Semi-submersible rigs: a vector transporting entire marine communities around the world

• Published in: Biological invasions 2010-08, Vol.12 (8), p.2573-2583
• Main Authors: Wanless, Ross M, Scott, Sue, Sauer, Warwick H. H, Andrew, Timothy G, Glass, James P, Godfrey, Brian, Griffiths, Charles, Yeld, Eleanor
• Format: Article
• Language: English
• Subjects: aquatic communities; Biogeography; Biomedical and Life Sciences; cleaning; Developmental Biology; Ecology; Fish; fouling; Freshwater & Marine Ecology; geographical distribution; introduced species; invasion routes; invasion vectors; Invasive species; Life Sciences; Marine; marine environment; marine fish; Marine organisms; marine science; Nonnative species; Offshore oil wells; Original Paper; Plant Sciences; population ecology; reefs; Risk assessment; risk management; semi-submersible rigs; Species diversity; Swimming
• ISSN: 1387-3547; 1573-1464
• DOI: 10.1007/s10530-009-9666-2

A virtually intact subtropical reef community (14 phyla, 40 families and 62 non-native taxa) was associated with a rig under tow from Brazil that became stranded on the remote island of Tristan da Cunha. This exposes rigs as a significant vector spreading alien marine organisms, and includes the first records of free-swimming marine finfish populations becoming established after unintentional movement. With relatively trivial effort, a pre-tow clean would have obviated the need to salvage and dispose of the rig (undertaken largely to address concerns about invasive species), at a cost of ~US$20 million. Our findings show that towing biofouled structures across biogeographic boundaries present unexcelled opportunities for invasion to a wide diversity of marine species. Better control and management of this vector is required urgently. Simultaneous, unintentional introductions of viable populations of multiple marine organisms are rare events, and we develop a basic framework for rapid assessment of invasion risks.