COMPLETE GUIDE TO TILAPIA FISH
FARMING IN EARTHEN AND CONCRETE PONDS IN NIGERIA
Tilapia has found its way from Oriental restaurants to grocery stores and restaurants in Nigeria. That is to say that a market exists for those wanting to raise tilapia commercially. How? We have a basic guide to tilapia farming that includes topics on the most commonly used system to raise tilapia and the parameters that must be controlled to effect maximum yield.
Due to the popularity and ethnic group demand for tilapia cuisines in Oriental restaurants in the Nigeria, large volumes of frozen tilapias are being shipped to the country from abroad.
Now, tilapia has become an established seafood item in the country. It is found in seafood restaurants and some grocery stores. Live fish are found in farmers market and stores with live tanks.
Raising tilapia can be simple or complex depending on how strict or lenient a breeder wants to apply his fish growing strategy. He can exercise stringent control over water quality and food supply to affect greater yield, or leave most of the fish growing process to nature. To start, a farmer can buy tilapia fingerlings and raise them until they are the size that can be sold or he can breed his own stock.
The most common tilapia genus raised commercially is Oreochromis. Generally, tilapias feed on almost all food sources and can thrive solely on pellets, but they could do well if fed with a few vegetables, aquatic plants and meat. A breeder can grow tilapias in ponds, tanks or cages. They say pond culture is the most commonly employed method employed because it is one of the best and requires less capital requirement. That is because for a fish farm to be profitable, it must produce the greatest yield in the smallest area available at the minimum cost. More complex methods of fish growing are the most effective, but they are also costly. The challenge for a breeder is to find the system that yields the most at the most cost effective way.
Tilapia Culture in Ponds
Ponds cost less to construct than, say tanks, and allows natural biological productivity to occur in the system. Further, it allows innovation such as the use of cages or net enclosures to allow more efficient collection and growing of fry. However, in the pond system where there are no predators, overpopulation is a tendency. Over population puts pressure in the system and could retard the growth of the fish to its maximum potential.
Sexing tilapia is important, since most farmers wish to cultivate males only. Male tilapias grow bigger and yield a higher profit for aquacultures. The fish is therefore sexed as early as possible and the females are destroyed. Manual sexing of tilapia is tricky and requires specially trained personal. Even experienced personal will normally get at least 2-5 percent wrong.
When a tilapia fingerling has reached a weight of 25 grams (1 ounce) it can normally be sexed by looking at the genital papilla. The genital papilla is located right behind the anus of the fish. If the genital papilla has one single opening you are looking at a male tilapia. Males have only one opening and both urine and milt will pass through this hole. If the genital papilla has two openings you are looking at a female tilapia, because tilapia eggs do not pass through the same hole as urine. If you find it hard to examine the genital papilla of fingerlings, try placing a drop of dye, such as food colouring or methylene blue, on the genital region. The colour will normally make it easier to distinguish the openings.
Growth rate
The growth rate of tilapia is determined by several factors and it is important to take all these factors into consideration. The growth rate will for instance be affected by water quality, temperature, oxygen levels and the general health of your fish. The type of food you provide them with and in which quantities will naturally also be of imperative importance. Last but not least, you have to pick an optimal stocking density.
In addition to this, it is important to choose a species, hybrid or strain that is fitting for your particular fish farm. Many producers advertise about strains with a super-fast growth rate, but this growth rate will not be attained unless the environment is ideal for that particular strain. You must for instance take the climate in your part of the world into account and the salinity level in the water you plan on using is also important.
Mixed-sex or mono-sex culture?
When male and female tilapias are kept together, they will readily breed and produce a lot of offspring. This can hamper the growth rate of the adult fish, since they will be forced to compete for food with fry and fingerlings. Three methods are commonly utilized to prevent this from happening.
1. Harvesting the mix-sexed culture before they reach sexual maturity or soon afterwards.
2. Raising the mix-sexed culture in cages or tanks that disrupts preproduction.
3. Raising a mono-sex culture consisting of males only.
Growth rate in mixed-sex culture
In a mixed-sex tilapia culture, the fish is normally harvested before the fish reaches sexual maturity or soon afterwards. This restricted culture period makes it even more important than normally to make the fish grow fast, since they have to reach their proper size within a limited time frame. It is therefore common to avoid dense stocking of mixed-sex tilapia cultures. It is also important to avoid using stunted fish since such fish will reach sexual maturity while they are still too small for the food market.
Nile tilapia (Oreochromis niloticus) and their hybrids are common in mixed-sex cultures since they will attain a marketable size before commencing spawning.
By choosing the right species or strains and providing the fish with a suitable environment and proper nutrition, it is possible to achieve a growth rate fast enough to allow fry produced in the spring to reach a marketable size by autumn in temperate regions. For a 4-5 month long culture period it is common to stock 2,000-6,000 one month-old fry per acre in growout ponds. With a stocking density of 4,000 fry per acre, the average weight at harvest can then be expected to be around 0.5 pounds (220 grams), if supplemental feedings with protein rich food has been carried out.
Growth rate for all-male fingerlings
In mono-sex cultures, it is common to opt for male fish only since the male tilapia grows faster and reaches a larger size than the female. All male batches can be obtained through hybridization, hormonal treatment or manual sexing and separation. It should be noted that none of these methods can guarantee 100% males in any batch. If you want really large tilapia, the amount of females in the growing unit should not exceed 4 percent. Many farmers therefore use more than one method to ensure a low degree of females in the growing unit. Predator fish of a suitable size can also be added to the growing unit to devour any offspring.
The normal stocking rate for all-male tilapia cultures varies from 4,000 to over 20,000 fishes per acre. If you have no supplemental aeration, it is safest to stay in the lower range. In a suitable environment with an adequate supply of nutrition, it is possible for 50 gram fingerlings to become 500 gram fishes within 6 months even without supplemental aeration if the stocking rate is 4,000/acre. This means an average growth rate of 2.5 grams per day and it is possible for such a culture to yield 2.2 tons/acre.
A stocking rate of 8,000/acre can yield up to 4.4 tons/acre, but will require night time emergency aeration. You can expect the average weight gain to be 1.5-2.0 grams/day. The culture period will need to be at least 200 days, often more, if you want to produce fish that weighs almost 500 grams.
Breeding mono-sex tilapia by using hormones
If newly hatched tilapia fry are subjected to sufficient amounts of male hormones, they will turn into reproductively functional males. This method is also known as the sex reversal-method. It is normally carried out by feeding newly hatched tilapia fry with special hormone treated food for 3-4 weeks. The size of tilapia fry is normally determined 2-6 weeks after hatching. It is important to keep in mind that the use of hormones is restricted in many parts of the world. You might for instance require a special license to produce hormone-food and/or feed it to your tilapia.
Fry Production Process
Example for a system of Brood-stock: Three groups of brood-stock (parents) 400 females + 200 males which will produce 2.500.000 fry per year.
Breeding stock enter the production cycle of 14 days in the spawning ponds. After 14 days the fry are separated from their parents and transferred to the sex reversal ponds
Production time intervals:
• Spawning: ~14 days
• Sex reversal: ~ 25 - 30 days
• Nursery for size of 1 gram to 50 grams:~ 75 days
• Growth from 50 gram to market size: ~ 150 days.
Tilapia has found its way from Oriental restaurants to grocery stores and restaurants in Nigeria. That is to say that a market exists for those wanting to raise tilapia commercially. How? We have a basic guide to tilapia farming that includes topics on the most commonly used system to raise tilapia and the parameters that must be controlled to effect maximum yield.
Due to the popularity and ethnic group demand for tilapia cuisines in Oriental restaurants in the Nigeria, large volumes of frozen tilapias are being shipped to the country from abroad.
Now, tilapia has become an established seafood item in the country. It is found in seafood restaurants and some grocery stores. Live fish are found in farmers market and stores with live tanks.
Raising tilapia can be simple or complex depending on how strict or lenient a breeder wants to apply his fish growing strategy. He can exercise stringent control over water quality and food supply to affect greater yield, or leave most of the fish growing process to nature. To start, a farmer can buy tilapia fingerlings and raise them until they are the size that can be sold or he can breed his own stock.
The most common tilapia genus raised commercially is Oreochromis. Generally, tilapias feed on almost all food sources and can thrive solely on pellets, but they could do well if fed with a few vegetables, aquatic plants and meat. A breeder can grow tilapias in ponds, tanks or cages. They say pond culture is the most commonly employed method employed because it is one of the best and requires less capital requirement. That is because for a fish farm to be profitable, it must produce the greatest yield in the smallest area available at the minimum cost. More complex methods of fish growing are the most effective, but they are also costly. The challenge for a breeder is to find the system that yields the most at the most cost effective way.
Tilapia Culture in Ponds
Ponds cost less to construct than, say tanks, and allows natural biological productivity to occur in the system. Further, it allows innovation such as the use of cages or net enclosures to allow more efficient collection and growing of fry. However, in the pond system where there are no predators, overpopulation is a tendency. Over population puts pressure in the system and could retard the growth of the fish to its maximum potential.
Sexing tilapia is important, since most farmers wish to cultivate males only. Male tilapias grow bigger and yield a higher profit for aquacultures. The fish is therefore sexed as early as possible and the females are destroyed. Manual sexing of tilapia is tricky and requires specially trained personal. Even experienced personal will normally get at least 2-5 percent wrong.
When a tilapia fingerling has reached a weight of 25 grams (1 ounce) it can normally be sexed by looking at the genital papilla. The genital papilla is located right behind the anus of the fish. If the genital papilla has one single opening you are looking at a male tilapia. Males have only one opening and both urine and milt will pass through this hole. If the genital papilla has two openings you are looking at a female tilapia, because tilapia eggs do not pass through the same hole as urine. If you find it hard to examine the genital papilla of fingerlings, try placing a drop of dye, such as food colouring or methylene blue, on the genital region. The colour will normally make it easier to distinguish the openings.
Growth rate
The growth rate of tilapia is determined by several factors and it is important to take all these factors into consideration. The growth rate will for instance be affected by water quality, temperature, oxygen levels and the general health of your fish. The type of food you provide them with and in which quantities will naturally also be of imperative importance. Last but not least, you have to pick an optimal stocking density.
In addition to this, it is important to choose a species, hybrid or strain that is fitting for your particular fish farm. Many producers advertise about strains with a super-fast growth rate, but this growth rate will not be attained unless the environment is ideal for that particular strain. You must for instance take the climate in your part of the world into account and the salinity level in the water you plan on using is also important.
Mixed-sex or mono-sex culture?
When male and female tilapias are kept together, they will readily breed and produce a lot of offspring. This can hamper the growth rate of the adult fish, since they will be forced to compete for food with fry and fingerlings. Three methods are commonly utilized to prevent this from happening.
1. Harvesting the mix-sexed culture before they reach sexual maturity or soon afterwards.
2. Raising the mix-sexed culture in cages or tanks that disrupts preproduction.
3. Raising a mono-sex culture consisting of males only.
Growth rate in mixed-sex culture
In a mixed-sex tilapia culture, the fish is normally harvested before the fish reaches sexual maturity or soon afterwards. This restricted culture period makes it even more important than normally to make the fish grow fast, since they have to reach their proper size within a limited time frame. It is therefore common to avoid dense stocking of mixed-sex tilapia cultures. It is also important to avoid using stunted fish since such fish will reach sexual maturity while they are still too small for the food market.
Nile tilapia (Oreochromis niloticus) and their hybrids are common in mixed-sex cultures since they will attain a marketable size before commencing spawning.
By choosing the right species or strains and providing the fish with a suitable environment and proper nutrition, it is possible to achieve a growth rate fast enough to allow fry produced in the spring to reach a marketable size by autumn in temperate regions. For a 4-5 month long culture period it is common to stock 2,000-6,000 one month-old fry per acre in growout ponds. With a stocking density of 4,000 fry per acre, the average weight at harvest can then be expected to be around 0.5 pounds (220 grams), if supplemental feedings with protein rich food has been carried out.
Growth rate for all-male fingerlings
In mono-sex cultures, it is common to opt for male fish only since the male tilapia grows faster and reaches a larger size than the female. All male batches can be obtained through hybridization, hormonal treatment or manual sexing and separation. It should be noted that none of these methods can guarantee 100% males in any batch. If you want really large tilapia, the amount of females in the growing unit should not exceed 4 percent. Many farmers therefore use more than one method to ensure a low degree of females in the growing unit. Predator fish of a suitable size can also be added to the growing unit to devour any offspring.
The normal stocking rate for all-male tilapia cultures varies from 4,000 to over 20,000 fishes per acre. If you have no supplemental aeration, it is safest to stay in the lower range. In a suitable environment with an adequate supply of nutrition, it is possible for 50 gram fingerlings to become 500 gram fishes within 6 months even without supplemental aeration if the stocking rate is 4,000/acre. This means an average growth rate of 2.5 grams per day and it is possible for such a culture to yield 2.2 tons/acre.
A stocking rate of 8,000/acre can yield up to 4.4 tons/acre, but will require night time emergency aeration. You can expect the average weight gain to be 1.5-2.0 grams/day. The culture period will need to be at least 200 days, often more, if you want to produce fish that weighs almost 500 grams.
Breeding mono-sex tilapia by using hormones
If newly hatched tilapia fry are subjected to sufficient amounts of male hormones, they will turn into reproductively functional males. This method is also known as the sex reversal-method. It is normally carried out by feeding newly hatched tilapia fry with special hormone treated food for 3-4 weeks. The size of tilapia fry is normally determined 2-6 weeks after hatching. It is important to keep in mind that the use of hormones is restricted in many parts of the world. You might for instance require a special license to produce hormone-food and/or feed it to your tilapia.
Fry Production Process
Example for a system of Brood-stock: Three groups of brood-stock (parents) 400 females + 200 males which will produce 2.500.000 fry per year.
Breeding stock enter the production cycle of 14 days in the spawning ponds. After 14 days the fry are separated from their parents and transferred to the sex reversal ponds
Production time intervals:
• Spawning: ~14 days
• Sex reversal: ~ 25 - 30 days
• Nursery for size of 1 gram to 50 grams:~ 75 days
• Growth from 50 gram to market size: ~ 150 days.
0 comments:
Post a Comment