Rearing experiment of Japanese eel

Three eels were kept in a 40-L water tank and aerated for water quality control and water circulation. 

(To make sure that the eDNA changed by rearing condition, not by individual differences, the same individual was used throughout the rearing experiment period.)

Eels were fasted for a month before rearing experiment started and acclimatized in a water tank with a set temperature of  15℃(measured water temperature 16-17℃).

→ Non-Feeding & Low temperature : NFL

After water sampling, the water temperature was set to 25℃ (measured water temperature 22-23℃) while fasting, and acclimatize for 2 weeks.

→ Non-Feeding & High temperature : NFH

After water sampling, feeding was started, the water temperature was returned to a low water temperature (measured water temperature 16-17℃), and acclimatized for 2 weeks.

→ Feeding & Low temperature : FL

After water sampling, the water temperature was raised (measured water temperature 22-23℃) while feeding, and acclimatize for 2 weeks.

→ Feeding & High temperature : FH

Water sampling was carried out after two weeks of acclimatization of every experimental condition, and water was filtered immediately after sampling.

(During the experiment period, eels were fed twice a week (Tuesday, Friday), and rearing tank was cleaned twice a week (Wednesday, Saturday) regardless feeding or non-feeding condition. On Tuesday of sampling day, eels were fed after water sampling.)

Triplicate samples were taken at 50 mL, 100 mL, and 200 mL, respectively (9 samples in total), to evaluate the relationship between the amount of filtration and eDNA concentration.