What does this mean He imagined countless others in outports strung along the coast like knots on a fishing line.

I think it mean that he is looking at all these other places (outports are Europian settlements in Canada) and watching them become tangled and hard to separate - like with a fishing line. Or they have to be careful and not become lost or tangled.

sensory details?

so i`m assuming you are writing something from a bats (the animal) point of view. if this is the case, you can use sights, sounds, feelings, and tastes.

and idk what you mean by domain, but all of the sensory details will depend on where the bat is.

a bat doesn't see color very well, so its surroundings will be dulled.

it can hear super well. so maybe it can hear the insects on the ground

feelings. you can imagine how a bat would feel from its perspective. it all depends on where it lives.

maybe it can taste the salt in the air, or smell water, or something. all of these details are completely dependent on where it is located.

hope this .