The latest water chemistry tests have been carried out at Darlow and ammonia levels are still low, with perhaps a trace amount detectable (0.03 mg/L, pH 8.4) – this could become more of a problem if the temperature rises, but at present levels are safe. Phosphate, nitrate and nitrite are all undetectable, which is probably due to the plant and algal growth. Clarity started to deteriorate in April and May, but has since stabilised and has improved a little during June; Secchi disc measurements (visible depth) were 1 m, but have improved to 2 m at the last reading. Oxygen levels are also good because the aquatic plants are producing plenty of oxygen during the day – we don’t routinely take night time samples, but have done so in the past and not seen any big drops in oxygen saturation at night.
Most of the water parameters are good, but as with other years, our biggest problem is the rising temperature. The reading on 18-Jun-2022 (the day after the very hot day!) was 21.4 °C, this is about 2.5 °C higher than at the same time last year. With the increasing temperatures, our fish become stressed and can often be seen in shallow water in the margins. It may sound obvious, but please try not to disturb them as you move around the lake, they are unlikely to take a fly under such conditions and this will hopefully help them to ride out the warm weather.
As a club, we are doing what we can with our available resources to improve Summer survival. We have the aerators; these obviously provide aeration, but also water movement, and may also contribute to water cooling at night by enhancing evaporation. We also have the floating reed beds that provide some shade during the warm days, and we aim to increase the size of these reed beds over future seasons to give even more cover in the deeper parts of the lake. Hopefully, we can also rely on the British Summer to provide us with a little respite to get us through to Autumn.
We monitor temperature and oxygen levels regularly at the lake, but will report the trends on here and on Facebook more frequently over the Summer, so you can make an assessment on when to fish (and what to fish for – some members seem rather adept at catching tench). There’s no strict rule, but trout prefer cooler water and our catch returns show that they struggle as temperatures approach 20 °C and above. The river tends to be a couple of degrees cooler that the lake.
However, remember that if you don’t want to fish and you’re still in the area, you are welcome to visit for a walk around!