Improving freshwater fish farming
Higher-yielding tilapia has bought more food and increased trade.
Many communities across the developing world depend on fishing and farming fish for their livelihoods. Fish are a healthy source of protein and require less energy to cultivate than livestock such as cattle.
But yields can be low and are naturally variable as well as vulnerable to pollution and other local events, particularly in fresh water habitats where toxins can be more concentrated. As a result, many rural fishing communities do not make a significant trading surplus, and remain poor because production is little higher than the subsistence level.
Demand for farmed fish, such as these freshly harvested GIFT tilapia, is increasing. Image: WorldFish
As world population increases, it is estimated that demand for fish and fish products will increase to 130.1M tonnes by 2020, up from 93.2M tonnes in 1997 and fish farming (aquaculture) is expected to contribute 41% to the total production, up from 31% in 1997 (ref 1).
Genetic improvement programs have made significant contributions increase to productivity and industrial viability in terrestrial agricultural species – wheat breeding programmes have, for example, yielded financial returns greater than US$50 for every dollar invested.
But most aquaculture fish stocks in developing countries are genetically similar or inferior to their wild, undomesticated counterparts and since the late 1980s efforts have been made to increase the productivity of freshwater fish cultivation (ref 2). The UK’s Department for International Development (DfID) has since joined an international partnership that has used conventional breeding techniques to improve tilapia, a fish native to Africa, into an affordable and marketable protein source for millions of people in 13 countries across Asia (ref 3).
Tilapia, sometimes called the ‘aquatic chicken’, was introduced into Asia in the 1950s but problems such as inbreeding and poor growth rates in the Mozambique tilapia, Oreochromis mossambicus, limited its success to small scale fish farmers (ref 3).
From 1988-97, the genetically improved farmed tilapia (GIFT) programme then set about using traditional breeding techniques to shorten harvest cycles and increase growth rates without affecting survival in the Nile talapia, Oreochromis niloticus. Nile tilapia is now widely cultured in nearly 100 countries because it is easy to breed, hardy, tolerates a range of water quality attributes, such as salinity and temperature, and has versatile food habits. It can be farmed without providing commercial feed, but does better in a good production environment including commercial feed (ref 3, ref 4).
Dr Raul Ponzoni, Principal Scientist and Project Leader of Aquaculture and Genetic Improvement at The WorldFish Center, which manages the research and has received core funding from DfID, says that genetic improvement is one of the most powerful technologies available to make aquaculture viable. “Everyone that learns about the GIFT strain is impressed and those involved in aquaculture want the strain,” he says, adding that those that do get the strain are impressed by its performance and farmers are satisfied too.
Between 1990 and 2007 in the Philippines for example, tilapia production expanded by 186% while production costs fell by a third; four cages harvested twice a year there can net US$3,120 a year. In Thailand, these fish are now a major source of protein for the poor and cost half as much as other popular freshwater species such as catfish (ref 3).
A girl in Bangladesh holding a GIFT tilapia. Image: WorldFish
It is estimated that more than 20 million Filipinos have benefited from the enhanced production characteristics of the improved tilapia. One study has measured a 64% increase in fish weight (equivalent to 44.2g per fish) in the nine generations since the base population was established (ref 4), and other studies have measured higher yield increases.
In economic terms, in an industry structure where a ‘best population’ (nucleus) provides brood stock to hatcheries, which in turn produce fry for farmers to grow out to market size, the yield increases equate to economic benefits estimated at between $4M and $32M over a ten-year period (ref 2).
Plenty more fish in the farm
The GIFT programme has thus become a template for other aquaculture breeding programmes, such as for common carp, Cyprinus carpio, in Vietnam where even greater yield and economic benefits are forecast of $11M to $226M US dollars (ref 5).
GIFT tilapia. Image: WorldFish
“Selective breeding is being applied with success to local tilapia in Ghana and in Malawi. It has also been successfully applied to carp in several Asian countries, such as India and Vietnam,” says Ponzoni, who adds that they are in the early stages of development of selective breeding with freshwater prawn.”
As well as providing funding for The WorldFish Center, DfID also contributed funding to upgrade facilities at the Department of Fisheries research station in Jitra, Malaysia, where the nucleus of the GIFT strain now resides. DfID has also funded specific research projects, such as the production of all‐male tilapia and the estimation of genetic change in the GIFT population (ref 3).
- From drawing board to dining table: the success story of the GIFT project
- Investment appraisal of genetic improvement programs in Nile tilapia (Oreochromis niloticus)
- Making a GIFT selection: improved tilapia in the Philippines (PDF)
- Estimation of genetic change in the GIFT strain of Nile tilapia (Oreochromis niloticus) by comparing contemporary progeny produced by males born in 1991 or in 2003
- Accounting for genotype by environment interaction in economic appraisal of genetic improvement programs in common carp Cyprinus carpio