In this excellent poem, the speaker describes the experience of catching a fish which hadn't really fought to escape. The poem describes the fish objectively, without emotion, talking about the "tiny white sea lice" that "infest" it. What moves the poem towards its shift is when the speaker begins to view the fish objectively. As she stares at it, we are told that the speaker "admired his sullen face." As she continues to contemplate the fish, she sees something else that brings on an epiphany in her and leads to her decision to let the fish go:

and then I saw
that from his lower lip
--if you could call it a lip
grim, wet, and weaponlike,
hung five old pieces of fish-line,
or four and a wire leader
with the swivel still attached,
with all their five big hooks
grown firmly in his mouth.

This evidence of the fish's earlier battles for survival and his evident success increases the speaker's admiration and respect for the fish. As nature and the light combine to make everything appear a "rainbow," the speaker lets the fish go as "victory filled up / The little rented boat." The speaker comes to some unspoken understanding with the fish and understands his battle for survival and cannot do anything else but let him go again.