Abstract:
A simulation experiment was conducted in the flume tank to investigate fish stress and physiological condition during swimming in active sampling methods through electrocardiograph (ECG) monitoring. Jack mackerel, Trachurus japonicus of 18.68±0.90 cm fork length (average ± S.D., n = 90) was forced to swim in the flume tank with the swimming speed levels of 1.09-9.12 FL/s at 10, 15 and 22°C respectively. The heart rate was measured by impleting a pair of electrode at pericardial cavity region of fish, which was conected to digital oscilloscope via an bio-amplifier. The highest stress level was occurred at vicinity of the maximum sustained and prolonged swimming speed. This indicated that the heart rate was increasing steadily to reach 3.60 times greater than control value for 10°C, 4.03 for 15°C, and 4.20 for 22°C. The recovery time for post-exercise was monitored to be the longest (up to 543 min) at these swimming speed levels. The physiological conditions of jack mackerels are discussed in relation to the cardiac activities during active sampling gear process.
