Fig. 2

a Development of the ratio between predation and growth (y-axis, moving from low to high) for large (M’, solid line) and small (M, discontinuous line) fish over time (Julian DOY on x-axis) in the natal (blue stream) and migratory habitat (red, lake). Low values of P/G show a high growth potential compared to the predation risk, with the growth in the denominator outweighing predation in the numerator. Crossing points between red (lake) and blue (stream) lines indicate the optimal time of migration based on a differential growth, ΔG(M), equal to 5 and higher predation risk for smaller individuals in the lake. b Optimal time of migration (ranging from early to late in the migratory season on the y-axis) from stream to the lake for fish of different sizes (ranging from smallest to largest on the x-axis), predicted based on size-dependent-predation and growth in both alternative habitats