Fig. 4

Short-term risk of invasibility. Reproductive number \( \mathcal{R} \) as a function of time. Water temperature is approximated as a sinusoidal signal (as for the computation of the DFT) and temperature-dependent parameters are taken as in Fig. 2. F _S (τ) and B _S (τ) follow the DFT. The red line refers to the reference parameter set reported in Table 3. The blue and the green lines show the effect of reducing one of the transmission parameters (π ^* _B or π ^* _F ) or the fish population size F _S by a factor 10 and 20, respectively