Shortage of freshwater is a global issue and changing climatic condition or global warming has made water supply unpredictable in many parts of the world. Therefore, there is a vital need for exploring the productivity of inland saline groundwater and suitability of organisms to be farmed in such waters.
The utility of saline water for agriculture has long been experimented but cost effective and practical solutions are rare. On the other hand, marine environment provides for viable production systems and is being cropped with marine animals and plants all over the world, which is known as mariculture. Besides mariculture, the aquaculture of marine animals and plants in saline groundwater in inland areas is relatively a new type of aquaculture (known as inland saline aquaculture) and has progressed in many parts of the world.
Inland saline groundwater is being successfully used to grow marine fishes, shrimps etc and many other organisms. The production of high value marine fish and vannamei shrimp in inland saline well water is a growing industry in several countries. In the US, inland saline aquifer is being used to grow marine species like Whiteleg shrimp and tiger shrimp on a commercial scale.
The inland saline aquaculture has tremendous potential for income generation and diversification; and offers an opportunity for a potentially productive use of salt-affected land.
The inland saline aquaculture has tremendous potential for income generation and offers an opportunity for the productive use of salt-affected land
In Pakistan, inland groundwater reserves over a large area of the country are saline and the saline land in the irrigation command area exceeds 11.1m acres. About 40,000 hectares are abandoned within the Indus Basin annually due to secondary salinisation. There are large numbers of saline groundwater pockets in the canal command areas. In Punjab, 23pc of the area has poor groundwater quality, while in Sindh, 78pc of the ground water is saline as the area of fresh groundwater is confined only to a narrow strip along the river Indus. Furthermore, about 56pc of the total irrigated land in Sindh is affected by salinity.
The number of people directly affected by saline, sodic and/or waterlogged soils was estimated to be about 16m in 1998 which is expected to double by the year 2020. There are many inland saline lakes. The surface water supplies are not enough to meet the actual crop water requirements which has affected farm productivity with more severity in the lower Punjab, Sindh and southwestern parts of Balochistan.
Land salinisation is a great threat to the agriculture sector. In this situation, the farmers need to be educated about making economic use of saline land and water, and that is possible by adopting inland saline aquaculture. Fishponds in saline lands may also serve as sacrificial basins (or salinity sink) for adjacent lands to recover from salinity, as already being practiced in saline and waterlogged areas in many places. This can revitalise the rural farming and help in employment generation in areas under extreme poverty.
With the salinisation of coastal lands due to increasing sea intrusion, which, according to some estimates has claimed more than 2.2m acres of fertile land, farmers, relying upon the traditional agriculture, have also shifted to fishing. The ever-increasing fishing activity combined with unsustainable fishing practices has resulted in devastation of the natural fisheries resources that are at the brink of collapse. The potential of the country’s fisheries sector once estimated to be $1bn is stagnant at $200-300m.
There is a need to establish a sound research base before gearing up for further development. Only meaningful research will lead to identify potential of inland saline areas for aquaculture of certain marine fish and shellfish species, based on the ionic composition of groundwater, which has great influence on the physiology of cultured animals, and thus their growth and survival. The successful research will lead to opening up of new vistas for small-scale aquaculture development in salinity-hit inland.
The research areas for the proper development of inland saline aquaculture may include but are not limited to identification of appropriate saline land tracts that are suitable for marine fish and shellfish culture, through water sampling and water quality analysis to identify certain limiting nutrients such as potassium and magnesium in the saline groundwater. Ascertain suitable marine fish and shellfish species for culture in identified inland saline areas through experimentation
In this era of multidisciplinary and integrated development, the traditional approach of solitary and single subject research needs to be abandoned. Besides water quality analysis, the inland saline groundwater areas need to be explored, mapped and monitored with scientific approaches and technologies such as Geographic Information System (GIS) and Remote Sensing, Develop spatial models for small-scale sustainable Inlandsaline aquaculture projects.
To ensure that the results of this research reach the common man, the outcomes ought to be presented through interactive GIS maps to be available online for selection of lands for farming and for further research, development and policymaking.
The writer is an aquaculture expert, currently doing his research in inland saline aquaculture at Auburn University, Alabama, US
Published in Dawn, Economic & Business, July 14th, 2014