1) Feeding your crew.
2) Selling to get some money.
3) Use a fuel for Steamboat.
Some of general tips I use regarding food and fishing:
1) I make sure to have ample supply of harpoons.
2) I try to not buy food most of the time, only when my crew is starving and I need to rest at port.
TO BE ADDED:
* More tips regarding food and best practice to manage it.
* Food worth per every type of fish.
* Adding missing & updated information.
This is when you go fishing on a regular sea water.
Whenever you go fishing under a storm, you get more fish jumping up the water, which give you easier fishing time.
Whenever you see a grey spot (or multiple grey spots) in the sea and you go fish while on top of it.
You get another fishing mini-game where the fish jump in an arc and you can catch multiple fish with a single harpoon throw.
When you see a whale on screen and go fishing, you’ll go into a different fishing mini-game.
In order to succeed, you’ll need to pull in the harpoon (by hitting the left mouse button) before it gets to the red section of the bar. You’ll have to keep doing that until the whale stamina is depleted as shown in the stamina bar below the screen.
A single whale is worth 7000 food supply, be sure not to miss it.