ArticlePDF Available

Tilapia culture in salt water: environmental requirements, nutritional implications and economic potentials

Authors:

Abstract

The shortage in freshwater in many countries, together with the competition for it with agriculture and other urban activities has increased the pressure to develop aquaculture in brackishwater and sea water. Tilapia are an excellent candidate for aquaculture in brackishwater and seawater is due to their ability to tolerate a wide range of water salinity. Salt tolerance depends on tilapia species, strains and size, adaptation time and method and environmental factors. Oreochromis mossambicus, O. aureus and T. zillii are the most salinity-tolerant tilapia species. O. mossambicus can tolerate up to 120‰ water salinity, but they can grow normally and reproduce at water salinity of 49‰, and their fry live and grow reasonably well at 69‰. Blue tilapia (O. aureus) and Nile tilapia (O. niloticus) are less salinity tolerant. Tilapia hybrids descended from salt-tolerant parents are highly salt-tolerant. Cold tolerance of tilapia reared under different salinities is species specific. The nutrient requirements of tilapia reared in seawater are not well-studied, and more research is needed in this regard. Published results indicated that tilapia reared in seawater and brackishwater environments may require lower protein levels for optimum growth than fish reared in fresh water. Feed consumption, digestion and utilization by these fishes are also affected by the changes in water salinity. In addition, the metabolic rate of tilapia increases with increasing water salinity. The economic potentials of tilapia culture in seawater have also not been well-investigated. However, the available information revealed that rearing these fishes in saltwater environments can be cost effective, if proper management measurements are adopted.
Abdel-Fattah M. El-Sayed. 2006. Tilapia Culture in Salt Water: Environmental Requirements, Nutritional Implications and Economic
Potentials. En: Editores: L. Elizabeth Cruz Suárez, Denis Ricque Marie, Mireya Tapia Salazar, Martha G. Nieto López, David A. Villarreal
Cavazos, Ana C. Puello Cruz y Armando García Ortega. Avances en Nutrición Acuícola VIII .VIII Simposium Internacional de Nutrición
Acuícola. 15 - 17 Noviembre. Universidad Autónoma de Nuevo León, Monterrey, Nuevo León, México. ISBN 970-694-333-5.
95
Tilapia culture in salt water: environmental requirements,
nutritional implications and economic potentials
Abdel-Fattah M. El-Sayed
Oceanography Department, Faculty of Science, Alexandria University
Alexandria, Egypt
E-mail: a_elsayed50@yahoo.com
Abstract
The shortage in freshwater in many countries, together with the competition for it with agriculture and other urban
activities has increased the pressure to develop aquaculture in brackishwater and sea water. Tilapia are an excellent
candidate for aquaculture in brackishwater and seawater is due to their ability to tolerate a wide range of water
salinity. Salt tolerance depends on tilapia species, strains and size, adaptation time and method and environmental
factors. Oreochromis mossambicus, O. aureus and T. zillii are the most salinity-tolerant tilapia species. O.
mossambicus can tolerate up to 120‰ water salinity, but they can grow normally and reproduce at water salinity of
49‰, and their fry live and grow reasonably well at 69‰. Blue tilapia (O. aureus) and Nile tilapia (O. niloticus) are
less salinity tolerant. Tilapia hybrids descended from salt-tolerant parents are highly salt-tolerant. Cold tolerance of
tilapia reared under different salinities is species specific. The nutrient requirements of tilapia reared in seawater are
not well-studied, and more research is needed in this regard. Published results indicated that tilapia reared in
seawater and brackishwater environments may require lower protein levels for optimum growth than fish reared in
fresh water. Feed consumption, digestion and utilization by these fishes are also affected by the changes in water
salinity. In addition, the metabolic rate of tilapia increases with increasing water salinity. The economic potentials of
tilapia culture in seawater have also not been well-investigated. However, the available information revealed that
rearing these fishes in saltwater environments can be cost effective, if proper management measurements are
adopted.
Abdel-Fattah M. El-Sayed. 2006. Tilapia Culture in Salt Water: Environmental Requirements, Nutritional Implications and Economic
Potentials. En: Editores: L. Elizabeth Cruz Suárez, Denis Ricque Marie, Mireya Tapia Salazar, Martha G. Nieto López, David A. Villarreal
Cavazos, Ana C. Puello Cruz y Armando García Ortega. Avances en Nutrición Acuícola VIII .VIII Simposium Internacional de Nutrición
Acuícola. 15 - 17 Noviembre. Universidad Autónoma de Nuevo León, Monterrey, Nuevo León, México. ISBN 970-694-333-5.
96
1. Introduction
Tilapia fishes, despite being freshwater fishes, are believed to have been evolved from marine
ancestors (Kirk, 1972). It is no surprise therefore that most of these fishes are able to tolerate a
wide range of water salinity. They can grow and reproduce normally in brackishwater. Some
species can even grow and reproduce at very high water salinity. However, limited data are
available on tilapia culture in brackishwater and seawater, compared to the voluminous
information available on their cultures in freshwater environments.
The shortage in freshwater in many countries, and the competition for it with agriculture and
other urban activities has increased the pressure to develop aquaculture in brackishwater and sea
water. Therefore, the first candidate that one may think of for aquaculture in brackishwater and
seawater is tilapia. The present review throws some lights on tilapia culture in
seawater/brackishwater, with emphasis on their environmental requirements, nutrient
requirements and economic potential.
2. Environmental requirements
The environmental factors affecting tilapia in the wild or under aquaculture conditions include
salinity, temperature, dissolved oxygen, ammonia and nitrites, pH, photoperiod and water
turbidity. However, this review will focus on salinity and temperature as the two most important
factors. For more details on the effects of other environmental factors on tilapia, the reader is
kindly referred to the author’s new book (Tilapia Culture) published by CABI in 2006.
2.1- Salinity tolerance
Extensive work has been published on the tolerance and adaptability of tilapia to water salinity
and the suitability of salt water for tilapia culture (Table 1). Most of this work indicated that salt
tolerance depends mainly on tilapia species, strains and size, adaptation time and method and
environmental factors (Chervinski, 1982; Philippart and Ruwet, 1982; Suresh and Lin, 1992).
Abdel-Fattah M. El-Sayed. 2006. Tilapia Culture in Salt Water: Environmental Requirements, Nutritional Implications and Economic
Potentials. En: Editores: L. Elizabeth Cruz Suárez, Denis Ricque Marie, Mireya Tapia Salazar, Martha G. Nieto López, David A. Villarreal Cavazos, Ana C. Puello Cruz y Armando García Ortega.
Avances en Nutrición Acuícola VIII .VIII Simposium Internacional de Nutrición Acuícola. 15 - 17 Noviembre. Universidad Autónoma de Nuevo León, Monterrey, Nuevo León, México. ISBN 970-694-
333-5.
97
Table 1. Salinity tolerance (‰) of tilapia (modified from El-Sayed, 2006).
Species Upper limit
Direct
transfer
Gradual
transfer
Optimum
limit
Remarks Reference
O. niloticus 181 361 5-102, 153 Reproduce at 13.5-29‰4
1Al-Amoudi (1987a), 2Payne and Collinson (1983),
3Alfredo and Hector (2002), 4Balarin and Haller (1982)
O. mossambicus 275 1206 17.57 Spawn at up to 49‰8 5Al-Amoudi (1987b), 6Whitefield and Blaber (1979),
7Canagaratnam (1966), 8Popper and Lichatowich
(1975)
O. aureus 275 544 10-159 Reproduce at 5-20‰, low growth and
high mortality at 36‰10
4Balarin and Haller (1982), 9Perry and Avault (1972),
10McGeachin, Wicklund, Olla and Winton (1987)
O. spilurus 334 4011 3-811 Good growth and survival in seawater,
but low fecundity11
11Al-Ahmed (2001)
S. galilaeus 294 194 Reproduce in the wild at 29‰4
T. rendalli 13-194 0
12 12Likongwe (2002)
T. zillii 4513 Grow and reproduce naturally at 10-
>30‰14
13Chervinski (1982), 14El-Sayed (pers. communication)
O. niloticus x O.
mossambicus
3515 1515 At 35‰, the fish failed to adapt 15Alfredo and Hector (2002)
Florida red tilapia 17.816 Grow normally up to 36.2‰ 16El-Ebiary et al. (1997)
Abdel-Fattah M. El-Sayed. 2006. Tilapia Culture in Salt Water: Environmental Requirements, Nutritional Implications and Economic
Potentials. En: Editores: L. Elizabeth Cruz Suárez, Denis Ricque Marie, Mireya Tapia Salazar, Martha G. Nieto López, David A. Villarreal
Cavazos, Ana C. Puello Cruz y Armando García Ortega. Avances en Nutrición Acuícola VIII .VIII Simposium Internacional de Nutrición
Acuícola. 15 - 17 Noviembre. Universidad Autónoma de Nuevo León, Monterrey, Nuevo León, México. ISBN 970-694-333-5.
98
Species, strain and size
It has been reported that O. mossambicus, O. aureus and T. zillii are the most salinity-tolerant
tilapia species. O. mossambicus can tolerate up to 120‰ water salinity (Whitefield and Blaber,
1979). Moreover, they can grow normally and reproduce at water salinity of 49‰, and their fry
live and grow reasonably well at 69‰ (Whitefield and Blaber, 1979). O. aureus are less salinity-
tolerant, but can grow well at a salinity of up to 36 to 44‰, while reproduction occurs at 19‰.
With gradual acclimation, they can tolerate a salinity of up to 54‰ (Balarin and Haller, 1982).
However, O. aureus reared at a salinity of 30‰ developed a toxic algae bloom and suffered from
epithelia erosion caused by the dinoflagellate Pfiesteria piscicida, and brighter flashing on the
dorsal and pectoral fins and tail (McMahon and Baca, 1999). Higher salinity also severely
restricted fish reproduction despite increasing somatic growth. Similarly, McGeachin et al.
(1987) found that O. aureus reared in seawater cages (36‰) showed a sharp reduction in growth
rates and were infected with Bacillus sp. which has lead to severe mortality.
T. zillii are also among the most salinity-tolerant tilapia species. They are found in highly saline
water (36-45‰) in many tropical and subtropical regions (Balarin and Hatton, 1979; A.-F.M. El-
Sayed, Alexandria, Egypt, 1996, pers. com.). T. zillii can also reproduce at 29->30‰. However,
this species is not suitable for aquaculture due to it low growth and overreproduction. On the
contrary, O. spilurus has also been successfully cultured in full sea water and trails are going on
in a number of countries for their commercial culture in seawater cages and tanks, with promising
results (Carmelo, 2002).
Other tilapias are generally less euryhaline and can tolerate water salinities ranging from about 20
to 35‰ (see details in Table 1). Most of these tilapia grow, survive and reproduce at 0-29‰,
depending on the species and acclimation period.
Salinity tolerance of tilapia is also affected by fish sex and size. Perschbacher and McGeachin
(1988) evaluated the salinity tolerance of red tilapia (O. mossambicus x O. urolepis hornorum)
fry, juveniles and adults. Adult fish were more salt-tolerant than fry and juveniles. Fry and
juveniles tolerated direct transfer to 19‰, without apparent stress and mortality, but 100%
mortality occurred at 27‰. On the other hand, adult fish tolerated a direct transfer to 27‰, with
a100% mortality at 37‰. Similarly, Watanabe, Kuo, & Huang (1985) studied the ontogeny of
salinity tolerance in Nile tilapia, blue tilapia and hybrids tilapia O. mossambicus female x O.
niloticus male. The median lethal salinity-96 h (MLS-96) for Nile tilapia and blue tilapia over an
age of 7-120 days post-hatching (dph) was 18.9 and 19.2‰. In contrast, MLS-96 of tilapia
hybrids changed with age and increased from 17.2‰ at 30 dph to 26.7‰ at 60 dph. The authors
referred these ontogenitic changes in salinity tolerance to body size than to chronological age.
Watanabe et al. (1985) reported also that male tilapia tend to be more salt tolerant than females.
Water salinity has also been reported to affect the reproduction of tilapia. Gonadal development
and spawning of Nile tilapia occurred at salinities of 17-29‰, while the onset of reproduction
was delayed with increasing water salinity from 25 to 50‰, and reproduction stopped completely
at salinity above 30‰ (Fineman-Kalio, 1988). On the other hand, Watanabe and Kuo (1985)
found that the total number of spawnings of Nile tilapia females was greater in brackishwater (5-
15‰) than in either full strength seawater (32‰) or freshwater.
Abdel-Fattah M. El-Sayed. 2006. Tilapia Culture in Salt Water: Environmental Requirements, Nutritional Implications and Economic
Potentials. En: Editores: L. Elizabeth Cruz Suárez, Denis Ricque Marie, Mireya Tapia Salazar, Martha G. Nieto López, David A. Villarreal
Cavazos, Ana C. Puello Cruz y Armando García Ortega. Avances en Nutrición Acuícola VIII .VIII Simposium Internacional de Nutrición
Acuícola. 15 - 17 Noviembre. Universidad Autónoma de Nuevo León, Monterrey, Nuevo León, México. ISBN 970-694-333-5.
99
It has also been reported that tilapia hybrids descended from salt-tolerant parents (such as O.
mossambicus and O. aureus) are highly salt-tolerant (Suresh and Lin, 1992a; Romana-Eguia and
Eguia, 1999). This may explain why Taiwanese red tilapia (Liao and Chang, 1983) and Florida
red tilapia (Watanabe, Ellingson, Wicklund & Olla, 1988) grow faster in SW and BW than in
FW.
Acclimation
Pre-acclimation to salt water and gradual transfer to high salinity have a significant effect on
tilapia growth and survival, as has been reported by Al-Amoudi (1987). The author found that O.
aureus, O. mossambicus and O. spilurus required shorter acclimation time (4 days) for a transfer
to full-strength seawater than O. niloticus and O. aureus x O. niloticus hybrids (8 days). These
results indicated that the former tilapia group is more euryhaline than the latter group. Al-
Amoudi, El-Sayed, & El-Ghobashy (1996) found also that O. mossambicus are more resistant to
thermohaline shocks than O. aureus x O. niloticus hybrids. Similarly, the physiological and
respiratory responses of O. mossambicus to salinity acclimation have been evaluated by Morgan,
Sakamoto, Grau & Iwama (1997). Fish reared in freshwater (FW) were transferred to FW,
isotonic salinity (Iso, 12‰) and 75% seawater (SW, 25‰) and a number of physiological
parameters were measured. The authors found that plasma Na+ and Cl- were elevated one day
after transfer to SW, but returned to FW levels on day 4. Plasma cortisol and glucose levels were
higher; while growth hormone, Na+, K+ ATPase activities and prolactins were lower in FW and
ISO than in SW.
These results suggested that the physiological changes associated with SW acclimation in tilapia
are short-term, energy demanding and may account for as much as 20% of total body metabolism
after 4 days in SW. The increase in the metabolic energy diverted into osmoregulation, with
increasing water salinity has also been reported in O. mossambicus and O. spilurus (Payne,
Ridgway & Hamer, 1988), O. niloticus x O. aureus and common carp (Payne, 1983).
Feeding tilapia broodstock with diets containing higher salt levels may produce seeds with better
adaptability to water salinity. Turingan and Kubaryk (1992) studied this assumption by feeding
Taiwanese red tilapia (O. mossambicus x O. niloticus) broodstock diets containing 0.8, 3, 6, 9 or
12% salt for 2 months prior to spawning. They found that egg hatchability was higher in SW than
in FW. The hatchability and larval growth were highest in fish fed 12% salt in SW and lowest in
FW. In another study, Watanabe et al. (1985) found that the survival of fry produced from
fertilized eggs of Nile tilapia spawned in FW and incubated at elevated salinities of 0, 5, 10, 15,
20, 25 and 32‰ was 85.5, 84.4, 82.5, 56.3, 37.9, 20.0 and 0%, respectively. Fry salinity tolerance
increased also with increasing the salinity of spawning, hatching or acclimatization. In addition,
at equivalent salinity, early exposure of tilapia broodstock to high salinity produced progeny with
high salinity tolerance than those spawned in FW and hatched at high salinity.
Steroid hormones may reduce the routine metabolism of euryhaline tilapia reared at high salinity
and, in turn, improve fish growth. The growth of O. mossambicus continuously treated with 17α-
methyltestostwerone (MT) was faster than early or delayed MT-treated fish in FW and SW. The
growth of continuously treated fish was 5-7 times higher in SW than in FW (Kuwaye, Okimoto,
Abdel-Fattah M. El-Sayed. 2006. Tilapia Culture in Salt Water: Environmental Requirements, Nutritional Implications and Economic
Potentials. En: Editores: L. Elizabeth Cruz Suárez, Denis Ricque Marie, Mireya Tapia Salazar, Martha G. Nieto López, David A. Villarreal
Cavazos, Ana C. Puello Cruz y Armando García Ortega. Avances en Nutrición Acuícola VIII .VIII Simposium Internacional de Nutrición
Acuícola. 15 - 17 Noviembre. Universidad Autónoma de Nuevo León, Monterrey, Nuevo León, México. ISBN 970-694-333-5.
100
Shimoda, Howerton, Lin, Pang & Grau, 1993). Similar results were reported by Ron, Shimoda,
Iwama & Gordon Grau (1995) who studied the effects of MT treatment and feeding rate on the
growth of O. mossambicus reared in FW and SW. The best growth was observed in MT-treated
fish fed double ration in SW. Oxygen consumption (routine metabolism) was also much lower in
SW than in FW. The authors suggested that the reduction in routine metabolism in fish reared in
SW may have accounted for the increase in growth rates, compared to fish reared in FW.
2.2- Temperature
Previous studies indicated that growth rates of Florida red tilapia reared at different salinities
increased with increasing temperature within the range 22-32C (Watanabe, Ernst, Chasar,
Wicklund & Olla, 1993). At 0‰, fish performance was maximized at 27ºC, while at 18 and 36‰,
the best growth and feed consumption were obtained at 32C. Under all temperatures, fish
performance was better at 18‰ than at 0 and 35‰, indicating an advantage of tilapia culture in
brackishwater compared to freshwater and seawater in subtropical regions.
However, it should be mentioned that cold tolerance of tilapia reared under different salinities is
species specific. O. spilurus reared in seawater survived and grew well under declining
temperature, while O. aureus showed lower growth and survival. Similarly, Allanson, Bok &
VanWyk (1971) found that O. mossambicus tolerated 11°C at 5‰, while fish reared in freshwater
did not survive at that temperature. Those authors suggested that the ability of O. mossambicus to
tolerate low water temperature is associated with the maintenance of high plasma sodium and
chloride concentration.
On the other hand, Jennings (1991) found that cold tolerance of Sarotherodon melanotheron did
not differ with water salinity ranging from 5 to 35‰. On the contrary, it has been reported that
the major obstacle of cage culture of this species in seawater in Kuwait and Malta was the
decrease in water temperature during winter times.
3- Nutrition
The nutritional requirements of tilapia farmed in seawater environments, including protein, lipids,
carbohydrates, protein-to-energy ratios, vitamins and mineral requirements have not been well
studied. Only few studies have been conducted in this regard. The results of those studies are
described below. It is, therefore, imperative that more research be carried out alongside this line.
3.1- Protein requirements
The protein requirement of Florida red tilapia reared in seawater pools has been investigated by
Clark, Watanabe & Ernst (1990). The performance and survival of fish fed isocaloric diets
containing 20, 25 and 30% CP were not significantly different. This simply demonstrates the
feasibility of lowering feed cost by using low-protein diets without reducing fish performance.
Shiau and Huang (1990) reported also that tilapia hybrids (O. niloticus x O. aureus) reared in
seawater can perform well on high energy (3.1 kcal/g)- low protein diet (20% CP). Similarly,
Orachunwong, Thammasart & Lohawatanakul (2001) compared two commercial feeds (20 and
25% CP) for red tilapia cage-cultured in BW ponds (15-18‰). They found that final yield,
Abdel-Fattah M. El-Sayed. 2006. Tilapia Culture in Salt Water: Environmental Requirements, Nutritional Implications and Economic
Potentials. En: Editores: L. Elizabeth Cruz Suárez, Denis Ricque Marie, Mireya Tapia Salazar, Martha G. Nieto López, David A. Villarreal
Cavazos, Ana C. Puello Cruz y Armando García Ortega. Avances en Nutrición Acuícola VIII .VIII Simposium Internacional de Nutrición
Acuícola. 15 - 17 Noviembre. Universidad Autónoma de Nuevo León, Monterrey, Nuevo León, México. ISBN 970-694-333-5.
101
average final body weight and FCR were not significantly different (see Table 2). However, the
cost of the 20% CP diet was 17% lower than the 25% CP diet. Consequently, production cost was
lower for the 20% CP diet.
Table 2. Performance of red tilapia (O. mossambicus x O. hornorum) fed 20% and 25% CP diets
in floating cages suspended in brackishwater earthen ponds (15-18 ‰). (modified from
Orachunwong et al., 2001).
The above results may indicate that tilapia reared in seawater and brackishwater environments
may require lower protein levels than fish reared in fresh water. However, El-Sayed, Mansour
and Ezzat (2003) found that spawning performance and protein requirements of Nile tilapia
broodstock were significantly affected by water salinity. The fish were fed test diets containing
25, 30, 35 and 40% crude protein at three water salinities (0, 7 and 14‰). The size at first
maturation increased with increasing dietary protein at all salinities. At 25 and 30% protein
levels, broodstock reared at 0 ‰ reached their sexual maturity at bigger sizes than those reared at
7 and 14‰. At 0 ‰, spawning intervals were not significantly affected by dietary protein levels,
while at 7 and 14‰, spawning intervals significantly decreased with increasing dietary protein
levels. Spawning frequency and number of eggs per spawn were increased with increasing
dietary protein levels. The total number of spawnings per female and absolute fecundity were
better in fish fed 40% protein in freshwater than at 7 and 14‰ salinity. It seems therefore,
nutrient requirements of tilapia reared in seawater and brackishwater are species specific.
3.2- Lipid requirements
As far as I know, no studies have been conducted to investigate the requirements of tilapia under
different salinities. Only recently, El-Sayed et al. (2005) have tackled this issue. Those authors
studied the effects lipid source on the reproductive performance of Nile tilapia broodstock reared
at different salinities (0, 7 and 14‰). They found that Nile tilapia broodstock reared in
brackishwater required n-3 HUFA for optimum spawning performance, while the reproductive
performance of fish reared in freshwater was not affected by dietary lipid source. Yet, the effect
of lipid source on the performance of other developmental stages of Nile tilapia (and also of other
tilapias) is not known.
Item 20% CP 25% CP
Culture period (days) 144 144
Stocking density (fish/m3) 50 50
Initial mean body weight (g/fish) 80 80
Harvest mean body weight (g/fish) 548 606
Harvest biomass (kg/ m3 26.5 28
Survival rate (%) 97 92
Average daily gain (g/fish) 3.26 3.65
Feed conversion ratio 1.4 1.39
Abdel-Fattah M. El-Sayed. 2006. Tilapia Culture in Salt Water: Environmental Requirements, Nutritional Implications and Economic
Potentials. En: Editores: L. Elizabeth Cruz Suárez, Denis Ricque Marie, Mireya Tapia Salazar, Martha G. Nieto López, David A. Villarreal
Cavazos, Ana C. Puello Cruz y Armando García Ortega. Avances en Nutrición Acuícola VIII .VIII Simposium Internacional de Nutrición
Acuícola. 15 - 17 Noviembre. Universidad Autónoma de Nuevo León, Monterrey, Nuevo León, México. ISBN 970-694-333-5.
102
3.3- Vitamin requirements
Again, very little information is available on vitamin requirement of tilapia grown in seawater.
Only Thiamine (Lim & Leamaster, 1991) and Riboflavin (Lim, Leamaster & Brock, 1993)
requirements have been quantified for red hybrid tilapia. When the fish were reared at 32‰, they
required 2.5 and 5 mg/kg thiamine and riboflavin, respectively.
3.4- Feed consumption/frequency
It has been reported that the metabolic rate of tilapia increases with increasing water salinity
(Bashamohideen and Parvatheeswararao, 1976). It is very likely that feed consumption, digestion
and utilization by these fishes will be affected by the changes in water salinity. In support,
Watanabe at al. (1988) found that the daily feed consumption of Florida red tilapia fed a 32% CP
diet increased with increasing salinity from 0 to 32‰. In another study, the maximum growth of
these fish was obtained at satiation feeding rates, while feed conversion was improved at lower
feeding rates (Clark et al., 1990).
A feeding trial was conducted to evaluate the appropriate feeding frequency for cage-cultured red
tilapia (O. mossambicus x O. hornorum) in Thailand (Orachunwong et al., 2001). Fish were
stocked in floating cages suspended in earthen BW ponds (15-18‰) and fed a commercial tilapia
feed (25% cp) ad libitum 2, 3, and 4 times daily. Feeding 3-4 times day-1 has resulted in better
growth and FCR than twice a day. Dividing the daily ration of tilapia reared in cages into 3-4
feedings would probably reduce feed loss compared to once or twice a day. When the fish were
reared in cages suspended in BW ponds (15-20‰) and fed diets containing 20-32%CP diets, for
143-154 days, they attained a yield of about 21 mt/ha/crop (Orachunwong et al., 2001).
4- Tilapia culture in sea cages
The scarcity of freshwater, and the competition for it with other activities such as irrigation,
drinking and other urban activities, make its use for tilapia culture unguaranteed and unsecured.
The challenge which faces fish farmers and aquaculture researchers is to use brackishwater and
sea water, which is available in most of the tropics and subtropics, for tilapia culture. The
euryhaline characteristics of tilapia make them an ideal candidate for culture in the saline waters.
Tilapia cage culture in sea water has been tried by a number of researchers, with varying degrees
of success, depending on cultured species, size and sex, stocking density and cage size and shape.
Watanabe, Clark, Dunhkam, Wicklund, & Olla (1990) successfully raised Florida red tilapia in
seawater cages in the Bahamas with survival of 84.1- 93.5%. However, the results of that study
may not be reliable due to the short duration through which it was carried out (30 days). Persand
and Bhikajee (1997) reared red tilapia (Oreochromis spp.) in cylindrical seawater cages in
Mauritius, for 95 days. The SGR (1.13%) and yield (9 kg m-1) were considered low as compared
to other similar rearing studies, such as that of Cruz and Ridha (1991) who found that the SGR of
O. spilurus grown in sea cages in Kuwait was 1.9%. The difference between both results may
have been related to stocking density and species and size, duration of the trials and
environmental conditions. Moreover, Al-Ahmed (2002) described the culture of O. spilurus in
sea cages in Kuwait. Fry are stocked at 600 m-3, while 200 fish m-3 are considered optimum for
Abdel-Fattah M. El-Sayed. 2006. Tilapia Culture in Salt Water: Environmental Requirements, Nutritional Implications and Economic
Potentials. En: Editores: L. Elizabeth Cruz Suárez, Denis Ricque Marie, Mireya Tapia Salazar, Martha G. Nieto López, David A. Villarreal
Cavazos, Ana C. Puello Cruz y Armando García Ortega. Avances en Nutrición Acuícola VIII .VIII Simposium Internacional de Nutrición
Acuícola. 15 - 17 Noviembre. Universidad Autónoma de Nuevo León, Monterrey, Nuevo León, México. ISBN 970-694-333-5.
103
growout phase. In one study, the fish grew from 118-323.3 g in 101 days, with a growth rate of
2.03 g d-1 and a production of 44 kg m-3. In another study, the fish gained 2.31-3.49 g d-1, with a
FCR of 1.47-2.13 and a survival of 95-97.7%. The main limitation of tilapia culture in sea cages
in Kuwait is the decrease in water temperature during winter times (Mid-November to mid-
April).
Commercial farming of O. spilurus in open–sea cages (125 m3) at a salinity of 37-38‰ has also
been carried out in Malta (Agius, 2001), with very promising results. The fish (50 g) were
stocked in the cages at the end of June and reached 450-500 g at the end of November (after 5
months), with a mortality rate less than 2%. Once again, as in case of Kuwait, the main obstacle
that limits the expansion of this culture system in Malta is the low water temperature during
winter months. It is clear, thus, that rearing certain species of tilapia in seawater cages can be an
excellent alternative tilapia culture system, if environmental conditions are favourable.
5- Economic Potential
Despite that the economic potentials of tilapia culture in seawater has not been well-investigated,
the available information revealed that rearing these fishes in saltwater environments can be cost
effective, if proper management measurements are adopted. Head, Zerbi & Watanabe (1996)
found that feed, processing and distribution and sex-reversed fry represented the highest variable
costs in commercial-scale, seawater pond production of Florida red tilapia in Puerto Rico, while
salaries and depreciation accounted for the highest fixed costs. At a stocking density of 2 fish m-2,
the proposed production was not economical, while increasing the density to 3.5 and 4 fish m-2
increased the profitability of the operation. Using locally prepared feed together with the
integration of hatchery and growout operations are also suggested for reducing operational costs
and increasing return.
Similarly, Head and Watanabe (1995) evaluated the economics of a commercial-scale,
recirculating, brackishwater hatchery for Florida red tilapia (O. urolepus hornerum x O.
mossambicus) in the Bahamas, using previously-collected production data. Salaries and benefits
were the largest fixed costs. Air-freight shipping to Miami, Florida, represented the largest
variable cost when air charters were used. The study indicated that the system is economically
feasible if fry can be sold year-round, while seasonal market demand may limit the economic
return. The authors reported also that more economic success can be achieved if more economical
building construction, modifications in rearing tank design, and vertical integration of hatchery
and growout operations, with external sales of excess fry and broodstock are adopted.
Samonte, Agbayani & Tumaliuan (1991) compared the economic feasibility of the
polyculture of tiger shrimp (Penaeus monodon) with Nile tilapia in brackishwater ponds in the
Philippines. A stocking combination of 6,000 shrimp and 4,000 tilapia ha-1 produced the highest
total yields and net income compared to monoculture of tilapia or shrimp. Two crops per year
provided a 70% return on investment and 1.2 years payback. Sensitivity analysis revealed that
shrimp/tilapia polyculture was profitable up to a 20% decrease in the selling price of both
species.
6- Global markets of Tilapia
Abdel-Fattah M. El-Sayed. 2006. Tilapia Culture in Salt Water: Environmental Requirements, Nutritional Implications and Economic
Potentials. En: Editores: L. Elizabeth Cruz Suárez, Denis Ricque Marie, Mireya Tapia Salazar, Martha G. Nieto López, David A. Villarreal
Cavazos, Ana C. Puello Cruz y Armando García Ortega. Avances en Nutrición Acuícola VIII .VIII Simposium Internacional de Nutrición
Acuícola. 15 - 17 Noviembre. Universidad Autónoma de Nuevo León, Monterrey, Nuevo León, México. ISBN 970-694-333-5.
104
Most of produced tilapia is consumed in domestic markets in production areas, especially in rural
Asia, Africa and South America. It plays a crucial role in food security and poverty alleviation in
these regions. However, the demand for tilapia is growing in non-traditional, non-producing
countries. Therefore, global trade in tilapia products has witnessed an impressive flourishing in
the last two decades, and are expected to continue (Vannuccini, 2001). One of the major
advantages of global tilapia marketing is their competitive prices and their white flesh that make
them an important substitute for white fish species which face shortages in supply (Vannuccini,
2001). It is also more profitable for North America and European markets to import tilapia from
producing regions than farming them, mainly due to the low cost of labour, energy and operating
costs in these regions (Watanabe, Losordo, Fitzsimmons & Hanley, 2002).
The US market is the largest market for tilapia import in the world. The tilapia import quantities
have sharply increased in recent years, to jump from 56,334 mt in 2001 to 90,206 mt in 2003,
with an increase of over 60% in just three years. A wide variety of tilapia products, including live
fish, fresh fish and frozen fillet, are currently marketed.
Tilapia imports from South America and the Caribbean region to the US market are increasing.
Fourteen countries from those regions are currently exporting tilapia and tilapia products to the
USA. The largest exporter are Ecuador, Costa Rica and Honduras. The three countries accounted
for over 90% of all imported fresh fillets in 2003 (El-Sayed, 2006). Some aquaculture producers
in Ecuador have switched from shrimp production, due to falling prices in the shrimp market, to
tilapia production. Other countries, such as Panama and Nicaragua are becoming important
tilapia exporters to the US market. It is very likely that the US tilapia market will attract the
attention of large tilapia producers such as Brazil and Mexico.
In conclusion, it is evident from the foregoing discussion that the potentials of tilapia culture in
brackishwater/seawater are high, if proper management measurements are adopted. However,
extensive work is needed alongside this line, particularly on the nutritional requirements and
economic potentials of tilapia reared under different water salinities.
References
Agius, C. (2001) Commercial culture of Oreochromis spilurus in open sea cages. In: Subasinghe, S. and Singh, T.
(eds) Tilapia: Production, Marketing and Technical Developments. Proceedings of the Tilapia 2001
International Technical and Trade Conference on Tilapia. Infofish, Kuala Lumpur, Malaysia, pp. 132-135.
Al-Ahmed, A.A. (2001) A review of tilapia culture in Kuwait. World Aquaculture 32 (2), 47-48.
Al-Ahmed, A.A. (2002) Tilapia culture in Kuwait. Global Aquaculture Advocate 5 (6), 31.
Al-Amoudi, M.M. (1987) Acclimation of commercially cultured Oreochromis species to sea water- an experimental
study. Aquaculture 65, 333-342.
Al-Amoudi, M.M., El-Sayed, A.-F.M. & El-Ghobashy, A. (1996) Effects of thermal and thermo-haline shocks on
survival and osmotic concentration of the tilapias Oreochromis mossambicus and Oreochromis aureus x
Oreochromis niloticus hybrids. Journal of the World Aquaculture Society 27, 456-461.
Allanson, B.R., Bok, A. & VanWyk, N.I. (1971) The influence of exposure to low temperature on Tilapia
mossambica Peters (Cichlidae). 2. Changes in serum osmolarity, sodium and chloride ion concentrations.
Journal of Fish Biology 3, 181-185.
Balarin, J.D. & Haller, R.D. (1982) The intensive culture of tilapia in tanks, raceways and cages. In: Muir, J.F. and
Roberts, R.J. (eds) Recent Advances in Aquaculture. Croom Helm, London and Canberra, Westview Press,
Boulder Colorado, pp 267-355.
Abdel-Fattah M. El-Sayed. 2006. Tilapia Culture in Salt Water: Environmental Requirements, Nutritional Implications and Economic
Potentials. En: Editores: L. Elizabeth Cruz Suárez, Denis Ricque Marie, Mireya Tapia Salazar, Martha G. Nieto López, David A. Villarreal
Cavazos, Ana C. Puello Cruz y Armando García Ortega. Avances en Nutrición Acuícola VIII .VIII Simposium Internacional de Nutrición
Acuícola. 15 - 17 Noviembre. Universidad Autónoma de Nuevo León, Monterrey, Nuevo León, México. ISBN 970-694-333-5.
105
Balarin, J.D. & Hatton, J.P. (1979) Tilapia: A guide to their Biology and Culture in Africa. University of Stirling,
Scotland.
Bashamohideen, M. & Parvatheeswararao, V. (1976) Adaptaions to osmotic stress in the freshwater euryhaline
teleost, Tilapia mossambica. Zool. Anz. Jena 197 (1/2), 47-56.
Carmelo, A. (2002) Commercial culture of Oreochromis spilurus in open seawater cages and onshore tanks. Israeli
Journal of Aquaculture/Bamidgeh 54, 27-33.
Chervinski, J. (1982) Environmental physiology of tilapias. In: Pullin, R.V.S. and Lowe-McConnell, R.H. (eds) The
biology and Culture of Tilapias. ICLARM Conference Proceedings No. 7, ICLARM, Manila, Philippines,
pp. 119-128.
Clark, J.H., Watanabe, W.O. & Ernst, D.H. (1990) Effect of feeding rate on growth and diet conversion of Florida
red tilapia reared in floating marine cages. Journal of the World Aquaculture Society 21, 16-24.
Cruz, E.M. & Ridha, M. (1991) Production of tilapia Oreochromis spilurus Gunther stocked at different densities in
sea cages. Aquaculture 99, 95-103.
El-Sayed, A.-F.M. (2006) Tilapia Culture. CABI Publishing, Wallingford, Oxon, UK, 294 pp.
El-Sayed, A.-F.M., Mansour, C.R. & Ezzat, A.A. (2003) Effects of dietary protein levels on spawning performance
of Nile tilapia (Oreochromis niloticus) broodstock reared at different water salinities. Aquaculture 220, 619-
632.
El-Sayed, A.-F.M., Mansour, C.R. and Ezzat, A.A. (2005) Effects of dietary lipid source on spawning performance
of Nile tilapia (Oreochromis niloticus) broodstock reared at different water salinities. Aquaculture 248, 187-
196.
Fineman-Kalio, A.S. (1988) Preliminary observations on the effect of salinity on the reproduction and growth of
freshwater Nile tilapia, Oreochromis niloticus (L.), cultured in brackishwater ponds. Aquaculture and
Fisheries Management 19, 313-320.
Head, W.D. & Watanabe, W.O. (1995) Economic analysis of a commercial-scale, recirculating, brackishwater
hatchery for Florida red tilapia. Journal of Applied Aquaculture 5, 1-24.
Head, W.D., Zerbi, A. & Watanabe, W.O. (1996) Economic evaluation of commercial-scale, saltwater pond
production of Florida red tilapia in Puerto Rico. Journal of the World Aquaculture Society 27, 275-289.
Jennings, D.P. (1991) Behavioural aspects of cold tolerance in blackchin tilapia, Sarotherodon melanotheron, at
different salinities. Environmental Biology of Fishes 31, 185-195.
Kirk, R.G. (1972) A review of the recent development in tilapia culture with special reference to fish farming in the
heated effluents of power stations. Aquaculture 1, 45-60.
Kuwaye, T.T., Okimoto, D.K., Shimoda, S.K., Howerton, R.D., Lin, H-R., Pang, P.K.T. & Grau, E.G. (1993) Effect
of 17 α-methyltestosterone on the growth of the euryhaline tilapia, Oreochromis mossambicus, in fresh
water and in sea water. Aquaculture 113, 137-152.
Liao, I.C. & Chang, S.L. (1983) Studies on the feasibility of red tilapia culture in saline water. In: Fishelson, L. and
Yaron, Z. (eds) Proceedings of the International Symposium on Tilapia in Aquaculture. Tel-Aviv
University, Israel, pp. 524-533.
Lim, C. & Leamaster, B. (1991) Thiamine requirements of red hybrid tilapia grown in seawater. Journal of the
World Aquaculture Society 22, 36A.
Lim, C., Leamaster, B. & Brock, J.A. (1993) Riboflavin requirements of fingerling red tilapia grown in seawater.
Journal of the World Aquaculture Society 24, 451-458.
McGeachin, R.B., Wicklund, R.I., Olla, B.L. & Winton, J.R. (1987) Growth of Tilapia aurea in seawater cages.
Journal of the World Aquaculture Society 18, 31-34.
McMahon, D.Z. & Baca, B. (1999) The effects of various salinities on the growth, pathology and reproduction of
blue tilapia Oreochromis aureus. World Aquaculture ’99 - Book of Abstracts. World Aquaculture Society,
Baton Rouge, Louisiana, USA, p. 508.
Morgan, J.D., Sakamoto, T., Grau, E.G. & Iwama, G.K. (1997) Physiological and respiratory responses of the
Mozambique tilapia (Oreochromis mossambicus) to salinity acclimation. Comparative Biochemistry and
Physiology 117A, 391-398.
Orachunwong, C., Thammasart, S. & Lohawatanakul, C. (2001) Recent developments in tilapia feeds. In:
Subasinghe, S. and Singh, T. (eds) Tilapia: Production, Marketing and Technical Developments.
Proceedings of the Tilapia 2001 International Technical and Trade Conference on Tilapia, Infofish, Kuala
Lumpur, Malaysia, pp. 113-122.
Payne, A.I. (1983) Estuarine and salt tolerant tilapias. In: Fishelson, L. and Yaron, Z. (eds) Proceedings of the
International Symposium on Tilapia in Aquaculture. Tel-Aviv University, Israel, pp. 534-543.
Abdel-Fattah M. El-Sayed. 2006. Tilapia Culture in Salt Water: Environmental Requirements, Nutritional Implications and Economic
Potentials. En: Editores: L. Elizabeth Cruz Suárez, Denis Ricque Marie, Mireya Tapia Salazar, Martha G. Nieto López, David A. Villarreal
Cavazos, Ana C. Puello Cruz y Armando García Ortega. Avances en Nutrición Acuícola VIII .VIII Simposium Internacional de Nutrición
Acuícola. 15 - 17 Noviembre. Universidad Autónoma de Nuevo León, Monterrey, Nuevo León, México. ISBN 970-694-333-5.
106
Payne, A.I., Ridgway, J. & Hamer, J.L. (1988) The influence of salt (NaCl) concentration and temperature on the
growth of Oreochromis spilurus, O. mossambicus and a red tilapia hybrid. In: Pullin, R.S.V., Bhukaswan,
T., Tonguthai, K. and Maclean, J.L. (eds) Proceedings of the Second International Symposium on Tilapia in
Aquaculture. ICLARM Conference Proceedings No. 15, Department of Fisheries, Thailand, and ICLARM,
Manila, Philippines, pp. 481-487.
Persand, S. & Bhikajee, M. (1997) Studies on an experimental fouling resistant mariculture cage for red tilapia in
Mauritius. In: Fitzsimmons, K. (ed.) Proceedings from the Fourth International Symposium on Tilapia in
Aquaculture. Northeast Regional Agriculture Engineering Service, Ithaca, New York, USA, pp. 408-415.
Perschbacher, P.W. & McGeachin, R.B. (1988) Salinity tolerance of red hybrid tilapia fry, juvenile and adults. In:
Pullin, R.S.V., Bhukaswan, T., Tonguthai, K. and Maclean, J.L. (eds) Proceedings of the Second
International Symposium on Tilapia in Aquaculture. ICLARM Conference Proceedings No. 15, Department
of Fisheries, Thailand, and ICLARM, Manila, Philippines, pp. 415-420.
Philippart, J-CL. and Ruwet, J-CL. (1982) Ecology and distribution of Tilapias. In: Pullin, R.S.V. and Lowe-
McConnell, R.H. (eds) The Biology and Culture of Tilapias. ICLARM Conference Proceedings No. 7,
ICLARM, Manila, Philippines, pp. 15-59.
Romana-Eguia, M.R.R. & Eguia, R.V. (1999) Growth of five Asian red tilapia strains in saline environments.
Aquaculture 173, 161-170.
Ron, B., Shimoda, S.K., Iwama, G.K. & Gordon Grau, E. (1995) Relationships among ration, salinity, 17 α-
methyltestosterone and growth in the euryhaline tilapia, Oreochromis mossambicus. Aquaculture 135, 185-
193.
Samonte, G.Ph., Agbayani, R.F. & Tumaliuan, R.E. (1991) Economic feasibility of polyculture of tiger shrimp
(Penaeus monodon) with Nile tilapia (Oreochromis niloticus) in brackishwater ponds. Asian Fisheries
Science 4, 335-343.
Shiau, S.-Y. & Huang, S.-L. (1990) Influence of varying energy levels with two protein concentrations in diets for
hybrid tilapia ( Oreochromis niloticus x O. aureus) reared in seawater. Aquaculture 91, 143-152.
Suresh, A.V. & Lin, C.K. (1992) Tilapia culture in saline waters: a review. Aquaculture 106, 201-226.
Turingan, J.E. & Kubaryk, J.M. (1992) The effect of high salt diet on survival and hatchability of Taiwanese red
tilapia (Oreochromis mossambicus x Oreochromis niloticus) eggs upon direct transfer to seawater.
Aquaculture’92 - Book of Abstracts. World Aquaculture Society, Baton Rouge, Louisiana, USA, p. 220.
Vannuccini, S. (2001) Global markets for tilapia. In: Subasinghe, S. and Singh, T. (eds) Tilapia: Production,
Marketing and Technical Developments. Proceedings of the Tilapia 2001 International Technical and
Trade Conference on Tilapia. Infofish, Kuala Lumpur, Malaysia, pp. 65-70.
Watanabe, W.O. & Kuo, C-M. (1985) Observations on the reproductive performance of Nile tilapia (Oreochromis
niloticus) in laboratory aquaria at various salinities. Aquaculture 49, 315-323.
Watanabe, W.O., Kuo, C-M. & Huang, M-C. (1985) The ontogeny of salinity tolerance in the tilapias Oreochromis
aureus, O. niloticus and O. mossambicus x O. niloticus hybrids, spawned and reared in freshwater.
Aquaculture 47, 353-367.
Watanabe, W.O., Ellingson, L.J., Wicklund, R.I. & Olla, B.L. (1988) The effects of salinity on growth, food
consumption and conversion in juvenile, monosex male Florida red tilapia. In: Pullin, R.S.V., Bhukaswan,
T., Tonguthai, K. and Maclean, J.L. (eds) Proceedings of the Second International Symposium on Tilapia in
Aquaculture. ICLARM Conference Proceedings No. 15, Department of Fisheries, Thailand, and ICLARM,
Manila, Philippines, pp. 515-523.
Watanabe, W.O., Clark, J.H., Dunhkam, J.B., Wicklund, R.I. & Olla, B.L. (1990) Culture of Florida red tilapia in
marine cages: The effects of stocking and dietary protein on growth. Aquaculture 90, 123-134.
Watanabe, W.O., Ernst, D.H., Chasar, M.P., Wicklund, R.I. & Olla, B.L. (1993) The effects of temperature and
salinity on growth and feed utilization of juvenile, sex-reversed male Florida red tilapia cultured in a
recirculating system. Aquaculture 112, 309-320.
Watanabe, W.O., Losordo, T.M., Fitzsimmons, K. & Hanley, F. (2002) Tilapia production systems in the Americas:
Technological advances, trends, and challenges. Reviews in Fisheries Science 10, 465-498.
Whitefield, A.K. & Blaber, S.J.M. (1979) The distribution of the freshwater cichlid Sarotherodon mossambicus in
estuarine systems. Environmental Biology of Fishes 4, 77-81.
... Farmed tilapia, including Nile tilapia (Oreochromis niloticus), and some other cichlid species, are currently the most important fish species in aquaculture in the tropics and subtropics (Mjoun et al., 2010a;Prabu et al., 2019). Limited freshwater resources and competition with agriculture and other urban activities, has increased the pressure to develop aquaculture in brackish water and sea water in many countries (El-Sayed, 2006). Tilapia is an excellent candidate for aquaculture in brackish or saline environments due to their ability to tolerate wide range of environmental conditions (Mjoun et al., 2010b;El-Sayed, 2019). ...
... Saline-tolerant tilapia is also well-suited for polyculture with saltwater shrimp, which can have both environmental and economic benefits by improving feed efficiency and reducing the effects of diseases (Junior et al., 2012;Martínez-Porchas et al., 2010;Fitzsimmons and Shahkar, 2017). Within the genus Oreochromis there are a number of saline-tolerant species, such as Mozambique tilapia (Oreochromis mossambicus) and blue tilapia (Oreochromis aureus) (El-Sayed, 2006). In contrast to Nile tilapia, these tilapia species have been a limited history of selection for high yield (Jaspe and Caipang, 2011;Zak et al., 2014). ...
Article
Tilapia is a group of originally fresh water species, some of which can be tolerate a wide range of salinities and can be cultured in estuaries or brackish water ponds in polyculture with shrimp. Although the physiological processes that underly osmoregulation have been studied extensively, it is less clear how artificial selection produce adaptation to salinity stress. Here we studied the genomic architecture of an Indonesian saline-tolerant strain, called “Sukamandi”, which was selected for rapid growth in brackish water. We also investigated the impact of selection for salinity tolerance on the genome. Because the Sukamandi strain was potentially derived from hybridization between Nile tilapia (Orechromis niloticus) and blue tilapia (Orechromis aureus), we also searched for introgression signatures to understand their influence on salinity tolerance. Our results show that overall the Sukamandi strain is genetically much closer to Nile tilapia than to blue tilapia. Thirty-three salinity tolerance genes identified by Fst, enriched in ion transmembrane transport processes, such as MAPK3 activity, potassium ion homeostasis, ATPase activity and response to calcium ion. Comparing signatures of selection and introgression revealed that eight salinity tolerance genes, including caprin1a, nucb2a, abcb10, slc12a10.1, cacna1ab, ulk2, slc25a24 and cdh1 were strongly selected (top 1% signal windows) based on genome-wide scans, while five (slc12a10.1, zgc:153039, slc9a2, slc25a24, cdh1) out of thirty-three genes that have been introgressed from blue tilapia and selected (above top 5% signal windows) in the Sukamandi strain. Our findings not only contribute to understanding the evolution of salinity tolerance in fish, but, more generally, provide an interesting model for hybrid introgression in a farmed fish species.
... Smallholder farmers, the majority in brackish water areas, cannot access the requisite financial and technical resources. Tilapia is the most attractive fin fish species in brackish water environments because it has the highest salinity tolerance and range, grows faster than most other freshwater fish species, including milkfish (Cnaani and Hulata, 2011;El-sayed, 2006;Popma and Masser, 1999), and in many areas, the selling price for tilapia is slightly higher than milkfish at the same size. In recent years, the rapid growth of tilapia in brackish water has encouraged many milkfish farmers to shift to tilapia, particularly in East and Central Java. ...
Article
Aquaculture plays a key role in Indonesian seafood production and food security. The most valuable species in Indonesian aquaculture is shrimp, which has been widely farmed since the early 1980s. Beginning in the 1990s, recurrent farm failures and increasing production losses caused by disease outbreaks have hampered the growth of shrimp production. Many small-scale shrimp farmers face severe financial challenges and are looking for alternative crops to supplement their livelihoods. In recent years, many farmers have adopted rotational cropping and polyculture systems as a sanitary practice to reduce disease outbreaks. One promising strategy is to add tilapia as a second species on existing shrimp farms. Few studies have investigated the economic potential for using tilapia in rotational cropping or co-culture systems with shrimp, especially in the context of high spatial and temporal variability that can reduce tilapia growth rate in saline coastal shrimp ponds. We conducted a survey to acquire information on current tilapia production covering 17 sites in four provinces of Java (Banten, West Java, Central Java and East Java). This paper presents an analysis on the extent to which and how tilapia has been incorporated into traditional shrimp farming systems, and its economic implications based on the survey data. We selected a total of 224 representative shrimp-tilapia farmers in consultation with the Extension and Community Empowerment Centre of Marine and Fisheries, Ministry of Marine Affairs and Fisheries (MMAF), and interviewed them in small focus groups from every site. Local fisheries extension officers guided the interviews. Our results indicate that a majority of small-scale farmers in all four provinces have low income status. To sustain their production levels, farmers have developed novel rotational and co-culture farming systems. The farmers' income status influenced their decisions to adopt specific farming systems. The poly-rotational farming system, which is farming shrimp and tilapia in the same ponds during the rainy season followed by farming only shrimp in dry season provided the highest farm gross profit. Higher income status farmers have more access to high quality feed, pond lining materials, and aeration systems, which resulted a higher farm gross profit across all four farming systems.
... Nile tilapia can tolerate a wide range of water salinities, making it a suitable fish species for sustainability. The optimum growth performance and well-being of Nile tilapia require a 0 to 19 ppt salinity level (El-Sayed, 2006). However, maintaining the optimum conditions of the remaining factors, such as water quality and nutritional manipulations, must be considered (El-Sayed, 2019). ...
Article
Full-text available
Farming Nile tilapia in brackish water is one of the choices in the areas suffering from a lack of fresh water. Hence this study tested the effects of different salinity levels and dietary menthol essential oil (MNT) on the productivity of Nile tilapia. Two test diets were formulated with MNT (0.25%) or without MNT and fed to Nile tilapia stocked in 0, 5, 10, and 15 ppt salinity levels for 60 days. The growth performance, feed efficiency ratio, and survival rate indices were markedly (p < 0.05) affected by different salinity levels, dietary MNT, and their interaction. All groups showed significantly higher survival rate than fish in 15 ppt without MNT feeding (p < 0.05). The histopathological investigation of gills, intestines, and livers was prominently affected by increased salinity, while the addition of MNT clearly improved the morphological abnormalities. Fish in 15 ppt without MNT had the highest ALT and AST levels, while fish in 0 ppt with MNT had the lowest ALT and AST levels (p < 0.05). The blood glucose level was markedly increased in 10 and 15 ppt with MNT (p < 0.05), followed by fish in 5 ppt with MNT and 15 ppt without MNT. The blood cortisol level was markedly increased in 10 and 15 ppt with MNT (p < 0.05), followed by fish in 5 ppt with MNT, then 0, 5, and 10 ppt without MNT. Fish in 0 and 5 ppt salinity levels had higher SOD, CAT, GPx, and lower MDA levels (p < 0.05) than fish in 10 and 15 ppt without MNT feeding. In all groups, the SOD, CAT, and GPx were markedly enhanced by the addition of MNT while MDA levels were reduced (p < 0.05). The regression analysis illustrated that the best performances of Nile tilapia could be occurred by 1.84–8.04 ppt. At the same time, the inclusion of MNT resulted in increased tolerance of Nile tilapia up to 14.85 ppt based on the overall regression analysis results. In conclusion, dietary MNT relived the impacts of brackish water conditions on the productivity and the histological structure of gills, intestines, and livers of Nile tilapia.
... The shortage in the freshwater availability for aquaculture as secondary to its consumption in agriculture and many other urban activities in multiple nations makes it urgent to develop aquaculture brackish water and seawater (El-Sayed, 2006). In addition to the lack of good freshwater resources in some regions like coastal areas and small islands in the middle of the open seas, the groundwater is salty or brackish (Nogueira et al., 2019). ...
Article
Full-text available
The limit of tolerance to salinity in freshwater fish has become an important environmental factor influencing growth performance. Therefore, this study aimed to explore the impact of different levels of salinity on behavioural responses, growth performance, haematological, oxidative and biochemical stress parameters, in addition to immune parameters of African catfish. Three‐hundred and Sixty juvenile African catfish were randomly distributed into six groups and exposed to different salinity levels (0, 4, 8, 12, 16 and 20 ppt) with three replicate tanks per treatment group; each tank contained 20 individuals for 42 days. Behavioural responses of fish were monitored during the experimental period. Growth performance, haematological, oxidative and biochemical stress parameters, in addition to immune parameters and osmotic pressure, were also determined at the end of the treatment period. Results revealed that the proportion of fish performing abnormal stress behavioural responses increased directly to the salinity level. In contrast, the survival rate and growth performance were decreased with high feed conversion at the higher salinities. Inconsistent, the haematological, oxidative, biochemical, immune and osmotic pressure parameters were altered gradually with the increase in the salinity level. Therefore, salinity level could influence the African catfish's behaviour, survival and growth when they exceed the tolerance limit.
... It can survive in highly polluted habitats (Atli and Canli, 2010) that make it an appropriate model to be used as an indicator species in bio-monitoring programs (Gadagbui et al., 1996). On the other hand, Nile Tilapia displays high growth rates, strong immune system, ease of reproduction and high market demand thus, giving it high commercial value (Eissa et al., 2012;El-Sayed, 2006). ...
Article
Lead (Pb) is a hazardous pollutant for living creatures including fish. This study addressed the possible ameliorating effect of dietary Beta-MOS® on Pb induced reproductive toxicity in Nile tilapia. One hundred eighty fish (35.43 ± 0.36 g, 8 weeks age) of mixed sex were randomly allocated into 4 equal groups (3 replicates/group). The first group was control and the second group, received 0.3% dietary Beta-MOS®. The third group was exposed to 10 mg Pb acetate L⁻¹ in water. The fourth group was exposed to 10 mg Pb acetate L⁻¹ in water and nourished with 0.3% dietary Beta-MOS®. The treatments were continued for 60 days. Body weight, gonado-somatic index (GSI), estradiol (E2), testosterone (T), cortisol, glucose, gonadal Malondialdehyde (MDA) and antioxidant enzymes were measured. Histopathological examination of testes and ovaries was performed. Exposure to Pb caused significant (p < 0.05) reduction in body weight, GSI, estradiol, testosterone, gonadal antioxidant enzymes and elevated cortisol, glucose and gonadal MDA than control. Co-administration of dietary Beta-MOS® with Pb significantly (p < 0.05) ameliorated Pb induced perturbations to the former parameters. The ameliorative effect of Beta-MOS to Pb induced reproductive impairments may be attributed to stress alleviating and antioxidant effects that improved gonadal sex steroids and pathology.
... Remarkably, the beneficial use of WPCP at the level of 20 g kg -1 diet was proved as a promising growth promoter and immune stimulant agent for O. niloticus fingerlings, and may in return, increase fish productivity, health, and profitability in fish farms. growth rates, high conversion ratio, and potential to reproduce in captivity (El- Sayed, 2006). ...
Article
Full-text available
Due to their nutritive value and functionality, whey proteins have been used in many food applications. The efficacy of adding different levels (0, 5, 10 and 20 g kg–1 diet) of whey protein concentrate powder (WPCP) was addressed on the growth performance, feed utilization, and the immune responses of Oreochromis niloticus fingerlings in the current study for 8 weeks. A significant increase was observed in the growth performance (final weight, total weight gain, average daily gain, relative growth rate, and specific growth rate), the feed utilization (feed conversion ratio, protein efficiency ratio, protein productive value, and energy utilization), and the whole-body composition (dry matter, and crude protein) parameters. These levels also significantly improved both the hematological parameters (hemoglobin, red blood cells, packed cell volume, and platelets), and the immune responses indicators (white blood cells, lymphocytes, and serum immunoglobulin M) of the O. niloticus fingerlings. Partially, in all tested parameters, the addition of the high-level 20g WPCP kg–1 diet showed a remarkable superiority among other levels. Remarkably, the beneficial use of WPCP at the level of 20 g kg–1 diet was proved as a promising growth promoter and immune stimulant agent for O. niloticus fingerlings, and may in return, increase fish productivity, health, and profitability in fish farms.
Article
Full-text available
Aquaculture is a key component of food security and central to sustainable development goals. However, the sustainability of the aquaculture industry depends on various aspects, for example, excellent breeding, effective policies, good ecology, and regulations. Besides, the integration of new technologies and extension services and collaboration among different stakeholders are important aspects for sustaining aquaculture production. Despite the exceptional result of aquaculture production in Benin in recent years through the quick development of new technologies and their extension, the country’s aquaculture production covers only 35% of demands. Therefore, aquaculture is an effective way to increase food supplies and promote economic and social development. High priority in Benin has been given to aquaculture in the national fisheries and aquaculture development plan in the context of rural development. This includes the promotion of aquaculture skills and new technologies and their extension, improvement of related regulations and laws, optimization of its structure, remediation and protection of the environment, and improvement of markets. Achieving this is very possible, as Benin is believed to be in a good position to contribute to the world’s aquaculture production to a positive and sustainable way in the future.
Article
Protein-sparing by lipid helps in conserving protein exclusively for growth with minimal inevitable protein breakage. It will subsequently reduce feed cost and nitrogenous pollutants in the habitat. In this context, an experiment of 60 days period was conducted to study the protein-sparing effect of lipid in the diet of Genetically Improved Farmed Tilapia (GIFT) (Oreochromis niloticus L) fingerlings reared in inland ground saline water (IGSW) at 10 g L⁻¹ salinity. The experiment followed 4 × 2 factorial design with eight purified diets of four crude protein (CP) levels (30%, 35%, 40% and 45%), each with two lipid levels (6% and 10%). GIFT fingerlings of uniform size (3.00 ± 0.01 g) were acclimatized and distributed into eight treatment groups in triplicates corresponding to each of the prepared diets and fed to satiation three times daily. The results showed significantly (p < 0.05) higher percent weight gain (WG, 693.26%), apparent net protein utilization (ANPU, 34.03), protein efficiency ratio (PER, 2.35) and improved digestive enzymes (protease, amylase, lipase) activity with lower feed conversion ratio (FCR) for diets containing 35–45% CP and 10% lipid. According to two-way ANOVA, high dietary lipid (10%) resulted highest WG% (678.95), PER (2.02), ANPU (30.67) and lowest FCR (1.31) values. Increased whole body CP (15.54%) and lipid (7.61%) contents were observed in the fish fed high lipid (10%) diets. The viscerosomatic and hepatosomatic index also increased with increasing dietary lipid. The dietary CP levels have not significantly affected the body composition except total ash content. The highest insulin like growth factor-I (IGF-I) gene expression was observed in the liver of fish fed 35% CP with 10% lipid. Results revealed that increasing dietary lipid exhibited enhanced protein-sparing effect in GIFT fingerlings. Thus, the study concludes that a diet containing 35% CP and 10% lipid is optimal for GIFT fingerlings reared in IGSW of 10 g L⁻¹ salinity.
Article
The use of yeasts as a dietary additive for fish can act as a source of nutrients and as an immunostimulant. This work aimed to evaluate the effects of the fermented biomass of the yeast Yarrowia lipolytica as a food additive on zootechnical and hematological parameters, and on immune response in the plasma and kidney of Nile Tilapia (Oreochromis niloticus). After supplementation with 3, 5, and 7% of the yeast biomass for 35 days, the blood and tissues of the animals of each experimental group were collected for analysis. The addition of this biomass in the feed promoted an improvement of zootechnical parameters in tilapia. There was also a rise in the number of neutrophils (groups with 3, 5, and 7%) and monocytes (group 3, 5, and 7%) compared with the control group. Moreover, there was an increase in the levels of lysozyme, myeloperoxidase, and nitrite/nitrate content in the blood of animals fed with yeast biomass. On the other hand, there were no observed alterations in survival and hematological parameters of animals fed with yeast biomass. In the analysis of the kidney, the addition of biomass in feed promoted an increase in levels of myeloperoxidase (group with 3%) but did not alter the levels of lysozyme and nitrite/nitrate content. In conclusion, this study demonstrated that Y. lipolytica had growth and immunostimulatory effects on Nile tilapia. These findings strongly suggest the potential application of a Y. lipolytica-based immunostimulant for tilapia aquaculture.
Article
Full-text available
The study aimed to evaluate the fatty acid and proximate composition of diets for Nile tilapia containing soybean meal (SBM), canola meal (CM) and sunflower meal (SFM) as replacements of fishmeal (FM). A control diet (D1) of 30% crude protein (CP) was formulated using fishmeal as main protein source. The test diets (D2, D3 and D4) were formulated by replacing 10% CP of FM by SBM, CM and SFM, respectively. The fatty acid profile of ingredients and diets were determined by MPA FT-NIR spectrometer. FM displayed higher CP content (62.60%) followed by SBM (47.38%), CM (34.39%) and SFM (24.81%). SFM had highest crude fibre content (p<0.05) while CM displayed higher figure for ether extracts (p<0.05). Substituting FM with SBM, CM and SFM increased the levels of crude fibre (p<0.05). Diet 4 recorded highest crude fibre (16.03%) content (p<0.05), while CM based diet recorded highest ether extract content (10.75%), (p<0.05). Diet 1 had lowest concentration (21.85mg/100g) of total saturated fatty acid and D2 lowest concentration of polyunsaturated fatty acid (29.90mg/100g). The study revealed that 10% CP substitution of FM with SBM, CM and SFM in Nile tilapia diets is possible without much negative change in diets proximate and fatty acid composition.
Article
Full-text available
Trials were conducted to establish commercial-scale production of all stages of Oreochromis spilurus. Fry were produced in a tank using recycled fresh water. Fingerlings were grown in full strength sea water either in cages in the open sea or in onshore tanks filled with water from the sea. Very promising results were obtained in terms of fish growth, survival and product quality, opening up significant new opportunities for the expansion of tilapia culture in tropical and sub-tropical seas.
Article
Full-text available
Tilapia culture is currently practised in 95 countries all over the world and the number is expected to increase. This book discusses in detail the principles and practices of tilapia culture in the world. It covers all the vital issues of farmed tilapia including: the biology, environmental requirements, semi-intensive culture, intensive culture systems, feed and feeding, reproduction and breeding, spawning and larval rearing, stress and diseases, harvesting and marketing and the role of tilapia culture in rural development. It also highlights and presents the experiences of leading countries in tilapia culture.
Article
The ontogeny of salinity tolerance was studied in the tilapias Oreochromis aureus, O. niloticus, and an O. mossambicus (♀) × O. niloticus (♂) (M × N) hybrid, spawned and reared in freshwater. Several indices were used as practical measures of salinity tolerance: (1) Median Lethal Salinity — 96 h (MLS-96), defined as the salinity at which survival falls to 50%, 96 h following direct transfer from freshwater to various salinities; (2) Mean Survival Time (MST), defined as the mean survival time over a 96 h period, following direct transfer from freshwater to full seawater (32‰); and (3) Median Survival Time (ST50), defined as the time at which survival falls to 50% following direct transfer from freshwater to full seawater.No significant age-specific differences in salinity tolerance were observed in either O. aureus or O. niloticus on the basis of the MLS-96 index. Mean MLS-96 values over all ages from 7 to 120 days post-hatching were 18.9‰ for O. niloticus, and 19.2‰ for O. aureus. In contrast, the M × N hybrid exhibited relatively greater changes in salinity tolerance with age, MLS-96 ranging from 17.2‰ at 30 days post-hatching to 26.7‰ at 60 days post-hatching. Distinct age-specific differences in salinity tolerance were observed in all three on the basis of the MTS and ST50 indices.These ontogenetic changes in salinity tolerance were determined to be more closely related to body size than to chronological age. No consistent relationship was observed between salinity tolerance and condition factor. The practical implications of these findings for the saltwater culture of tilapias are discussed.
We have examined several physiological variables related to salinity acclimation in the euryhaline tilapia, Oreochromis mossambicus. Tilapia reared in fresh water (FW) were transferred to FW, isosmotic salinity (ISO, 12‰) and 75% seawater (SW, 25‰). Oxygen consumption, plasma levels of cortisol, growth hormone (GH), prolactins (tPRL177 and tPRL188), glucose, ions (Na+, K+, Cl−), and gill Na+,K+-ATPase activities were measured for up to 4 days in each salinity treatment. Plasma Na+ and Cl− concentrations were elevated 1 day after transfer to SW, but returned to FW values on day 4. Plasma cortisol and glucose levels were higher in FW and ISO than in SW 1 day after transfer. Plasma GH levels of tilapia in SW increased above FW and ISO values after 4 days, whereas plasma PRL levels decreased in ISO and SW compared to FW at 4 days. These results are consistent with the possible osmoregulation roles of GH and PRL in SW and FW, respectively. Gill Na+,K+-ATPase activity of tilapia in SW increased more than 2-fold over the FW value after 4 days, but activity of this enzyme did not change in ISO. Oxygen consumption rates of tilapia in SW were significantly elevated 4 days after transfer compared to FW and ISO. The results of this study indicate that the physiological changes associated with SW acclimation in tilapia represents a significant short-term energetic cost, and may account for as much as 20% of total body metabolism after 4 days in SW.
Article
A test to determine the stocking density for optimum production of tilapia (Oreochromis spilurus Gu¨nther) in sea cages was conducted in nine 2.5×2.5×2.0 m net cages installed at Kuwait Bay. Fingerlings acclimated to 33 ppt salinity were stocked at 200, 250 and 300 fish m−3. The fish were fed daily with seabream sinking pellets at the rate of 6.0% decreasing to 2.5% of the fish biomass as the fish grew bigger.After 193 culture days, no significant differences (P > 0.05) in the mean individual weight and total yield were observed among the three stocking densities. Feed conversion ratio increased significantly (P < 0.002) and survival rate decreased significantly (P < 0.006) with an increase in stocking density. Males were significantly heavier (P < 0.001) than females, regardless of stocking density. The condition factor of small fish (< 250 g) was significantly lower (P < 0.01) than that of big fish (> 250 g). The findings indicate that the stocking density for optimum tilapia production in sea cages at the experimental site is 200 fish m−3.
Article
Red hybrid tilapia (Oreochromis mossambicus × 0. niloticus) fingerlings were fed purified diets supplemented with pyridoxine hydrochloride at levels of 0, 3, 6, 12, 24, and 48 mg/kg diet for 10 weeks. Fish fed the diet without pyridoxine supplementation developed abnormal neurological signs, anorexia and convulsions followed by muscle spasms and lethargy after 9 days. These conditions progressed rapidly, and heavy mortality occurred at the end of week 2. Severe caudal fin erosion and mouth lesions were observed during the 3rd week. None of these symptoms were seen in fish fed pyridoxine-supplemented diets. At the end of 14 days, fish fed the pyridoxine-deficient diet had the lowest weight gain and poorest feed conversion (P < 0.01). Hematocrit values measured at the end of weeks 2, 6, and 10 were also consistently lower for fish on this treatment. Fish fed pyridoxine-supplemented diets for 10 weeks did not differ with regard to weight gain, feed conversion, and hematocrit. Histological study of various tissues revealed no apparent abnormalities in any of the treatment groups. It was concluded that 3 mg of pyridoxine/kg diet was sufficient for maximum growth, feed efficiency and survival, and prevention of various deficiency signs in red hybrid tilapia fingerlings grown in sea water.
Article
An experiment was conducted to investigate growth, survival and feed conversion of Florida red tilapia reared in floating cages in seawater under different feeding regimens. Twenty-four cages (1 m3) were anchored in a sea pass on Great Exuma, Bahamas, and each was stocked with 300 juvenile, monosex males (10 g mean weight). Growth was monitored every 14 days for 84 days. Fish were fed daily a floating pelletized diet (32% protein) at 4 programed rates representing 50, 70, 90, and 110% of the estimated satiation rate, ad libitum, and by demand feeders, with each treatment comprised of 4 replicate cages. Final mean weight was significantly lower for the 50% treatment (94.1 g) than for all other treatments (range = 121.8–155.7 g). Final mean biomass per cage ranged from 24.2 to 39.4 kg/m3, and survival ranged from 98.2 to 99.8%. Mean specific growth rate was significantly lower under the 50% programed feeding treatment (2.42%/day) than for all other treatments (range = 3.15–3.56%/day) while feed conversion ratios (dry weight/wet weight) were significantly lower under the 50% (1.57) and 70% (1.68) programed feeding treatments than under all other treatments (range = 1.98–2.26). Thus, maximum growth was achieved at feeding rates near satiation while feed conversion was improved at lower feeding rates. Under demand feeding, growth and feed conversion were not significantly different than those of the ad libitum, 100%, and 90% treatments.