餌: feed for fish and bait on a fishing hook
Compare 餌 as feed given to pond fish and bait attached to a hook. Read the recipient and attachment point, without adding a catch to the casting action.
魚に餌を与える and the recipient
餌 (えさ) means feed or bait. 「朝になると池の魚に餌を与える。」 means “Every morning, I feed the fish in the pond.” 魚に identifies the fish receiving feed.
餌を与える is the feeding action, linked to morning by 朝になると. The fish are recipients of feed, rather than the bait being used.
釣り針に餌を付ける and the attachment point
「釣り針に餌を付けて静かに川へ投げた。」 means “I put bait on the hook and quietly cast it into the river.” 餌 is bait here, and 釣り針に names the hook to which it is attached.
付けて connects attachment with the past casting action 投げた. The sentence reports casting into the river, without reporting that a fish ate the bait or was caught.
Reading に with its verb
In the first example, に relates to the fish receiving feed; in the second, it relates to the hook carrying bait. Read 与える and 付ける together with their objects to keep the relationships distinct.
These uses concern animal feed and fishing bait. The examples do not make 餌 exclusively human food or exclusively an inedible object; the stated activity determines the reading here.
What does に relate to in 魚に餌を与える and 釣り針に餌を付けて投げた, and is a successful catch reported?
Show the answer and why
It relates to the fish receiving feed in the first phrase and the hook to which bait is attached in the second. Attachment and casting are stated, but eating or catching a fish is not. The recipient fish are not themselves the bait.