Management and Prevention of Stress in Aquaculture with a Focus on Farmed Shrimp
Over the last twenty years commercial aquaculture has experienced spectacular growth. A significant component of the fish and shrimp based protein that humans consume, especially in first world countries, is now provided by these activities. Many species have gone from small-scale regional production to large-scale global production. Concomitant with this rapid growth there also has been the increased occurrence of problems that accompany all agricultural endeavors. Disease has substantially impacted the profitability of many of these industries and has been instrumental in shaping the evolution of the aquaculture industry. Shrimp farming has failed to realize its potential as a direct result of disease.
Monoculture, or the rearing of a single species at a time, has few of the ecological safeguards present found in more complex natural ecosystems. It is much easier for diseases to proliferate in these environments than in the wild, where the diversity of the ecosystem provides safeguards against species threatening diseases. Stress plays a very important role in susceptibility to disease and the outcome of the disease process. Stress has been defined in many different ways, though the basic components are universally the same. The definition of Bayne (1), based on his work in mollusks, exemplifies an appropriate definition of stress for aquaculture.