potential to increase rates of change further (Simm et al., 2004). In recent years there has been a growing trend in developed countries for breeding programs to focus more on product quality or other attributes, rather than yield alone. There is also growing interest in breeding goals that meet wider public needs, such as increasing animal welfare or reducing environmental impact.

Gains in productivity have been variable if breeds are not matched to the environment

The gains in productivity per animal have been greatest in developed countries, and in the more "industrialized" production systems in some developing or "transition" countries. The enormous opportunities to increase productivity through wider adoption of appropriate techniques and breeding goals in developing countries are not always achieved. Breed substitution and crossing have both given rapid improvements, but it is essential that new breeds or crosses are appropriate for the environment and resources available over the entire production life cycle. Failure to do this has resulted in herds that have succumbed to diseases or to nutritional deprivation to which local breeds were tolerant, e.g., the introduction of high performing European dairy breeds into the tropics that had lower survival than pure Zebu animals and their crosses. The reproductive rate of the pure European breeds is often too low to maintain herd sizes (de Vaccaro, 1990). It is also important that valuable indigenous Farm Animal Genetic Resources are protected.

Large scale livestock production can lead to environmental problems..

Recently, livestock production has increased rapidly, particularly in developing countries where most of the increased production comes from industrial farms clustered around major urban centers (FAO, 2005c). Such large concentration of animals and animal wastes close to dense human population often causes considerable pollution problems with possible negative effects on human health. Large industrial farms produce more waste than can be recycled as fertilizer and absorbed on nearby land. When intensive livestock operations are crowded together, pollution can threaten the quality of the soil, water, air, biodiversity, and ultimately public health (FAO, 2005c). In less intensive mixed farming systems, animal wastes are recycled as fertilizer by farmers who have direct knowledge and control of their value and environmental impact. However in industrial production, there is a longer cycle in which large quantities of wastes accumulate.

Livestock production is a major contributor of emissions of polluting gases.

Livestock production is a major contributor of emissions of polluting gases, including nitrous oxide, a greenhouse gas whose warming potential is 296 times that of carbon dioxide. Livestock contributes 18% of the total global warming effect, larger even than the transportation worldwide (Steinfeld et al., 2006). The share of livestock production in human-induced emissions of gases is 37% of total methane, 65% of nitrous oxide, 9% of total carbon dioxide emissions and 68% of ammonia emissions (Steinfeld et al., 2006). This atmospheric pollution is in addition to the water pollution caused by large-scale industrial livestock systems.

Aquaculture has made an important contribution to poverty alleviation and food security in many developing countries.

TAquaculture, including culture-based fisheries, has been the world's fastest growing food-producing sector for nearly 20 years (FAO, 2002c; Delgado et al., 2003a; Bene and Heck, 2005a; World Bank, 2007b). In 1999, 42.8 million tonnes of aquatic products (including plants) valued at US$53.5 billion were produced, and more than 300 species of aquatic organisms are today farmed globally. Approximately 90% of the total aquaculture production is produced in developing countries, with a high proportion of this produced by small-scale producers, particularly in low income food deficit countries (Zeller et al., 2007). While exportoriented, industrial and commercial aquaculture practices bring in needed foreign exchange, revenue and employment, more extensive and integrated forms of aquaculture make a significant grassroots contribution to improving livelihoods among the poorer sectors of society and also promote efficient resource use and environmental conservation (FAO, 2002c). The potential of aquaculture has not yet been fully realized in all countries (Bene and Heck, 2005ab; World Bank, 2007b).

Globally, per capita fish consumption increased by 43% from 11 kg to 16kg between 1970 and 2000..

In developing countries, fish have played an important role in doubling animal protein consumption per capita over the last 30 years-from 6.3 to 13.8 kg between 1970 and 2000. In the developed world, fish consumption increased by less than one-half during the same period. Urbanization, income and population growth are the most significant factors increasing fish consumption in developing countries, particularly in Asia (Dey et al., 2004).

The recent increase in aquaculture production is primarily due to advances in induced breeding or artificial propagation techniques (hypophysation).

Induced breeding and hypophysation have particularly occurred in the carp polycultures and in freshwater fish farming in rice fields, seasonal ditches, canals and perennial ponds.