MEPS 311:103-114 (2006) - doi:10.3354/meps311103
Differential resistance to extended copper exposure in four introduced bryozoans
Richard F. Piola*, Emma L. Johnston
ABSTRACT: Resistance to copper by some fouling species may have the 2-fold effect of both facilitating the introduction of nonindigenous species via the painted hulls of vessels, and providing these species with a competitive advantage in ports or estuaries already exposed to anthropogenically elevated copper concentrations. This study tested the tolerance of 4 introduced bryozoans, Bugula neritina, Watersipora subtorquata, Schizoporella errata and Tricellaria occidentalis, to a range of Cu concentrations (0, 10, 50, 100 and 500 µg l1). Larval attachment after 24 h was not found to be a reliable indicator of post-metamorphic survival. Recruits of all species survived in 0 and 10 µg l1 Cu for 20 d, with only Bugula neritina and Watersipora subtorquata recruits surviving exposure to 50 and 100 µg l1 Cu. B. neritina and W. subtorquata colonies exhibited reduced post-metamorphic growth in 50 µg l1 Cu compared to controls, with no growth observed in 100 µg l1 Cu. Growth for S. errata and T. occidentalis was higher at 0 µg l1 than 10 µg l1 Cu. Post-exposure growth of surviving colonies was assessed by transplanting colonies to the field. W. subtorquata colonies exposed to 50 µg l1 Cu were the only colonies to show decreased survival and growth post Cu-exposure. Overall, B. neritina and W. subtorquata showed the greatest tolerance to Cu. These findings have important implications for the management, control and assessment of invasion potential of these invasive marine hull-fouling species.
KEY WORDS: Cu · Attachment · Post-metamorphic survival · Post-metamorphic growth · Antifouling paint · Tolerance · Introduced species · Hull fouling
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