Effects of sudden changes in salinity on the oxygen consumption of the glass eels, Anguilla japonica
김완수; 윤성진; 이태원
During upstream migration, glass eels experience physiological stress due to salinity changes. In this study, glass eels Anguilla japonica were exposed to different salinity regimes (from 27 psu down 10 psu, 5 psu, fresh water), and the endogenous rhythm in oxygen consumption was studied using an automatic intermittent-flow respirometer (AIFR). When exposed to salinities reduced from 27 psu to 10 psu and 5 psu under constant temperature and darknees, their oxygen consumption rate did not changed significantly. However, when exposed to salinities reduced from 27 psu to fresh water, their oxygen consumption rate was depressed for about 12 to 48 h and then recovered to a normal level. The results indicate that the glass eels can withstand sudden drops in salinity from 27 psu to fresh water, and yet maintain a regular though somewhat dampened endogenous rhythm inoxygen consumption. The possible mechanisms underlying these salinity responses are discussed, highlighting the implications of the findings for the eco-physiology and metabolic activity rhythms of glass eels.