THE EFFECT OF TEMPERATURE ON THE SWIMMING OF A TELEOST (CLUPEA-HARENGUS) AND AN ASCIDIAN LARVA (DENDRODOA-GROSSULARIA)

1. Using a high-speed video system operating at 400 frames/sec, the effects of temperature on tail beat frequency, swimming speed and stride length were examined in newly hatched larvae of herring (Clupea harengus L.) and in tadpole larvae of the ascidian Dendrodoa grossularia van Beneden. 2. The effect of temperature was linear; the tail beat frequency of 8 mm-long herring larvae increased from 19 Hz at 5.6-degrees-C to 37 Hz at 14.9-degrees-C (Q10 = 2.04); that of 2 mm-long Dendrodoa larvae increased from 10 Hz at 9.6-degrees-C to 23 Hz at 18.1-degrees-C (Q10 = 2.52). 3. Burst swimming speeds of herring larvae increased from 80 mm/sec at 5-degrees-C to 150 mm/sec at 15-degrees-C, stride length remaining constant at about 0.5 of the body length for each tail beat. 4. More continuous swimming of Dendrodoa increased from 4.0 mm/sec at 10-degrees-C to 11.5 mm/sec at 18-degrees-C, the stride length increasing from about 0.15 to 0.25.