Seasonal variation of domoic acid in a bivalve Spondylus versicolor in association with that in plankton samples in Nha Phu Bay, Khanh Hoa, Vietnam

Abstract

Previously we reported that a significant level of domoic acid, a causative toxin for amnesic shellfish poisoning, was detected in bivalves belonging to a genus Spondylus from various tropical Asian countries. These findings indicate that causative plankton species for domoic acid widely distribute in these areas. In the present study, we monitored seasonal change of domoic acid level of Spondylus versicolor in association with that of plankton samples in Nha Phu Bay, Khanh Hoa, Vietnam from December 2004 to October 2005. The toxicity of S. versicolor showed distinct seasonal variation. During the period when domoic acid level of S. versicolor was increasing, a significant level of domoic acid was detected in the plankton samples, showing the correlation between these two parameters. These findings show that plankton causative for domoic acid occurred in the bay, and S. versicolor accumulate domoic acid during a bloom of the toxic plankton by food web transfer.

Accumulation of domoic acid in marine organisms from Sriracha bay, Chonburi province, Thailand

“…Total DA content in both sizes of plankton at 0.5 m from the sea surface was still very low (12.13-115.47 ng/l) compared to Vale and Sampayo, who recorded maximum DA levels in phytoplankton samples greater than 700 ng/l 35 . However, DA content from the fraction larger than 20 µm (12 ng/l) of this study was higher than in Nha Phu Bay, Vietnam 28 . Yotying found that total DA content in phytoplankton at Kham Yai island, Chonburi province, ranged between 0.49 and 2.04 ng/l 29 , which was low compared to our results.…”

“…Most previous DA studies focused on phytoplankton larger than 20 µm 9, 28 . Dao et al sug-gested that the width of the Pseudo-nitzschia cell was narrow enough to pass through a 20 µm mesh plankton net 28 . Yotying reported that DA can be detected in phytoplankton both larger and smaller than 20 µm 29 .…”

“…Diverse environmental and oceanographic conditions could stimulate DA production of phytoplankton and affect growth stages. Dao et al described DA production of Pseudo-nitzschia as changing greatly during the life cycle 28 . This suggestion concurred with Bates and Richard, who stated that DA content in Pseudo-nitzschia multiseries was very high in the stationary phase 34 .…”

Domoic acid uptake and elimination kinetics in oysters and mussels in relation to body size and anatomical distribution of toxin

“…blooms: 30.0 gg −1 for C. gigas (Trainer et al, 2007) and 790 gg −1 for M. edulis (Bates et al, 1989). In addition, comparable to higher DA concentrations have been found in whole tissues of slow-depurating bivalves, such as the oyster Spondylus versicolor [(147 gg −1 (Dao et al, 2009)], the clam S. patula [308 gg −1 (Trainer et al, 2000)] and the scallop P. maximus [1569 gg −1 (Campbell et al, 2001)]. High DA concentrations in natural bivalve populations (up to 70 gg −1 ) usually occur during massive blooms of highly toxic Pseudo-nitzschia spp.…”

Pseudo-nitzschia physiological ecology, phylogeny, toxicity, monitoring and impacts on ecosystem health

“…Significant levels of DA (145 mg DA g À1 whole tissue) have been detected in the spiny oyster (Spondylus), collected from the Philippines and Vietnam (Dao et al, 2009). However, the responsible species of Pseudo-nitzschia have not yet been identified.…”