Victorian Subtidal Reef Monitoring Program - Parks Victoria

Parks Victoria Technical Series No. 28PPB Sanctuaries Subtidal Reef Monitoring4. POINT COOKE MARINE SANCTUARY4.1 Monitoring SitesPoint Cooke Marine Sanctuary is close to Werribee on the northwestern shore of the bay.The subtidal reef at Point Cooke consists of low-relief, textured basalt reef interspersed withpatches of sand and mud. The Point Cooke monitoring site (Site 4101) was positioned alongthe 3-4 m depth contour over the reef and patches of sand.A reference monitoring site was located offshore from the RAAF Base at Laverton (RAAFBase; Site 4102), approximately 3 km southwest of Point Cooke Marine Sanctuary. The reefat RAAF Base is similar to Point Cooke. It consists mostly of low-relief reef but with lessextensive patches of sand and mud. The RAAF Base monitoring site is at 3-4 m depth.4.2 MacroalgaeThe reef at Point Cooke (Site 4101) was patchy and interspersed with large areas of baresediment. This was reflected in the patchy distribution and cover of algae at this site. Thedominant species was common kelp Ecklonia radiata, but this occurred in low abundance.Smaller species in low abundance during the first survey, but much higher in abundanceduring the second survey included the green algae Ulva sp. and Caulerpa remotifolia. Otherspecies present included brown algae Dilophus marginatus and Dictyota dichotoma andthallose red algae such as Gigartina sp.The RAAF Base (Site 4102) was predominantly a Caulerpa bed assemblage dominated byCaulerpa flexilis, but also included C. longifolia, C. brownii, C. remotifolia, and C.simpliciuscula. Ecklonia radiata and patches of encrusting corallines were also present at thissite. In general, there was a higher total cover of algae at RAAF Base than at Point Cooke.Changes in species cover were observed between the three surveys. The green carpetingalga Caulerpa remotifolia increased its cover at Point Cooke, and at RAAF Base (Figure 4.1).There was also an apparent decline in the cover of the common kelp Ecklonia radiata at theRAAF Base and the cover of pink encrusting coralline at both sites (Figure 4.1).21