Abstract
The present distributions of exotic fishes were investigated in creeks flowing into farmlands around northern Ariake and Yatsushiro Bay, Kyushu Island, Japan. Six exotic species introduced from foreign countries and six exotic species introduced from other internal regions in Japan were captured from several creeks in this area. In particular, Carassius cuvieri, Gambusia affinis, Opsariichthys uncirostris uncirostris, and Lepomis macrochirus were found in 83, 29, 29 and 20 sites, respectively. As other exotic species, Oreochromis niloticus, Ischikauia steenackeri, and Squalidus chankaensis tsuchigae were first recorded from this area. The tendencies on sympatric or allopatric appearances were investigated on the basis of the distributions of each of the exotic and native species. A few exotics such as C. cuvieri, G. affinis, and L. macrochirus, and a few natives such as Pseudorasbora parva and Abbottina rivularis indicated their sympatric appearances. In contrast, the allopatric appearances were indicated between these exotics and several natives. The allopatric tendency was estimated to be attributed to differences in habitat that each species preferred. Although Oryzias latipes preferred the dead water regions similarly to these exotics, this species showed its allopatric appearances with G. affinis and L. macrochirus. The distribution of this species was estimated to be limited by the distributions of these exotics.
