1.1  
Background
of the study

   Aquaculture has emerged as one of the most
promising and fast-growing food- producing sector, which provides high-quality
animal protein, raises nutritional levels, and generates income and employment
around the globe (FAO, 2010).According to recent data, world aquaculture
production of food fish reached 62.7 million tonnes in 2011, up by 6.2% from 59
million tonnes in 2010. The estimated value of farmed fish food is US$ 130
billion. Aquaculture contributed 40.1% to the world total fish production (FAO,
2013). Importance of aquaculture is increasing dramatically because of
overfishing of the world's waters and exponential increase in demand for
seafood. Sustained and enhanced productivity are the need of the hour in
aquaculture. Various measures including different techniques such as intensive
aquaculture, spatial and temporal expansion of aquaculture activities,
introduction of new species for aquaculture, and improved health management
strategies are some of the important reasons for the current steep rise in
aquaculture productivity (Panigrahi and Azad, 2007). Nigerians are large
consumers of fish and its remains one of the main products consumed in terms of
animal protein. It is cheap and highly acceptable, with little or no religion
bias,which gives it an advantage over pork or beef (Eyo, 2001). Only about 50%
of the demand for fish is currently been met by local supply.