The secrets of koi breeders at Nagaoka
A certain amount of sake can help overcome any language barriers, but it's no good if neither party can remember anything the next morning. To the disappointment of the Japanese, the expedition leader Heiko Blessin does not drink alcohol (no, he is not an ex-alcoholic, he simply does not like alcohol).
But over the past few years a very friendly relationship has developed even without the help of sake, and some of the koi breeders have been working closely with the JBL research department on koi nutrition and water tests.
This friendship rewarded us with some useful information and with access to the natural ponds and the indoor keeping facilities, using water testing equipment to analyse the water. Don’t forget, the value of koi far exceeds the value of cars in the showrooms of a licensed Porsche dealer! So you are not simply allowed to go to the ponds or take water from the ponds. You might be a germ carrier!
On the subject of koi nutrition, it was interesting to note that the amount of food given means that young koi do not receive very high quality food for up to one year. Only after this period, once the new selection has taken place, is there a switch to high-quality and therefore expensive food. And this includes JBL PROPOND koi food.
Water measurements at the koi breeders
We were interested in the water values of the natural ponds called mud-ponds as well as the water values of the “Porsche hall”, the koi ponds in the indoor facilities. Thanks to our friend Martin Symonds from Japan Koi Export we even had access to the koi when the breeder himself was away from home.
Manabu Yamazaki from the Yamasan Koi Farm was most interested in the oxygen levels. Like many others, he noticed that the practical oxygen electrodes are very sensitive and only last a short time. He really appreciated the JBL oxygen test. We’ll send him some from Germany!
At Master Kaneko’s the following values were determined in three indoor ponds:
| Conductivity: |
GH: |
KH: |
pH: |
| 922 µS/cm |
15 |
5 |
7.4 |
| 921 µS/cm |
15 |
5 |
7.4 |
| 914 µS/cm |
15 |
5 |
7.4 |
The different conductivities indicate that the water pollution in two of the three tanks had increased slightly. The conductivity only indicates a quantitative increase in electrical conductivity resulting from the salts (ions) present, regardless of their composition. Nitrates and phosphates are the cause here. However, the relatively high conductivities here also indicate that salt (table salt, pond salt) is involved. It can’t be sea salt, because then the GH and the KH would be much higher. Only the sodium in table salt is neither covered by the GH, nor by the KH!
At the Yamamatsu koi farm we measured the following values:
| Water temperature (surface |
Conductivity: |
GH: |
KH: |
pH: |
| 18.1 °C |
151 µS/cm |
2 |
2 |
7 |
The low conductivity value clearly shows that no salt had been added. The water was relatively fresh from the nearby mountain stream and therefore exhibited low degrees of hardness.
The low pH values are not surprising. At the rather low carbonate hardness values (2-5 °dKH) the pH-value is barely stabilised and can easily drop when nitrates etc. create water pollution. All the measurements were taken in the morning and it would be interesting to have them measured in the evening sometime.
We measured as follows in the natural ponds:
| Water temperature (surface) |
Conductivity: |
GH: |
KH: |
pH: |
| 19.8 °C |
92 µS/cm |
1 |
1 |
8.2 |
| 19.6 °C |
89 µS/cm |
|
0.5 |
7 |
| 19.3 °C |
115 µS/cm |
1 |
1.5 |
8 |
The ratio of GH/KH and conductivity indicates that calcium and magnesium are hardly present and therefore other salts are influencing the conductivity. We could guess the different pH values as soon as we looked at the mud ponds.We always found higher pH-values when algae were visible in the water. The algae extract CO2 from the water, and that way they indirectly extract carbonic acid. When acid is removed from the water, the pH increases. It’s that simple!
Almost all of the koi breeders in the Nagaoka Ojiya area live in the mountains. Former rice terraces were converted into koi ponds and then largely destroyed during the Chuetsu earthquake in 2004. In a museum in Ojiya, photos, films and a 3D simulation of the earthquake, which had a magnitude of 6.4, are on display and they vividly illustrate the devastating consequences for the people (and koi) of the region. Our friend Martin Symonds was involved in the rescue work at the time and appears in some of the photos.
32 curious minds on the JBL Expedition 2019 in Japan
The dive boat at Ishigaki was the reason we limited the maximum number of participants on this expedition. The Japanese owner of the ship only allowed a maximum of 15 divers. In the end there were 17 scuba divers and 15 snorkelers on another boat.
Here a photo of all participants together with koi breeder Yasuaki Kaneko:
Among the participants were (from left to right): Uwe Hartmann, Thomas Krause, Norbert & Anke Kressin, Michael Schmölzing, Prof. Christian Steinberg, Christian Oswald, Maik Figura, Sebastian Gemmecke, Stefan Lekon, Christina Schmölzing, Alexander Stroba, Claudia Voss, Jörg Koroll, Anke Morbitzer, Roland Böhme, Silke Figura, Nick Schenk, Justus Böhme, Anna Piesik, Andreas Geisler, Yasuaki Kaneko, Thomas Pazurek, Heiko Blessin, Robin Geisler, Piotr Piesik, Dr. Ludwig Neurohr, Astrid Christ, Maxence Jambon, Manon Tanguy, Vincent Montagnier, Benoit Jadot, Didier Lergenmuller
