Poppy Hill - Lake 3 Update

Jun 7, 2013
Posted by: Admin
Category: Club News

As many of you are aware Lake 3 has suffered a significant loss of fish of all species. The Environment Agency have been involved and have taken water samples and a sample of stock for analysis.

Please follow the link for information on what we know so far.

The results of the water testing showed normal Ammonia levels, the PH levels were within an acceptable range and the oxygen levels were showing above 100% meaning super saturation. Oxygen levels were monitored 3 times a day for a week to see if there were any fluctuations and everything was in the normal ranges. Nitrate levels were showing as being a little higher than average and has been attributed to the persistent and long period of rain fall we had over the winter and spring, releasing nutrients locked in the surrounding fields. There was no evidence of any chemical pollution found, either directly added or indirectly by field run off. Neither was there a build-up of toxins caused by excess baiting, and decaying matter.

The sample of stock removed for testing by the EA was sent to Scotland for further analysis after local testing was found to be inconclusive. The final results received from the EA showed the cause of fish deaths to be hypoxia caused by an abnormal increase of Diatoms (a type of algae) that are found naturally in almost all lakes. Diatoms are single celled organisim that have spikes that can attach themselves to the fishes gills causing irritation which in turn cause a mucous to form and prevent the gills from functioning. Because of the loss of gill function, emergency treatments such as using an aerator or in more extreme cases where deoxygenation has occurred, adding Hydrogen Peroxide, would have no effect. As mentioned previously the oxygen tests showed a level of  over 100% so disolved oxygen was not a problem. The appearance of the fishes gills remain normal and Diatoms are invisible to the naked eye making it is impossible to identify the problem without laboratory investigation.

At present we do not know what, if any, fish stocks are left, and at this time the lake will remain open this season. Advice from both the EA and other sources suggest that it is pretty rare that a lake is 100% totaly wiped out, however to date there has been little evidence of much fish activity. Weed growth is still present in areas of the lake and lilies appear to be growing as normal.
At the time of writing this, the water has gone gin clear suggesting that the algae has now run its course. Barley straw has now been added to the lake to try and prevent the reoccurrence of the algae / diatoms. Research suggests that Barley straw is most effective when applied before an algae bloom occurs rather than to an existing bloom, and is dependant on higher water temperatures.

LGCAA are in constant communication with the lake owner to discuss how we can move forward with the situation but at this time have nothing further to report. We will continue to monitor the situation over the coming months and try keep you informed.

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