The relationship between the effective concentration (CE) of the anaesthetic MS-222 and body mass was examined at 20°C in porgy ranging in size from 0.00022 g (just after hatching) to 320 g (595 days old). CE was defined as the concentration which required 3-5 min to induce deep anaesthesia in the fish. Values of CE (ppm) increased monophasically with increasing body mass (W in g), following the equation CE = 79 W0.0549 (N = 30, r = 0.936 between log CE and log W). The recovery ratio (RR in %), i.e., the number of fish as a percentage which recovered after being placed back in ordinary seawater, varied depending on the developmental stage. RR was lowest in fish of around 0.01 g (30 days old), corresponding to the transitional stage between the post-larval and juvenile stage, whereas it was highest (nearly 100%) in the pro-larval stage (about 0.00023 g in size and 0-6 days of age).
All Science Journal Classification (ASJC) codes
- Aquatic Science