KIOST Suggests Possible Expansion of Paralytic Shellfish Toxin Occurrence Period

The Korea Institute of Ocean Science and Technology (KIOST) has discovered that Alexandrium, the main causative species of paralytic shellfish toxins causing food poisoning symptoms along the southern coast from March to June each year, possesses excellent adaptability to changes in water temperature.

KIOST recently suggested the possibility that the occurrence period of paralytic shellfish toxins in areas where the dormant cysts, which are the seeds of Alexandrium, are distributed may not be limited to the spring season.

Paralytic shellfish toxins are one of the toxins produced by phytoplankton. Humans who consume shellfish contaminated with this toxin experience symptoms such as headaches, nausea, vomiting, and muscle paralysis, which can lead to death in severe cases.

Paralytic shellfish toxins are frequently detected in spring due to the massive proliferation of Alexandrium containing toxins in Jinhae Bay, Korea. However, recently, the occurrence of paralytic shellfish toxins has expanded beyond the spring season to other seasons as well.

In response, Dr. Shin Hyun-ho’s research team at the Marine Sample Library of KIOST Namhae Research Institute, together with Dr. Lee Jun from the Korea Research Institute of Bioscience and Biotechnology and Dr. Son Moon-ho from the National Institute of Fisheries Science, identified the ecological causes of Alexandrium, the causative species of paralytic shellfish toxins, as the reason for this phenomenon.

Schematic diagram of the survival and bloom of Alexandrium, the causative species of paralytic shellfish toxins.

They confirmed that the dormant cysts of Alexandrium isolated from sediments in Jinhae Bay during summer and winter have different genotypes.

Until now, it has been known in academia that the dormant cysts formed by Alexandrium have a dormancy period during which they do not germinate regardless of any environmental stimuli.

However, the dormant cysts of Alexandrium discovered in this study were able to germinate over a wide temperature range, adapting to seasonal changes in water temperature regardless of dormancy and were not affected by changes in salinity.

Dr. Shin Hyun-ho, the lead researcher, stated, “Alexandrium in Jinhae Bay has excellent adaptability to changes in water temperature for survival, so the occurrence of paralytic shellfish toxins caused by Alexandrium may not be limited to specific seasons,” and emphasized, “Monitoring research related to paralytic shellfish toxins should be strengthened.”

Director Kang Do-hyung said, “Research related to the occurrence of paralytic shellfish toxins is closely linked to securing safe food for the public,” and added, “KIOST will continue to do its best to minimize fisheries damage and human casualties caused by harmful marine organisms such as Alexandrium.”

The results of this study were published online in the Marine Pollution Bulletin under the title ‘Bloom development of toxic dinoflagellate Alexandrium catenella (Group I) in Jinhae-Masan Bay, Korea: Germination strategy of resting cysts in relation to temperature and salinity.’

This content was produced with the assistance of AI translation services.