One reason that specific details are essential in a paper is that they

organize the paper.

state the writer's point in writing the paper.

excite the reader's interest.

unify the paper.

He had fished in the river since ten years and he was a good fisherman. he know where to found the slim sliver chilwa fish, a big beautiful mahseer and the long moustache singhara. he know where the river was deep but where it is shallow; he knew which baits to use - which fish like worms and which liked gram. edit the above