I have nearly a year’s temperature data from the Notaires. There would have been more, but unfortunately the data cable was cut in July by some kind of vermin so the results ground to a halt then.
Even so, having continuous data for all four seasons is quite interesting:
- The ground water temperature is quite stable around the 10°C mark. The groundwater / swimming pool measurements came to abrupt halt when the probe corroded in the salt water.
- The lake temperature follow the air temperature rather than the groundwater temperature.
- The response to air temperature is quite rapid.
- The lake temperature is more influenced by the amount of sunshine than actual air temperature. This is not really surprising because the sun is stronger as you travel south. (Actually, the incident radiation varies with the sine of the latitude; a back-of-the-envelope calculation suggests that the sunshine is 30% stronger at Notaire’s than in London.)
What does this mean for the fishing?
Well, in winter it means that when the sun comes out, the water temperature goes up rapidly. The fish will be less torpid and more likely to start hunting for food. I’ve seen anglers catch fish when half the lake was iced up.
In summer the fish are likely to seek cooler water in the heat of the day, namely near the inflow of the stream, under the shade of the trees or in deeper water.
The catch reports show that the total catch does drop a little in the summer months (down to 20 carp per angler per week – still a very good result) but I suspect that this is also largely due to family holiday fishing where there are other pressures on the angler’s time.
I am working on a radio-based system to transmit the lake temperature back to a base station at the house and then extend the monitoring down to Alder Lake. If all goes to plan, you will be able to check the water temperatures on-line and factor that into your decision on what features to fish to.
For more information on Notaires follow the link – Fishing Holidays with Accommodation