Abstract:
Ninety jack mackerels (18.68±0.90 cm, Fork Length (FL) (average ± S.D., n = 90) and twenty nile tilapias (14,80±1,20 cm, n = 20)
were forced to swim in swimming channel of flume tank at various swimming speed level as 20.40-147.00 cm/s, which
corresponded to 1.09-9.12 FL/s at 10, 15 and 22°C respectively for jack mackerel and 5.97-47.73 cm/s, which corresponded to
0.37-3.85 FL/s for nile tilapia. The heart rate was measured by impleting a pair of electrode at pericardial cavity region of both
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 of jack mackerel 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 in prolonged swimming speed. The
incremental of heart rate was reach 3.85 times greater than control value at 25°C for tilapia. The recovery time for post-exercise
was monitored to be the longest (up to 543 min) at these swimming speed levels for jack mackerel. The incremental of heart
rate in relation to swimming speed level are discussed deeply in this paper.
