The metabolic rate of roach in relation to body size and temperature

Standard and routine metabolic rates of roach Rutilus rutilus for a wide size and temperature range (3-200 g, 5-23degrees C) were analysed by automated, computerized intermittent flow respirometry. The mass exponent h ranged from 0.68 to 0.82 for standard metabolism, and from 0 65 to 0.92 for routine metabolism depending on the experimental temperature. For routine metabolism b was lowest at 10degrees C. At both decreasing and increasing temperatures, b increased significantly. Roach were exponentially temperature-dependent for both metabolic levels. For roach <20g, however, an asymptotic relationship was observed between temperature and routine metabolic rate. The 'flattening of the curve' in the latter ease may be explained by reduced spontaneous activities at the lower threshold of the preferred temperature range. (C) 2003 The Fisheries Societe of the British Isles.