Barging in: A Temperate Marine Community Travels to the Subantarctic

Abstract

A diverse fouling community discovered encrusting a barge intended for deployment at subantarctic Macquarie Island is described and its role as a transport vector for non-indigenous marine organisms is discussed. The barge proved to be a potential vector capable of transporting entire epi-bethic communities, 20 species in total, from a temperate estuarine system (Derwent River, Tasmania, Australia) into the subantarctic. For one invasive amphipod species Monocorophium acherusicum, over 136000 individuals including ovigerous females were calculated to be associated with the barge fouling community. Although distinct differences exist between the thermal ranges of Macquarie Island and the Bruny bioregion of Tasmania, a hazard assessment based on the Gower similarity coefficient suggested sufficient similarity between the two environments to allow for survival of transported organisms for eight months of the year. Several invasive species are able to survive the thermal conditions of the subantarctic irrespective of the time of year. This study identifies the need for effective quarantine measures aimed at identifying and managing marine biosecurity hazards in association with human activities in high latitude regions.