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Mid May, and 2 good spawnings out in the fry ponds


It's worth a moment to reflect on last year.  A good spawning early May, and then I couldnt get another decent batch of hatchlings for the rest of the year - and I managed to get a partial hatch, from spawning a female for the second time in the same year.

This year - it's only mid May and I've had 4 spawnings - 1 failed, 1 produced a modest batch of good eggs but I failed to rear them right, and 2 have produced bumper hatches - I think the number of hatchlings I've had this year may be more than the total number of hatchlings I've had in the first 2 years combined.

The okawa female's fry are out in the top fry pond.  I estimate at least 100k of them - there were enough to fill both ponds.  Advice from Mark at Cuttlebrook in the past was not to overpopulate the fry ponds; but I didnt have time to do a proper count, and felt the least risky option was simply to put them all in.  All 100k of them (estimated numbers) went into one fry pond and we'll see how they get on.  I may adjust the feeding regime to account for them using up the natural food faster than I'd like.  This is a repeat of the July 14 spawning - so all being well (and so much can still go wrong!), we'll have a decent harvest in around 5 weeks and the opportunity to see if we get the same kind of result quality wise as last year, or whether it's different.
Famcy a cuppa?  Green water, and kohaku fry mix.  Lovely.

Step 1: drain down the water.  we used a 4k liter per hour pump, placed in the base of the fish basket, and with a 0.5mm hole sized net wrapped around the basket to stop the fry being sucked in.

Step 2: We narrowed the water pocked by propping up the base of the show vat - as the water level went down, I'd narrow the pocket of water further; until we ran out of depth for the pump.  Then the final job was to catch up the fry, cup by cup, put them into a bucket and transport them to the fry pond
Here's a pic of inside one of the 10l buckets while we were filling  it up.  I moved loads of buckets.  I lost count.  probably 20 or so full buckets.  And this one is only 1/4 full......

This is the spawning set up I'm going with now.  It's the green vortext tank , with spawning ropes suspended from bamboo canes/ Water level is c.1ft below the rim of the tank.  Tank depth is 6 foot, made up of 4 foot straight side, 1 foot of narrowing, and then 1 foot at the base which has the bottom drain built in,  I placed 10 spawning ropes in the tank for the okawa female kohaku spawning.  The green vortext tank is connected up to the growin on tanks - one of which you can see immediately behind the vortext tank in the picture, and the other growing on tank is further back, on the top right of the picture.

A reflection on the kohaku spawning - I only reared the eggs that were laid onto the spawning ropes. I left the eggs laid on the sides of the tank  - and amazingly, they've also hatched and I have a few thousand little kohaku fry swimming around my green vortex tank!  The spawning ropes' eggs produced the largest hatch I've had yet; I think the key was a good fertilisation rate.  And then there are so many eggs just on the spawning ropes that they alone have produced more fry then I need.  I will be continuing with this new approach for spawnings.

ofcourse, the big question mark right now is - are there any shiro's in the other fry pond?  We put in thousands - it was also a good hatch, and I'm sure many 10's of thousands of shiro fry went in.  But the number we've been able to see has dwindled over the last week. yet, we've been able to see the sample batch of shiro fry - these were white fry with a little piece of black on them; interestingly, some are developing as black fish, whilst most are developing as white fish.  But the key thing is that they have survived; that's around 70 fry in around 4k litres of water.  no food, just the zooplankton they can find in the tnak.  The water in that tank has been in situ for a year, and there's plenty of wildlife in the tank.

So - why can we see fry in the sample tank, but not in the shiro's fry pond?

Could it be that something went wrong with the cycling in the fry pond?  No enough of the right type of zooplankton for the shiro fry?

Could it be that most of the fry in the fry pond are black (we did improve the % black through kuroku), and we simple cant see them because it's like looking for tiny black objects on top of a black liner?   This is possible - but I can't help think it's wishful thinking.

I remember in 2013, I went over to see Mark at Cuttlebrook, and he took me round his fry ponds mid summer and showed me what fry ponds should look like with the right amount of fry in them and examples with fry of different ages.  I remember we looked at the pond with his shiro fry, and it was really tough to spot the fry at 2 weeks old, and this is because they're black, and we spoted some in the end on the margin of the pond where the mud was a light brown - so a small black fish visible over a light brown background.

I will have a closer look at the pond this weekend, and carry out some sampling with a net and see whether we can find any of these elusive shiros.....

If they've gone the way of the dodo - then that will be tough to take, but it doesnt take away from the fact that I have still made a significant step forward in delivering 2 successfull spawnings before mid May...  And with this improved spawning approach, maybe I'll have some luck with the showa set that Shintaro put together for us.  You remember the female and males Amanda bought back from her visit to Shintaro - a fantastic female, and the full set of 1 female and 3 males put together for us by such an expert. A privaledge, and a big investment for us...  but frustratingly, they didnt spawn for us last year...  Perhaps this is their year?