Factors affecting survivorship of defouled communities and the effect of fragmentation on establishment success

• Published in: Journal of experimental marine biology and ecology 2011-01, Vol.396 (2), p.233-243
• Main Authors: Hopkins, Grant A., Forrest, Barrie M., Piola, Richard F., Gardner, Jonathan P.A.
• Format: Article
• Language: English
• Subjects: Animal and plant ecology; Animal, plant and microbial ecology; aquaculture; Ascidiacea; biofouling; Bioinvasion; Biological and medical sciences; colonizing ability; field experimentation; Fundamental and applied biological sciences. Psychology; In-water defouling; Marine; marine environment; Marine non-indigenous species; oils; Orientation; Predation; predators; risk; Sea water ecosystems; sediment deposition; Sedimentation; survival rate; Synecology; turbidity
• ISSN: 0022-0981; 1879-1697
• DOI: 10.1016/j.jembe.2010.10.027

The environmental risks associated with the defouling of artificial structures (e.g., vessels, oil rigs, marina pontoons, aquaculture structures) in the marine environment are gaining international attention. This paper presents a series of laboratory- and field-based experiments that collectively aimed to elucidate biotic and abiotic factors that influence re-establishment success of biofouling organisms and fragmented colonial organisms defouled to the seabed. Reattachment success of colonial organisms experimentally fragmented was found to be species specific and dependent on fragment size. In both laboratory and field trials, some colonial ascidians had consistently greater reattachment success for larger size classes of fragments, while other encrusting and erect taxa showed poor reattachment capabilities. This study also revealed that sedimentation and turbidity are likely to have a strong influence on the survivorship of defouled material. Furthermore, for both high and low sedimentary environments, survivorship was found to be greater where predators were excluded. Despite risks posed by non-indigenous species (NIS), it is proposed that in-water defouling may be an appropriate management response in situations where a “do nothing” approach is potentially more detrimental. Moreover, results from this study suggest that environmental risks associated with defouling may be mitigated through appropriate defouling strategies (e.g., defouling location, frequency and method). In order to increase our predictive abilities for NIS establishment success resulting from in-water defouling, future studies should aim to further elucidate the relative importance of factors affecting survivorship of defouled material at locations where defouling is routinely undertaken. ► Reattachment success of colonial taxa varied with fragment size ► Encrusting and erect taxa showed poor reattachment capabilities ► Sedimentation and turbidity influenced the survivorship of defouled material ► Survivorship was found to be greater where predators were excluded