Fig. 4. Relative mobilisation of fatty acids from the digestive glands of mussels and oysters overwintered at 0, 4 and 9°C during the overwintering period (A), the spring–summer simulation (B) and the overall period of study (C). The relative mobilisation of individual fatty acids was calculated as the ratio of initial to final levels in the TAG for each time interval. Values are means ± s.e.m, N=2. A ratio greater than, equal to, or lower than unity shows that the fatty acid is released more, equally, or less readily, respectively, than the total TAG-fatty acids. Values for fatty acids >2 mol % of the total are arranged in increasing order of relative mobilisation from bottom to top.