Prediction of paralytic shellfish toxin based on a projected future climate scenario for South Korea

- Effects of environmental conditions and shellfish species are assessed on PSP.
- The patterns of PSP occurrence are predicted based on future climate scenarios.
- A censored regression model was used with potentially influential covariates.
- Shellfish poisoning outbreaks will occur during earlier months in the future.

This study aimed to predict the seasonal patterns of paralytic shellfish poison (PSP) level in the next 90 years based on a future climate scenario, Representative Concentration Pathway (RCP) 8.5. To achieve this goal, we constructed a censored regression model using seawater temperature, weekly change in seawater temperature, salinity, rainfall, insolation, shell species, and areas prone to red tide as potentially influential environmental factors on PSP level in the coastal areas of South Korea. The censored regression model is used instead of the ordinary regression model because the PSP data had a large portion of non-detectable (ND) data. All of the continuous environmental covariates had significant quadratic relationships with the PSP toxin level except insolation. These results indicated that there are favorable ranges of seawater temperature, weekly change in seawater temperature, salinity, and rainfall to PSP production. To predict the future PSP distribution, we plugged the environmental condition data under a future climate scenario, RCP 8.5 scenario, in the estimated regression model. In the future, it is expected that the highest frequency of shellfish poisoning outbreaks will occur during the earlier months in the year, such as February and March, whereas most outbreaks of shellfish poisoning have occurred in April and May during recent years in South Korea.