NND kuroko selection and fry released to mud pond
Posted 28 May 2010 - 17:33 by Mark Gardner
Following last week's spawning Sanke and Showa spawning at NND, see pics and videos at the following links - http://www.niigata-nishikigoi.com/node/794 and http://www.niigata-nishikigoi.com/node/799 - it was time for the kuroko selection from the Showa to take place and release of the Sanke fry to the mud ponds.
Outside the house the used spawning ropes were drying having been cleaned and disinfected.
Under shelter of the storage area Makoto Tanaka, Fujio Oomo, Tamikazu Kobayashi and a member of staff were busy working their way through the tiny fry selecting only the kuroko, the black coloured fry, as only these are kept from Showa spawnings, as with other black based varieties such as Utsurimono and Kumonryu.
This is Makoto san's mother who also helped out with the selection.
The picture below, a random selection, shows 4 kuroko and 10 shirobo.
A tiny kuroko about to make its way up the siphon tube which has an internal diameter of 4mm.
Makoto Tanaka netting up some of the Sanke fry to transfer them to a mud pond situated in the mountains above the farm.
Makoto Tanaka holding a bag containing approximately 50,000 fry. In total this Sanke spawning produced approximately 900,000 fry which have been released to the mud pond.
From this bag Oomo san suggested that come September when harvested would realise just 10 Sanke which were 'top of the top', 20 that were 'very high grade' and 30 that were 'high grade'. I got the impression that Makoto Tanaka thought even those numbers a little optomistic.
Some video of the kuroko selection and fry release will be available over the next couple of days.
Hello, Mark!
Really glad to read your posts! Keep writing interesting stuff for us, please!
I was always wondering how do the Japanese breeders take care of the fry between spawning until releasing them into mud ponds for growing.
Please, share this information.
Thanks a lot!
Hi
To be honest the breeders don't have to do much during that time and it also varies from breeder to breeder how they handle the fry.
When the fry hatch they have a yolk sak wich they absorb over the next few days providing them with all the nutrition they need.
With Showa, and other black based fry which will go through Kuroko selection, they are invariably kept in concrete ponds until that takes place.
For Kohaku and Sanke Torazo will hatch them indoors and keep them indoors iin fine mesh holding nets for the first week, the period between spawning and them absorbing the yolk sak and being free swimming, i.e. detaching from the spawning ropes.
Shintaro and Maruju place the spawning ropes into mud ponds the day after spawning, having first sterilised them with malachite or methylene blue, allowing them to hatch in the mud pond and then become free swimming into the pond.
The first few weeks see them feeding on the natural food which has been 'cultured' in the mud pond. Thereafter they are fed powdered food. After the first cull (1 month) they start to get more 'solid' pelleted food.
Hope that gives some idea.
Mark