly scene. "We were having a really good time. We were with our dog, the sun was setting and the weather was beautiful, and then we came up to the 1st dead dolphin," she said. "And then we found another one, and we looked up and we realized the beach was kind of scattered with dead dolphins."
On Friday morning [19 Aug 2011], volunteers from the Channel Islands Marine and Wildlife Institute found 4 dead dolphins and 4 dead sea lions at a site not far from the power plant at Mandalay Beach.
"They were all different sizes. 2 of the dolphins were smaller and appeared to be younger," [the woman] said. "We didn't understand what was going on, and we felt very sad for the dolphins."
According to Tom McCormick, a marine biologist who has worked in biological assessment along the Ventura County coast for more than 20 years, the deaths probably are linked to a natural neurotoxin called domoic acid.
"People are quick to point the finger at the power plant, but quite frankly the operators don't add anything to the water they use except a little heat," McCormick said.
"At this time of year, you often get the red tides, and associated with that are plankton species that produce domoic acid," he said.
"This is a neurotoxin that is picked [up] by the filter feeders in the water. The smaller fishes, such as anchovies and sardines, eat the filter feeders, and the toxins get concentrated in the animals that eat the smaller fishes. Sometimes, you will see a sea lion on the beach jerking and contorting due to this toxin -- it's really heart-wrenching."
Ron Barrett, a field assessment volunteer who has been working with the institute for 16 years, confirmed the animals died of natural causes not related to the plant or to fishing.
"Basically, every year, we have a season where domoic acid presents itself," he said. "Some seasons are worse than others. This year [2011] has been fairly light in Ventura County."
The decomposing carcasses attracted a vast aerial crowd of seagulls, buzzards, and vultures. "The bodies were covered with seagulls," [the woman] said. "It was pretty gross."
[Byline: Christopher Stolz]
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[Domoic acid, an acidic cyanotoxin, a neurotoxic tricarboxylic amino acid structurally related to kainic and glutamic acids, associated with certain algal blooms and possibly produced by the diatom _Pseudonitzschia_ is also called amnesic shellfish poison (ASP).
Domoic acid was named for the seaweed from which it was discovered, _Chondria armata_, called 'domoi' in Japan. The toxic acid is accumulated by marine organisms (including sea lions) feeding on phytoplankton, anchovies, sardines, and shellfish. Domoic acid is essentially a neurotoxin in mammals causing brain damage, neurological dysfunction, and death in severe cases.
In 1987, several people died and more than 100 became ill after eating blue mussels caught off Prince Edward Island, Canada. It was determined by Canadian scientists that domoic acid had entered the food chain when the mussels fed on a toxic algae bloom of the pennate diatom _Pseudonitzschia pungens_ forma _multiseries_.
In 1991, in Monterey Bay, California, a bloom of _Pseudonitzschia australis_ also produced domoic acid that was then concentrated in anchovies feeding upon it. The deaths of pelicans and cormorants that ate the anchovies were reported to be related to their exposure to domoic acid.
Transient elevations of plasma BUN (blood urea nitrogen) levels, as well as neurodegeneration of the hippocampus, and memory deficits have been associated with near-lethal domoic acid exposures.
References
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1. Perl TM, et al: An outbreak of toxic encephalopathy caused by eating mussels contaminated with domoic acid. N Engl J Med 1990;
322(25): 1775-80 (available at
<http://www.nejm.org/doi/full/10.1056/NEJM199006213222504#t=article>).
2. Garrison DL, et al: Confirmation of domoic acid production by _Pseudonitzschia australis_ (bacillariophyceae) cultures. J Phycol 1992; 28(5): 604-7 (abstract available at <http://onlinelibrary.wiley.com/doi/10.1111/j.0022-3646.1992.00604.x/abstract>).
3. Scallet AC, et al: Domoic acid-treated cynomolgus monkeys (_M.
fascicularis_): effects of dose on hippocampal neuronal and terminal degeneration. Brain Res 1993; 627(2): 307-13 (abstract available at <http://www.ncbi.nlm.nih.gov/pubmed/8298975>).
The state of California can be seen on the HealthMap/ProMED-mail interactive map at <http://healthmap.org/r/1agH>. Ventura County in southern California can be seen on the map at <http://www.digital-topo-maps.com/county-map/california.shtml>. - Mod.TG]
[see also:
Domoic acid, sea lions - USA: (CA) 20110413.1160 Undiagnosed die-off, fish - USA (CA): domoic acid susp. 20110313.0814 2010
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Domoic acid, sea lion deaths - USA: (CA) 20100620.2064
2007
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Domoic acid, animal deaths - USA (CA) 20070428.1384
2005
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Sea lions, domoic acid - USA (CA) 20050616.1692
2004
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Dolphin die-off - USA (FL) (04): domoic acid 20040617.1615 Otter deaths, domoic acid - (CA): not (06) 20040615.1607 Otter deaths, domoic acid - USA (CA): not (05) 20040528.1450 Otter deaths, domoic acid - USA (CA): not (04) 20040526.1425 Otter deaths, domoic acid - USA (CA): not (03) 20040525.1397 Otter deaths, domoic acid - USA (CA): not 20040523.1382 Otter deaths, domoic acid - USA (CA): susp. 20040417.1071 Dolphin die-off - USA (FL)(03): Domoic acid 20040323.0806
2003
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Whale die-off, domoic acid - USA (East Coast): susp. 20031028.2684 Dolphin, sea lion die-off, domoic acid - USA (CA) 20030604.1363 Domoic acid, razor clams - USA (OREGON) 20030508.1142
2002
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Flying squid, domoic acid - USA (California) 20021209.6025 Mammal, bird die-off, domoic acid - USA (CA) 20020708.4702 Mammal, bird die-off, domoic acid - USA (CA) 20020526.4323 Dolphin/sea lion die-off, domoic acid - USA (CA) (02) 20020426.4035 Dolphin/sea lion die-off, domoic acid - USA (CA) 20020422.4011 Shellfish ban, domoic acid - Canada (NB) 20020422.4010 Domoic acid, razor clams - USA (Washington) 20020405.3886 Dolphin die-off, domoic acid - USA (Calif.) (02) 20020331.3846 Dolphin die-off, domoic acid? - USA (California) 20020325.3817 2000
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Sea lions, seizures, domoic acid - USA (Calif.) 1998 20000107.0018
1996
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Domoic acid 19960209.0275]
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