Fig. 1

Map of the study area with the names of the rivers and estuary indicated in italics. Solid triangles indicate acoustic receivers where crabs were detected, hollow triangles indicate acoustic receivers in the study area where crabs were not detected. The map below shows the three tidal classes: a tidal zone with meso- to macrotidal influence in blue, a tidal transition zone with microtidal influence in yellow, and non-tidal river sections in orange