Mud ponds - flat land versus the mountains

At around 5.15pm this evening Tsuyoshi san released the last batch of tosai to a mudpond on the flatlands close to Katakai.

I was surprised to learn that this pond had been used by Torazo for over 40 years.  It wasn't part of a complex of ponds, just a single pond surrounded by rice fields.  How this particular irregular shaped piece of land became to be dug out as a pond I've no idea.  All around it the rice fields are now relatively large angular shapes.  Tsuyoshi san explained that when the pond was first created all the rice fields around it were irregular curved shapes with different people owning each small piece of land.  In those days each rice field would be planted, and harvested, by hand.  Nowadays the planting and harvesting of the rice fields is done using automated machinery hence large angular shapes are more efficient to deal with.

Interestingly Saito san and Hiromi san had made the same comment about rice fields and ponds when we'd looked through some old photos a few weeks back - http://www.niigata-nishikigoi.com/node/359.

As I mentioned last year, since the earthquake many breeders now have complexes of mudponds, mainly used as fry ponds, on the flat lands.  Tsuyoshi san that one of the great things about the ponds on the flat lands is their ready supply of high quality fresh water from bore holes at the flick of a switch.  In the mountains lack of natural running water can present a problem during the summer.  However, he stated, the mud in the mountains is very special, which concurred with something Shigeyoshi Tanaka had said to me whilst at their fry ponds last year.

The mud found in the mountains, and it's effect on the water, is often stated as one of the reasons why the original mutations of magoi took place to become the origins of what we now know as Nishikigoi.

Tsuyoshi san believes that the ponds on the flat land are fine for fry and and ake-nisai (Koi that will become 2 years old) however, any Koi older than that need to go into the mountain ponds in order to develop the full beauty of their skin.

The pond we released the tosai into was heavily protected against predators.  There is an additional predatory threat on the flatlands which, thankfully, doesn't seem to occur in the mountains - cormorants, indeed, as we finished releasing the tosai one flew over head.  There are many cormorants that can be found living and fishing along the Shinano River.  The cormorant is of course also used by the famous night fisherman to catch Ayu (sweetfish) - http://www.city.gifu.gifu.jp/kankou/08_eng_01.html.  Where I live in the UK they can be found in their hundreds along the River Thames and they dive tirelessly to catch fish.  I would imagine one getting into a tosai or fry pond could cause complete devastation to stocks in no time at all.