Use the [Horn of the Tide] to summon and illuminate the fishes you attract. This will also activate an Ocean Scanner, pinpointing their heading and distance, while you extend or retract your line.

The [Ocean Scanner] will activate when you retract your line, pinpointing the heading and distance of nearby rare fish.

Protect your line from pulling back upon accidentally hitting a fish on the way down. You have a limit of two accidents without penalties per round, and can use the [Reel] to gain another two.

The ocean depths are very dark, drastically reducing your visibility. Use a [Lantern] to illuminate more of your surroundings here.