STRESS PHYSIOLOGY OF ECHINODERMS IN AQUACULTURE

Invertebrates, such as sea urchins and sea cucumbers, have been widely consumed throughout Asia for centuries and are of growing importance as a resource in the United States. They are both a source of high quality protein and of valuable pharmaceuticals. Sea cucumbers, especially, have been found to have a variety of anticancer and regenerative properties, as well as many other valuable medical and pharmaceutical attributes. Sea urchins have long been used as a research model and as a food source. Due to these various factors, the natural population has become the of a growing fishery system. However, as is commonly found in fisheries when the demand increases, the natural population becomes overexploited, and eventually, the population collapses. As the sea cucumber has recently become of great importance as an export from the United States to various countries, it is essential that measures be taken to prevent overexploitation, while at the same time growing and maintaining the market. In order to prevent overexploitation and to grow and maintain the market, it is expedient to establish aquaculture facilities that can successfully raise these invertebrates for both research and consumption. One of the ways of doing this is to establish inland intensive aquaculture facilities that avoid the problems associated with raising animals on the coast, particularly loss to predation. Though intensive aquaculture provides the clear benefits of preventing overexploitation of the natural population and producing large amounts of product, animals raised in this way are vulnerable to a variety of stressors. These sources of stress include crowding, handling, and fluctuations in salinity and temperature. If an animal is stressed, its immune function decreases, and its vulnerability to diseases increases. Since there is currently no effective treatment to disease in echinoderms, the authors examined the impacts of handling and salinity fluctuations on the physiological and immunological responses of sea urchins and sea cucumbers. The sea urchins were much more susceptible to stress and decrease immune functions due to lowered salinity and handling than the sea cucumbers were. Although sea cucumbers did show negative effects, none of them was significant.