11 Jun 2019
Students have provided vital research to Hastings Council and the Revive Lake Cathie group as part of their Marine Studies learning.
On Friday 31st May Year 11 and 12 Marine Studies students kayaked from the Perch Hole in Lake Cathie and into Lake Innes (a total of 9 km) to collect information on the water quality and health of Lake Innes and Lake Cathie for the community group “Revive Lake Cathie”.
Unfortunately Lake Innes is in a worse state of health than Lake Cathie with salinity measuring 60 ppt (parts per thousand). There were dead and dying fish throughout the Lake System (adult Stripped Scats and Adult Longtom fish measuring up to a meter long). These fish species are extremely hardy, but they cannot tolerate these kinds of salinity levels. Also, dead Pipis, crabs and yabbies were scattered on the shore. Ammonia was also detected in the water at Lake Innes, which is indicative of decomposing organisms.
Results at the Perch Hole for salinity were very high at 50 ppt (a rise of 3 ppt in the last two weeks alone as the water is evaporating so fast leaving behind excess salt). Normal ocean seawater has a salinity of 35 ppt and therefore the salinity is almost double in Lake Innes! pH varied throughout the sites tested (some areas with high pH 8.8 + and some areas at normal levels of 8.2. Some areas had lower pH levels which could be indicative of other biological processes happening such as acid/sulphate sediments.
Tests are still being undertaken on other water parameters.
Related Article: Students Help Revive Local Lakes