Capture of larval and juvenile non-native freshwater fish by light traps

We tested the use of a light trap to catch larval and juvenile non-native fish (largemouth bass, smallmouth bass, and bluegill) in lakes, reservoirs, and rivers at nine sites across four prefectures in Japan. A total of 18,409 individuals were captured in light traps lit with blue LEDs, with a trend towards capturing higher numbers of individuals in the early larval stages. The non-native fish were also captured in environments with a water clarity of <100 cm, confirming that light traps could be used to remove them even from muddy lakes. This method enabled the previously difficult capture of larval and juvenile non-native fish to be carried out effectively with little effort. However, it is necessary to consider the location and timing of installing traps to minimize bycatch.