Marel

USA - Mike Sipe`s Fish Farming Manual

09 Jan 2010

HATCHERY MANUAL 
 
FISH FARMING AT HOME FOR FUN AND PROFIT
By
Mike Sipe
Tilapia Aquaculture International
Palmetto, Florida, USA
 
 
2004 Mike Sipe
Table of Contents
 
Introduction.........................................................................................1
Tilapia – An Ideal Fish for Aquaculture...........................................1
Tilapia Hybrids Offer Superior Growth............................................4
Sources of Tilapia...............................................................................5
Fish Farming Stages.......................................................................5
Wild Capture...................................................................................5
Purchasing Tilapia..........................................................................6
Breeding Tilapia..............................................................................7
Breeding Tilapia at Home...................................................................8
Lesson 1: Behavior and Biology of Breeding Tilapia........................18
Hatchery Lessons.........................................................................18
Lesson 2: Aquarium Breeding Tilapia...............................................24
Breeder Selection from Wild or Available Stocks..........................24
Fish Sexing and Breeder..............................................................25
Sexing the Tilapia.........................................................................26
Territory Definition.........................................................................26
Lesson 3: Daily Breeding Management............................................28
Equipment Checks........................................................................28
Feeding.........................................................................................28
Feeding Process...........................................................................29
Lighting Timer Checks..................................................................29
Air Pump Check............................................................................29
Filter Cleaning...............................................................................30
Lesson 4: Breeder Management......................................................31
Breeder Clues...............................................................................31
Lesson 5: Post Breeding Behavior...................................................32
Lesson 6: Nursery Tank Management.............................................34
Motherly Behavior.........................................................................35
Lesson 7: Fry to Fingerlings.............................................................37
Fry Food.......................................................................................37
Moving the Fry..............................................................................38
Lesson 8: Fingerling Growing Resources.........................................39
Lesson 9: Deciding on a Production Goal........................................41
Lesson 10: Understanding Weight Gain and Measurement.............43
Lesson 11: Growing Strategies........................................................46
Lesson 12: Cage Culture Strategies for Tilapia................................49
 
2004 Mike Sipe
Cage Culture Strategies for Tilapia...............................................49
Lesson 13: Feed & Growth Requirements for Tilapia.......................51
Lesson 14: Space versus Power Requirements for Tilapia..............53
Densities.......................................................................................53
Hatchery Operations.....................................................................54
Cage Construction........................................................................54
Breeder Selection.........................................................................62
Tank Set Up..................................................................................64
Incubation.....................................................................................65
Moving The Fry.............................................................................70
Sizing Tanks.................................................................................73
F1 Hybrid Breeder Ponds.............................................................74
Biography.........................................................................................87
 
 
2004 Mike Sipe
Figures
 
Figure 1. Breeders in 55-gallon Aquarium..........................................8
Figure 2. Two females with eggs in mouth.........................................9
Figure 3. Pennyfish.......................................................................10
Figure 4. Chocolate Hybrid...............................................................11
Figure 5.  F1 Supermale Hybrid Production.....................................12
Figure 6. Tilapia breeder cage..........................................................13
Figure 7 This beautiful male T. mossambica is an exceptional
example of the red red strain.  It is the best of the best after 77
generations of selection for the red color..................................30
Figure 8. Red Butterball Female Holding Eggs................................33
Figure 9. Female with fry..................................................................36
Figure 10. Tilapia Culture Cage........................................................55
Figure 11. Arena Cage.....................................................................56
Figure 12. Arena Cage (Pot Further Toward the Rear)....................57
Figure 13. Female Safe Area...........................................................58
Figure 14. Tilapia Breeder Cage (alternative design).......................61
Figure 15. Tilapia Breeder Cage immersed underwater showing
breeding area............................................................................62
Figure 16. Mesh for Grading Fingerlings..........................................63
Figure 17. Tilapia Cage....................................................................67
Figure 18. One Kilogram Pennyfish Grown by George Hale in a 5-
Acre Pond between Mar 15 and Sept. 15,  1998......................68
Figure 19. Breeder pen with cages inside it.....................................68
Figure 20.  Breeder Cage with Description of Materials...................69
Figure 21. Moving fry........................................................................72
Figure 22. Breeder Cages................................................................75
Figure 23. Cage Configuration - Week 1..........................................76
Figure 24. Cage Configuration - Week 2..........................................77
Figure 25. Cage Configuration - Week 3..........................................78
Figure 26. Cage Configuration - Week 4..........................................79
Figure 27. Cage Configuration - Week 5..........................................80
Figure 28. Cage Configuration - Week 6..........................................81
Figure 29. Cage Configuration - Week 7..........................................82
Figure 30. Cage Configuration - Week 8..........................................83
Figure 31. Cage Configuration - Week 9..........................................84
Figure 32. Cage Configuration - Week 10........................................85
 
 
 
2004 Mike Sipe
 
 
2004 Mike Sipe                                                               1
Introduction
 
Outside of the United States and in many areas of this country
malnutrition is a way of life.  In most cases this malnutrition is due to
the unavailability of low cost proteins such as lysine and others.  
Home fish farming offers a solution to the availability of an affordable
source of fish.  
 
Part of this solution requires knowledge of how to grow, harvest,
purge, process, prepare and cook fish, and preserve fish. The farmed
fish will be healthy and acceptable in many forms to those who would
like to include more fish in their diets.
 
Fish are very high in lysine and very small amounts of fish in the diet
can go a long way toward creating longer, healthier and more
enjoyable lives by supplying the body’s protein needs.
 
This book is written to help you understand the major factors that
affect success in growing tilapia on a small scale.
Tilapia – An Ideal Fish for Aquaculture 
 
The name tilapia is a taxonomic name (genus) given to a group of
fish that belong to the cichlid family of fishes. The cichlids populate
many of the tropical and semi-tropical areas of the world and have
many things in common with each other, but there are major
differences between most of them and the tilapias. 
 
The Tilapias are one of the major groups of food fishes around the
world, especially in the tropical and semi-tropical areas, and have
been cultivated for thousands of years. Pictures or carvings appear
on artifacts and monoliths in Egyptian tombs as far back as 2,000 BC,
but only in the last 50 years have we began to focus on developing
them as an alternative to harvesting wild fish.
 
The tilapias have a number of special capabilities.  Some of these
capabilities occur in one fish or another, but seldom occur within the
same fish.  The fact that all of these characteristics occur within the
 
2004 Mike Sipe                                                               2
same fish is what makes tilapia a very good fish for home
aquaculture.
 
These capabilities include:
 
FILTER FEEDING:  The tilapia have tiny combs located on their gills,
called gill rakers, that allow them to remove organisms from water
passing through their gills. Tilapia can filter organisms as tiny as 3
microns, which is about the size of human blood cells.  This filtering is
so efficient that it can be compared with the best swimming pool
filters in removing microbes from the water.
 
EFFICIENT DIGESTION:  The acid content in the tilapia stomach is
one of the strongest known and allows them to efficiently digest a
wide range of microbes, including diatoms, bacteria, fungi and other
organisms, by simply dissolving their cell walls.  Tilapia feed on dead
leaves and organic debris that fall to the bottom of a pond. Tilapia
have been shown to be able to digest up to 70% of the “mud” as it
passes through their gut.
 
STRONG IMMUNE SYSTEM:  When well fed and kept in warm
water, tilapia are resistant to diseases. This means that for the
beginner and the experienced fish farmer, we a least do not have to
worry about losses of fish due to strange diseases, such as those
found in catfish, trout, and most other fish.
 
FREQUENT BREEDING AND MOUTH BROODING:  At
temperatures of 85 degrees F, they can produce baby tilapia (fry)
almost every week year round.  The mouth brooding and maternal
protection of the fry helps to create a high survival rate.  This
combination of continuous production and high survival rate, allows
the tilapia farmer to have a constant supply of fingerlings to replace
those that get big enough to eat.
 
REASONS FOR GROWING FISH AT HOME
The reasons for growing tilapia at home are many and include some
of the following:
 
(1) Family Diet Improvement-Nutrition  Since the tilapia provide a
high quality meat source that is high in protein and very low in fat,
 
2004 Mike Sipe                                                               3
they provide an ideal meal in terms of a balanced amino acids
and protein intake.
 
(2) Extra Income  Since it is so easy to learn to produce tilapia at
home it is possible to produce more than the needs of the family
in a small space. These extra tilapia can be sold as fry,
fingerlings or eating fish when there are more than needed.
 
(3) Lower Food Cost for Family  Waste from the tilapia growing
tank can be used to grow organic vegetables and the kitchen
waste can be ground and fed back to the tilapia. This recycling of
energy and nutrients allows you to create a sustainable
production system.  
 
A. Recycling food & vegetable waste lower the cost of the
feed needed to raise the fish. The recycled waste provides
much more food per pound when fed to the fish than when
used to make compost.
 
B. Feeding the fish cost less than buying fish.  Even when
supplemental fish foods are purchased from feed suppliers,
the cost of the feed required to produce one pound of tilapia
is far less than to buy the same amount of fish in the grocery
store.
 
(4) Lower Cost for Animal Food  The tilapia by product, such as
the scales, bones, and stomach contents make excellent feed
supplements for other farm animals such as chickens or hogs, at
a much lower cost than buying the feeds for them.
 
(5) Education  Working and playing with the tilapia breeding system,
water systems, air systems, feeding programs and many other
activities provide many opportunities for learning the basics in
science and social fields.
 
For instance the breeding and maternal care, and the aggression
and territorial behavior provide opportunities to understand the
basics of the establishment of animal social systems.  The
measurement of water quality parameters provides opportunities
to understand basic water chemistry. The physical dissolving of
 
2004 Mike Sipe                                                               4
the oxygen in the water provides an opportunity to understand the
mechanics of air compression, expansion, water air interfaces
and what it means to dissolve a gas into water.
 
The processing of the waste water provides an opportunity to
learn about suspended solids, dissolved solids and the role of
bacteria and other aquatic organisms in keeping the water clean
and suitable for growing fish.
 
(6) Entertainment  Watching the fish in the breeding and growing
tanks allows for countless hours of enjoyment as they perform
their mating and territorial rituals.  This is one reason I
recommend that each new breeder setup be put indoors in a
suitable place where it will be viewed often during the day and
evening so that the fish can be enjoyed while learning from them.
Tilapia Hybrids Offer Superior Growth
 
In the last 25 years, we have concentrated on developing better gene
lines in pure species of T. mossambica, T. hornorum, T. nilotica and
T. aurea. These pure tilapia gene lines can then be crossed to create
F1 hybrids with improved characteristics and also with hybrid vigor
and evenness of growth rate.
 
These new varieties of hybrids, such as the Pennyfish™, offer
improvements in cost of production that promise to reduce the cost of
producing fish for food to match that of chicken, and to do it in a
fraction of the space of other animal crops. All in all, these tilapia may
prove to be the cheapest source of low cost, high quality protein on
Earth.
 
 
2004 Mike Sipe                                                               5
Sources of Tilapia 
 
Fish Farming Stages 
The process for farming tilapia includes the following stages:
 
Breeding → Fry Sizing → Fingerling production → Grow-out to
market size → Purging → Harvesting → Processing → Packaging →
Marketing → Cooking → Eating
 
Before fish can be farmed we must first have a source of fry or
fingerling fish, so the first section of this book and of this course will
be devoted to methods of getting growable fish.
Wild Capture
 
The advantages of wild capture of tilapia are:
 
1. Larger fish can be captured and moved to a properly designed
growing environment so that the amount of time and food
required to get the fish to edible sizes is less (saves time and
money on feeding). Sometimes 4 to 5 ounce fish can be captured
in outside areas in climates which support year round growth, and
these wild recruits can then be sexed to select all males for
placing into the growing environment.
 
2. Larger fish gain weight faster and so the weight gain per day in
the growing environment is greater.
 
3. Tilapias are easily available in Florida and many countries
because they are in many rivers and lakes and can be captured
easily by either cast netting or seine fishing.
 
The disadvantages of collecting wild fish are:
 
1. The possibility of introducing parasites or diseases into your
growing tanks, and then having then to deal with cleaning up the
problem.
 
 
2004 Mike Sipe                                                               6
2. There can be questions as to the food quality of wild or locally
captured tilapia due to the fact that you may not know what
chemicals or pollutants may be in the water from where they
came. 
 
3. Another disadvantage is that it may require special knowledge
and time to find the tilapia and capture them. Transporting tilapia
alive requires some special skills and knowledge and so the
number being moved that remain alive may be low due to
mishandling.
 
4. The availability of wild caught tilapia can vary widely throughout
the year depending on outside conditions and water temperature
and so fish may not be available when wanted for restocking.
Purchasing Tilapia
 
The advantages of purchasing tilapia are:
 
1. Purchasing tilapia allows you to concentrate on learning how to
set up and operate a growing system. You can focus on learning
one skill at a time. If the tilapia are available on a reliable and
regular basis this can be a good choice.
 
2. If you can find someone who is producing a high yielding fast
growing fingerling, then you can get a head start on the
production cycle and this will allow you to grow more fish per
year in the space you provide.
 
3. Another advantage of purchasing fingerlings is that survival
should be good when the fingerlings are purchased from a
reliable dealer with experience in the live shipping and transport
of fingerlings.
 
The disadvantages of purchasing fingerlings:
 
1. The cost per fingerling of purchased fingerlings over homegrown
is often more expensive.
 
 
2004 Mike Sipe                                                               7
2. Another disadvantage of purchasing the fingerlings is that even
reliable producers do not always have them when you need them.
This can make it difficult to even out your production schedule.
 
3. If you produce your own fingerlings and have excess, the extra
fingerlings may be sold for additional income.
 
Breeding Tilapia
 
The advantages of breeding your own fry and raising them to
fingerlings for stocking are:
 
1. A small number of well-kept breeders can produce a continuous
supply of fry and fingerlings so that a known number of
replacements are always available for the tilapia reaching usable
size in your growing system.
 
2. Extra fingerlings may be sold for extra income.
 
3. Breeding tilapia is fun.
 
4. Bred fingerlings are less expensive and are of known quality
because you know what they have been eating and most
importantly who their parents were.
 
 
 
 
2004 Mike Sipe                                                               8
Breeding Tilapia at Home
 
We have examined the reasons for growing tilapia at home and the
possibilities for getting started. We can now discuss the biology and
behavior of tilapia and the possibilities of getting started breeding
them at home.
 
 
 
Figure 1. Breeders in 55-gallon Aquarium
The breeders in this 55-gallon aquarium can provide twenty five
thousand fry to grow to fingerlings for stocking growing systems in
one year.  This makes it possible for a very modest investment to
grow over 2,000 pounds of live Supermale Pennyfish (tm) to market
size each year.
 
This section discusses some of the advantages of using Pennyfish
breeders in a home production system.
 
 
 
2004 Mike Sipe                                                               9
 
Figure 2. Two females with eggs in mouth
 
First, you need to concentrate on is the production of a suitable
fingerling. The fingerlings I most seriously recommend right now are
the Pennyfish which are the result of crossing the Male T. hornorum
with the female Orange T. mossambica.  Both gene lines are special
gene lines that I have created here on my farm in Palmetto, Florida.  
 
The T. hornorum gene line has more than 100 generations of
selection for body form while maintaining its purity as a pure gene
line.  
 
The body form improvement allows the farmer to get about 9% more
fillets out of a 1.25 pound or 600-gram fish. This is about 54 more
grams more than the normal T. hornorum ancestor formerly provided. 
The total yield is around 252 grams of fillet from a 600-gram hybrid,
or 126 grams per fillet instead of 90 grams per fillet from a normal
body form.
 
In addition the fingerlings can grow at just above 5.5 grams per day
average so that from a ten-gram fingerling you can get a 600-gram
 
2004 Mike Sipe                                                               10
fingerling in around 110 days (5.5 grams times 110 days = 605
grams).
 
Because Pennyfish are a true unmixed hybrid they all grow at around
the same rate of speed so that less than 7% are below 600 grams at
the 110-day mark while approximately the same number are above it.
Also because they are an F1 hybrid and the father is a natural
SUPERMALE, having both chromosomes for maleness when
crossed with a pure natural XX female like T. mossambica or T.
nilotica the only chromosome combination possible is the ZX
chromosome, and since the Z chromosome is dominant in 99.9% of
the offspring you get virtually 100% males.  This means that in an
outdoor mud pond you can stock a known number such as 6,000 per
acre and with proper fertilization and feeding harvest 6,000 1.25-
pound fish in around 120 days.
 
 
 
Figure 3. Pennyfish 
 
 
2004 Mike Sipe                                                               11
 
Figure 4. Chocolate Hybrid 
 
The Chocolate Hybrid shown in Figure 4 is displayed on a 16-inch by
8-inch grid and actually overlaps the grid.  This fish was produce
along with 600 other Chocolate Hybrids in a cage.  They were
stocked at 100 grams on March 15, 1998 and weighted out at an
average of just over 3 pounds or 1,362 grams on September 15,
1998.
 
The Chocolate Hybrid is produced by breeding the Supermale T.
hornorum male with the T. nilotica female.  Since the male has a sex
chromosome complement of ZZ and the female has one of XY the
only thing the fry or fingerlings can be is XZ or ZX either way they are
100% males.  This fingerling has both the hybrid vigor imparted by
being an F1 hybrid of two species and the extra growth of being all
males.
 
 
2004 Mike Sipe                                                               12
 
Figure 5.  F1 Supermale Hybrid Production
One advantage of using our Orange mossambica brood stock is that
the parents are different and it is virtually impossible to set up
breeding colonies that will not produce 99.9% males (see Figure 5). It
seems that one fish out of a thousand just has to be female due to
the differences inherent in the individual chromosomes coming from
both the male and the female.
 
 
2004 Mike Sipe                                                               13
The cost for the breeding and selection program that results in the
ability to produce such fast growing fish is very high. To produce both
the male and female breeders of the pure line T. hornorum and T.
mossambica parent stocks, will cost you around $2,000,000 US.  
 
However if you leave the breeding and selection process to us, and
just buy male T. hornorum and female T. mossambica at the price of
$50 each for small numbers the total cost per fingerling is
dramatically lower. 
 
Since each male can breed in a natural environment with up to ten
females or more, the male can be responsible for as many as 50,000
fingerlings per year.
 
The female and male brood stock for T. mossambica is also available
for $10,000 in the orange and we will ship you up to 2,000 fry for that
price which should result in around 1,000 or more females that will be
breedable females on the first breeding and unlimited numbers by
later breedings.  
 
Figure 6. Tilapia breeder cage
 
Once your breeders are in cages like the ones shown in Figure 6 and
breeding you will be moving the cages once a week to a new pond or
fresh tank. If the breeders are in a pond, you should ensure that they
 
2004 Mike Sipe                                                               14
have clean water rich with algae and no other animals for the fry to
compete with, such as dragonfly larvae.
 
The size of pond for breeding 20,000 fry per week should be around
2,700 square feet (90 feet by 30 feet). The depth should be around 5
feet in the middle sloping gradually to the banks.
 
With 200 females you should have 40 cages and the cages should be
about 2 feet by 2 feet by 4 feet.  You should use either plastic or vinyl
coated galvanized steel wire for the cages.  This many breeders kept
at 85 degree F temperature in ponds like this will produce 20,000 fry
per week, or one million per year.
 
The bottom panel should have a layer of window screen or other fine
weave mesh attached to it with stainless steel hog rings about every
1.5 inches around the perimeter of the 2 X 4 foot panel.
 
Then you should attach 2 (two gallon) plastic pots, which are
ordinarily used for planting plants in.  You should attach them so the
open end of the pot faces one of the long sides and is about 10
inches from the end of the panel where it starts and around 20 inches
where it ends, and the other pot attached the same way from the
other end.  When you are finished with the bottom of the cage you will
have the fine mesh material secured every 1.5 inches and the two
pots facing the same way toward where the side panel will be when
you attach it.
 
Then the four side panels should be attached first by using the 3/8-
inch stainless steel hog rings every one inch along the bottom, and
when you have all four side panels attached, two (2-foot by 2-foot),
and 2 (2-foot by 4-foot), then you fold the side panels up and clip
them together every one inch until you reach the top.  When you are
done you will have a box made from cage material that contains two
plastic pots facing one side of the cage about 10 inches from that
side.  The back of the pots will be around 5 or so inches from the
other side panel.
 
Then you cut two pieces of cage material so they are two foot by two
foot, and you attach one of them around the top of the cage on three
sides at 2-inch intervals with the stainless steel hog rings.  The other
 
2004 Mike Sipe                                                               15
piece of 2 foot by 2-foot material you will just attach to the edge of the
first piece that runs across the top, so it will swing open when you
need to tend to the fish.  
 
You then attach 8 pieces of No. 8 vinyl coated electrical wire, 4
inches long each, around the perimeter of the other three edges at
one foot intervals, so that 2 inches of the wire are attached to the
cage material and the other 2 inches stick up in the air above the
edge of the cage.
 
You will use these to bend down over the edge of the cage to hold
the top of the cage shut.
 
The next job is to supply flotation to the cage, which we do here by
cutting 4 inch by 4-inch Styrofoam logs, 8 foot in length so that each
log is 4 foot long.  Then two of the logs are tied with the same
electrical wire mentioned earlier, at one-foot intervals along the cage. 
The Styrofoam logs should be attached inside of the cages.  
 
When you put the Styrofoam logs in, through the top, you will have to
secure them at the end where you have placed the top of the cage by
having someone hold the log while you slip the wire under it and fish
it out of the top of the cage.  You will now have two logs of Styrofoam
running the length of the cage.  
 
Now you hold another piece of Styrofoam up against the edge of the
cage and measure so that when you cut it there is about 1 inch extra
to go between the two long pieces inside the cage.  Then when it is
cut you will need to force it in to fit.
 
Then you tie each piece twice with the same wire.  The Styrofoam
has now become an integral part of the structure of the cage so that
when you go to move the cage you will be using that structure to hold
the shape of the cage.
 
Now you are ready to put the cage in the water.  You leave the door
to the cage open and put the breeders you have in a net deep
enough to hold them in a sort of bag with one hand while you place
them into the cage, you do this up on the bank so if one of them
jumps you can recover it before it gets into the water. Place the net
 
2004 Mike Sipe                                                               16
into the cage and turn it so the exit is down, and let go of the net so
the fish can swim into the water.  As soon as all of the breeders are in
the cage you fold down the lid and bend over the tie holds you
previously installed.
 
You then string a rope across the pond, which you will use to tie each
cage of breeders so that it will be within about a yard (meter) of the
bank.  You can place the rope so that it will go across the middle of
the cage with the end that opens toward the bank and then use 2
clothespins to attach the rope to the center of the cages.  Space the
cages about 2 feet apart.
 
Now you feed the fish twice a day with a good trout chow, placed
inside of the cage from the top so the Styrofoam will keep it from
floating out.  One bag of trout chow should last about a month for the
breeders, as you will only have four cages and you only use about
1.2 cup for each cage twice a day.
 
In about 8 to 10 days you will see fry swimming around the pond, and
so you start counting for seven days when you see this which will
bring you to the 15th or the 17th day after placement of the breeders. 
Meanwhile you pump out or otherwise drain the pond next to the
pond your breeders are in and rotenone the bottom or use some
chemical to sterilize it that will go away in 7 days.  Then you refill the
pond a couple of days before you want to move the breeders, and
then test the water with a couple of live fry by removing a bucket of
water about half full and placing the fry in the bucket where they
cannot accidentally fall into the pond.
 
Once you move the cages, the fry will then continue to grow with no
difficulty for about 30 days or so until you need the pond again.  
Then you can use some fish traps which we can send to you or the
Cooperative we work with can, to trap out the fingerlings to stock in
the grow out ponds which by that time you should have the first 1/2
acre pond ready.  It is important that nothing else be in the ponds.
You should also fertilize the pond with 100 pounds of triple super
phosphate which is suspended in about 5 bags of 20 pounds each
and tied with a string to a flotation device in the pond.
 
 
2004 Mike Sipe                                                               17
The process should be repeated if the green algae begins to clear up
so that you can see your fingers when your elbow is at the water.
 
2004 Mike Sipe                                                               18
Lesson 1: Behavior and Biology of
Breeding Tilapia
Hatchery Lessons
 
The male tilapia’s goal in life once he reaches breeding age is to
establish a territory that he can defend and to attract into his territory
as many females as possible. The male tilapia seeks females who
are ready to drop eggs for him to fertilize and to keep out of this
territory any tilapia or other fish that is not ready to breed with him.
 
The female tilapia’s biological goal is to reach breeding maturity.  She
then searches for a suitable male who is able to keep other fish out of
his breeding territory while they are breeding.
 
In natural ponds, lakes or rivers the male generally chooses a site to
establish his territory up against a barrier of some sort such as the
edge of the pond bank, a tree stump, an outcropping a large rock or
anything that allows him to restrict the area which he will need to
defend while undergoing the breeding ritual.
 
When he finds a suitable territory, the male will start by chasing out
any other fish and then he will attempt to dig a shallow bowl shaped
hole in the mud, sand, gravel or other substrate where he has chosen
his territory.  The size of the territory he will usually choose to defend
is generally 2 to 4 times his body length in diameter in a circle or
semicircle if he is successful in establishing his territory against a
natural barrier.  The actual size depends also on visibility.
 
The pit he digs is formed by scooping out a mouthful of the substrate
and spitting it out over the top edge of what is to be his spawning site
until he has created a pit with a diameter of about 1.5 times his body
length.  The size of his territory and of the pit in its center is important
to understand because we are trying to create in our breeding tanks
acceptable substitutes for these areas.
 
The breeding follows a very precise pattern with the male first
establishing a territory, which in the case of controlled breeding we
 
2004 Mike Sipe                                                               19
help to establish by placing a flowerpot in the breeding. Then, when a
female is ready to breed, she will swim into the “arena” the male is
defending, and they will do a shake rattle and roll sort of dance while
circling each other.  
 
When she is properly courted, the female will lay 3 to 5 eggs at a time
in the center of the males territory, usually in the flower pot, then she
will swim a little distance away. The male will swim over the eggs and
fertilize them, then she will return and pick them up in her mouth and
repeat the dance with the male while they circle each other head to
tail wriggling and vibrating the whole time.  She will often on this
occasion suck at the area of the sperm tube as if to draw extra sperm
to insure fertilization of the eggs.  When they have done this for a
minute or so she will return to the center of the pit and lay more eggs,
and so on until she has a full mouth of fertilized eggs.  
 
The number of eggs the female produces is related to several factors. 
The most important is her size in grams and her condition in terms of
being well fed.  The female mossambica for instance start breeding at
20 to 30 grams and continue up to and over 1,000 grams.
A well-fed healthy female can lay one to two eggs per breeding for
each gram of weight she has attained.  This means that even a small
one-ounce female can produce as many as 50 or more eggs per
breeding and up to 2,000 or more when she is fully-grown.
The male and female continue their spawning until the female has a
full mouth and this can take from 3-0 or 40 minutes to 2 or 3 hours for
a large female.
 
Once she has these eggs in her mouth she will leave the breeding
area and join the other females in an area of the pond or tank where
she is out of sight of the male.  She must be able to do this, as he will
continue to harass her as long as she remains in the breeding arena.
Once she has left the arena she will continue to hold the eggs for 7 to
10 days depending on how warm the water is.  The warmer the water
the shorter the incubation time.  
 
During the incubation process she slowly and continuously rolls the
eggs gently to keep them well oxygenated and clean.  The female
tilapia is capable of telling sick or dead eggs from healthy live eggs
and swallows any that are not right.
 
2004 Mike Sipe                                                               20
 
The fertilized eggs begin development almost immediately after the
female picks them up in her mouth and within 48 hours at 85 degrees
F, the beginnings of eyes and tails can be seen on the eggs.  
 
By the fourth day the fry begin to resemble small fish attached to little
yellow balls, which are the egg sacks.   These are called
appropriately egg sac fry, and usually by this stage if separated from
the mother are easy to keep alive.
 
By the fifth day the fry can swim and navigate well enough to be
released by the mother for brief excursions out into the world.  At first
she lets them out for a brief swim and sucks them back in within a
few minutes.
 
By the sixth day she allows them to browse on bacteria, algal, and
fungal growths on the surface of plants or walls.  While the fry are out
the mother tilapia keeps a sharp eye out for any intruders such as
other fish and will aggressively chase them away if they approach the
area where the fry are feeding.
 
If she perceives any danger she will signal the fry by a sideways
wiggle of her body and an open mouth at which signal the fry will
immediately swim towards and into her mouth.  When this is viewed it
looks like a film in slow motion reverse where she just spit out a
mouthful of tiny pebbles.
 
The older the fry get, the longer the time the mother allows them to
spend outside and by the tenth day she will often no longer tend them
or allow them oral sanctuary. 
 
It is also the true that the older the fry are when the mother is
disturbed, the more likely she is to spit them out to fend for
themselves if she feels her life is in danger. 
 
When we substitute our own breeding areas for the natural ones the
tilapia use for breeding there are a number of containers we can
choose to use. 
 
 
 
2004 Mike Sipe                                                               21
Some possible containers include:
 
 aquariums
 tanks
 cages
 pens in tanks
 pens with cages
 ponds
 ponds with cages
 ponds with pens with cages
 
In this manual we will just consider aquarium breeding because that
is something anyone can get into for a small amount of money. 
However if you have a tank or pond we can also advise on a way of
setting up breeding in your situation.  In the next lesson we will look
at a simple aquarium system for breeding a small number of tilapia.
 
One other important consideration in this lesson however is the kind
of tilapia to choose to breed, their size and the reasons for these
choices.
 
The beginner can find tilapia from many sources and can achieve
good results in breeding the tilapia. Producing fry in aquariums with
almost any tilapias of the right size is possible as long as the tilapia
are healthy and the system is set up correctly.
 
Fry are of course the first stage of the small fish following the egg
stage and are from 1/8 to 1/4 of an inch in length.
 
The fry are easy to produce, but after that the choice of breeding
stock begins to affect each growth stage from fry to fingerling and
from fingerling to edible size fish.
 
There are several important factors to understand.

 


Source: cherrysnapper

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