Every fish, what it pays, and how often it comes up. Read live from the pier — the same numbers the engine casts against, not a copy somebody keeps up to date by hand.
Reading the table…
The Tide Potion is the reason. It pays nothing when you land it — look at its row, it is a dash — so adding up the payout column leaves it out entirely and lands you short. What it hands over instead is free casts that pay double, and those are worth exactly the difference.
The arithmetic is in the last two rows, done in front of you, and it lands on the same return to player the pier publishes. If it ever did not, that would be the story.
Pays is a multiple of your bait: land a Cod and you get its multiple times your bait back. Chance is how often that fish is the one on the hook. Share of the payout is what that fish contributes to the return — how much it pays, weighted by how rarely it turns up. That last column is the one that adds up.
Weight is rolled separately and does not touch the money: a heavy Cod and a light Cod pay the same. It is there for the leaderboard and your own satisfaction.
Prefer it unformatted? The same figures as raw JSON, straight from the pier.