Shiro Utsuri 2003

Shiro Utsuri 2003

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03/06/03

Because of the low fertility rate from the kohaku spawning, I quickly decided I had room for some more fry in the mud pond that they were placed in. It had to be a smallish spawning, also of a type that could easily be identified and not mixed up at culling time. This would give me chance to do an experimental spawning to test the quality of babies produced from an untried pairing.

Time was short, as the two sets of fry must be very similar in size, less the smaller fry would not fair well through the summer with regard to chasing down food.

I had an untried female Yamabuki Ogon that was being grown on, this would be a good chance to test the quality of her babies, so she was paired with the two males I used last year. Nothing happened the first night they were together, so 4.00pm next afternoon I injected her with PITUITARY EXTRACT to induce spawning. 20% of the dose was given, that is normally enough to trigger spawning, but nothing happened. So 4.00pm next afternoon the main dose of 80% was given, but alas nothing happened.

06/06/03

I had to decide whether to try another night or scrap the yamabuki plans and go another way. Within a few minutes my mind was made and bagged the yamabuki up and set off home. I picked a female Seki Shiro Utsuri I had been keeping to try and two males from Oofuchi.

These were placed in the breeding tank and unaided had spawned the next morning. Only a few thousand, but that was perfect for my plans and will give me chance to see if this set will produce babies of any quality.

10/06/03

The fry hatched and most were on the bottom of the spawning net, as before many had gone through the net and were on the bottom of the tank.

13/06/03

The fry were free swimming. This is my first Shiro utsuri spawning and am surprised to see that there are many yellow fry as with showa babies.

17/06/03

The fry have been fed on new hatched brine shrimp for the last few days, today they are off to the mud pond. It took several attempts and a couple of days to catch them all from their 1,200 gallon tank.

This photo is of one batch just about to leave for the mud pond. Complete with their last feed of brine shrimp.

Through the summer it was hard to view the fry in the mud pond they shared with the kohaku, their general dark colour made them blend into the background. As live food starts to decline I feed the fry on sinking food so in the earlier stages they rarely come to the surface. When the larger fry get to around 2" I start throwing in a few floating pellets, it takes a while for the fry to learn that food can be on the surface as well as the pond bottom. Slowly over a period the fry learn to nibble on floating pellets and it is from this time on I was able to see the shiro babies. They looked fairly nondescript, but occasionally one would pop up that had a nice pattern and those times were pleasing.

I have seen Seki tosai shiro utsuri a couple of times while in Japan over winter, they look fairly uninteresting with little white showing anywhere. When it came to harvesting this pond in late September growth had not been as good as I may of hoped, due to work I was unable to feed as often as I would have liked and this left the tosai a little small. Best kohaku form this pond was around 4" with most 2.5", the shiro utsuri were a little smaller, with the best around 3".

I had culled the kohaku twice through the season, their quality was very poor, but the shiro utsuri were left unculled. I found it difficult to determine good from bad so decided to leave them be. At harvest time I selected the ones that showed a pattern of some sort, this amounted to about 150 or so. These were returned to Wrington, where they will spend the winter growing on, the rest were returned to the mud pond, to fair the English winter. I will see what these have turned into come spring.

The ones that were returned to Wrington all had defined sumi pattern, but no white was visible, they were a mix of blackish grey and grey, instead of black and white. This was how the Seki shiro looked in Japan, so was quite content. As time has gone on these little shiro utsuri have grow well and many are catching the larger tosai from other spawnings. The best at this time mid December are around 5". After they were placed in the tank most of the sumi disappeared, this is slowly returning.

Below are some photos taken 29th November, I am hoping some of these will turn out reasonable quality. When they first went into the tank, there was little or no white showing on any of these babies, but slowly white is starting to show.

These first six are from the darker bunch that have the sumi up already, these are not likely to be the best.

These are some with the sumi still underlying. I have more hope for these.

I shall keep you all informed as to how well they are doing. I not sure with any of my predictions, as this is the first time with shiro utsuri, but hopefully I shall be able to identify them from these photo as they develop. There are a few more that I would have liked to show pictures of, but taking photos of these little tosai is a real game, snap the shutter and their gone out of shot. They are too quick to catch most of the time, so some will have to wait for another day.

Updated 10/12/03/03