Ship mediated fish invasions in Australia: two new introductions and a consideration of two previous invasions

摘要

Two species of fishes, the northwest Pacific Acentrogobius pflaumi (Bleeker 1853) (Perciformes: Gobiidae) and the New Zealand Forsterygion lapillum Hardy (1989) Perciformes: Tripterygiidae), are newly reported as recent introductions in Port Phillip Bay, southeastern Australia. Forsterygion lapillum is restricted to a commercial port in the western area of the bay, while A. pflaumi occurs in all areas of the bay except the entrance. Both species are among the most abundant fishes collected in occupied habitats. It seems probable that they were introduced as eggs, larvae or juveniles in ships' ballast water. While both A. pflaumi and F. lapillum appear to be well suited to conditions in Australia, populations of two previously introduced marine fishes (the gobiids Acanthogobius flavimanus and Tridentiger trigonocephalus) have failed to rapidly expand their distributions and seem to be controlled by factors yet to be determined.