Changes in Metabolites of African Catfish (Clarias Gariepinus) Exposed to Different Salinity Levels

Abstract

Salinity refers to the degree of saltiness of a water body. It has been described as one of the important factors exerting selective effectson aquatic organisms. Salinity is defined as a measure of the amount of dissolved salts in the water [1]. Salinity is the correct chemical term for the sum concentration of all ionic constituents dissolved in inland waters, both fresh and saline. Habitat salinity represents a major abiotic factor that governs the activity and distribution of fishes and other aquatic animals. Furthermore, aquatic animals can either be stenohaline or euryhaline, which shows the level of osmotic tolerance of the organism. Stenohaline species such as the African catfish, can only withstand little ranges of salinity. While euryhaline species like the sea bass and some tilapias are able to tolerate a wide range of salinity, which enables them to move between freshwater and salt water and it is leading to many diverse adaptation strategies for different species to survive in different osmotic pressure regimes [2]. Because the autonomous osmoregulation in aquatic organisms is an energy demanding process, certain prevailing salinities might help to optimize growth or reproduction by decreasing osmoregulatory energy expenditure [3].The metabolic cost would be expected to be minimized during culture of fish in isotonic conditions, thus it can minimize the cannibalistic behavior of fishes, and indirectly improve the survival and growth performance of the African catfish [4].