Breeding and growth

[dizzyfish]

Does breeding a female koi keep it from growing to full size. I have heard that it might. The logic is that energy used for growth is diverted into egg production. In reading Koi 2 Kichi, Waddy says you need to limit food intake to female koi in winter (cooler temps), since they can over-produce eggs because this is not the time their energy is normally spent for growth anyway. If that is the case then it would seem that breeding would not necessarily be robbing growth energy. Am I looking at this wrong, and is this urban legend that makes sense?
Mitch

[dick benbow]

the truth of the matter is that in all things there is a time and place for everything....in the winter time females instinctively put any food into egg production to insure the continuation of the species. That's why Toshio sakai
shares with us all that we hold the koi at 52 F and let them experience winter. This way we are feeding so minimally that nothing goes into egg production, infact they may very well have to re-absorb the protein back to keep up with their motabolism. Which is a good thing to keep them from getting egg bound.

Once a female has spawned her energy goes back into rebuilding her body and then growing in length and girth again like any other normal animal.

so the readers digest version of all this is: let your mature females* experience winter so that after spawning or the time to spawn has passed they will be able to put their food energy into length and girth.

* females generally sexually mature at 3/4 years of age. So this means basically the time to grow your babies is the first two winters with heat and food. After that the girls need to slow down. Koi as our beloved JR is apt to say 'are four season' fish....

[dizzyfish]

Thanks Dick,
That's all useful information for sure. I think these global warming winters may cause people to overfeed koi that wouldn't even normally be hungry and begging.

Do you think a female koi that is bred every year in the Spring will grow as large as it would, if it was not allowed to breed? I understand the dangers of having aggressive males in with show females, but if your goal was jumbo pond fish, would breeding be a hindrance?
thanks,
Mitch

[dick benbow]

I think in all living things there is a balance. If a female spawns and is not challeneged with other health issues the body has to muster resources to, then she is able to fullfil her destiny of reproduction and still recoup and grow. If she has a bad time of spawning, then her resources will have to be used for other purposes than growth.

From a strictly show sense, if a female is allowed to experience winter, reabsorb her eggs, and then be allowed to smoothly engage in good temps and food, she has got to have an advantage over the female that has to deal with more challenges.

How much difference it would make between the two is hard to gauge. many times a show fish allowed to go thru winter will still need to be bred for health reasons or to regain a shape after many seasons with the same regime. This is where the experience of the keeper can help to make the right decisions. One size does not fit all, the same way people's health is different ( say sister to sister ) from each other. We can set out with the best plan, but have to be flexible to adjust according to the needs. indescriminate feeding can cause tumors in a female's reproductive system, so just because we get her thru winter correctly and move her up in temps and food amounts we still have to be careful about how and what we feed!

My advice would be to set out to handle a show fish and adjust according to her needs. One of my hot buttons is the topic of koi health and i feel too many folks fatten up their show fish with poor food and too much food and that impacts their overall health. better to buy a koi with great body potential and then keep them fit instead of Obese.

If you've ever done a disection on a female that died of egg impaction, you'll see things that will tell you why you don't want them to be storeing fat where the eggs are suppose to go......

[Russell Peters]

Quote: Originally Posted by dizzyfish Thanks Dick, That's all useful information for sure. I think these global warming winters may cause people to overfeed koi that wouldn't even normally be hungry and begging. Do you think a female koi that is bred every year in the Spring will grow as large as it would, if it was not allowed to breed? I understand the dangers of having aggressive males in with show females, but if your goal was jumbo pond fish, would breeding be a hindrance? thanks, Mitch

This year we were able to see a lot of Oyagoi while in Japan. They were all in the 75cm to 90 cm range. My guess is that breeding does not affect their growth.

[bekko]

Quote: Does breeding a female koi keep it from growing to full size.

I am not sure that we have an effective technique to control whether or not a female invests energy in egg production. If you starve her she will not invest energy in egg production, but growth will suffer even more.

Once energy is expended for egg production it cannot be recouped. Even if the eggs are reabsorbed, 90% of the energy used to create them is lost. I believe that, yes, egg production does divert energy away from growth. Whether or not she actually spawns those eggs is probably immaterial.

In the absence of effective techniques to inhibit egg production, "full size" is defined by females which regularly produce eggs. Correct?

-s tev

[dizzyfish]

Quote: Originally Posted by bekko In the absence of effective techniques to inhibit egg production, "full size" is defined by females which regularly produce eggs. Correct? -s tev

If I was working off the premise of that definition as being correct, I wouldn't have started this thread in the first place. I believe the words "reproductively mature" would more accurately describe what you are suggesting. Unless the female was producing immature eggs, if that is possible. For the purpose of this discussion full size would mean the largest size a certain individual specimen was capable of attaining under optimal conditions. Granted we may never know what that would be, but we can be aware that certain environmental factors or inadequate nutrition may prevent such optical growth from occuring. Are you aware of the word *stunting*? My definition of full size would be a koi that wasn't stunted.

The urban legend states that koi that are allowed to begin breeding at a young age are somewhat stunted as a result. I was trying to find out learn if the legend is false.
Thanks,
Mitch

[dick benbow]

Mitch,
I have no college degree in a science that can answer your question...but as a student of nature I see how species always seem to have a certain % of individuals that reach sexual maturity faster and yes they don't seem to get as big, but that's not their purpose.
as an avid fly fisherman I spent many hrs fishing for 2 year old salmon and steelhead jennies and jacks that were 2-3 pounds and sexually mature. the 3-4 year stuff was more like 10-20 lbs. There were years when the run was
high in returns and you never saw these individuals. there were years where the return was small and the numbers of these jennies and jacks were abundant.
How does mother nature know to tell them? I don't know.....I think with koi
you buy an individual based on what we've learned here about head size and body shape and then fully expect it to reach it's potential if we provide proper feed and accompanyments.....

[bekko]

Quote: koi that are allowed to begin breeding at a young age are somewhat stunted as a result

I am not trying to be argumentative Mitch, but how do you "allow" a koi to spawn and how do you forbid it from spawning? I thought you had to just take whatever is handed to you.

Do precocious koi grow up to be smaller than average? Dick thinks so. I agree.

However, it may be the frequency of spawning and the size of the spawn as well as the age at first spawning which matters. We all know that some females spawn more frequently than others and some females release a lot more eggs when they spawn than others. In my limited experience, frequent predictable spawners also tend to produce a lot of eggs. I suspect that precocious spawners are also more likely to be frequent spawners, but am even less sure of that fact.

-s

[dizzyfish]

Quote: Originally Posted by bekko but how do you "allow" a koi to spawn and how do you forbid it from spawning? I thought you had to just take whatever is handed to you. -s

Steve it takes two to tango. If you wanted to keep your female koi from spawning you could send them to an all girl Catholic pond. You could probably keep them away from males until they were a certain age easy enough. If it was better to wait until they were 4 instead of 3 I think it could be done, and that's what I'm trying to get at. How ever if any body has any "my female begin popping fry at 2 and grew to a 100cm" stories, feel free to post them. If the eggs are developed during the winter when growth is not taking place I don't quite understand how this would be competing with growth energy. Now if a female spawned early in the season, and then spent energy in the growth season making more eggs it might make sense. Beware of the double clutch I guess.
Mitch