著者

Tomohiro Nishimura Wittaya Tawong Hiroshi Sakanari Takuji Ikegami Keita Uehara Daiki Inokuchi Masatoshi Nakamura Takuya Yoshioka Shota Abe Haruo Yamaguchi Masao Adachi

出版者

The Plankton Society of Japan, The Japanese Association of Benthology

雑誌

Plankton and Benthos Research (ISSN:18808247)

巻号頁・発行日

vol.13, no.2, pp.46-58, 2018-05-30 (Released:2018-05-24)

参考文献数

68

被引用文献数

13

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Ciguatera fish poisoning (CFP) is caused by toxins originating from an epiphytic/benthic dinoflagellate of the genus Gambierdiscus. In Japan, CFP cases have been increasingly reported not only in subtropical areas but also in temperate areas. It is therefore important to study Gambierdiscus cell occurrences, cell densities, and population dynamics to address CFP outbreaks in Japan. This study assessed the densities in Japanese shallow waters (0.1–3 m depths) and revealed that the densities were lower than those in tropical and subtropical areas worldwide. In the shallow waters of Tosa Bay, a Japanese temperate area, population dynamics of Gambierdiscus cells were assessed monthly between 2007 and 2013. Gambierdiscus did not show substrate preferences for macroalgal species. The cell densities in the area ranged from 0 to 232.2 cells g−1 wet weight algae. The average cell densities in spring, summer, autumn, and winter were 0.1±0.4, 0.9±2.6, 4.0±20.6, and 0.4±1.4 cells g−1 wet weight algae, respectively. The cell densities in summer and autumn were not significantly different (p>0.05), whereas those in summer and autumn were significantly higher than those in spring and winter (p<0.01). A significant positive correlation between cell densities and sea surface temperatures (SSTs) was observed (rs=0.21, p<0.001), while a significant negative correlation between cell densities and salinity was recognized (rs=−0.18, p<0.001). These results suggest that cell densities of Gambierdiscus in Japanese temperate shallow waters increase in summer and autumn when the SST is high and salinity is moderately low.

著者

Haruo Yamaguchi Yuji Tomaru

出版者

The Plankton Society of Japan, The Japanese Association of Benthology

雑誌

Plankton and Benthos Research (ISSN:18808247)

巻号頁・発行日

vol.17, no.1, pp.100-103, 2022-02-22 (Released:2022-02-23)

参考文献数

14

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This study investigated the temporal and spatial variations of Takayama blooms in Uranouchi Inlet, Japan. From July to September 2017, Takayama cells appeared (≥1 cell mL−1) at depths of 0–10 m, temperatures of 25.4–31.7°C, and salinities of 23.1–34.2. The maximum cell density was 1.37×103 cells mL−1. By analyzing partial rDNA sequences of Takayama strains collected at the bloom initiation, we found Takayama acrotrocha/Takayama xiamenensis and Takayama tasmanica in the Uranouchi Inlet. This study contributes to understanding of the dynamics of and risk to aquaculture of Takayama blooms in the coastal waters of Japan.