Physiological and Genetic Aspects of Growth in the Mussel Mytilus edulis. I. Oxygen Consumption, Growth, and Weight Loss

Abstract

Small (S; shell length, 4 mm) and large (L; shell length, 10 mm) Mytilus edulis spat were grown singly in plastic racks in a tidal salt marsh for 72 days, then starved in the laboratory for 2 mo. Dry weight gain in the racks, dry weight loss during starvation, and net dry weight gain were estimated for individuals of both groups; rate of oxygen consumption (V̇o2) was measured during the period of starvation. Heterozygosity at five polymorphic enzyme loci was measured for a subset of the sample. L individuals were significantly more heterozygous and had significantly lower weight-standardized V̇o2 ($$\dot{V}O_{2_{s}}$$.) than S individuals. There was a negative relationship between $$\dot{V}O_{2_{s}}$$ and dry weight gain in the racks for all individuals. During starvation in both groups, a positive relationship existed between $$\dot{V}O_{2_{s}}$$ and dry weight loss; the slopes of the S group were significantly greater than those of the L group. Lower $$\dot{V}O_{2_{s}}$$ is associated more with resistance to weight loss than with the capacity for weight gain.