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Spawnings update

The spawnings may be going better than last year - but I'm still a long way from a good harvest outcome.  I'm worried about the shiro fry....

Update on the kohaku eggs; first up - the momotaro female's eggs.  they started well - maintaining around 30% viable eggs until the point of hatch. But it all seems to have gone wrong at around that point.  there's no sign of hatchlings in the tank and I emptied the tank this evening; open egg casings, and you can see the hatchlings didnt make it past the point of hatch.  I'm not sure exactly what went wrong, and it supports the decision I made a week ago to run the backup kohaku spawning.  Nevertheless - gutting that I didnt get anything from this female; she's the female I most wanted to rear fry from this year.  Gutting.  Only 1 more year to wait for the next opportunity...  again!

Here's a picture of the spawning rope a day or two after the spawning - the white eggs are dead, the transparent/yellowy ones with pair's of black eyes have koi developing in them.




The backup kohaku spawning with the okawa female, and a repeat of the July 14 spawning; this has gone well.  Lots of viable eggs, and the first hatchlings are visible today.  early signs suggest a good yield of hatchlings.  the fry pond they're due to fill has the early signs of a daphnia bloom - and I'm concerned it's starting too early.  There's nothing I can do about it - I just have to hope the timing of fry and daphnia bloom works out.

you can see from this picture of the spawning rope the significantly higher proportion of eggs are viable.  very few white ones, and you can see pairs of eyes in lots of the eggs.  the easiest eggs to spot this on is at the end of one of the spawning brush hairs - at about 10 o'clock position on the picture.



The shiro spawning - the fry have been outside in the fry pond for almost 2 weeks; and we can't see many of them :-(  Amanda gets to review them during the week more than I do, and confirmed the number she has seen today around the margins is significantly less than a week ago.  That's not good.  Even allowing for the fact that it's difficult to see a black fish swimming over a black liner, with patches of dark green algea on it; I'm seriously worried that the fry pond stage simply hasnt gone well for fry and at this point, I'm almost ready to empty the pond and start again.  I will probably give them 1 more week, and at that point decide whether to cut my losses.  Refilling the pond and getting it ready for a new batch of fry will take at least 4 weeks - probably 5 or 6. As its still early in the season - if I refill soon, I could have a new spawning back into the pond before the end of June.  Apart from the probable loss of a good shiro harvest - I have a limited amount of time available for the project, and I could have done with a better yield from the work I've put in.  But, that's koi breeding for you; I took a risk trying the early spawning, and it looks as though it's not paid off - and set me back!  Whether it was the cooler temperatures the fry had to suffer, or something completely different, I dont know.  I'll investigate, ...

What's interesting is the test sample of shiro's that we put into a vat...  we spotted a few of them today, and they have grown about the right amount considering the time they've been in the vat.  And they've had the same temperature swings that the main group of hatchlings had in the fry pond.  We spotted 6, which is  around 10% of the hatchlings introduced - and that's not a bad result.  There will be plenty more in there that we didnt spot.

On the upside, the kohaku hatchlings look really promising - there are plenty of them, and - when I consider that last year I couldnt get a second spawning done properly over the whole summer - I've achieved that already this year.  So, thats promising.





2 comments:

  1. Hi Adam, was just wondering what nets you use throughout your process (Especially the ones in the growing on vats) and how you got them.

    Would you also please explain to me how to find a good oyagoi, such as where to buy from, price ranges, sizes, ages, the qualities I should be looking for, etc etc... (particularly interested in Kohaku)

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  2. Sorry to be a pain... But what are the sizes of your vats/tanks and what are the dimensions of your pond?

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