The macrofouling organisms most commonly encountered during intermittent
plate exposures in Sydney Harbour over 10 years (1947-57) comprised a barnacle
(mainly Balanus (Balanus) amphitrite var. cirratus Darwin), several serpulids and
bryozoans (Hydroides norvegica Gunnerus, Spirorbis sp.; Bugula neritina L., Bugula
avicularia L., Watersipora cucullata (Busk)), a mussel (Mytilus planulatus Lamarck),
and an oyster (Crassostrea commercialis Iredale & Roughley). With the exception
of the mussel, settlement was heaviest during the summer months. Surface water
temperatures averaged from about 15°C in midwinter to 24� in midsummer and
were over 20°C for 6 months of the year. Two cases where freshwater dilution
apparently affected biological populations are recorded. The effects of colour,
surface texture, depth, aspect, and horizontal distance on settling were investigated
using paired series of plates. The results were treated statistically and compared
with those reported by others. It is suggested that during antifouling raft tests
at this locality the control plates for any group of experimental plates need to be
placed at the same site, same depth, facing the same way, and 5-10 ft apart
horizontally. Providing the most common macrofouling organisma settling at the
station were considered as a whole, this arrangement seemed to give a reasonably
accurate assessment of their settling intensity at the test site.
Can bacterivory sustain survival and growth in early juveniles of the bryozoan Bugula neritina, the polychaete Hydroides elegans and the barnacle Balanus amphitrite?