Koi growth- early vs late vs final size

[KoiCop]

Quote: Originally Posted by Spike Cover Regarding the subject, I think I know that the "general wisdome" within the koi cummuinty says that if fish are big early in life, that they will likely be bigger later in life. This applies to the "jumbo tosai" we all see in the shops - and pay more for. But I believe I have seen (can't remember where) that some respected breeders (probably from the colder country, i.e., Niigata) have said that fish grow as big or bigger eventually if they are not forced (implying forced in warm water during times that warm water does not naturally occure) even though they grow slower. And, it is said that these "slow grown" fish are healthier in general.

Hello Spike . . .

On the contrary, I think you'll find on this board that that 'general wisdom' does not prevail.

Most agree with you that forced growth comes at a cost and without asymtotoic length gains.

Here's a post from JR you might enjoy:

I can add a little perspective to whatever answers you do get by saying, Japanese koi have grown larger over the last ten plus years on a steady basis. Yet the lower end of each year’s growth range has remained remarkably stable. It is the leading end that has increased.

And further, that koi are raised the traditional way and the intensive aquaculture way. The traditional way is further sub-divided into low density and hi density, heated winters and non heated winters. In the old days fish were simply covered; now they are almost all brought inside.

Intensive aquaculture focuses on an eternal summer in which fish are kept inside and heated and fed all year round to produce abnormally large juvenile koi for marketing purposes.

If you look at data collected years ago the range of growth was as follows:

One year old 6 - 8 inches
Two year old 10 - 12 inches
Three year old 15- 18 inches
Four year old 19 - 22 inches
Five year old 24 - 28 inches

Today this range has increased due to genetics, indoor winters and feeding technique as well as better mud ponds. So . . .

One year olds are often 10- 12 inches
Two year olds can be 15 - 16 inches
Three year olds can be 20-24 inches
Four year olds can be 24- 28 inches
Five plus can now be 28 - 32 inches (and 34- 36 is not unusual for adult koi)

Intensive aquaculture has produced a very confused picture if you do not step back and look at the forest thru the trees! There is marketing technique to make most fish larger and there is applied intensive aquaculture for 'gifted fish' that the breeder wishes to maximize growth natural growth potential.

So if jumbo fish are sold in numbers you are typically looking at one and two year old fish that are as large as three year old fish. But they will be no larger than the second group of traditional fish listed above when they are full adults.

The second intensively bred fish from group two, the gifted tategoi types, will be the marketing driver as warm or very short winters PLUS exceptional genetics enhanced with low density heated water and special care to diet will reach legendary sizes under expert care (mud pond and endless summer). They can easily reach 32 inches and records of 40 inches are considered the ultimate goal.

With exceptional rarity, non gosanke types can get to 44 or so inches. I do not believe that a 46 inch koi, of any variety, has ever been produced. This would include with the use of hormone or steroid food or injections. JR

Source: James Reilly 22 Jul 2007
http://koishack.com/forums/index.php?showtopic=11682

[Mtn ponder]

Quote: Originally Posted by dick benbow Those with genetically predisposed ability to grow are kept from tosai on, in heated winter facilities and minimally stocked mudponds and pushed thru the first 3 winters as well as summers to gain maximum growth. Because of sexual maturity (females) at 3-4 they then are slowed in winter to allow for reabsorption of the egg protein and then selected for the mud pond that best suits their needs, protected beni, developing sumi etc. By the age of 5 they are atleast 80 cm plus, many these days are 90 cm. But along the way, many shiro muji and shiro bekko and shiro utsuri emerge where kohaku,sanke and showa were oririginally stocked. But breeders and top end hobbists who entrust their possible national koi into their hands accept that under the best of conditions you can still have losses. It's acceptable in the quest for the best. It is my opinion that many of these koi that were pushed could have developed later and NOT lost their color. A big young fibrant koi full of life exzudes what the judges are looking for. In bonsai there is a trend these days to take a tree and do a complete makeover so that it goes from being a prospect to finished bonsai in one season. Some accept this and others want to do one portion per year so as always to maintain the health of the subject. It may take several years but the shock of a one year treatment is averted. your finances, your quest, your patience or lack there of and your philosophy all combine into making koi keepers ( or bonsai) comfortable in which application they choose. For me, All the years I studied the japanese culture, I admired the respect for age and the ability to have patience. But then nothing stays the same and ultimately it comes down to our choice.

Thank You. good stuff on here

[Spike Cover]

Thanks all... Spike

[JasPR]

another country heard from-

This is not too hard to figure out once you come to understand or accept what a koi is and how it got to be the success story it is today.

It is an indeterminate grower, albeit, slower growing with age.

It is a four season creature with distinct physiological changes based on seasons ( due to light, temperature and dietary calorie count and mix).

It is a creature subject to stress once you push it out of it's optimal range of water/temperature parameters and into it's survival range. And the resulting stress from survival events effect growth negatively.

And finally there is the human factor- The Japanese absolutely know what they are doing when they push the growth of fish in the first three years of life with heat. This is a much a marketing ploy as a husbandry technique. Yet within this physiological manipulation there is real benefit and quite often fish that would run out of time before they got to their genetic potential maximum size, are able to realize this size at an earlier age.
Indeed guys like Toshio Sakai ship hot prospects to the growers in the south to see if they can get the last 4 cm's in potential giants. And in return they/he buys fish from the south for resale as the tosai grow so much faster and bigger down there.
So there is truth and benefit in some grow out practices. Young fish do well with a long summer. And slow growers can be kicked on with a long summer. The key to all of this is a muted winter, a long summer and an appreciation of optimal seasonal conditions without stress to shift hormonal pathways and redirect growth to 'other kinds of growth'.

The final point to be made is this- a seasonal fish is tested by winter slow down. This is as nature intended to create sturdy healthy breeding populations. A non seasonal fish could be a weak fish fostered by a man made system for it's color or size potential. If that is true, then it will remain a vulnerable fish when adverse conditions do arise.
So is the forced grown fish a fish that dies because it is never fasted, never draws down stored reserves or deanimated proteins, never slowed down in it's growth as nature intended ? Or is it a fish that has been spared any evironmental challenges and when the challenge does happen it is ill equipped to respond? I suspect it is all of these factors.
In the end, a hot house koi will be within cm of a wintered adult of the same genetic potential. But it will always be larger at a younger age and in theory a larger fish at the age of slowed growth ( 12 years plus) But that extra length will be a matter of a few cm at best in the final analysis.

Maybe the question should not be 'which gets bigger'. But rather, which lives longer?
The comparison of 'inches vs. years' in the focus of marketing is all consuming these days. But in a big picture sense, no one focuses on the 'ultimate inches' vs 'the ultimate years' in the life of individual fish. Interesting.

[PapaBear]

At times like this I wish some of our members from Singapore and Malaysia would speak up. (I know you're out there...)

Big fish in a hurry with long term health issues is something I've read plenty of anecdotal evidence about on the Malaysian forum, but it sure would be nice to hear from the "voice of experience". Since they have very warm water all year, heavy feeding and rapid growth are the norm and keeping their charges from outgrowing their patterns is a constant struggle. It probably helps to explain why so many extremely high quality Koi go to that market, as lesser grade fish would never hold up to the accelerated growth without patterns breaking apart.

How about it? Anybody out there care to add to our conversation???

[JasPR]

Taiwan is who you want to hear from. They have the experience. The other countries are collector countries.