Are the fish safe to eat? [Archive] - Fishing Network Message Boards

DockRat

02-26-2013, 06:54 AM

That domoic acid in the summer has me concerned.

Other birds that eat sand crabs include sandpipers, willets, godwits, surf scoters, blackbellied plovers and curlews. The sea otter also enjoys them. The crabs are hosts to the intermediate stages of various parasitic worms. These get passed on to the predators when the crabs are eaten by them and the number of worms ingested has been known to kill the predator.

The barred surfperch (Amphistichus argenteus), found off the coast of California, consumes a large number of sand crabs. Surf fishermen use the crabs for bait and there are commercial bait fisheries extracting them from the beach. The sand crabs with soft shells that have just moulted are kept for bait while the hard shelled crabs are thrown back into the sea.

The sand crab has been evaluated as an indicator species for monitoring the level of domoic acid-synthesizing diatoms (Pseudo-nitzschia spp.) which sometimes cause toxic blooms off the coast of California.

http://en.wikipedia.org/wiki/Emerita_analoga

Occurrence

In 1958, domoic acid was originally isolated from the red alga called "doumoi" or "hanayanagi" (Chondria armata[2]) in Japan. "Doumoi" is used as an anthelmintic in Tokunoshima, Kagoshima.[3] Domoic acid is also produced by some diatoms of the genus Pseudo-nitzschia[1] and by some strains of the diatom species Nitzschia navis-varingica.[1][4]

Pseudo-nitzschia multiseries loses most of its ability to produce domoic acid when it is cultured axenically. However, domoic acid production recovers when bacteria from the original culture are reintroduced to axenic cultures, indicating a bacterial association with domoic acid production in this species.[5] Other factors that affect the biosynthesis of domoic acid are reviewed by Bates and Trainer (2006),[6] Trainer et al. (2008),[7] Lelong et al. (2012)[8] and Trainer et al. (2012).[9]

The increasing frequency and geographic extent of toxic algal blooms along populated coastlines is generally attributed to human activities.[10]
Chemistry
[icon] This section requires expansion. (June 2008)

Domoic acid is a structural analog of kainic acid and proline. General aspects of domoic acid chemistry, including its isomers and degradation, are reviewed by Lelong et al. (2012).[8]
Toxicology

Considerable recent research has been carried out by the Marine Mammal Center and other scientific centers on the association of domoic acid-producing harmful algal blooms and neurological damage in marine mammals of the Pacific Ocean.

Domoic acid can bioaccumulate in marine organisms such as shellfish, anchovies, and sardines that feed on the phytoplankton known to produce this toxin. DA can accumulate in high concentrations in the tissues of these plankton feeders when the toxic phytoplankton itself is high in concentration in the surrounding waters.

In mammals, including humans, domoic acid acts as a neurotoxin, causing short-term memory loss, brain damage and, in severe cases, death. DA-producing algal blooms are associated with the phenomenon of amnesic shellfish poisoning (ASP). In marine mammals, domoic acid typically causes seizures and tremors. In the brain, domoic acid especially damages the hippocampus and amygdaloid nucleus. It damages the neurons by activating AMPA and kainate receptors, causing an influx of calcium. Although calcium flowing into cells is a normal event, the uncontrolled increase of calcium causes the cell to degenerate. Because the hippocampus may be severely damaged, short-term memory loss occurs.