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What
we do:
We produce Red and Gray O.Mossambicus Tilapia.
Tilapia
*Characteristics*
Tilapia is a common name for a popular farmed fish belonging to the
family Cichlidae, (derived from the African word “thiapa,” which means
fish). A tropical fish native to Africa and the Middle East, it has been
farmed for about 2,500 years as can be seen in Egyptian paintings. In
some areas it is called the St. Peter’s Fish, stemming from the belief
that Tilapia was the fish that the Bible referred to when Jesus fed the
5000. It requires water temperatures from 76 to 84 degrees Fahrenheit,
and has a lower limit of 70 F, where growth ceases.
*Husbandry*
Tilapia are known for their ability to sexually mature at a small size,
around 3-4 in. in body length, and a young age (sometimes when 2-3
months old). Adult fish are known to live six to eight years, but some
fish eleven to twelve years of age have been reported.
They are prolific breeders, with females producing up to 1000 eggs per
pound of weight. Males are very territorial, cleaning out a round nest
on the substrate where they live, protecting it aggressively. Females
are attracted to “their” male and will spawn eggs onto the substrate,
whereupon the male will immediately fertilize the eggs, with the female
following and scooping up the eggs into her mouth. The eggs are
yellow-brown in color, egg shaped, and will sink to the bottom when
spawned. The eggs vary in size from an average of 0.08-0.16 in. in
diameter, depending on the species and number of spawns
The female incubates and protects the young in their mouth (mouth
brooding), for a period of 6 to 8 days, when they will hatch. The mother
will keep the fry in her mouth until they are old enough to fend for
themselves, normally about 6 to 10 days.
The progression of growth is from egg, to sac-fry (the yolk-sac is still
visible under the fry), then fee swimming, to fry, then fingerling, then
juvenile, then adult. The complete cycle growth rate varies from species
to species. O. Niloticus is from the Nile (northern) area of Africa, and
grows approximately 40% faster that O. Mossambicus, which is from
Southern Africa. O. Mossambicus can live both in fresh and salt water
(where it grows as fast as O. Niloticus).
*Culture*
In California, Tilapia is only permitted to be grown south of the
Tehachapi Mountains. The species allowed is O. Mossambicus as it is
considered indigenous, having been planted in the mid-1960s in
irrigation channels to fight the invasion of the waterway-clogging
hydrilla weed. The Tilapia slowly found their way to the Salton Sea, and
thrived in its saline waters. Over time, due to agricultural runoff, the
Salton sea has become hyper-saline, limiting the survivability of the
Tilapia found therein.
*Market*
Market size in California is around 1 ¼ lbs, which takes about 10 to 11
months to achieve from egg. Fish are sold live to markets in San Diego,
Los Angeles, Sacramento and San Francisco.
*Food*
Tilapia can survive on a diversity of food. Algae is probably their most
common food in the wild. On fish farms they are fed a high-protein
pelletted feed. When raised in a controlled environment they can achieve
growth rates of up to 3 percent of body weight per day, but 2 percent is
more the norm. The fish gains about one pound for every 2 pounds of food.
*Production systems and facts*
In the United States, especially California. Tilapia are considered
important for their food value. These fish have also been popularized
for their use in waste-water treatment schemes and aquatic-weed control
programs. Currently Tilapia ranks number 6 in whole world in farmed
fish, with China producing the lion’s share at 75%. All are shipped to
the USA as frozen. South American countries supply a large amount as
fresh fillets, that are flown into the country, daily.
Because of the diversity of culture systems it is impractical to
describe all the different operations used for raising Tilapia
commercially. Domestically, Tilapia are raised primarily as a
high-quality fish for human food. Culture is carried out in indoor
tanks, water recirculating systems, outdoor raceways, ponds, and
floating cages. In several states, primarily Florida and California,
Tilapia are also fished commercially. "Extensive" pond culture
methods
for Tilapia, traditional in many countries throughout the world, are not
commonly used in the United States. For example, culture of Tilapia in
wastewater fed ponds, a viable and less expensive production system, is
not considered acceptable for ecological or sanitary reasons.
Tilapia growth rates are influenced by a variety of factors; water
temperature, sex, supplemental feeding, and stocking density noticeably
affect their growth rate. Tilapia are susceptible to cold water
temperatures, and will not over-winter in most temperate climates. Most
Tilapia will stop eating at water temperatures below 16°C (61°F), and
will begin to die at around 13°C (55°F). Water temperatures between
25-32°C (77-90°F) are preferred for raising hybrid Tilapia in intensive
culture.
Little data is available on the efficiency of Tilapia to convert feed
into meat. With the use of high-quality formulated diets, the feed
conversion should range between 0.33 to 0.67 g of fish weight gain per
gram of practical diet consumed (e.g 1.5-3 pounds of feed/1 pound of
fish). Young Tilapia are easily weaned and grow fast to market size when
fed formulated diets. Fast growth rates are common when fish are fed
foodstuffs containing levels of 35-50% protein for fish < 1 g (0.04) oz;
30-40% for 1-5 g (0.04-0.18 oz) fish and 25-30% for 5-25 g (0.18-0.88
oz) animals. For larger fish, recommended dietary levels vary from 25%
protein for fish raised in ponds, 28-32% when reared in cages, to 35-40%
when fish are grown in tanks. Tilapia growth rates also increase with
multiple daily feedings (3-8 times a day depending on fish size). Feed
allowance for young fish (<25 g) is usually 6-15% of their body weight
per day, and older fish (>25 g), 1-3% of their body weight.
Recommended stocking densities for table-size Tilapia production are
extremely variable, and vary according to fish size and system of
production. In fed and aerated production ponds, young (50 g) hybrid
Tilapia are usually stocked at 4,000 to 8,000 fish per acre. In tanks or
raceways, Tilapia of 0.88-1.77 oz in body size are stocked at densities
between 4-7 fish/ft3 of container space. In final grow-out
production
cages, range from 7-11 fish/ft3 of cage. When cages are placed in
ponds, the pond stocking density cannot exceed those numbers (e.g.
fish/acre) which would be achieved by growing the fish free-swimming in
the pond.
The estimated time to raise hybrid Tilapia from egg to food-size fish is
highly variable, but is usually in a range between 6 and 12 months. The
time required is primarily dependant on water temperature, fish density,
and quality of diet.
Environmental requirements
* Water Temperatures for
o Optimum growth: 28-32°C
o Optimum spawning and
embryo development: 25-30°C
* Dissolved Oxygen (DO): above 3.0 mg/l
* Carbon Dioxide: below 15 mg/l
* Salinity: 0-28 ppt
* Turbidity: 25-100 mg/l
* pH: 6.0-8.5
* Alkalinity: 50-700 mg/l
* Total Ammonia Nitrogen (TAN): 0.5-1 mg/l
Courtesy California Aquaculture Association:
http:www.californiaaquacultureassociation.org
Contact/Email
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