The potential for translocation of marine species via small-scale disruptions to antifouling surfaces

Abstract

Vessel hull fouling is a major vector for the translocation of nonindigenous species (NIS). Antifouling (AF) paints are the primary method for preventing the establishment and translocation of fouling species. However, factors such as paint age, condition and method of application can all reduce the effectiveness of these coatings. Areas of hull that escape AF treatment (through limited application or damage) constitute key areas that may be expected to receive high levels of fouling. The investigation focused on whether small-scale (mm² to cm²) areas of unprotected surface or experimental ‘scrapes’ provided sufficient area for the formation of fouling assemblages within otherwise undamaged AF surfaces. Recruitment of fouling taxa such as algae, spirorbids and hydroids was recorded on scrapes as narrow as 0.5 cm wide. The abundance and species richness of fouling assemblages developing on scrapes ≥1 cm often equalled or surpassed levels observed in reference assemblages totally unprotected by AF coatings. Experiments were conducted at three sites within the highly protected and isolated marine park surrounding Lady Elliott Island at the southernmost tip of the Great Barrier Reef, Australia. Several NIS were recorded on scrapes of AF coated surfaces at this location, with 1-cm scrapes showing the greatest species richness and abundance of NIS relative to all other treatments (including controls) at two of the three sites investigated. Slight disruptions to newly antifouled surfaces may be all that is necessary for the establishment of fouling organisms and the translocation of a wide range of invasive taxa to otherwise highly protected marine areas.

Keywords:

• antifouling paint
• fouling
• copper antifouling
• fouling assemblages
• nonindigenous species
• recreational vessels
• boat hulls
• recruitment
• species richness
• scrapes
• unprotected

Acknowledgments

The authors thank K. Stuart, M. Roughan and D. Roberts for assistance in the field. Special thanks to the staff of the Lady Elliot Island Resort Dive Centre for their assistance in identifying and accessing suitable field site locations, and help with the deployment and retrieval of experimental units. K. Wright provided valuable feedback on earlier drafts of the manuscript. This research was conducted with the permission of the Great Barrier Reef Marine Park Authority (under the GBRMPA research permit # G06/17511.1). R.F.P. was supported throughout this study by an Australian Postgraduate Award. This research was partially funded by an Australian Research Council Discovery Grant awarded to E.L.J.