Pennyfish Parents
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The t. hornorum shown above here has been selected over a period of 33 years. This has allowed for over a hundred complete generations where a selected fry at about 1/4 inch was able to grow to a breeder size of one and a half inches and either produce eggs or sperm and become a contributing breeder that can add its genetic traits to the gene pool. So, when I come across a single fry that looks broader or deeper than the thousand or so fry it is swimming with, I can put it in a special tank with controlled temperature at 90 -94 degrees f. and feed it high protein of good quality and assist it to grow more quickly which helps shorten the cycle between generations.
As it is, the fact that it is even possible to get a tilapia that can produce or add to the production of tilapia, in such a short amount of time is a considerable help to the process of developing fish that are different.
An improvement in a single characteristic, such as a smaller head, or a larger area above the stomach, can be again improved on by selecting from a large number (1,000) or more and helping the tilapia become a contributor to the gene pool of that species. 
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The t. hornorum shown here has been selected over a period of years that have allowed for a hundred complete generations where a selected fry of about one inch was able to grow to a size that could produce eggs or sperm. The development of the improved gene line of the t. hornorum has made it possible to produce 100% male hybrids that have the broad body and the ability to grow quickly to 400 to 1,000 grams from an average starting size of 10 grams, provided that good conditions for optimal growth are provided in the growing project.
Good conditions for rapid growth include a minimum amount of:
1. oxygen dissolved in the water........6 parts per million
When I first began to learn about aquaculture I had recently completed some course work at the University of Florida, in the department of Psychology where certain new philosophies were being studied by such ground breakers as Carl Rogers who spoke of the new Psychology which were providing what seemed like totally new answers to the "science of Mental Health Management. What He and his followers had done was to ask some basic questions about the philosophy of health care. which included such radical ideas as examining large groups of people defined as healthy to find out what their methods for coping with reality were and what characteristics were commen to them and therefore was a "healthy response" to such things as stress and discomfort.
So instead of making up a list of characteristics common to people who say were troubled by schitzophrena and designing or creating a language for defining unhealthy people they were interested in definging what could be defined as healthy people
These researchers were finally beginning to map mental and physical responses by healthy people to stresses and difficulties formerly only examined in conjunction with unhealty responses by unhealty people.
These new concepts were being examined during that time and they suggested stratagies to me that could possibly help to understand what good growth and development of healthy well cared for fish would be.
So I was interested in what could be done to creat situations that provided what could be considered optimal conditions for good growth and good health conditions for the fish.
The internal design and organization of the genes that control body form and therefore where bones could be or not be, of course could have an impact on the overall yield of flesh to the fillet knife. The high yield of skinless boneless fillet was improved by selecting for a better genetic architecture which allowed for easier access during filetting and the improved body form that allowed this improvement to occure was continously selected for in each generation and gradually improved over the years since we acquired this species or gene line of t. hornorum. So, from 1976 when we began the selection of hornorum to use for breeders which had a broad body and a thick body we have gradually improved the yield of the hybrids produced by crossing this breeder with suitable females that have other good characteristics to add to the total genetic package.
We have worked our way through this selection process from young breeder to young breeder approximatly 200 times over the 30 years of continouse
found that fish that I could select at a small size .5 inches or less and kept a continous temperature of 92 degrees would grow to a breeding adult in a very short time and add its genetic material to that already in the gene pool of pure line breeders.
Many times I would get fish that were less than 2 inches but provide viable sperm or eggs. This meant that a fish with a desirable improvement could become part of the group of breeders producing the next generation in as little as 45 to 60 days, and be selecting from offspring that had been produced by this fish in under 70-80 days which would make possible up to four new selections a year. This makes for very fast breeding success.
In general for each fish selected for improving each of the criteria I was selecting for I eliminated or culled between 500 and a thousand as being not good enough, or not having enough improvement, before working my way to the best choice. In this period of time I have improved the skinless boneless yield of the hybrids that can be bred with these improved breeders from 25% in 1976 to 42% by the year 2,000. One customer in Spain has reported an average of 49% skinless boneless fillets when he grew the pennyfish to a kilogram or more
I belive that the rapid improvement I got in fillet yield was primarily due to the process of summation in many generations. This process of finding a summation event is accellerated to some degree by the elimination of 499 to 999 t. hornorum for each one selected as having a better body form
This extreem level of elimination during the selection process literally forces or at least makes possible the finding of unusual fish where certain chromosomes or genes have crossed over which occurs when the paired genes seperat during meiosis and certain spots where the genes are attached are a little loose and the gene or portion of chromosome is transferred to the opposite strand pair and so that strand ends up with twice as much or more of the instructions for whatever is required to create a beneficial change.
The finding of a specimen that has a considerable improvement in the expression of a particular critera of improvement often occurs as often as once a year.
Three criteria are responsible for the improved performance of the f-1 hybrid over the performance of almost any other tilapia.
The first Criteria is the selected improvement of fillet yield which allows the farmer to deliver more meat for the same amount of resources put into growing the fish.
The second criterial is the creation of a true f-1 hybrid which multiplies the innate advantages of having all systems with working genes present in the fish which allows for faster and more uniform growth across the board.
The third criteria is the creation of growing stocks that are truely all male hybrids.
The creation of all males is attemped throughout the tilapia growing world because of the affect of having females present in the growing population which allows vast increases in the numbers of mouths to feed and a consequent disimprovement of the feed ratio that the farmer is able to achieve.
This rapid growth is made possible by the creation of a suitable hybrid such as the pennyfish hybrid and then providing optimal growing conditions for this hybrid
So, we needed to ask what the tilapia f-1 hybrids could do if placed in optimal conditions.
Now to find out what conditions can be considered optimal the hybrid needs to be exposed to a range of conditions that can be measured and accurate records need to be kept that will chronical the growth.
Since it is not always possible to set up large amounts of water and fish to find out what a good level of oxygen, CO2, nitrates, nitrites, ammonia, Ph, alkalinity and other parameters when these large situations are created a great deal can be learned by trying to gather information from it.
Such a situation occured in a project set up by a researcher by the name of Harry Burkle who at the time was working with the department of In Wyoming where a new dam was being installed and about 50,000 acres of a mixture of farmland and other properties were flooded to hold the water retained by the new dam. Harry had heard about tilapia and the work being done with them in Tishamingo Oklahoma by Dr. Inslee who was successfully breeding large numbers of the all male hybrid produced by breeding tilapia mossambica females with tilapia hornorum males.
Dr. Inslee was able to provide approximatly 50,000 fingerlings consisting of 3 to 4 inch fingerlings all of which were tagged and released into the damn in Mid may of 1963.
This was about one tilapia hybrid per acre and since the dam was created by flooding vast fields of corn, soy beans, millet and other crops it is probable that each fish had unlimited supply of food, both from the available grains underwater and from the growth of microorganisms such as daphnia. The water quality can also be assummed to be very fresh and pure, in any case each fish had good growing conditions with the possible exception of temperature during the beginning of the test which began in mid may of 1963. Also oxygen levels were generally topped out and remained at or above 6 parts per million during this period. By September of this same year fisherman were catching hybrids of the tagged fish which were put in the damn at about 30 grams each out of the damn at an average of at3.5 to 4 pounds each.
So, we can say that under the presumably optimal conditions of unlimited food and oxygen the hybrids can grow from about one ounce to 4 pound is a little as 120 days.
With all males there is a known number of mouths which are sharing the available feed, oxygen and clean water and so they can and do grow very evenly whereas with sex reversed fish only approximatly 50% of the male fish being grown are natural males and grow at the rate of a natural male. The reversed females grow faster than the normal females in most species but not as fast as the natural males.
The difference in growth rate betwee natural females converted to males and natural males is usually more than 10% difference or ,which of course increases the cost of pond time and sorting.
This is further complicated by the lack of assuredness that the reversed fish will indeed be male and as it is a known fact that most buyers and growers experience a range of percentages of sex reversed fish that can go as high as 8% or more females which places a very real time line on the time it will take for the reproduction and reproduction of the reproduction begins to eat away at the food ratio which can drop from 1.8 pounds of tilapia feed to one pound of weigh gain to 3-4 pounds of feed to each pound of weight gain in the pond in just a few weeks.
The second criteria is that the f-1 hybrid is a true f-1 hybrid and so has all of the growth advantages attributed to f-1 hybrids pretty much across the board. 
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xx yy Pennyfish
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Orange mossambica female with two "X" chromosomes which code for female characteristics when there are two sets in the same fish, but when eggs are formed the two chromosomes split apart and one goes into each egg which has half of the total chromosomes present and is therefore called haploid prior to being fertilized by the arrival of a sperm which carries a package that includes matching genes to those already in the eggs which makes the egg diploid which means it will develop into a normal baby fish. So, before fertilization each egg is haploid and each egg has an X chromosome which helps to determine its sex to be female, but only if another X chromosome comes in the package of genes being delivered by the sperm. If however the sex determining chromosome that is delived by the sperm is Z then the combination of the two genes (XZ) will program the new fish to be male.
Since 100% of the eggs produced by t. mossambica have one X chromosome and 100% of the sperm delivering genes to the egg in order to make the fertilized egg diploid always delivers a Z chromosome to each egg so, since each egg already has an x chromosome which pairs with the Z chromosome from the sperm then each egg is programmed to develop into a male by the (XZ) chromosomal pair. The Pennyfish which is the f-1 Hybrid cross produced by mating t. mossambica with t. hornorum f-1, have been produced for over 20 years on hundreds of farms. When the brood stocks are pure they generally produce over 98% males.
This particular cross is new because with this system we use Orange mossambica crossed with Improved Yield black hornorum which produces a hybrid that is a true hybrid in that a fully color coded hybrid is produced. The all male F-1 hybrids This color coding allows the breeding farmer to know if the breeders were properly sexed because the color of the hybrids is distinct from that of both the mother and the father. The f-1 male hybrids are a copper color and are always male.
If orange fry turn up among the fry, it means that one of the breeders was improperly sexed and is male.
The Farmer/breeder can then go back and check the sex of each orange fish and remove any male breeders from the breeder group. This allows the Farmer breeder to control the breeding by making sure that the orange breeders are all female and the black breeders are all male (t. hornorum).
This is a very important improvement in production of all male hybrids because prior to discovering that this color coding could be used it was virtually impossible to determin which fish were t. mossambica and supposed to be female and which fish were t. hornorum and supposed to be male.
One farm manager in Trinidad sexed 50,000 3 to 4 inch fingerling pennyfish and found only 5 females. This is 99.9% male by actual count. Prior to the development of the Orange mossambica there were many researchers and breeders who lost the ability to produce all male hybrids. This was because the people breeding the hybrids of the pure lines often mixed the breeders up because they were both black and looked so much alike.
If 100 black t. mossambica were sexed and determined to be females were selected to go into a breeder pond and 20 black males were taken from the t. hornorum brood stock and were selected as males and were placed in the same pond and allowed to breed for a few weeks, then the large breeders were seined up and the females which now down to 99 were resexed and placed in the t. mossambica pond and the males were sexed and put into the t. hornorum pond and there were now still 20 males and sometime during this period one of the male hornorum had died or been eaten by a bird without anyone seeing it happen, so the numbers still appear to match and the breeders are carried back to the pond from which they came when the original sexing occurred.
A single mistake made with the sexing of any of the 100 female t. mossambica could have destroyed each and every breeding program set up to produce the all male hybrids.
Suppose that just one of the 100 t. mossambica sexed and found to be female t. mossambica and placed in the breeder pond which shuld be carrying the XX chromosome for sex determination turned out to be a late developing male and now you have 99 properly sexed females and one improperly identified as female but was now clearly male.
If these were orange t. mossambica once you examied each fish you would find that there was an orange male which would then be disposed of. But since the males in this pond were t. hornorum and the appearance of the t. hornorum would be identical to the appearance of the t. mossambica male and the t. hornorum males would carry the ZZ chromosomes for sex determination and the t. mossambica males would be carrying XY chromosomes for sex determination any mistake that took place at this point would put the breeder carrying the wrong chromosomes for sex determination into the breeder pond holding the hornorum males which have the ZZ set of chromosomes.
These eronious breeders would very probably have bred with any females located in the same pond and thus further spread the occurance of the XY genes which within a few years destroyed the integrity of the XY breeders so that they no longer provided only eggs with X chromosomes and the gene lines would have been usless as far as producing any all male hybrids.
It is almost impossible to tell the difference between a male t. mossambica and a male t. hornorum with any currently known method.
Any mistakes made in the original sexing could not be discovered by sexing the breeders and so the mistakes could and did end up back in the wrong pond and the "'ZZ" system in the t. hornorum or "XX" system in the t.mossambica was forever comprimized and so within a few years each of the people trying to breed all male hybrids failed to get all male hybrids.
The color coded breeding system thus prevents this possibility from occuring because while mistakes can be made when it comes to picking the right sex and you can end up with an orange mossambica male in the hybrid breeding pond it is not possible to mistake this orange male for a t. hornorum black male breeder nor is it possible to mistake a black female breeder to be an orange t. mossambica female.
So, due to the development of the orange gene line of t.mossambica and the selection resulting in widening and thickining of the t. hornorum gene line resulting in easier access to the fillet Both species can now be reliably identified and therefore be maintained in the same production facility without the fear that any mistakes will end up causing a mix up in the genetic capability for producing the all male hybrid.
The color coded breeding system works as follows: the females to be used in the breeding of the pennyfish are selected from the orange gene line of the t. mossambica and placed in a cage or in a tank that has been cleaned out and has no other fish in it.
Generally we use 5 orange females and then we add One t. hornorum which has been selected for its body form and has the wide body associated with this selection. The breeding colony thus produced now has 5 bright orange t. mossambica females and one black inproved broad body form male.
The breeders generally take 10 to 20 days to become familiar with each other and then the female orange t. mossambica will drop eggs into the breeding areana prepared by the male. The male will then squirt a stream of sperm fluid containing millions of sperm, each of which carries half of the genes that controll everything in the fish including the Z chromosome which controls the development within the complete egg of male characteristics. This is done with the genetic pairing up of the Z chromosome with the X chromosome which is supplied by the female.
The egg now equipped with two complete sets of chromosomes (including the XZ sex determining gene complex,) then begins to develop the first stage in the formation of a minature fish. During the first stages of development the egg will develop a pair of eyes on one end and a small tail on the opposite end. This occurs during the first 48 hours after fertilization, and continues through about 72 additional hours until the egg has become a fry. These fry are called egg sac fry as they retain most of the nutrients of the egg which is suppling the developing fry with nutrients it needs to continue developing into a fry. By the end of about the 4th day at a temperature of 80 degrees or more the small fry now have a nearly developed tail and developed eyes. At this stage the fry can keep itself in motion which means that if for some reason the mother spits or spills them out the fry will generally survive if something does not come along and eat them, whereas if the mother spits them out before the tails are fully or partially developed they cannot keep themselves in motion which leads to suffication from a lack of motion in the water surrounding the eggs so that oxygen is not supplied in sufficient quantity to support the development in process.
When the eggs are spit out of the mouth of the mother too early they can be collected from the bottom and put in an incubator that is designed to keep oxygen rich water moving around the eggs and so supply the needed oxygen.
Once the eggs have fully developed into fry the fry will begin to travel around the tank or pond is small groups or swarms and can usually be caught with a fine mesh net and placed in a safe place for development. At this stage the color of the fry becomes apparent and it is quite easy to tell whether you are getting pennyfish or if there were any mistakes in the selection process for picking the breeders.
The color of fry that are pennyfish are a sort of dark bronze with only a small spot of orange yellow around the gills.
If a fry has a father that is orange because the female orange picked was selected too early and actually developed into an male the fry will be a bright orange instead of the dark bronze. These bright orange fry are not pennyfish and will generally develop into 50% male and 50% female fingerlings which will proceed to the breeding stage within a matter of weeks, thus destroying the possibility of growing an affordable crop because about 4 to 6 weeks after they produce their first broods half of the broods will be developed females which also begin breeding and so within 10 or 12 weeks the conversion of feed will drop from one pound of fish per pound and a half of feed to two pounds of feed and then three, four and five pounds of feed per pound of fish produced. The oxgen that needs to be dissolved and put into the water will go up at an exponential rate until you will not be able to keep enough oxygen in the water for the fish to be able to digest the feed aerobically and so much of the feed digestion will become anerobic and the possibility of oxygen crashes that result in large numbers of dead fish will become more and more likely. So, the presence of orange fry are a signal to the grower or breeder to check each of his breeders and make sure that the orange ones are female and to destroy any orange males that are discovered and to make sure that all of the black breeders are male and to destroy any that are female.
At this point the color coded system has now deliverd the warning needed to avoid disaster and get back to breeding all male hybrids.
What must be done is that each breeder must be examined and any fish is not the right sex for its color must be removed and destroyed. The orange fish should all be female and the black breeders should all be males. Once this step is taken the breeders should thereafter produce only male f-1 hybrids.
When people begin a breeding program that requires two different species to be seperatly bred and reproduced and then selected for will generally be somewhat short of breeders it would be normal for these breeders to recover their breeders after putting them in a pond to breed by going through them and resexing them and placing the males back into a growing pond with what was thought to be their own species and any females would also be put back in the pond with their own species.
So, this practice which depends on complete accuracy in each step of determining the sex of each fish leads to an ultimate failure of the program for producing all male hybrids because of the effects a single mistake will have on the program over a few years.
In Fact when I checked with various breeders to see why they had given up on the all male hybrid it was because each of them suffered from the failure of the program to produce all male hybrids within about five years of their beginning. The color coded system now elimantes this kind of mistake from occuring. |
