Cockrone Lagoon Aquatic Biological Survey-Final Report (PDF File ...

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Australian Aquatic Biological Pty Ltd 5.6. Site Results Generally the catchment of Cockrone Lagoon was in a relatively good state without any large aquatic weed outbreaks. Results 5.6.1. Winney Bay Access was obtained by parking the vehicle at the water reservoir tank located on Cape Three Points Road (POI020) and following the gravel track down to Winney Bay. The creek system draining into Winney Bay has two branches. The northern branch was sampled at (POI018). Here the creek was owing mostly underground but damp wet areas were common and turning rock is the wet conditions indicated good numbers of amphipods and insect larvae. The creek was also sampled further upstream at (WPT001). Here the creek was owing with water in the stream bed. Stream conditions were clear owing water but a thick brown orange sediment layer covered the bottom of the small stream. Generally the streams have a steep gradient owing down the hillside to the lower sections of the small valley where it attens and water movement slows. Water was owing but ow was low and clarity was high. The lower sections of the stream had all surfaces coated with a brown/orange scum layer that I would generally associate with the presence of iron bacteria. This thrives in waters with high iron concentrations, low oxygen and lower sunlight levels. It’s not toxic as such, but it will smoother other aquatic plants and makes life hard for other aquatic organisms. Our survey of the small sections of the northern creek indicated no macroinvertebrates within the stream but amphipods and dobsony’s larvae (Archichauliodes sp) under rocks in damp sections of stream with some lamentous algae cover and no iron bacteria. The southern stream was sampled at (POI1019). The stream was not owing and consisted of damp areas/cumbungi swamps without water and some smaller deep pools with low water levels and solid brown orange scum. No macroinvertebrates or other species identied at this site. The stream was also sampled at WPT002 after the junction of the northern and southern streams before they entered the sea. The stream was owing with high clarity and all surfaces coated with iron bacteria. No macroinvertebrates were present. The small catchments, small ows and ephemeral nature of these streams would make them unsuitable for most molluscs and crustaceans. During rain events they would ow and ush rapidly then dwindle to nothing as dry spells ensue. Figure 14. WPT002 Creek Winney Bay Figure 15. Winney Bay Cockrone Lagoon Catchment Aquatic Biodiversity Report 20
Australian Aquatic Biological Pty Ltd Figure 16. POI011 Creek draining Copacabana at Del Rio Drive 5.6.2. Copacabana The township of Copacabana has a small stream draining it running directly to the sea through Copacabana Beach. This unnamed watercourse has a fully developed urban catchment and is a small short stream. Despite the urbanized catchment the creek was in reasonably good condition with good biodiversity. Figure 17. POI011 Creek draining Copacabana at Del Rio Drive looking toward bridge at Del Monte Place The creek was sampled at (POI011) on Del Rio Drive. Here the stream was no more than an open stormwater drain that was heavily vegetated. Native cumbungi, common reed and soft reeds were common in the stream bed. These native aquatic plants attract native species so that’s another good sign. There was also a smattering of nasturtium (fast growing annual from Peru) that is common along Central Coast streams. There was also small amount of “parrot’s feather” (Myriophyllum aquaticum) another South American weed but otherwise quite good. The stream was gently owing with high clarity and no iron bacteria, which was encouraging. Aquatic biodiversity was high reecting the water conditions with large numbers of macroinvertebrates present, water beetles and mudeyes most common. Mosquito sh (Gambusia holbrooki) were common as were native freshwater snails (Glyptophysa gibbosa). Cockrone Lagoon Catchment Aquatic Biodiversity Report 21
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