Comparison of consumption of bluegill by Far Eastern catfish and largemouth bass

Abstract

The consumption of bluegill by Far Eastern catfish and largemouth bass was examined in aquaria. Twenty or more live bluegill were introduced into each aquarium with one catfish or largemouth bass. Bluegill were captured in Lake Sugawa, Nagano Prefecture, and almost all of them could be preyed upon by the catfish and bass. The consumption of bluegill was correlated with the body weight of catfish and bass except for the very large predator individuals. Far Eastern catfish consumed comparatively more bluegill (9.4% of the catfish body weight per day) than largemouth bass (4.5%). Stocking Far Eastern catfish is potentially an effective method for reducing bluegill, although prey‐selection experiments using bluegill, native Japanese prey fish and the catfish are required before actively advocating the biological control of bluegill using Far Eastern catfish.

Prey fish selection by Far Eastern catfish Silurus asotus and largemouth bass Micropterus salmoides

“…Therefore, the difference in predating behavior between catfish and bass, together with the use of space and the flight ability of the prey fish, might affect the difference in the consumption of prey species between the two predatory species. In a previous experiment where only bluegill was supplied to catfish in the same aquaria, catfish consumed 9.4% per day of the catfish body mass 12 . However, catfish consumed bluegill at only 1.7% per day of catfish body mass in ponds in experiment 3 in the present study, suggesting a wider space restricted catfish predation.…”

“…All these fishes were stocked in indoor (bluegill) and outdoor (dace and crucian carp) ponds and were given pellets and dried krill. The body length of prey fish used in the experiments (Table 1) was within the range that can be preyed on by catfish or bass based on the data by Tabata and Shibata 10 and Katano et al 12,17 …”

“…Bluegill is considered harmful for Japanese fisheries and ecosystems because the fish preys on eggs, larvae and small fish of other species and depletes their food resources such as zooplankton and aquatic insects 13–15 . The use of Far Eastern catfish as a predator of bluegill in order to eradicate bluegill from Japanese ponds and lakes was suggested 12 . However, to do so, it is necessary to clarify if Far Eastern catfish prefer bluegill as prey to other indigenous fish.…”

“…In a previous paper, the authors clarified that Far Eastern catfish prey on another alien fish, bluegill Lepomis macrochirus , more than largemouth bass under controlled laboratory conditions. 12 Bluegill is considered harmful for Japanese fisheries and ecosystems because the fish preys on eggs, larvae and small fish of other species and depletes their food resources such as zooplankton and aquatic insects. [13][14][15] The use of Far Eastern catfish as a predator of bluegill in order to eradicate bluegill from Japanese ponds and lakes was suggested.…”

“…[13][14][15] The use of Far Eastern catfish as a predator of bluegill in order to eradicate bluegill from Japanese ponds and lakes was suggested. 12 However, to do so, it is necessary to clarify if Far Eastern catfish prefer bluegill as prey to other indigenous fish. Therefore, the authors conducted prey fish selection experiments using Far Eastern catfish and largemouth bass as predators, and bluegill, Japanese dace, and crucian carp Carassius gibelio langsdorfi as prey fish.…”