The Use of A New Tilting Tunnel Respirometer to Investigate Some Aspects of Metabolism and Swimming Activity of the Plaice (<i>Pleuronectes Platessa</i> L.)

Abstract

ABSTRACT Plaice and other flatfish can be induced to swim down a slope of about 6o° against an upwelling water flow in a water tunnel. A tilting Brett-type tunnel respirometer based on the above principle enabled laboratory experiments on swimming plaice to be carried out. From trials at 5°, 10°, 15 °C, the relationship between specific swimming speed, V (body lengths s-1), oxygen consumption, R (mg-1, kg-1 h-1) and temperature, T is: log10 = 0·3318V+log10(2·4T + 26·52). If the fish is resting (i.e. V = 0), the oxygen consumption is lower than predicted by the above equation. At rest: The cost of swimming in plaice is very similar to that of typical round fish such as haddock but the resting metabolic rate is lower than for haddock. Before swimming, a negatively buoyant fish such as plaice must lift off the bottom. This cost of lift-off or posture effect makes it uneconomical for plaice to swim at speeds below 0·6V