Dodge down. Hook up. Beat the quota every cast.
Tap to cast, then drag to steer (mouse or arrow keys on a computer). On the way down, dodge everything: touching a fish ends the dive and the line reels up from there. On the way up, steer into fish to hook them, and keep clear of jellies, which cut your last three. Hook the same species back to back for a chain, up to ×8. Every cast must beat the Haul Quota, or the run is over.
Five days in a row. Miss a day and it starts over.