What is the effect of the author comparing humans to cargoes in paragraph 8

Which character shows external character development in the crucible

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

Hurry i will give 50 pts to whoever answers.