Biological Monitoring of the HMAS Swan
Abstract
Biological monitoring of the fish community that established on the HMAS Swan over a two year period has shown an increase in average richness from 2 to 32 species and an increase in abundance from 10 to nearly 1,300 individuals when compared to a nearby control site. The fish community on the vessel has rapidly shifted from omnivorous weed/sand fishes to one dominated by planktivorous and carnivorous reef fishes. The species richness and abundance on the HMAS Swan is beginning to approximate that of other natural reefs in the region; however, the species composition on the vessel is still distinctly different.
Monitoring of encrusting marine life over the same period has shown that the first biota to colonise the vessel were hydroids which rapidly covered approximately 70-90% of the area surveyed. Substantial algal growth was present during the summers of 1998 and 1999 and dominated the encrusting marine life on the starboard and upper surfaces. Other fauna groups such as sponges, ascidians, anemones and soft corals are showing marked signs of proliferation on the shaded portions of the vessel; however, the areas receiving full sunlight are less well colonised.