Contrasting diets of the Japanese eel, Anguilla japonica, in the upper and lower areas of Tsuchikawa-gawa River, Kagoshima, Japan

To understand the differences in diet and utilization of trophic resources between the upper and the lower reaches of rivers by the Japanese eel Anguilla japonica, we investigated the stomach contents of 207 specimens from both reaches of Tsuchikawa-gawa River, Kagoshima, Japan. The results indicate that there may be greater influence of terrestrial resources on the Japanese eel in the upper reach than that in the lower reach. In light of this, it is important to secure the connectivity between terrestrial and aquatic zones in the upper reaches of river which will aid in conservation efforts for the Japanese eel.