A Second Look at Mozambique Tilapia
The Mozambique Tilapia(Oreochromis mossamicus) was the first tilapia species from Thailand introduced in the Philippines in 1950. Then regarded as the “wonderfish” for its prolific breeding habit and hardiness, it was widely promoted for backyard freshwater pond culture as a food fish.
The tilapia craze, however, waned in the 1960s due to the poor yields of the fish attributed to its early maturation and uncontrolled reproduction. Becoming mature and capable of breeding at an early age of only 2-3 months and with the capacity to breed as frequent as once a month in ponds, the growth of the fish was stunted with overpopulation.
While freshwater pond culture of the Mozambique tilapia was problematic (without population control), the fish got established in brackishwater waterways and ponds to which it had escaped and became an “invasive non-native species.” Being euryhaline (thriving in fresh and salty waters), it easily adapted itself in the brackishwater environment.
Even during the boom in freshwater tilapia farming with the Nile tilapia (Oreochromis niloticus) in the 1980s, the Mozambique tilapia already contributed significantly to the country’s food basket. In 1989, the production of the fish from brackishwater ponds was recorded at 23,080 metric tons. However in 2006, its production was down to only less than 10,000 metric tons.
Is there hope for the comeback of the Mozambique tilapia?
The answer is yes, according to Prof. Valeriano Corre Jr., director of the University of the Philippines in the Visayas’ (UPV) Brackishwater Aquaculture Center in Leganes, Iloilo. He has worked with the Mozambique tilapia since the mid-’70s and is still much into it today.
“The Mozambique tilapia is the second most important cultured fish in its culture, it is contributing a lot in preventing the luminous bacteria disease of cultured shrimp and should be further utilized to fill the gap in the production of our ponds.”
In the brackishwater fishfarm of the Oversea Feeds Corp. (OFC) in Carcar, Cebu with which Prof. Corre is consulting, 300,000-500,000 sex-reversed fingerlings of Mozambique tilapia are produced monthly for its own use and for selling to other growers.
The OFC farm has about 10,000 tilapia breeders in its hatchery. The fish, weighing 50-150 grams each, are stocked in net enclosure installed in brackishwater ponds with a salinity of 10-15 parts per thousand and sex ratio of 3-4 females to 1 male. Sex reversal treatment of the fry is done for a period of three weeks to produce all-male fingerlings that grow faster than the mixed-sex fish and do not reproduce in ponds. The sexreversed fingerlings, now much in demand, are sold at P0.50-P 1 each.
With feeding at stocking rates of 10,000-20,000 per hectare in brackishwater ponds with water depths of 0.5-1 meter, sex-reversed Mozambique fingerlings can grow to market sizes of 150-200 grams in 3-4 months with a survival rate of 80 percent or more, Prof. Corre avers. The fish sell at P70-80 per kilo (retail) in wet markets. It is more desired by consumers than its freshwater counterpart, the Nile tilapia, because of its delectable meat quality.
For the culture of the Mozambique tilapia in “green water” used for preventing the outbreak of bacteriosis in shrimp ponds, a biomass of at least 2.5 tons per hectare of the fish is needed.
The fish can either be grown in separate ponds or in cages within the shrimp ponds. Certain algal species such as Chlorella in green water are believed to have an antibiotic effect on the disease-causing organisms.
Aside from its monoculture in ponds, the Mozambique tilapia can also be used in polyculture systems with other cultured species such as the milkfish, grouper, and seabass. With milkfish, the stocking rate of sex-reversed tilapia should only be 500-1,000 per hectare along with 1,000-2,000 per hectare of milkfish in fertilized lablab ponds. With grouper or seabass at 1,000-2,000 per hectare, mixed-sex juvenile or mature tilapia at 10,000-20,000 per hectare are stocked at least a month ahead of the carnivorous fish to provide them with “live feed.”
For more information on the improved techniques for the breeding and culture of the Mozambique tilapia in brackishwater ponds, interested readers may contact Prof. Corre at the UPV College of Fisheries and Ocean Sciences’ Institute of Aquaculture at Miag-ao, Iloilo (tel. (+6333) 524-0252).
