Two Tropical Marine Copepods Demonstrate Physiological Properties Needed for Mass Production

Two live feed relevant copepods for larval fish and shrimps, Pseudodiaptomus annandalei and Apocyclops royi, were predominant year-round in a tropical brackish fishpond system. The ponds environment is harsh concerning physicochemical properties; temperature 20–32 °C, salinity 15–23 besides abrupt salinity drops 15–9, frequent severe hypoxia, and poor nutritional seston quality. In 50 studies investigating several physiological endpoints, P. annandalei performs optimally within 18–32 °C and salinity 10–30 and A. royi within 24–32 °C and salinity 10–32. Most extreme, A. royi is reported in situ at salinity 50 and in the laboratory; it can adjust from salinity 20 to freshwater within just two generations when fed on Baker’s yeast. Both species and in particular A. royi have developed an outstanding capability to convert ingested seston with poor fatty acid composition into the necessary long-chained polyunsaturated fatty acids (PUFAs) characterizing their tissues. Hence, they self-enrich their bodies’ fatty acid profiles. Their physiological plasticity is likely a prerequisite for existing extensive mass production in the harsh pond environment. Moreover, A. royi exhibit additional traits, that is, high density tolerance qualifying also for intensive mass production suggesting it as the most promising live feed of the two species for fish and shrimp hatcheries.