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

Australian Aquatic Biological Pty Ltd
7. Conclusion
Copacabana, Cockrone Lagoon and MacMasters Beach is another scenic coastal residential and
recreational area. This high level of scenic and natural beauty is a major attraction drawing both
residents and holiday makers to the area. The area has it all, rocky headlands, beautiful sandy
beaches, tranquil Lagoon, rainforests and reserves all located within a high population suburban
setting
Preliminary surveys of the Lagoon indicated a range of native species present within the Lagoon
proper. However, aquatic biological surveys of the catchment area indicate the biodiversity
within the freshwater aquatic tributary system is extremely low. As we progressed upstream from
the Lagoon proper, biodiversity diminished rapidly. The upper reaches of the catchment were
seemingly devoid of aquatic life. The Cockrone Lagoon and surrounding areas aquatic ecosystems
consisted of a very poor diversity of aquatic fauna which was very disappointing.
Exotic invasive aquatic weeds, however, were absent from the majority of the catchments which
was an encouraging sign. The majority of riparian zones were also in good condition with few
terrestrial weeds, etc.
Most steams were heavily laden with orange brown iron bacteria which was unsightly. This
bacteria thrives in low light, low oxygen and high iron environments, it is not toxic but also not
inducive to native aquatic ora or fauna and is usually a precursor to exotic weeds that thrive in
these conditions.
Both Winney Bay and Copacabana creeks are too small and short to sustain much in the way of
aquatic biodiversity.
The freshwater tributary streams feeding into Cockrone Lagoon are very small with highly
urbanized catchments; there just isn’t sufcient catchment or stream ow rates to adequately
sustain and ush these short creeks systems. The small catchment size limits the capacity of the
system to be self cleansing and this is amplied in drought conditions but wet conditions rapidly
ush and clean the system. This uctuation creates unstable conditions not inducive to native
species.
8. Recommendations
This survey records the current status of the ecological health of streams in the Cockrone Lagoon
and Surrounding Catchments. It provides a baseline for future comparison after initiation of any
catchment or local remediation strategies. The following recommendations are offered to Gosford
City Council for the Cockrone Lagoon and surrounding area.
• Continued support and encouragement of local environmental community or landcare
groups to continue with riparian regeneration and weed control, etc.
• biodiversity monitoring of the freshwater catchment streams on an ongoing basis would
also be recommended. To obtain signicant information approximately 5 sites should be
monitored for aquatic biodiversity twice per year (winter/summer) on the same day and
then over time trends can be seen, etc.
• water quality monitoring of the freshwater catchment streams on an ongoing basis would
also be recommended. To obtain signicant information approximately 5 sites should be
monitored for water quality twice per year (winter/summer) on the same day and then
Cockrone Lagoon Catchment Aquatic Biodiversity Report 32