Victorian Subtidal Reef Monitoring Program - Parks Victoria

Parks Victoria Technical Series No. 28PPB Sanctuaries Subtidal Reef Monitoring6.3 InvertebratesThere were relatively few invertebrate species at Ricketts Point and Halfmoon Bay, with theassemblage structure being similar at both sites. The assemblages were dominated by veryhigh abundances of the sea urchin H. erythrogramma, with 900-960 per 200 m 2 at RickettsPoint and 480-550 per 200 m 2 at Halfmoon Bay. Other predominant species were blacklipabalone Haliotis rubra, biscuit star Tosia australis, eleven armed seastar Coscinasteriasmuricata and velvet star Petricia vernicina.Fewer common urchins Heliocidaris erythrogramma were observed at both sites during thethird survey, representing a decrease over the three periods (Figure 6.2). Similarly, Tosiaaustralis showed a decrease at Ricketts Point. There were no major changes in abundanceobserved for other species (Figure 6.3).The average blacklip abalone length at Ricketts Point increased from 77 mm to 92 mm, whilethe average length at Halfmoon Bay decreased from 88 mm to 85 mm (Figure 6.4).37