Effect of water temperature on occurrence of Edwardsiella tarda in olive flounder Paralichthys olivaceus farms in Jeju island, South Korea

Abstract Objective: Edwardsiellosis is an important disease associated with high economic losses in aquaculture. In the present study we wanted to determine whether occurrence of Edwardsiella tarda infections in Olive flounder (Paralichthys olivaceus) correspond with changes in water temperature on fish farms in Jeju island, South Korea. Results: In 2017, the number of cases were highest in August and September reaching up to 70% of the sampled fish when the average monthly water temperature was highest at 21.7°C. The number of cases declined to <5% during the cold months of January to March when the mean monthly water temperatures were lowest varying between 15.6°C and 16.4°C in 2017. However, the number of cases in 2018 where lower than in 2017 despite the average annual temperature for both years being equal at 18.2°C. Interestingly, the number of cases observed in the first three months of 2019 corresponded with cases observed in 2017 during the first three months when the average water monthly temperature was 16.4°C and 15.2°C. Data presented herein could be useful in understanding the effect of water temperature on occurrence of E. tarda infection leading to developing intervention control measures against E. tarda infections in aquaculture.