What happens when a predator wanders by? Do you change your behavior?
Now we know that scary predators can change the ecology of important habitats, and this "ecology of fear" makes a difference. Wolves affect grazing herbivores and may protect sensitive habitats. Meanwhile sharks scare dugongs out of shallow water areas (see video below).
I've personally seen harbor seals flatten themselves against the bottom in big shark habitat, and the behavior looks so dramatic that absence of sharks would probably make a difference in what seals eat, etc.