Fig. 6
A conceptual overview of the migration dynamics of Sognefjord brown trout smolts (N = 175), derived from the conditional Arnason-Schwarz (CAS) model described in Table 3a. Shaded regions represent each habitat zone (F, I, M, O), dashed lines separate values for each natal river. Estimates of survival probability (S) are weighted as an exponent of observed residence duration (t, weeks) within each habitat zone. Arrows indicate the direction (inwards/outwards) and timing (spring/summer, autumn) of migration probability between zones (ψ). Note: Fjord residence is calculated as the mean accumulated duration of all migrant smolts (N = 100) dependent upon maximum migration distance (habitat zone), for each river. Freshwater residence is calculated as the mean accumulated duration of all migrant fish in freshwater, per river (Table S4). Transition probabilities (ψ) were estimated according to season and direction, except ψFI which is estimated according to natal river. Seasons were defined accordingly: spring/summer: WoY = 13 – 26, autumn: WoY = 27 – 40. Combined transition probabilities e.g., transition to the outer-fjord includes ψ.XO where X includes F, I and M, to ease complexity in illustration. For specific transition estimates see Tables 3a and S7