A comfortable fry harvest for a nursery pond of the size that we have is about 30,000 but most of our ponds have produced much more this year. That’s great in so much as the better survival rate of fry, the more choice we have, the harder we can select down and the higher the quality that we keep to grow on, but the down side of it is that it makes managing the pond a much harder job and it means more stages of selection. So far, we have harvested around 100,000 fry from C1 alone and that’s only half the spawning! The other half went into B2 where the survival rate was not as high.
I always find it fascinating how each mud pond has its own cycle and they each need to be treated differently. B2 got off to a sticky start and it took a bit longer to settle down than C1 which is why the survival rate isn’t as good as C1. C1 on the other hand, which has been great for producing fry this year has a really unusual algae cycle going on at the moment. The fish aren’t affected adversely by it but the pond starts the day bright red and then ends the day bright green!
In the last couple of weeks we have selected through our two ponds of Sanke and production in A1 has been great and has meant that we harvested 58,000 fry. It took us 3 and a half days to select through them all! We then had a break for a day and harvested a silly amount of Shiro Utsuri fry from C1. Then last Friday we harvested just a couple of thousand Shusui fry from no4 pond and selected through those.
Last year, we decided that we only wanted one nursery pond of Shusui fry but had so many fry from the spawning that we did that there was only room for about one third them in the pond. We didn’t want to destroy the other two thirds of the spawning and so put them into No4 pond with the Nisai and older fish. We expected that a lot of them would be eaten but that a few would survive and that those would be a bonus when we drained the pond down in the autumn. As it happened, we actually got about 40,000 fry out from No4 pond at the end of the season. It worked so well in fact that this year we decided to put ALL our Shusui fry in No4 pond!
There are certainly lots of them swimming around quite happily and the bigger fish don’t seem to be too interested in them so it will be interesting to see how many we harvest at the end of this season. Of course it means that we can’t carry out a proper selection process on them as the season progresses but they are in such a large body of water that overstocking isn’t a problem. It’s an experiment really but if it works, it’s one that we will be repeating. We’ve done a similar thing with the Chagoi fry that we spawned this year and have put them into No3 pond with the fish that we bred last year.
When putting the fry we choose to keep back into the mud ponds after first or second selection, we have not necessarily been putting them back into the pond that they came from. We don’t mix fry of the same variety, but different spawnings, in the same pond as this would make it impossible to judge how a particular parent set have performed, but we can put fry from different varieties together, as long as they are of a similar size and growth rate. This makes further selections a little tricky as you have to get your head around the key points that you are looking for in each variety. It also means that selection takes longer but the benefits are that we don’t have all our eggs in one basket, as fry are spread amongst two or three ponds, and also that we can put faster growing fry from each spawning in the same pond and slightly slower growing fry get a better chance to catch up.
When we harvested our second lot of Sanke fry from A 2 on 11 July, we were lucky enough to have Bob (Kayoss) helping us.
Here they were in the pond a couple of days before we harvested.
We both carry out selection and the third net is for either one of us to put anything really interesting into so that we can discuss and compare. It’s quite useful to do this and is also a bit of fun as we can play a kind of Koi Top Trumps with who gets the best Koi in their net!
Here are few of the keepers that went back to be grown on for a few more weeks. The hi is stronger on some fry than on others and the strong sumi that is typical of young Sanke often masks the hi that is underlying – it’s what makes selecting Sanke at first selection such a challenge. This is a new parent set and our second Sanke spawning of the season so it will be interesting to see how they develop.
We harvested this pond for the third time on 16 July and still got about 45,000 out! We kept about 3400 and some went back into the pond they had come from and some went into the same pond as some of our Yamatonishiki.
Now I know what we’re doing for the next few days!
After selection – job done for a few more weeks.
At second selection the pattern is more distinct on some fry and as they grow it changes. The skin quality and the quality of the sumi is evident at this size though.
Now you know what we’ve been up to the last couple of weeks and why I don’t get to post as often as I would like to – too busy doing it to talk about it!